1
|
Tschaikner M, Powell K, Jungklaus M, Fritz M, Ellmerer M, Hovorka R, Lane S, Pieber TR, Regittnig W. Novel Single-Site Device for Conjoined Glucose Sensing and Insulin Infusion: Performance Evaluation in Diabetes Patients During Home-Use. IEEE Trans Biomed Eng 2019; 67:323-332. [PMID: 31251175 DOI: 10.1109/tbme.2019.2925434] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE This study evaluated a novel diabetes treatment device that combines commercially available continuous glucose monitoring and insulin infusion technology in such a way as to perform insulin delivery and glucose sensing through a single skin insertion site (single-port device). METHODS Ten type 1 diabetes patients used the device for up to six days in their home/work environment for open-loop insulin delivery and glucose sensing. On an additional day, the device was used in combination with an algorithm to perform automated closed-loop glucose control under hospital settings. To assess the performance of the device, capillary blood glucose concentrations were frequently determined and a continuous glucose sensor was additionally worn by the patients. RESULTS The average mean absolute relative deviation from blood glucose concentrations obtained for the sensor of the device was low (median, 13.0%; interquartile range, 10.5-16.7%; n = 10) and did not differ from that of the additionally worn glucose sensor (versus 13.9%; 11.9-15.3%; P = 0.922). Furthermore, insulin delivery with the single-port device was reliable and safe during home use and, when performed in combination with the control algorithm, was adequate to achieve and maintain near normoglycemia. CONCLUSION Our data show the feasibility of open- and closed-loop glucose control in diabetes patients using a device that combines insulin delivery and glucose sensing at a single tissue site. SIGNIFICANCE The reduction in device size and invasiveness achieved by this design may largely increase patient convenience and enhance acceptance of diabetes treatment with continuous glucose monitoring and insulin delivery technology.
Collapse
|
2
|
Tschaikner M, Simic A, Jungklaus M, Fritz M, Ellmerer M, Pieber TR, Regittnig W. Development of a Single-Site Device for Conjoined Glucose Sensing and Insulin Delivery in Type-1 Diabetes Patients. IEEE Trans Biomed Eng 2019; 67:312-322. [PMID: 31144621 DOI: 10.1109/tbme.2019.2919234] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Diabetes patients are increasingly using a continuous glucose sensor to monitor blood glucose and an insulin pump connected to an infusion cannula to administer insulin. Applying these devices requires two separate insertion sites, one for the sensor and one for the cannula. Integrating sensor with cannula to perform glucose sensing and insulin infusion through a single insertion site would significantly simplify and improve diabetes treatment by reducing the overall system size and the number of necessary needle pricks. Presently, several research groups are pursuing the development of combined glucose sensing and insulin infusion devices, termed single-port devices, by integrating sensing and infusion technologies created from scratch. METHODS Instead of creating the device from scratch, we utilized already existing technologies and introduced three design concepts of integrating commercial glucose sensors and infusion cannulas. We prototyped and evaluated each concept according to design simplicity, ease of insertion, and sensing accuracy. RESULTS We found that the best single-port device is the one in which a Dexcom sensor is housed inside a Medtronic cannula so that its glucose sensitive part protrudes from the cannula tip. The low degree of component modification required to arrive at this configuration allowed us to test the efficiency and safety of the device in humans. CONCLUSION Results from these studies indicate the feasibility of combining commercial glucose sensing and insulin delivery technologies to realize a functional single-port device. SIGNIFICANCE Our development approach may be generally useful to provide patients with innovative medical devices faster and at reduced costs.
Collapse
|
3
|
Regittnig W, Urschitz M, Lehki B, Wolf M, Kojzar H, Mader JK, Ellmerer M, Pieber TR. Insulin Bolus Administration in Insulin Pump Therapy: Effect of Bolus Delivery Speed on Insulin Absorption from Subcutaneous Tissue. Diabetes Technol Ther 2019; 21:44-50. [PMID: 30620643 DOI: 10.1089/dia.2018.0295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND This study assessed subcutaneous absorption kinetics of rapid-acting insulin administered as a bolus using bolus delivery speeds commonly employed in commercially available insulin pumps (i.e., 2 and 40 s for delivering 1 insulin unit). MATERIALS AND METHODS Twenty C-peptide-negative type 1 diabetic subjects were studied on two occasions, separated by at least 7 days, using the euglycemic clamp procedure. After an overnight fast, subjects were given, in random order, a subcutaneous insulin bolus (15 U of insulin lispro, Eli Lilly) either for 30 s using an Animas IR2020 pump (fast bolus delivery) or for 10 min using a Medtronic Minimed Paradigm 512 pump (slow bolus delivery). RESULTS Fast bolus delivery resulted in an earlier onset of insulin action as compared with slow bolus delivery (21.0 ± 2.5 vs. 34.3 ± 2.7 min; P < 0.002). Furthermore, time to reach maximum insulin effect was found to be 27 min earlier with fast bolus delivery as compared with slow bolus delivery (98 ± 11 vs. 125 ± 16 min; P < 0.005). In addition, the area under the plasma insulin curve from 0 to 60 min for fast bolus delivery was greater than the one for slow bolus delivery (10,307 ± 1291 vs. 8192 ± 865 min·pmol/L; P = 0.027). CONCLUSIONS Results suggest that insulin bolus delivery with fast delivery speed may result in more rapid insulin absorption and, thus, may provide a better control of meal-related glucose excursions than that obtained with bolus delivery using slow delivery speeds. Our findings may have important implications for the future design of the bolus delivery unit of insulin pumps.
Collapse
Affiliation(s)
- Werner Regittnig
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Martina Urschitz
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Barbara Lehki
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Michael Wolf
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Harald Kojzar
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Julia K Mader
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Martin Ellmerer
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Thomas R Pieber
- Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| |
Collapse
|
4
|
Bodenlenz M, Ellmerer M, Schaupp L, Jacobsen LV, Plank J, Brunner GA, Wutte A, Aigner B, Mautner SI, Pieber TR. Bioavailability of insulin detemir and human insulin at the level of peripheral interstitial fluid in humans, assessed by open-flow microperfusion. Diabetes Obes Metab 2015; 17:1166-72. [PMID: 26260082 DOI: 10.1111/dom.12551] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 07/30/2015] [Accepted: 08/06/2015] [Indexed: 11/28/2022]
Abstract
AIMS To find an explanation for the lower potency of insulin detemir observed in humans compared with unmodified human insulin by investigating insulin detemir and human insulin concentrations directly at the level of peripheral insulin-sensitive tissues in humans in vivo. METHODS Euglycaemic-hyperinsulinaemic clamp experiments were performed in healthy volunteers. Human insulin was administered i.v. at 6 pmol/kg/min and insulin detemir at 60 pmol/kg/min, achieving a comparable steady-state pharmacodynamic action. In addition, insulin detemir was doubled to 120 pmol/kg/min. Minimally invasive open-flow microperfusion (OFM) sampling methodology was combined with inulin calibration to quantify human insulin and insulin detemir in the interstitial fluid (ISF) of subcutaneous adipose and skeletal muscle tissue. RESULTS The human insulin concentration in the ISF was ∼115 pmol/l or ∼30% of the serum concentration, whereas the insulin detemir concentration in the ISF was ∼680 pmol/l or ∼2% of the serum concentration. The molar insulin detemir interstitial concentration was five to six times higher than the human insulin interstitial concentration and metabolic clearance of insulin detemir from serum was substantially reduced compared with human insulin. CONCLUSIONS OFM proved useful for target tissue measurements of human insulin and the analogue insulin detemir. Our tissue data confirm a highly effective retention of insulin detemir in the vascular compartment. The higher insulin detemir relative to human insulin tissue concentrations at comparable pharmacodynamics, however, indicate that the lower potency of insulin detemir in humans is attributable to a reduced effect in peripheral insulin-sensitive tissues and is consistent with the reduced in vitro receptor affinity.
Collapse
MESH Headings
- Adult
- Biological Availability
- Calibration
- Cross-Over Studies
- Dose-Response Relationship, Drug
- Extracellular Fluid/metabolism
- Glucose Clamp Technique
- Humans
- Hypoglycemic Agents/administration & dosage
- Hypoglycemic Agents/blood
- Hypoglycemic Agents/metabolism
- Hypoglycemic Agents/pharmacokinetics
- Infusions, Intravenous
- Insulin Detemir/administration & dosage
- Insulin Detemir/blood
- Insulin Detemir/metabolism
- Insulin Detemir/pharmacokinetics
- Insulin, Regular, Human/administration & dosage
- Insulin, Regular, Human/blood
- Insulin, Regular, Human/metabolism
- Insulin, Regular, Human/pharmacokinetics
- Inulin/administration & dosage
- Inulin/blood
- Inulin/metabolism
- Inulin/pharmacokinetics
- Lipoylation
- Male
- Metabolic Clearance Rate
- Muscle, Skeletal/metabolism
- Subcutaneous Fat/metabolism
- Tissue Distribution
- Young Adult
Collapse
Affiliation(s)
- M Bodenlenz
- HEALTH, Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H, Graz, Austria
| | - M Ellmerer
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - L Schaupp
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | | | - J Plank
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - G A Brunner
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - A Wutte
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - B Aigner
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- Division of General Dermatology, Department of Dermatology and Venereology, Medical University of Graz, Graz, Austria
| | - S I Mautner
- HEALTH, Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H, Graz, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - T R Pieber
- HEALTH, Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft m.b.H, Graz, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| |
Collapse
|
5
|
Sendlhofer G, Brunner G, Schaupp L, Wutte A, Ellmerer M, Pieber TR. Estimation of human leptin concentration in the subcutaneous adipose and skeletal muscle tissues. Eur J Clin Invest 2015; 45:445-51. [PMID: 25708725 DOI: 10.1111/eci.12424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 02/18/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Interstitial leptin concentrations in subcutaneous adipose and skeletal muscle tissues were determined by open-flow microperfusion. METHOD In 12 lean male subjects (age: 25.6 ± 1.1 years), a zero flow rate experiment using different flow rates was applied. Recovery was determined by urea as an internal reference. In the no-net-flux experiments, catheters were perfused with five solutions containing different concentrations of leptin. Concentrations of interstitial leptin were calculated by applying linear regression analysis to perfusate as opposed to sampled leptin concentrations. RESULTS The zero flow rate protocol showed significantly higher concentrations of leptin in the interstitial fluid of subcutaneous adipose compared to skeletal muscle tissue [36.8 ± 10.32 vs. 7.1 ± 2.5% of the corresponding plasma level (P = 0.018)]. The recovery of urea in the samples was comparable for all catheters [79.4 ± 6.8 vs. 83.0 ± 5.8 of the corresponding plasma level, flow rate of 0.3 μL/min; (P = ns)] and was higher when compared to leptin. In the no-net-flux protocol, the concentration of leptin in subcutaneous adipose tissue was almost identical to plasma [90. 5 ± 7.0%] and the skeletal muscle tissue concentration of leptin was 23.7 ± 2.5% of the corresponding plasma level. CONCLUSION Open-flow microperfusion enables the estimation of leptin concentrations in subcutaneous adipose and skeletal muscle tissues in humans in vivo. This is the first documentation on the use of open-flow microperfusion to demonstrate that relevant amounts of leptin are also found in skeletal muscle tissue.
