Intensive insulin therapy during cardiovascular surgery

Impact of newly developed, next-generation artificial endocrine pancreas

BACKGROUND

Recent studies have shown that strict perioperative blood glucose management may reduce mortality and morbidity in critically ill adult patients. The purpose of this study was to assess the accuracy and efficacy of the intraoperative application of a newly developed, next-generation artificial endocrine pancreas (STG-55, Nikkiso Co., Ltd., Tokyo, Japan).

METHODS

Twenty patients scheduled to undergo surgery were enrolled in this study. The STG-55 is designed to be more user-friendly than its conventional counterpart (STG-22) while maintaining the latter's fundamental functions, such as a closed-loop system using algorithms for insulin and glucose infusion. After anesthetic induction, a 20G intravenous catheter was inserted into a peripheral forearm vein and connected to a continuous blood glucose monitor. The resultant 105 scores for paired blood glucose values were compared by Bland-Altman analysis.

RESULTS

Stable blood glucose values were maintained automatically, and there were no complications related to use of the STG-55. A close correlation (r=0.96) was observed between continuous glucose measurements using the STG-55 and conventional intermittent glucose measurements. The difficulty of manipulation using this system was decreased by improved preparation procedures.

CONCLUSION

The glycemic control system using the STG-55 could provide an alternative way to achieve effective and safe perioperative glycemic control.

Feasibility and precision of subcutaneous continuous glucose monitoring in patients undergoing CABG surgery

OBJECTIVES

To evaluate if subcutaneous continuous glucose monitoring (sCGM) is feasible in cardiac surgery and if reliable glucose values are reported under hypothermic extracorporeal circulation.

DESIGN

Feasibility trial.

SETTING

University hospital.

PARTICIPANTS

Ten consecutive patients undergoing coronary artery bypass grafting.

INTERVENTIONS

Prior to surgery, during hypothermic extracorporeal bypass, and 48 hours postoperatively, arterial blood glucose samples were compared with sCGM every 30 minutes. Statistical analysis utilized Clarke's error grid and Bland-Altman plot.

MEASUREMENTS AND MAIN RESULTS

Three hundred fifty-one pairs of glucose measurements were recorded including 59 during hypothermic extracorporeal circulation. Agreement between these measurements was acceptable, with a regression line slope of 0.88 and an offset of 17.4 (p = 0.87). Error grid analysis indicated a safe margin of 99.1% within zone A (no clinical action needed) or zone B (values would not lead to inappropriate treatment). Only 0.9% were plotted in zone D (potentially dangerous failure). Measurements during hypothermic extracorporeal circulation were comparable. Correlation coefficient was 0.760. The offset regression line was more pronounced (50.9) with a flatter slope (0.640). Within the error grid all plot values were in zone A or B.

CONCLUSIONS

sCGM compared with arterial blood gas glucose monitoring under hypothermic extracorporeal circulation appears to be feasible and reliable.

Microarray analysis of gene expression profiles in the rat kidney demonstrates a local inflammatory response induced by cardiopulmonary bypass

CONTEXT

Cardiopulmonary bypass (CPB) is a commonly used technique in cardiac surgery but is associated with acute, transient, renal dysfunction that has a negative impact on long-term survival.

OBJECTIVE

To unravel the molecular pathogenesis of renal injury following CPB.

DESIGN

To obtain insight into the pathogenesis of renal dysfunction following CPB, we performed a microarray analysis of renal gene expression in the rat.

SETTING

University Medical Centre Groningen.

INTERVENTION

Rats underwent CPB or a sham procedure for 60 min and were sacrificed at 60 min, 1 and 5 days after the procedure.

MAIN OUTCOME MEASURES

Renal gene expression profile as determined by microarray analysis.

RESULTS

Expression of 420 genes was significantly altered in CPB compared to the sham procedure, and in 407 genes, this was evident in the acute phase (60 min) following CPB. Gene ontology analysis revealed 28 of these genes were involved in inflammatory responses, with high expression of genes downstream of mitogen-activated protein-kinase (MAP-kinase) signalling pathways. Potent inducers identified are from the interleukin-6 cytokine family that consists of interleukin-6 and oncostatin M (OSM), which signal through the gp130-cytokine receptor complex. The plasma concentration of interleukin-6 was hugely increased by CPB as measured by ELISA. Expression of genes downstream of these signalling pathways that lead to production of chemokines, adhesion molecules and molecules involved in coagulative pathways, was upregulated.