Collapse
Affiliation(s)
- Gerald Sendlhofer
- Department of Quality and Risk Management, University Hospital Graz, Graz, Styria, Austria; Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University Graz, Graz, Styria, Austria
| | | | | | | | | | | |
Collapse
|
6
|
Leelarathna L, Dellweg S, Mader JK, Barnard K, Benesch C, Ellmerer M, Heinemann L, Kojzar H, Thabit H, Wilinska ME, Wysocki T, Pieber TR, Arnolds S, Evans ML, Hovorka R. Assessing the effectiveness of 3 months day and night home closed-loop insulin delivery in adults with suboptimally controlled type 1 diabetes: a randomised crossover study protocol. BMJ Open 2014; 4:e006075. [PMID: 25186158 PMCID: PMC4158197 DOI: 10.1136/bmjopen-2014-006075] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION Despite therapeutic advances, many people with type 1 diabetes are still unable to achieve optimal glycaemic control, limited by the occurrence of hypoglycaemia. The objective of the present study is to determine the effectiveness of day and night home closed-loop over the medium term compared with sensor-augmented pump therapy in adults with type 1 diabetes and suboptimal glycaemic control. METHODS AND ANALYSIS The study will adopt an open label, three-centre, multinational, randomised, two-period crossover study design comparing automated closed-loop glucose control with sensor augmented insulin pump therapy. The study will aim for 30 completed participants. Eligible participants will be adults (≥18 years) with type 1 diabetes treated with insulin pump therapy and suboptimal glycaemic control (glycated haemoglobin (HbA1c)≥7.5% (58 mmol/mmol) and ≤10% (86 mmol/mmol)). Following a 4-week optimisation period, participants will undergo a 3-month use of automated closed-loop insulin delivery and sensor-augmented pump therapy, with a 4-6 week washout period in between. The order of the interventions will be random. All analysis will be conducted on an intention to treat basis. The primary outcome is the time spent in the target glucose range from 3.9 to 10.0 mmol/L based on continuous glucose monitoring levels during the 3 months free living phase. Secondary outcomes include HbA1c changes; mean glucose and time spent above and below target glucose levels. Further, participants will be invited at baseline, midpoint and study end to participate in semistructured interviews and complete questionnaires to explore usability and acceptance of the technology, impact on quality of life and fear of hypoglycaemia. ETHICS AND DISSEMINATION Ethical approval has been obtained at all sites. Before screening, all participants will be provided with oral and written information about the trial. The study will be disseminated by peer-review publications and conference presentations. TRIAL REGISTRATION NUMBER NCT01961622 (ClinicalTrials.gov).
Collapse
Affiliation(s)
- Lalantha Leelarathna
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Sibylle Dellweg
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Julia K Mader
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Katharine Barnard
- Faculty of Medicine, Department of Human Development and Health, University of Southampton, Southampton, UK
| | - Carsten Benesch
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Martin Ellmerer
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Lutz Heinemann
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Harald Kojzar
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Hood Thabit
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Malgorzata E Wilinska
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Tim Wysocki
- Center for Health Care Delivery Science, Nemours Children's Health System, Florida, USA
| | - Thomas R Pieber
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sabine Arnolds
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Mark L Evans
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Roman Hovorka
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| |
Collapse
|
7
|
Leelarathna L, Dellweg S, Mader JK, Allen JM, Benesch C, Doll W, Ellmerer M, Hartnell S, Heinemann L, Kojzar H, Michalewski L, Nodale M, Thabit H, Wilinska ME, Pieber TR, Arnolds S, Evans ML, Hovorka R. Day and night home closed-loop insulin delivery in adults with type 1 diabetes: three-center randomized crossover study. Diabetes Care 2014; 37:1931-7. [PMID: 24963110 DOI: 10.2337/dc13-2911] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate the feasibility of day and night closed-loop insulin delivery in adults with type 1 diabetes under free-living conditions. RESEARCH DESIGN AND METHODS Seventeen adults with type 1 diabetes on insulin pump therapy (means ± SD age 34 ± 9 years, HbA1c 7.6 ± 0.8%, and duration of diabetes 19 ± 9 years) participated in an open-label multinational three-center crossover study. In a random order, participants underwent two 8-day periods (first day at the clinical research facility followed by 7 days at home) of sensor-augmented insulin pump therapy (SAP) or automated closed-loop insulin delivery. The primary end point was the time when sensor glucose was in target range between 3.9 and 10.0 mmol/L during the 7-day home phase. RESULTS During the home phase, the percentage of time when glucose was in target range was significantly higher during closed-loop compared with SAP (median 75% [interquartile range 61-79] vs. 62% [53-70], P = 0.005). Mean glucose (8.1 vs. 8.8 mmol/L, P = 0.027) and time spent above target (P = 0.013) were lower during closed loop, while time spent below target was comparable (P = 0.339). Increased time in target was observed during both daytime (P = 0.017) and nighttime (P = 0.013). CONCLUSIONS Compared with SAP, 1 week of closed-loop insulin delivery at home reduces mean glucose and increases time in target without increasing the risk of hypoglycemia in adults with relatively well-controlled type 1 diabetes.
Collapse
Affiliation(s)
- Lalantha Leelarathna
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.Department of Diabetes and Endocrinology, Addenbrooke's Hospital, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K
| | - Sibylle Dellweg
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Julia K Mader
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Janet M Allen
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Carsten Benesch
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Werner Doll
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Martin Ellmerer
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sara Hartnell
- Department of Diabetes and Endocrinology, Addenbrooke's Hospital, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K
| | - Lutz Heinemann
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Harald Kojzar
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | | | - Marianna Nodale
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Hood Thabit
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.Department of Diabetes and Endocrinology, Addenbrooke's Hospital, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K
| | - Malgorzata E Wilinska
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K
| | - Thomas R Pieber
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Sabine Arnolds
- Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
| | - Mark L Evans
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.Department of Diabetes and Endocrinology, Addenbrooke's Hospital, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge, U.K
| | - Roman Hovorka
- Wellcome Trust-Medical Research Clinical Institute of Metabolic Science, University of Cambridge, Cambridge, U.K.
| | | |
Collapse
|
8
|
Ader M, Stefanovski D, Kim SP, Richey JM, Ionut V, Catalano KJ, Hucking K, Ellmerer M, Van Citters G, Hsu IR, Chiu JD, Woolcott OO, Harrison LN, Zheng D, Lottati M, Kolka CM, Mooradian V, Dittmann J, Yae S, Liu H, Castro AVB, Kabir M, Bergman RN. Hepatic insulin clearance is the primary determinant of insulin sensitivity in the normal dog. Obesity (Silver Spring) 2014; 22:1238-45. [PMID: 24123967 PMCID: PMC3969862 DOI: 10.1002/oby.20625] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/15/2013] [Accepted: 09/10/2013] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Insulin resistance is a powerful risk factor for Type 2 diabetes and a constellation of chronic diseases, and is most commonly associated with obesity. We examined if factors other than obesity are more substantial predictors of insulin sensitivity under baseline, nonstimulated conditions. METHODS Metabolic assessment was performed in healthy dogs (n = 90). Whole-body sensitivity from euglycemic clamps (SICLAMP ) was the primary outcome variable, and was measured independently by IVGTT (n = 36). Adiposity was measured by MRI (n = 90), and glucose-stimulated insulin response was measured from hyperglycemic clamp or IVGTT (n = 86 and 36, respectively). RESULTS SICLAMP was highly variable (5.9-75.9 dl/min per kg per μU/ml). Despite narrow range of body weight (mean, 28.7 ± 0.3 kg), adiposity varied approximately eight-fold and was inversely correlated with SICLAMP (P < 0.025). SICLAMP was negatively associated with fasting insulin, but most strongly associated with insulin clearance. Clearance was the dominant factor associated with sensitivity (r = 0.53, P < 0.00001), whether calculated from clamp or IVGTT. CONCLUSIONS These data suggest that insulin clearance contributes substantially to insulin sensitivity, and may be pivotal in understanding the pathogenesis of insulin resistance. We propose the hyperinsulinemia due to reduction in insulin clearance is responsible for insulin resistance secondary to changes in body weight.
Collapse
Affiliation(s)
- Marilyn Ader
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Luijf YM, DeVries JH, Zwinderman K, Leelarathna L, Nodale M, Caldwell K, Kumareswaran K, Elleri D, Allen JM, Wilinska ME, Evans ML, Hovorka R, Doll W, Ellmerer M, Mader JK, Renard E, Place J, Farret A, Cobelli C, Del Favero S, Dalla Man C, Avogaro A, Bruttomesso D, Filippi A, Scotton R, Magni L, Lanzola G, Di Palma F, Soru P, Toffanin C, De Nicolao G, Arnolds S, Benesch C, Heinemann L. Day and night closed-loop control in adults with type 1 diabetes: a comparison of two closed-loop algorithms driving continuous subcutaneous insulin infusion versus patient self-management. Diabetes Care 2013; 36:3882-7. [PMID: 24170747 PMCID: PMC3836152 DOI: 10.2337/dc12-1956] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To compare two validated closed-loop (CL) algorithms versus patient self-control with CSII in terms of glycemic control. RESEARCH DESIGN AND METHODS This study was a multicenter, randomized, three-way crossover, open-label trial in 48 patients with type 1 diabetes mellitus for at least 6 months, treated with continuous subcutaneous insulin infusion. Blood glucose was controlled for 23 h by the algorithm of the Universities of Pavia and Padova with a Safety Supervision Module developed at the Universities of Virginia and California at Santa Barbara (international artificial pancreas [iAP]), by the algorithm of University of Cambridge (CAM), or by patients themselves in open loop (OL) during three hospital admissions including meals and exercise. The main analysis was on an intention-to-treat basis. Main outcome measures included time spent in target (glucose levels between 3.9 and 8.0 mmol/L or between 3.9 and 10.0 mmol/L after meals). RESULTS Time spent in the target range was similar in CL and OL: 62.6% for OL, 59.2% for iAP, and 58.3% for CAM. While mean glucose level was significantly lower in OL (7.19, 8.15, and 8.26 mmol/L, respectively) (overall P = 0.001), percentage of time spent in hypoglycemia (<3.9 mmol/L) was almost threefold reduced during CL (6.4%, 2.1%, and 2.0%) (overall P = 0.001) with less time ≤2.8 mmol/L (overall P = 0.038). There were no significant differences in outcomes between algorithms. CONCLUSIONS Both CAM and iAP algorithms provide safe glycemic control.
Collapse
|
10
|
Schaupp L, Feichtner F, Schaller-Ammann R, Mautner S, Ellmerer M, Pieber TR. Recirculation—a novel approach to quantify interstitial analytes in living tissue by combining a sensor with open-flow microperfusion. Anal Bioanal Chem 2013; 406:549-54. [DOI: 10.1007/s00216-013-7493-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 11/30/2022]
|
11
|
Facchinetti A, Sparacino G, Guerra S, Luijf YM, DeVries JH, Mader JK, Ellmerer M, Benesch C, Heinemann L, Bruttomesso D, Avogaro A, Cobelli C. Real-time improvement of continuous glucose monitoring accuracy: the smart sensor concept. Diabetes Care 2013; 36:793-800. [PMID: 23172973 PMCID: PMC3609535 DOI: 10.2337/dc12-0736] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Reliability of continuous glucose monitoring (CGM) sensors is key in several applications. In this work we demonstrate that real-time algorithms can render CGM sensors smarter by reducing their uncertainty and inaccuracy and improving their ability to alert for hypo- and hyperglycemic events. RESEARCH DESIGN AND METHODS The smart CGM (sCGM) sensor concept consists of a commercial CGM sensor whose output enters three software modules, able to work in real time, for denoising, enhancement, and prediction. These three software modules were recently presented in the CGM literature, and here we apply them to the Dexcom SEVEN Plus continuous glucose monitor. We assessed the performance of the sCGM on data collected in two trials, each containing 12 patients with type 1 diabetes. RESULTS The denoising module improves the smoothness of the CGM time series by an average of ∼57%, the enhancement module reduces the mean absolute relative difference from 15.1 to 10.3%, increases by 12.6% the pairs of values falling in the A-zone of the Clarke error grid, and finally, the prediction module forecasts hypo- and hyperglycemic events an average of 14 min ahead of time. CONCLUSIONS We have introduced and implemented the sCGM sensor concept. Analysis of data from 24 patients demonstrates that incorporation of suitable real-time signal processing algorithms for denoising, enhancement, and prediction can significantly improve the performance of CGM applications. This can be of great clinical impact for hypo- and hyperglycemic alert generation as well in artificial pancreas devices.
Collapse
Affiliation(s)
- Andrea Facchinetti
- Department of Information Engineering, University of Padova, Padova, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Luijf YM, Avogaro A, Benesch C, Bruttomesso D, Cobelli C, Ellmerer M, Heinemann L, Mader JK, DeVries JH. Continuous glucose monitoring accuracy results vary between assessment at home and assessment at the clinical research center. J Diabetes Sci Technol 2012; 6:1103-6. [PMID: 23063036 PMCID: PMC3570844 DOI: 10.1177/193229681200600514] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Continuous glucose monitoring system (CGMS) accuracy is of critical importance both in delivering therapeutic value and as a component of a closed-loop system. This study aims at assessing the differences between accuracy assessments of CGMS at home and at the clinical research center (CRC). METHODS Twelve patients with type 1 diabetes used the Dexcom® SEVEN® PLUS (DexCom, Inc.) CGMS for 7 days. Patients performed ≥6 finger pricks [self-measurement of blood glucose (SMBG)] per day while at home. Reference blood glucose measurements were taken during a 24 h CRC admission (YSI 2300 STAT Plus™). Continuous glucose monitoring system data were compared with YSI and SMBG values. Outcome measures included mean absolute relative difference (MARD) and Clarke error grid analysis (CEGA). RESULTS During CRC admission, the MARD of CGMS vs YSI glucose values was 19.2% (n = 509)--significantly higher than 16.8% at home (n = 611) (p = .004). In the hypoglycemic range, MARD was 23.9% at CRC (n = 26)--not significantly different from 41.6% at home (n = 39) (p = .269). In the hyperglycemic range, CRC MARD at 20.3% (n = 115) was significantly higher than home MARD at 11.2% (n = 118) (p = .001). Clarke error grid analysis showed no significant difference in distribution of data pairs (overall p = .317). CONCLUSIONS This study illustrates the importance of the setting used when assessing CGMS accuracy. Continuous glucose monitoring system accuracy at home appeared better than at the CRC. This is probably due to the higher sampling rate of reference measurements, feasible only in the CRC. Testing CGMS accuracy in the CRC provides valuable information over and above home testing.
Collapse
Affiliation(s)
- Yoeri M Luijf
- Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Amrein K, Ellmerer M, Hovorka R, Kachel N, Fries H, von Lewinski D, Smolle K, Pieber TR, Plank J. Efficacy and safety of glucose control with Space GlucoseControl in the medical intensive care unit--an open clinical investigation. Diabetes Technol Ther 2012; 14:690-5. [PMID: 22694176 DOI: 10.1089/dia.2012.0021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND We aimed to investigate the performance of the Space GlucoseControl system (SGC) (B. Braun, Melsungen, Germany) in medical critically ill patients. The SGC is a nurse-driven, computer-assisted device for glycemic control combining infusion pumps with the enhanced Model Predictive Control algorithm. SUBJECTS AND METHODS The trial was designed as a single-center, open clinical investigation in a nine-bed medical intensive care unit in a tertiary center in Graz, Austria. Efficacy was assessed by percentage of time within the target range (4.4-8.3 mmol/L; primary end point), mean blood glucose, and sampling interval. Safety was assessed by the number of hypoglycemic episodes (≤2.2 mmol/L). RESULTS Twenty mechanically ventilated patients (age, 63±16 years; body mass index, 31.0±10.7 kg/m(2); Acute Physiology and Chronic Health Evaluation II score, 25.4±6.3; 14 males; six with diabetes) were included for a period of 7.0±3.6 days. Time within target range was 83.4±8.9% (mean±SD), and mean arterial blood glucose was 6.8±0.4 mmol/L. No severe hypoglycemic episodes (<2.2 mmol/L) occurred, and the percentage of time within 2.2 and 3.3 mmol/L was low (0.03±0.07%). The sampling interval was 2.0±0.4 h. The mean insulin dose was 93.5±80.1 IU/day, and the adherence to the given insulin dose advice was high (98.3%). A total of 11 unintended therapy interruptions (0.08 events/treatment day) caused by software problems occurred in four patients. CONCLUSIONS SGC is a safe and efficient method to control blood glucose in critically ill patients in the medical intensive care unit.
Collapse
Affiliation(s)
- Karin Amrein
- Division of Endocrinology and Metabolism, Medical University of Graz, Auenbruggerplatz 15, Graz, Austria.
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Mader JK, Feichtner F, Bock G, Köhler G, Schaller R, Plank J, Pieber TR, Ellmerer M. Microdialysis--a versatile technology to perform metabolic monitoring in diabetes and critically ill patients. Diabetes Res Clin Pract 2012; 97:112-8. [PMID: 22402305 DOI: 10.1016/j.diabres.2012.02.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 01/20/2012] [Accepted: 02/14/2012] [Indexed: 11/24/2022]
Abstract
Continuous subcutaneous glucose monitoring has been tested in type 1 diabetes (T1D). Since in critically ill patients vascular access is granted vascular microdialysis may be preferential. To test this hypothesis comparative accuracy data for microdialysis applied for peripheral venous and subcutaneous glucose monitoring was obtained in experiments in T1D patients. Twelve T1D patients were investigated for up to 30 h. Extracorporeal vascular (MDv) and subcutaneous microdialysis (MDs) was performed. Microdialysis samples were collected in 15-60 min intervals, analyzed for glucose and calibrated to reference. MDv and MDs glucose levels were compared against reference. Median absolute relative difference was 14.0 (5.0; 28.0)% (MDv) and 9.2 (4.4; 18.4)% (MDs). Clarke Error Grid analysis showed that 100% (MDv) and 98.8% (MDv) were within zones A and B. Extracorporeal vascular and standard subcutaneous microdialysis indicated similar performance in T1D. We suggest microdialysis as a versatile technology for metabolite monitoring in subcutaneous tissue and whole blood.
Collapse
Affiliation(s)
- Julia K Mader
- Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Mader JK, Lucarelli F, Scuffi C, Friedrich S, Korsatko S, Ellmerer M, Köhler G, Valgimigli F, Pieber TR. Bewertung der Sicherheit und Genauigkeit des GlucoMen®Day-Systems zur kontinuierlichen subkutanen Glukosemessung bei Patienten mit Typ-1-Diabetes. DIABETOL STOFFWECHS 2012. [DOI: 10.1055/s-0032-1314567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
16
|
Homsy A, van der Wal PD, Doll W, Schaller R, Korsatko S, Ratzer M, Ellmerer M, Pieber TR, Nicol A, de Rooij NF. Development and validation of a low cost blood filtration element separating plasma from undiluted whole blood. Biomicrofluidics 2012; 6:12804-128049. [PMID: 22662072 PMCID: PMC3365324 DOI: 10.1063/1.3672188] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 12/04/2011] [Indexed: 05/09/2023]
Abstract
Clinical point of care testing often needs plasma instead of whole blood. As centrifugation is labor intensive and not always accessible, filtration is a more appropriate separation technique. The complexity of whole blood is such that there is still no commercially available filtration system capable of separating small sample volumes (10-100 μl) at the point of care. The microfluidics research in blood filtration is very active but to date nobody has validated a low cost device that simultaneously filtrates small samples of whole blood and reproducibly recovers clinically relevant biomarkers, and all this in a limited amount of time with undiluted raw samples. In this paper, we show first that plasma filtration from undiluted whole blood is feasible and reproducible in a low-cost microfluidic device. This novel microfluidic blood filtration element (BFE) extracts 12 μl of plasma from 100 μl of whole blood in less than 10 min. Then, we demonstrate that our device is valid for clinical studies by measuring the adsorption of interleukins through our system. This adsorption is reproducible for interleukins IL6, IL8, and IL10 but not for TNFα. Hence, our BFE is valid for clinical diagnostics with simple calibration prior to performing any measurement.