CONCLUSION

CPB induces an acute and local inflammatory response in the kidney, which might contribute to renal injury. The signalling pathways involved identified by gene expression analysis may represent pharmacological targets to limit renal injury following CPB.

Long term effects of the implantation of autologous bone marrow mononuclear cells for type 2 diabetes mellitus

Previous studies have shown that several types of stem cells can differentiate into insulin-secreting islet beta-cells and that these cells can reduce blood glucose in some trials, but there has been no report of a long-term follow-up. We assessed the long-term effects of the use of autologous bone marrow mononuclear cells in the treatment of type 2 diabetes mellitus (T2DM). Based on the willingness to receive implantation of bone marrow mononuclear cells, One hundred and eighteen patients with T2DM were divided into two groups; the patients in group I were treated with autologous bone marrow mononuclear cells and patients in group II were treated with insulin intensification therapy. Mononuclear cells from bone marrow were injected back into the patient's pancreas via a catheter. Patients were followed-up after the operation at monthly intervals for the first 3 months and thereafter every 3 months for the next 33 months, the occurrence of any side effects and the results of laboratory examinations were evaluated. There were no reported acute or chronic side effects in group I and both the HbA1c and C-peptide in group I patients were significantly better than either pretherapy values or group II patients during the follow-up period. These data suggested that the implantation of autologous bone marrow mononuclear cells for the treatment of T2DM is safe and effective. This therapy can partially restore the function of islet beta-cells and maintain blood glucose homeostasis in a longer time.

Perioperative glycemic management in 2011: paradigm shifts

PURPOSE OF REVIEW

The publication of Van den Berghe's landmark study in 2001 supported the use of intensive insulin therapy (IIT) to target normoglycemia in the critically ill and triggered a new era in glycemic management in the perioperative period and in the ICU. In 2009, the normoglycemia in intensive care evaluation-survival using glucose algorithm regulation (NICE-SUGAR) trial demonstrated increased mortality and incidence of hypoglycemia in patients managed with IIT, resulting in a shift toward higher blood glucose targets in this patient population. This review distills clinically pertinent principles from the related literature published in the months since the NICE-SUGAR trial.

RECENT FINDINGS

A target blood glucose level in the acute care setting supported by many of the pertinent societies and frequently quoted in the literature is 140-180 mg/dl. Hyperglycemia, hypoglycemia, and glucose variability are detrimental. Accurate and efficient glucose monitoring devices are essential. Insulin infusion protocols (IIPs) employed to achieve desired blood glucose targets must be individualized and validated for the ICU and institution in which they are being implemented.

SUMMARY

Appropriate glycemic management in the acute care setting can be achieved by targeting a reasonable blood glucose range and employing specific and institutionally validated IIPs.

Anti-inflammatory effects of perioperative intensive insulin therapy during cardiac surgery with cardiopulmonary bypass

PURPOSE

Recent studies have reported that controlling blood glucose with insulin can suppress systemic inflammation. In the present study, we evaluated how perioperative intensive insulin therapy (IIT) influences the inflammatory response in an artificial pancreas during cardiac surgery with cardiopulmonary bypass.

METHODS

We randomly divided the patients undergoing cardiac surgery with cardiopulmonary bypass into two groups: an IIT group (n = 13) and a conventional treatment (CT) group (n = 12). For the IIT group, blood glucose control was initiated with an artificial pancreas at initiation of surgery. Blood glucose was maintained at 100 mg/dl until 24 h postoperatively. Blood samples were collected to determine changes in serum cytokine levels over time.

RESULTS

Patients' characteristics did not differ significantly between groups. Blood glucose levels were significantly higher in the CT group after surgery. Serum levels of tumor necrosis factor-α, interleukin-6, and high-mobility group box 1 were higher in the CT group than in the IIT group.

CONCLUSIONS

Use of IIT in the artificial pancreas during the perioperative period significantly decreased the inflammatory response. Moreover, we did not find evidence of hypoglycemia in those treated with IIT. This suggests that use of IIT in an artificial pancreas can be safe and effective for critically ill patients.