Collapse
|
17
|
Wilinska ME, Blaha J, Chassin LJ, Cordingley JJ, Dormand NC, Ellmerer M, Haluzik M, Plank J, Vlasselaers D, Wouters PJ, Hovorka R. Evaluating glycemic control algorithms by computer simulations. Diabetes Technol Ther 2011; 13:713-22. [PMID: 21488803 DOI: 10.1089/dia.2011.0016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Numerous guidelines and algorithms exist to achieve glycemic control. Their strengths and weaknesses are difficult to assess without head-to-head comparison in time-consuming clinical trials. We hypothesized that computer simulations may be useful. METHODS Two open-label randomized clinical trials were replicated using computer simulations. One study compared performance of the enhanced model predictive control (eMPC) algorithm at two intensive care units in the United Kingdom and Belgium. The other study compared three glucose control algorithms-eMPC, Matias (the absolute glucose protocol), and Bath (the relative glucose change protocol)-in a single intensive care unit. Computer simulations utilized a virtual population of 56 critically ill subjects derived from routine data collected at four European surgical and medical intensive care units. RESULTS In agreement with the first clinical study, computer simulations reproduced the main finding and discriminated between the two intensive care units in terms of the sampling interval (1.3 h vs. 1.8 h, United Kingdom vs. Belgium; P < 0.01). Other glucose control metrics were comparable between simulations and clinical results. The principal outcome of the second study was also reproduced. The eMPC demonstrated better performance compared with the Matias and Bath algorithms as assessed by the time when plasma glucose was in the target range between 4.4 and 6.1 mmol/L (65% vs. 43% vs. 42% [P < 0.001], eMPC vs. Matias vs. Bath) without increasing the risk of severe hypoglycemia. CONCLUSIONS Computer simulations may provide resource-efficient means for preclinical evaluation of algorithms for glycemic control in the critically ill.
Collapse
|
18
|
Feichtner F, Mader JK, Schaller R, Schaupp L, Ellmerer M, Korsatko S, Kondepati VR, Heise HM, Wilinska ME, Hovorka R, Pieber TR. A stepwise approach toward closed-loop blood glucose control for intensive care unit patients: results from a feasibility study in type 1 diabetic subjects using vascular microdialysis with infrared spectrometry and a model predictive control algorithm. J Diabetes Sci Technol 2011; 5:901-5. [PMID: 21880232 PMCID: PMC3192596 DOI: 10.1177/193229681100500412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Glycemic control can reduce the mortality and morbidity of intensive care patients. The CLINICIP (closed-loop insulin infusion for critically ill patients) project aimed to develop a closed-loop control system for this patient group. Following a stepwise approach, we combined three independently tested subparts to form a semiautomatic closed-loop system and evaluated it with respect to safety and performance aspects by testing it in subjects with type 1 diabetes mellitus (T1DM) in a first feasibility trial. METHODS Vascular microdialysis, a multianalyte infrared spectroscopic glucose sensor, and a standard insulin infusion pump controlled by an adaptive model predictive control (MPC) algorithm were combined to form a closed-loop device, which was evaluated in four T1DM subjects during 30-hour feasibility studies. The aim was to maintain blood glucose concentration in the target range between 80 and 110 mg/dl. RESULTS Mean plasma glucose concentration was 110.5 ± 29.7 mg/dl. The MPC managed to establish normoglycemia within 105 ± 78 minutes after trial start and managed to maintain glucose concentration within the target range for 47% of the time. The hyperglycemic index averaged to 11.9 ± 5.3 mg/dl. CONCLUSION Data of the feasibility trial illustrate the device being effective in controlling glycemia in T1DM subjects. However, the monitoring part of the loop must be improved with respect to accuracy and precision before testing the system in the target population.
Collapse
Affiliation(s)
- Franz Feichtner
- HEALTH-Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft mbH, Graz, Austria.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Ikeoka DT, Pachler C, Mader JK, Bock G, Neves AL, Svehlikova E, Feichtner F, Koehler G, Wrighton CJ, Pieber TR, Ellmerer M. Lipid-heparin infusion suppresses the IL-10 response to trauma in subcutaneous adipose tissue in humans. Obesity (Silver Spring) 2011; 19:715-21. [PMID: 21088675 DOI: 10.1038/oby.2010.227] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
An imbalance between pro- and anti-inflammatory cytokine productions in adipose tissue is thought to contribute to chronic, systemic, low-grade inflammation and consequently to an increased risk of cardiovascular complications in obese and type 2 diabetic patients. Nonesterified fatty acids (NEFA), whose serum levels are elevated in such patients, have been shown to interfere with cytokine production in vitro. In order to evaluate the effects of elevated NEFA levels on cytokine production in adipose tissue in vivo we used an 18-gauge open-flow microperfusion (OFM) catheter to induce local inflammation in the subcutaneous adipose tissue (SAT) of healthy volunteers and to sample interstitial fluid (IF) specifically from the inflamed tissue. In two crossover studies, nine subjects received either an intravenous lipid-heparin infusion to elevate circulating NEFA levels or saline over a period of 28 h. The former increased the circulating levels of triglycerides (TGs), NEFA, glucose, and insulin over the study period. NEFA effects on locally induced inflammation were estimated by measuring the levels of a panel adipokines in the OFM probe effluent. Interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) levels increased during the study period but were not affected by lipid-heparin infusion. In contrast, the level of IL-10, an anti-inflammatory cytokine, was significantly reduced during the final hour of lipid-heparin infusion (saline: 449.2 ± 105.9 vs. lipid-heparin: 65.4 ± 15.4 pg/ml; P = 0.02). These data provide the first in vivo evidence that elevated NEFA can modulate cytokine production by adipose tissue.
Collapse
Affiliation(s)
- Dimas T Ikeoka
- Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Amrein K, Ellmerer M, Hovorka R, Smolle KH, Kachel N, Pieber TR, Plank J. Space GlucoseControl with the incorporated enhanced model predictive control algorithm is a safe and reliable tool for glycaemic control in medical ICU patients. Crit Care 2011. [PMCID: PMC3068330 DOI: 10.1186/cc9821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
21
|
Schaupp L, Plank J, Köhler G, Schaller R, Wrighton C, Ellmerer M, Pieber TR. Prediction of glucose concentration in post-cardiothoracic surgery patients using continuous glucose monitoring. Diabetes Technol Ther 2011; 13:127-34. [PMID: 21284479 DOI: 10.1089/dia.2010.0117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This study evaluated the predictive capability of simple linear extrapolation of continuous glucose data in postsurgical patients undergoing intensive care. METHODS Twenty patients, both with or without an established diagnosis of diabetes mellitus, scheduled to undergo cardiothoracic surgery were included. Glucose was continuously monitored in the intensive care unit with a microdialysis-based subcutaneous glucose monitoring system. The prediction horizon (PH) with respect to a given glucose reading was calculated by extrapolating the linear trend of the glucose signal and subjected to both analytical and clinical assessment (by calculation of the average duration of consecutive positive and negative glucose signal trends, the root mean squared error [RMSE], and by insulin titration error grid [ITEG] analysis, respectively). RESULTS In total, 609 h of continuous glucose data from 17 patients were analyzed. The average duration of consecutive positive and negative glucose signal trends was 7.97 (3.99-19.98) min (median, interquartile range). An increase in the RMSE of 0.5 mmol/L (9 mg/dL) was associated with a PH of 37 min. A strong increase in the number of data points in the unacceptable violation zone of the ITEG was associated with a PH of approximately 20 min. CONCLUSIONS Our data provide evidence that simple linear extrapolation of glucose trend information obtained by continuous glucose monitoring can be used to predict the course of glycemia in critically ill patients for up to 20-30 min. This "glimpse into the future" can be used to proactively prevent the occurrence of adverse events.
Collapse
Affiliation(s)
- Lukas Schaupp
- Department of Internal Medicine, Medical University of Graz, Graz, Austria.
| | | | | | | | | | | | | |
Collapse
|
22
|
Feichtner F, Schaller R, Fercher A, Ratzer M, Ellmerer M, Plank J, Krause B, Pieber T, Schaupp L. Microdialysis based device for continuous extravascular monitoring of blood glucose. Biomed Microdevices 2010; 12:399-407. [PMID: 20101469 DOI: 10.1007/s10544-010-9396-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Glycemic control of intensive care patients can be beneficial for this patient group but the continuous determination of their glucose concentration is challenging. Current continuous glucose monitoring systems based on the measurement of interstitial fluid glucose concentration struggle with sensitivity losses, resulting from biofouling or inflammation reactions. Their use as decision support systems for the therapeutic treatment is moreover hampered by physiological time delays as well as gradients in glucose concentration between plasma and interstitial fluid. To overcome these drawbacks, we developed and clinically evaluated a system based on microdialysis of whole blood. Venous blood is heparinised at the tip of a double lumen catheter and pumped through a membrane based micro-fluidic device where protein-free microdialysate samples are extracted. Glucose recovery as an indicator of long term stability was studied in vitro with heparinised bovine blood and remained highly stable for 72 h. Clinical performance was tested in a clinical trial in eight healthy volunteers undergoing an oral glucose tolerance test. Glucose concentrations of the new system and the reference method correlated at a level of 0.96 and their mean relative difference was 1.9 +/- 11.2%. Clinical evaluation using Clark's Error Grid analysis revealed that the obtained glucose concentrations were accurate and clinically acceptable in 99.6% of all cases. In conclusion, results of the technical and clinical evaluation suggest that the presented device delivers microdialysate samples suitable for accurate and long term stable continuous glucose monitoring in blood.
Collapse
Affiliation(s)
- Franz Feichtner
- Institute of Medical Technologies and Health Management, Joanneum Research GmbH, Elisabethstrasse 11a, 8010, Graz, Austria.
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Amrein K, Ellmerer M, Hovorka R, Kachel N, Parcz D, Korsatko S, Smolle K, Perl S, Bock G, Doll W, Köhler G, Pieber TR, Plank J. Hospital glucose control: safe and reliable glycemic control using enhanced model predictive control algorithm in medical intensive care unit patients. Diabetes Technol Ther 2010; 12:405-12. [PMID: 20388051 DOI: 10.1089/dia.2009.0147] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND The aim of this study was to investigate the performance of the enhanced Model Predictive Control (eMPC) algorithm for glycemic control in medical critically ill patients for the whole length of intensive care unit (ICU) stay. METHODS The trial was designed as a single-center, open, noncontrolled clinical investigation in a nine-bed medical ICU in a tertiary teaching hospital. In 20 patients, blood glucose (BG) was controlled with a laptop-based bedside version of the eMPC. Efficacy was assessed by percentage of time within the target range (4.4-6.1 mM; primary end point), mean BG, and BG sampling interval. Safety was assessed by the number of severe hypoglycemic episodes (<2.2 mM). RESULTS Twenty patients (69 +/- 11 years old; body mass index, 27.4 +/- 4.5 kg/m(2); APACHE II, 25.5 +/- 5.2) were included for a period of 7.3 days (median; interquartile range, 4.4-10.2 days) in the study. Time within target range was 58.12 +/- 10.05% (mean +/- SD). For all patients with at least 7 days in the ICU, there was no statistically significant difference between the daily mean percentage of times in target range in respect of the averages. Mean arterial BG was 5.8 +/- 0.5 mM, insulin requirement was 101.3 +/- 50.7 IU/day, and mean carbohydrate intake (enteral and parenteral nutrition) was 176.4 +/- 61.9 g/day. Three hypoglycemic episodes occurred in three subjects, corresponding to a rate of 0.02 per treatment day. CONCLUSIONS In our single-center, noncontrolled study the eMPC algorithm was a safe and reliable method to control BG in critically medical ICU patients for the whole length of ICU stay.
Collapse
Affiliation(s)
- Karin Amrein
- Medical University of Graz , Department of Internal Medicine, Austria
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Lindpointner S, Korsatko S, Köhler G, Köhler H, Schaller R, Schaupp L, Ellmerer M, Pieber TR, Regittnig W. Glucose levels at the site of subcutaneous insulin administration and their relationship to plasma levels. Diabetes Care 2010; 33:833-8. [PMID: 20097778 PMCID: PMC2845037 DOI: 10.2337/dc09-1531] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To examine insulin's effect on the tissue glucose concentration at the site of subcutaneous insulin administration. RESEARCH DESIGN AND METHODS A CMA-60 microdialysis (MD) catheter and a 24-gauge microperfusion (MP) catheter were inserted into the subcutaneous adipose tissue of fasting, healthy subjects (n = 5). Both catheters were perfused with regular human insulin (100 units/ml) over a 6-h period and used for glucose sampling and simultaneous administration of insulin at sequential rates of 0.33, 0.66, and 1.00 units/h (each rate was used for 2 h). Before and after the insulin delivery period, both catheters were perfused with an insulin-free solution (5% mannitol) for 2 h and used for glucose sampling only. Blood plasma glucose was clamped at euglycemic levels during insulin delivery. RESULTS Start of insulin delivery with MD and MP catheters resulted in a decline of the tissue glucose concentration and the tissue-to-plasma glucose ratio (TPR) for approximately 60 min (P < 0.05). However, during the rest of the 6-h period of variable insulin delivery, tissue glucose concentration paralleled the plasma glucose concentration, and the TPR for MD and MP catheters remained unchanged at 83.2 +/- 3.1 and 77.1 +/- 4.8%, respectively. After subsequent switch to insulin-free perfusate, tissue glucose concentration and TPR increased slowly and reattained preinsulin delivery levels by the end of the experiments. CONCLUSIONS The results show the attainment of a stable TPR value at the site of insulin administration, thus indicating that insulin delivery and glucose sensing may be performed simultaneously at the same adipose tissue site.
Collapse
Affiliation(s)
- Stefan Lindpointner
- Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Graz, Austria
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Ikeoka D, Pachler C, Korsatko S, Mader JK, Weinhandl H, Bodenlenz M, Plank J, Smolle KH, Ellmerer M, Pieber TR. Interleukin-6 produced in subcutaneous adipose tissue is linked to blood pressure control in septic patients. Cytokine 2010; 50:284-91. [PMID: 20303782 DOI: 10.1016/j.cyto.2010.02.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 10/14/2009] [Accepted: 02/22/2010] [Indexed: 11/19/2022]
Abstract
Cytokines are inflammatory mediators of major relevance during sepsis. Recent evidence shows that adipose tissue can produce many distinct cytokines under physiological and pathological conditions, but the role of cytokines produced in adipose tissue was not addressed in sepsis. In the present study the open-flow microperfusion (OFM) technique was used to investigate whether the cytokines produced in subcutaneous adipose tissue (SAT) of patients with severe sepsis correlate with clinical variables. Interstitial fluid effluent samples were collected using an OFM catheter inserted in the abdominal SAT of nine patients with severe sepsis. Blood samples were withdrawn concomitantly and interleukin-1beta (IL-1beta), IL-8, IL-6 and tumor necrosis factor alpha (TNF-alpha) were measured both in SAT effluent and serum samples. Different time profiles were registered for each cytokine. IL-1beta increased in a time-dependent manner, indicating a localized response against the catheter insertion. Interleukin-1beta, 6 and 8 were higher in SAT than in serum suggesting they were locally produced. Diastolic blood pressure (DBP) negatively correlated with IL-1beta, IL-6 and IL-8 in SAT indicating a possible interaction between adipose tissue inflammation and vascular tone regulation. A multiple regression analysis disclosed that mean DBP was significantly related to IL-6 concentrations in SAT (B=-43.9; R-square=0.82; P=0.002).
Collapse
Affiliation(s)
- Dimas Ikeoka
- Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, A-8010 Graz, Austria.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Lindpointner S, Korsatko S, Köhler G, Köhler H, Schaller R, Kaidar R, Yodfat O, Schaupp L, Ellmerer M, Pieber TR, Regittnig W. Use of the site of subcutaneous insulin administration for the measurement of glucose in patients with type 1 diabetes. Diabetes Care 2010; 33:595-601. [PMID: 20040654 PMCID: PMC2827515 DOI: 10.2337/dc09-1532] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To simplify and improve the treatment of patients with type 1 diabetes, we ascertained whether the site of subcutaneous insulin infusion can be used for the measurement of glucose. RESEARCH DESIGN AND METHODS Three special indwelling catheters (24-gauge microperfusion [MP] catheters) were inserted into the subcutaneous adipose tissue of subjects with type 1 diabetes (n = 10; all C-peptide negative). One MP catheter was perfused with short-acting insulin (100 units/ml, Aspart) and used for insulin delivery and simultaneous glucose sampling during an overnight fast and after ingestion of a standard glucose load (75 g). As controls, the further two MP catheters were perfused with an insulin-free solution (5% mannitol) and used for glucose sampling only. Plasma glucose was measured frequently at the bedside. RESULTS Insulin delivery with the MP catheter was adequate to achieve and maintain normoglycemia during fasting and after glucose ingestion. Tissue glucose concentrations derived with the insulin-perfused catheter agreed well with plasma glucose levels. Median correlation coefficient and median absolute relative difference values were found to be 0.93 (interquartile range 0.91-0.97) and 10.9%, respectively. Error grid analysis indicated that the percentage number of tissue values falling in the clinically acceptable range is 99.6%. Comparable analysis results were obtained for the two mannitol-perfused catheters. CONCLUSIONS Our data suggest that estimation of plasma glucose concentrations from the glucose levels directly observed at the site of subcutaneous insulin infusion is feasible and its quality is comparable to that of estimating plasma glucose concentrations from glucose levels measured in insulin-unexposed subcutaneous tissue.
Collapse
Affiliation(s)
- Stefan Lindpointner
- Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Graz, Austria
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Mader JK, Weinhandl H, Köhler G, Plank J, Bock G, Korsatko S, Ratzer M, Ikeoka D, Köhler H, Pieber TR, Ellmerer M. Assessment of different techniques for subcutaneous glucose monitoring in Type 1 diabetic patients during 'real-life' glucose excursions. Diabet Med 2010; 27:332-8. [PMID: 20536497 DOI: 10.1111/j.1464-5491.2009.02924.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To compare the accuracy of two marketed subcutaneous glucose monitoring devices (Guardian RT, GRT; GlucoDay S, GDS) and standard microdialysis (CMA60; MD) in Type 1 diabetic patients. METHODS Seven male Type diabetic patients were investigated over a period of 26 h simulating real-life meal glucose excursions. Catheters of the three systems were inserted into subcutaneous adipose tissue of the abdominal region. For MD, interstitial fluid was sampled at 30- to 60-min intervals for offline glucose determination. Reference samples were taken at 15- to 60-min intervals. All three systems were prospectively calibrated to reference. Median differences, median absolute relative differences (MARD), median absolute differences (MAD), Bland-Altman plot and Clark Error Grid were used to determine accuracy. RESULTS Bland-Altman analysis indicated a mean glucose difference (2 standard deviations) between reference and interstitial glucose of -10.5 (41.8) % for GRT, 20.2 (55.9) % for GDS and 6.5 (35.2) % for MD, respectively. Overall MAD (interquartile range) was 1.07 (0.39; 2.04) mmol/l for GRT, 1.59 (0.54; 3.08) mmol/l for GDS and 0.76 (0.26; 1.58) mmol/l for MD. Overall MARD was 15.0 (5.6; 23.4) % (GRT), 19.7 (6.1; 37.6) % (GDS) and 8.7 (4.1; 18.3) % (MD), respectively. Total sensor failure occurred in two subjects using GRT and one subject using GDS. CONCLUSIONS The three investigated technologies had comparable performance. Whereas GRT underestimated actual blood glucose, GDS and MD overestimated blood glucose. Considerable deviations during daily life meal glucose excursions from reference glucose were observed for all three investigated technologies. Present technologies may require further improvement until individual data can lead to direct and automated generation of therapeutic advice in diabetes management.
Collapse
Affiliation(s)
- J K Mader
- Division of Endocrinology and Nuclear Medicine, Department of Internal Medicine, Medical University Graz, Austria.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Mader JK, Bock G, Plank J, Köhler G, Pieber TR, Ellmerer M. Incidence of hypoglycemia in NICE sugar not so nice after consideration of the treatment period. Crit Care 2010. [PMCID: PMC2934271 DOI: 10.1186/cc8801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
29
|
Ellmerer M, Haluzik M, Blaha J, Kremen J, Svacina S, Plasnik A, Ikeoka D, Bodenlenz M, Schaupp L, Plank J, Pieber TR. Clinical evaluation of subcutaneous lactate measurement in patients after major cardiac surgery. Int J Endocrinol 2009; 2009:390975. [PMID: 19946427 PMCID: PMC2778464 DOI: 10.1155/2009/390975] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 01/08/2009] [Accepted: 03/03/2009] [Indexed: 11/17/2022] Open
Abstract
Minimally invasive techniques to access subcutaneous adipose tissue for glucose monitoring are successfully applied in type1 diabetic and critically ill patients. During critical illness, the addition of a lactate sensor might enhance prognosis and early intervention. Our objective was to evaluate SAT as a site for lactate measurement in critically ill patients. In 40 patients after major cardiac surgery, arterial blood and SAT microdialysis samples were taken in hourly intervals. Lactate concentrations from SAT were prospectively calibrated to arterial blood. Analysis was based on comparison of absolute lactate concentrations (arterial blood vs. SAT) and on a 6-hour lactate trend analysis, to test whether changes of arterial lactate can be described by SAT lactate. Correlation between lactate readings from arterial blood vs. SAT was highly significant (r2 = 0.71, P < .001). Nevertheless, 42% of SAT lactate readings and 35% of the SAT lactate trends were not comparable to arterial blood. When a 6-hour stabilization period after catheter insertion was introduced, 5.5% of SAT readings and 41.6% of the SAT lactate trends remained incomparable to arterial blood. In conclusion, replacement of arterial blood lactate measurements by readings from SAT is associated with a substantial shortcoming in clinical predictability in patients after major cardiac surgery.
Collapse
Affiliation(s)
- Martin Ellmerer
- Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, 8036 Graz, Austria
- *Martin Ellmerer:
| | - Martin Haluzik
- 3rd Department of Medicine, 1st Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic
| | - Jan Blaha
- 3rd Department of Medicine, 1st Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic
| | - Jaromir Kremen
- 3rd Department of Medicine, 1st Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic
| | - Stepan Svacina
- 3rd Department of Medicine, 1st Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic
| | - Andreas Plasnik
- Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Dimas Ikeoka
- Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Manfred Bodenlenz
- Joanneum Research GmbH, Institute of Medical System Technologies and Health Management, Elisabethstraβe 11a, 8010 Graz, Austria
| | - Lukas Schaupp
- Joanneum Research GmbH, Institute of Medical System Technologies and Health Management, Elisabethstraβe 11a, 8010 Graz, Austria
| | - Johannes Plank
- Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Thomas R. Pieber
- Department of Internal Medicine, Medical University Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| |
Collapse
|
30
|
Schaller R, Feichtner F, Köhler H, Bodenlenz M, Plank J, Wutte A, Mader JK, Ellmerer M, Hainisch R, Pieber TR, Schaupp L. An automated discontinuous venous blood sampling system for ex vivo glucose determination in humans. J Diabetes Sci Technol 2009; 3:110-6. [PMID: 20046655 PMCID: PMC2769855 DOI: 10.1177/193229680900300112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Intensive insulin therapy reduces mortality and morbidity in critically ill patients but places great demands on medical staff who must take frequent blood samples for the determination of glucose levels. A cost-effective solution to this resourcing problem could be provided by an effective and reliable automated blood sampling (ABS) system suitable for ex vivo glucose determination. METHOD The primary study aim was to compare the performance of a prototype ABS system with a manual reference system over a 30 h sampling period under controlled conditions in humans. Two venous cannulae were inserted to connect the ABS system and the reference system. Blood samples were taken with both systems at 15, 30, and 60 min intervals and analyzed using a Beckman glucose analyzer. During the study, blood glucose levels were altered through four meal ingestions. RESULTS The median Pearson coefficient of correlation between manually and automatically withdrawn blood samples was 0.976 (0.953-0.996). The system error was -3.327 ± 5.546% (-6.03-0.49). Through Clark error grid analysis, 420 data pairs were analyzed, showing that 98.6% of the data were in zone A and 1.4% were in zone B. Insulin titration error grid analysis revealed an acceptable treatment in 100% of cases. A 17.5-fold reduction in the occurrence of blood-withdrawal failures through occluded catheters was moreover achieved by the added implementation in the ABS system of a "keep vein open" saline infusion. CONCLUSIONS Our study showed that the ABS system described provides a user-friendly, reliable automated means for reproducible and accurate blood sampling from a peripheral vein for blood glucose determination and thus represents a promising alternative to frequent manual blood sampling.
Collapse
Affiliation(s)
- Roland Schaller
- Institute of Medical Technologies and Health Management, Joanneum Research Forschungsgesellschaft mbH, Graz, Austria.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Schaller R, Feichtner F, Köhler H, Bodenlenz M, Plank J, Wutte A, Mader JK, Ellmerer M, Hellmich R, Wedig H, Hainisch R, Pieber TR, Schaupp L. A novel automated discontinuous venous blood monitoring system for ex vivo glucose determination in humans. Biosens Bioelectron 2008; 24:2239-45. [PMID: 19135351 DOI: 10.1016/j.bios.2008.11.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 11/27/2008] [Accepted: 11/28/2008] [Indexed: 11/26/2022]
Abstract
Intensive insulin therapy reduces mortality and morbidity in critically ill patients but imposes great demands on medical staff who must take frequent blood samples for the determination of glucose levels. A solution to this resourcing problem would be provided by an automated blood monitoring system. The aim of the present clinical study was to evaluate such a system comprising an automatic blood sampling unit linked to a glucose biosensor. Our approach was to determine the correlation and system error of the sampling unit alone and of the combined system with respect to reference levels over 12h in humans. Two venous cannulae were inserted to connect the automatic and reference systems to the subjects. Blood samples were taken at 15 and 30 min intervals. The median Pearson coefficient of correlation between manually and automatically withdrawn blood samples was 0.982 for the sampling unit alone and 0.950 for the complete system. The biosensor had a linear range up to 20 mmoll(-1) and a 95% response time of <2 min. Clark Error Grid analysis showed that 96.93% of the data (228 data pairs) was in zone A and 3.07% in zone B. Insulin Titration Error Grid analysis suggested an acceptable treatment in 99.56% of cases. Implementation of a "Keep Vein Open" saline infusion into the automated blood sampling system reduced blood withdrawal failures through occluded catheters fourfold. In summary, automated blood sampling from a peripheral vein coupled with automatic glucose determination is a promising alternative to frequent manual blood sampling.
Collapse
Affiliation(s)
- R Schaller
- Joanneum Research Forschungsgesellschaft mbH, Institute of Medical Technologies and Health Management, Elisabethstrasse 11a, 8010 Graz, Austria
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Korsatko S, Ellmerer M, Schaupp L, Mader JK, Smolle KH, Tiran B, Plank J. Hypoglycaemic coma due to falsely high point-of-care glucose measurements in an ICU-patient with peritoneal dialysis: a critical incidence report. Intensive Care Med 2008; 35:571-2. [PMID: 19057894 DOI: 10.1007/s00134-008-1362-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2008] [Indexed: 11/25/2022]
|
33
|
Kulnik R, Plank J, Pachler C, Wilinska ME, Groselj-Strele A, Röthlein D, Wufka M, Kachel N, Smolle KH, Perl S, Pieber TR, Hovorka R, Ellmerer M. Evaluation of implementation of a fully automated algorithm (enhanced model predictive control) in an interacting infusion pump system for establishment of tight glycemic control in medical intensive care unit patients. J Diabetes Sci Technol 2008; 2:963-70. [PMID: 19885285 PMCID: PMC2769812 DOI: 10.1177/193229680800200606] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The objective of this study was to investigate the performance of a newly developed decision support system for the establishment of tight glycemic control in medical intensive care unit (ICU) patients for a period of 72 hours. METHODS This was a single-center, open, non-controlled feasibility trial including 10 mechanically ventilated ICU patients. The CS-1 decision support system (interacting infusion pumps with integrated enhanced model predictive control algorithm and user interface) was used to adjust the infusion rate of administered insulin to normalize blood glucose. Efficacy and safety were assessed by calculating the percentage of values within the target range (80-110 mg/dl), hyperglycemic index, mean glucose, and hypoglycemic episodes (<40 mg/dl). RESULTS The percentage of values in time in target was 47.0% (+/-13.0). The average blood glucose concentration and hyperglycemic index were 109 mg/dl (+/-13) and 10 mg/dl (+/-9), respectively. No hypoglycemic episode (<40 mg/dl) was detected. Eleven times (1.5% of all given advice) the nurses did not follow and, thus, overruled the advice of the CS-1 system. Several technical malfunctions of the device (repetitive error messages and missing data in the data log) due to communication problems between the new hardware components are shortcomings of the present version of the device. As a consequence of these technical failures of system integration, treatment had to be stopped ahead of schedule in three patients. CONCLUSIONS Despite technical malfunctions, the performance of this prototype CS-1 decision support system was, from a clinical point of view, already effective in maintaining tight glycemic control. Accordingly, and with technical improvement required, the CS-1 system has the capacity to serve as a reliable tool for routine establishment of glycemic control in ICU patients.
Collapse
Affiliation(s)
- Roman Kulnik
- Department of Internal Medicine, Medical University of Graz, Austria
| | - Johannes Plank
- Department of Internal Medicine, Medical University of Graz, Austria
| | - Christoph Pachler
- Department of Internal Medicine, Medical University of Graz, Austria
| | | | | | | | | | | | - Karl Heinz Smolle
- Department of Internal Medicine, Medical University of Graz, Austria
| | - Sabine Perl
- Department of Internal Medicine, Medical University of Graz, Austria
| | | | - Roman Hovorka
- Paediatrics, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Martin Ellmerer
- Department of Internal Medicine, Medical University of Graz, Austria
| |
Collapse
|
34
|
Abstract
Focused research is underway to improve the delivery of tight glycaemic control at the intensive care unit. A major component is the development of safe, efficacious and effective insulin titration algorithms, which are normally evaluated in time-consuming resource-demanding clinical studies. Simulation studies with virtual critically ill patients can substantially accelerate the development process. For this purpose, we created a model of glucoregulation in the critically ill. The model includes five submodels: a submodel of endogenous insulin secretion, a submodel of insulin kinetics, a submodel of enteral glucose absorption, a submodel of insulin action and a submodel of glucose kinetics. Model parameters are estimated utilizing prior knowledge and data collected routinely at the intensive care unit to represent the high intersubject and temporal variation in insulin needs in the critically ill. Bayesian estimation combined with the regularization method is used to estimate (i) time-invariant model parameters and (ii) a time-varying parameter, the basal insulin concentration, which represents the temporal variation in insulin sensitivity. We propose a validation process to validate virtual patients developed for the purpose of testing glucose controllers. The parameter estimation and the validation are exemplified using data collected in six critically ill patients treated at a medical intensive care unit. In conclusion, a novel glucoregulatory model has been developed to create a virtual population of critically ill facilitating in silico testing of glucose controllers at the intensive care unit.
Collapse
Affiliation(s)
- Roman Hovorka
- Institute of Metabolic Science, Metabolic Research Laboratories, Level 4, Box 289, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK.
| | | | | | | | | |
Collapse
|
35
|
Abstract
Single center randomized controlled trials could demonstrate a benefit of strict glycemic control on the mortality and morbidity outcomes for critically ill patients. Although observational studies also demonstrate a benefit of tight glucose control for patients in general wards, direct evidence is still lacking. Overall, the implementation of glucose control both in the very controlled setting of an intensive care unit and even more so in the clearly less controlled setting of a general ward has proven to be difficult. Standardization of all required working steps to establish glycemic control needs to be considered to be able to achieve safe and good blood glucose control. Recent developments from diabetes technology will have an important impact in facilitating glucose control in the hospital, although the already established workflows in hospitals will require a substantial reconsideration of diabetes-oriented technology to allow an area-wide implementation and acceptance by health care personnel.
Collapse
Affiliation(s)
- Martin Ellmerer
- Department of Internal Medicine, Diabetes Metabolism, Medical University Graz, Graz, Austria.
| | | | | |
Collapse
|
36
|
Chiu JD, Richey JM, Harrison LN, Zuniga E, Kolka CM, Kirkman E, Ellmerer M, Bergman RN. Direct administration of insulin into skeletal muscle reveals that the transport of insulin across the capillary endothelium limits the time course of insulin to activate glucose disposal. Diabetes 2008; 57:828-35. [PMID: 18223011 DOI: 10.2337/db07-1444] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Intravenous insulin infusion rapidly increases plasma insulin, yet glucose disposal occurs at a much slower rate. This delay in insulin's action may be related to the protracted time for insulin to traverse the capillary endothelium. An increased delay may be associated with the development of insulin resistance. The purpose of the present study was to investigate whether bypassing the transendothelial insulin transport step and injecting insulin directly into the interstitial space would moderate the delay in glucose uptake observed with intravenous administration of the hormone. RESEARCH DESIGN AND METHODS Intramuscular injections of saline (n = 3) or insulin (n = 10) were administered directly into the vastus medialis of anesthetized dogs. Injections of 0.3, 0.5, 0.7, 1.0, and 3.0 units insulin were administered hourly during a basal insulin euglycemic glucose clamp (0.2mU x min(-1) x kg(-1)). RESULTS Unlike the saline group, each incremental insulin injection caused interstitial (lymph) insulin to rise within 10 min, indicating rapid diffusion of the hormone within the interstitial matrix. Delay in insulin action was virtually eliminated, indicated by immediate dose-dependent increments in hindlimb glucose uptake. Additionally, bypassing insulin transport by direct injection into muscle revealed a fourfold greater sensitivity to insulin of in vivo muscle tissue than previously reported from intravenous insulin administration. CONCLUSIONS Our results indicate that the transport of insulin to skeletal muscle is a rate-limiting step for insulin to activate glucose disposal. Based on these results, we speculate that defects in insulin transport across the endothelial layer of skeletal muscle will contribute to insulin resistance.
Collapse
Affiliation(s)
- Jenny D Chiu
- Department of Physiology and Biophysics, University of Southern California, Keck School of Medicine, 1333 San Pablo St., MMR 626, Los Angeles, CA 90033, USA
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Pachler C, Plank J, Weinhandl H, Chassin LJ, Wilinska ME, Kulnik R, Kaufmann P, Smolle KH, Pilger E, Pieber TR, Ellmerer M, Hovorka R. Tight glycaemic control by an automated algorithm with time-variant sampling in medical ICU patients. Intensive Care Med 2008; 34:1224-30. [PMID: 18297268 DOI: 10.1007/s00134-008-1033-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Accepted: 01/02/2008] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Tight glycaemic control (TGC) in critically ill patients improves clinical outcome, but is difficult to establish The primary objective of the present study was to compare glucose control in medical ICU patients applying a computer-based enhanced model predictive control algorithm (eMPC) extended to include time-variant sampling against an implemented glucose management protocol. DESIGN Open randomised controlled trial. SETTING Nine-bed medical intensive care unit (ICU) in a tertiary teaching hospital. PATIENTS AND PARTICIPANTS Fifty mechanically ventilated medical ICU patients. INTERVENTIONS Patients were included for a study period of up to 72 h. Patients were randomised to the control group (n = 25), treated by an implemented insulin algorithm, or to the eMPC group (n = 25), using the laptop-based algorithm. Target range for blood glucose (BG) was 4.4-6.1 mM. Efficacy was assessed by mean BG, hyperglycaemic index (HGI) and BG sampling interval. Safety was assessed by the number of hypoglycaemic-episodes < 2.2 mM. Each participating nurse filled-in a questionnaire regarding the usability of the algorithm. MEASUREMENTS AND MAIN RESULTS BG and HGI were significantly lower in the eMPC group [BG 5.9 mM (5.5-6.3), median (IQR); HGI 0.4 mM (0.2-0.9)] than in control patients [BG 7.4 mM (6.9-8.6), p < 0.001; HGI 1.6 mM (1.1-2.4), p < 0.001]. One hypoglycaemic episode was detected in the eMPC group; no such episodes in the control group. Sampling interval was significantly shorter in the eMPC group [eMPC 117[Symbol: see text]min (+/- 34), mean (+/- SD), vs 174 min (+/- 27); p < 0.001]. Thirty-four nurses filled-in the questionnaire. Thirty answered the question of whether the algorithm could be applied in daily routine in the affirmative. CONCLUSIONS The eMPC algorithm was effective in maintaining tight glycaemic control in severely ill medical ICU patients.
Collapse
Affiliation(s)
- Christoph Pachler
- Department of Internal Medicine, Medical University Graz, Stiftingtalstrasse 24, 8010, Graz, Austria.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Plank J, Kulnik R, Pachler C, Hovorka R, Röthlein D, Kachel N, Wufka M, Smolle K, Perl S, Zweiker R, Pieber T, Ellmerer M. Evaluation of the implementation of a fully automated algorithm (eMPC) in an interacting infusion pump system for the establishment of tight glycaemic control in medical ICU patients. Crit Care 2008. [PMCID: PMC4088527 DOI: 10.1186/cc6377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
39
|
Pachler C, Ikeoka D, Plank J, Weinhandl H, Suppan M, Mader JK, Bodenlenz M, Regittnig W, Mangge H, Pieber TR, Ellmerer M. Subcutaneous adipose tissue exerts proinflammatory cytokines after minimal trauma in humans. Am J Physiol Endocrinol Metab 2007; 293:E690-6. [PMID: 17578890 DOI: 10.1152/ajpendo.00034.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inflammatory cytokines released from adipose tissue play an important role in different pathological processes. In the present study, we investigated the inflammatory cytokine response of human subcutaneous adipose tissue (SAT) by applying the open-flow microperfusion technique. Four standard 18-gauge microperfusion catheters were inserted into periumbilical SAT of eight healthy male volunteers [29 +/- 3 yr, BMI 24.3 +/- 1.9 (mean +/- SD)]. SAT probe effluents were collected at 60-min intervals for 8 h after catheter insertion. Different perfusion fluids were used to measure the local effect of insulin and/or glucose on the cytokine response. SAT probe effluents were analyzed for IL-1beta, IL-6, CXCL8 (IL-8), and TNF-alpha. SAT concentrations of IL-1beta increased 100-fold from 1.0 +/- 0.2 pg/ml (mean +/- SE) to 101.5 +/- 23.2 pg/ml (P < 0.001) after 8 h. A 130-fold increase was observed for CXCL8, from 49 +/- 29 to 6,554 +/- 1,713 pg/ml (P < 0.001). Furthermore, a 20-fold increase of IL-6 was observed within the first 5 h (from 159 +/- 123 to 3,554 +/- 394 pg/ml; P < 0.001), and a significant decline to 2,154 +/- 216 pg/ml (P < 0.01) was seen thereafter. Finally, TNF-alpha increased from 1.4 +/- 0.6 to 2.5 +/- 0.5 pg/ml (P < 0.05) in hour 2 and remained stable thereafter. Local administration of insulin exerted a stimulatory effect on the inflammatory response of IL-6. In conclusion, SAT exerts a highly reproducible and consistent proinflammatory cytokine response after minimally invasive trauma caused by the insertion of a catheter in humans.
Collapse
Affiliation(s)
- Christoph Pachler
- Department of Internal Medicine, Diabetes and Metabolism, Medical University Graz, Graz, Austria
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Weinhandl H, Pachler C, Mader JK, Ikeoka D, Mautner A, Falk A, Suppan M, Pieber TR, Ellmerer M. Physiological hyperinsulinemia has no detectable effect on access of macromolecules to insulin-sensitive tissues in healthy humans. Diabetes 2007; 56:2213-7. [PMID: 17601990 DOI: 10.2337/db07-0238] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Physiologically elevated insulin concentrations promote access of macromolecules to skeletal muscle in dogs. We investigated whether insulin has a stimulating effect on the access of macromolecules to insulin-sensitive tissues in humans as well. RESEARCH DESIGN AND METHODS In a randomized, controlled trial, euglycemic-hyperinsulinemic clamp (1.2 mU x kg(-1) x min(-1) insulin) and saline control experiments were performed in 10 healthy volunteers (aged 27.5 +/- 4 years, BMI 22.6 +/- 1.6 kg/m(2)). Distribution and clearance parameters of inulin were determined in a whole-body approach, combining primed intravenous infusion of inulin with compartment modeling. Inulin kinetics were measured in serum using open-flow microperfusion in interstitial fluid of femoral skeletal muscle and subcutaneous adipose tissue. RESULTS Inulin kinetics in serum were best described using a three-compartment model incorporating a serum and a fast and a slow equilibrating compartment. Inulin kinetics in interstitial fluid of peripheral insulin-sensitive tissues were best represented by the slow equilibrating compartment. Serum and interstitial fluid inulin kinetics were comparable between the insulin and saline groups. Qualitative analysis of inulin kinetics was confirmed by model-derived distribution and clearance parameters of inulin. Physiological hyperinsulinemia (473 +/- 6 vs. 18 +/- 2 pmol/l for the insulin and saline group, respectively; P < 0.001) indicated no effect on distribution volume (98.2 +/- 6.2 vs. 102.5 +/- 5.7 ml/kg; NS) or exchange parameter (217.6 +/- 34.2 vs. 243.1 +/- 28.6 ml/min; NS) of inulin to peripheral insulin-sensitive tissues. All other parameters identified by the model were also comparable between the groups. CONCLUSIONS Our data suggest that in contrast to studies performed in dogs, insulin at physiological concentrations does not augment recruitment of insulin-sensitive tissues in healthy humans.
Collapse
Affiliation(s)
- Heinz Weinhandl
- Division of Diabetes and Metabolism, Department of Internal Medicine, Medical University Graz, Graz, Austria
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Ikeoka D, Pachler C, Korsatko S, Bodenlenz M, Mader J, Weinhandl H, Plasnik A, Suppan M, Smolle KH, Plank J, Pieber T, Ellmerer M. 60 Local Stimulated Secretion of Inflammatory Cytokines from Adipose Tissue is Reduced in Septic Patients in Comparison to Healthy Controls. Cytokine 2007. [DOI: 10.1016/j.cyto.2007.07.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
42
|
Kim SP, Ellmerer M, Kirkman EL, Bergman RN. Beta-cell "rest" accompanies reduced first-pass hepatic insulin extraction in the insulin-resistant, fat-fed canine model. Am J Physiol Endocrinol Metab 2007; 292:E1581-9. [PMID: 17284579 DOI: 10.1152/ajpendo.00351.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
During insulin resistance, glucose homeostasis is maintained by an increase in plasma insulin via increased secretion and/or decreased first-pass hepatic insulin extraction. However, the relative importance of insulin secretion vs. clearance to compensate for insulin resistance in obesity has yet to be determined. This study utilizes the fat-fed dog model to examine longitudinal changes in insulin secretion and first-pass hepatic insulin extraction during development of obesity and insulin resistance. Six dogs were fed an isocaloric diet with an approximately 8% increase in fat calories for 12 wk and evaluated at weeks 0, 6, and 12 for changes in 1) insulin sensitivity by euglycemic-hyperinsulinemic clamp, 2) first-pass hepatic insulin extraction by direct assessment, and 3) glucose-stimulated insulin secretory response by hyperglycemic clamp. We found that 12 wk of a fat diet increased subcutaneous and visceral fat as assessed by MR imaging. Consistent with increased body fat, the dogs exhibited a approximately 30% decrease in insulin sensitivity and fasting hyperinsulinemia. Although insulin secretion was substantially increased at week 6, beta-cell sensitivity returned to prediet levels by week 12. However, peripheral hyperinsulinemia was maintained because of a significant decrease in first-pass hepatic insulin extraction, thus maintaining hyperinsulinemia, despite changes in insulin release. Our results indicate that when obesity and insulin resistance are induced by an isocaloric, increased-fat diet, an initial increase in insulin secretion by the beta-cells is followed by a decrease in first-pass hepatic insulin extraction. This may provide a secondary physiological mechanism to preserve pancreatic beta-cell function during insulin resistance.
Collapse
Affiliation(s)
- Stella P Kim
- Department of Physiology and Biophysics, Keck School of Medicine of USC, 1333 San Pablo St. MMR 626, Los Angeles, CA 90033, USA
| | | | | | | |
Collapse
|
43
|
Vlasselaers D, Schaupp L, van den Heuvel I, Mader J, Bodenlenz M, Suppan M, Wouters P, Ellmerer M, Van den Berghe G. Monitoring Blood Glucose with Microdialysis of Interstitial Fluid in Critically Ill Children. Clin Chem 2007; 53:536-7. [PMID: 17327506 DOI: 10.1373/clinchem.2006.078089] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
44
|
Heise HM, Damm U, Bodenlenz M, Kondepati VR, Köhler G, Ellmerer M. Bedside monitoring of subcutaneous interstitial glucose in healthy individuals using microdialysis and infrared spectrometry. J Biomed Opt 2007; 12:024004. [PMID: 17477719 DOI: 10.1117/1.2714907] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
An IR-spectroscopy-based bedside device, coupled to a subcutaneously implanted microdialysis probe, is developed for quasicontinuous glucose monitoring with intermittent readouts at 10-min intervals, avoiding any sensor recalibration under long-term operation. The simultaneous estimation of the microdialysis recovery rate is possible using an acetate containing perfusate and determining its losses across the dialysis membrane. Measurements are carried out on four subjects, with experiments lasting either 8 or 28 h, respectively. Using the spectral interval data either from 1180 to 950 or 1560 to 1000 cm(-1), standard errors of prediction (SEPs) between 0.13 and 0.28 mM are achieved using multivariate calibration with partial least-squares (PLS) or classical least-squares (CLS) calibration models, respectively. The transfer of a PLS calibration model using the spectral and reference concentration data of the dialysates from the three 8-h-long experiments to a 28-h monitoring episode with another healthy subject is tested. Including microdialysis recovery for the determination of the interstitial glucose concentrations, an SEP of 0.24 mM is obtained versus whole blood glucose values. The option to determine other metabolites such as urea or lactate offers the possibility to develop a calibration- and reagent-free point-of-care analyzer.
Collapse
Affiliation(s)
- H Michael Heise
- ISAS-Institute for Analytical Sciences at the University of Dortmund, Bunsen-Kirchhoff-Str. 11, D-44139 Dortmund, Germany.
| | | | | | | | | | | |
Collapse
|
45
|
Pachler C, Plank J, Weinhandl H, Hovorka R, Chassin L, Kaufmann P, Smolle KH, Pieber TR, Ellmerer M. Evaluation of a model predictive control algorithm using time-variant sampling to establish tight glycaemic control in clinical practice. Crit Care 2007. [PMCID: PMC4095192 DOI: 10.1186/cc5298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
46
|
Feichtner F, Schaller R, Fercher A, Schaupp L, Plank J, Wutte A, Ellmerer M, Pieber T. Continuous glucose monitoring for intensive care patients using whole blood microdialysis. Crit Care 2007. [PMCID: PMC4095197 DOI: 10.1186/cc5303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
47
|
Ikeoka D, Pachler C, Korsatko S, Bodenlenz M, Mader J, Weinhandl H, Plasnik A, Suppan M, Smolle K, Plank J, Pieber T, Ellmerer M. Reduced local inflammatory reactivity in septic patients compared with healthy controls. Crit Care 2007. [PMCID: PMC4095075 DOI: 10.1186/cc5181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
48
|
Schaller R, Feichtner F, Fercher A, Schaupp L, Bodenlenz M, Köhler H, Plank J, Wutte A, Ellmerer M, Hainisch R, Pieber T. System for automated discontinuous venous blood withdrawal for glucose determination of patients in the intensive care unit. Crit Care 2007. [PMCID: PMC4095183 DOI: 10.1186/cc5289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
49
|
Mader JK, Korsatko S, Ikeoka D, Plank J, Bodenlenz M, Suppan M, Sinner F, Smolle KH, Pieber TR, Ellmerer M. Subcutaneous glucose monitoring in patients with severe sepsis. Crit Care 2007. [PMCID: PMC4095198 DOI: 10.1186/cc5304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
50
|
Kremen J, Bláha J, Matias M, Anderlová K, Ellmerer M, Plank J, Pieber T, Svacina S, Haluzík M. [Monitoring of glucose concentration in critical patients, comparing arterial blood glucose concentrations and interstitial glucose concentration measured by microdialysis technique]. Vnitr Lek 2006; 52:777-81. [PMID: 17091600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
INTRODUCTION Recent studies have shown that normalization of blood glucose in critically ill patients by intensive insulin therapy significantly decreases their mortality and morbidity. The aim of our study was to compare interstitial glucose concentrations in subcutaneous adipose tissue (measured by microdialysis technique) and arterial blood glucose concentrations to test the suitability of subcutaneous adipose tissue for long-term placement of biosensors for glucose measurement in critically ill patients. PATIENTS AND METHODS 20 patients (16 men and 4 women) after cardiac surgery hospitalized at postoperative intensive care unit were included into the study. Mean age was 68 +/- 10 years, BMI was 28.3 +/- 3.9 year. Only patients with glycemia higher than 6.7 mmol/l at a time of admission to the ICU were included. Samples for measurement of interstitial glucose concentrations were collected in 60 minutes intervals during 48 hours using microdialysis of the subcutaneous adipose tissue. Perfusion fluid was 5% mannitol, perfusion rate was 1 microl/min. Arterial blood glucose concentration was measured in 60 minutes intervals, absolute concentrations of interstitial glucose were calculated using ionic reference technique. RESULTS Mean arterial glucose concentration during the study was 6.7 +/- 0.56 mmol/l, absolute concentration of glucose in interstitial fluid was 3.55 +/- 0.58 mmol/l. Mean correlation coefficient between arterial and interstitial concentrations was 0.77 +/- 0.15. CONCLUSION Our study demonstrated good correlation between interstitial glucose concentrations in subcutaneous adipose tissue and arterial blood glucose concentrations in post-cardiac surgery patients. Further studies are needed to evaluate this relationship in patients with more severely disturbed perfusion of subcutaneous adipose tissue.
Collapse
Affiliation(s)
- J Kremen
- III. interní klinika 1. lékarské fakulty UK a VFN, Praha.
| | | | | | | | | | | | | | | | | |
Collapse
|