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Hasanien AA, Albusoul RM. Knowledge of pulse oximetry among emergency and critical care nurses. Nurs Crit Care 2023. [PMID: 37632206 DOI: 10.1111/nicc.12971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
BACKGROUND The pulse oximeter is a simple, cost-effective and reliable device for estimating arterial blood oxygen saturation. Nurses are required to be knowledgeable in pulse oximeter use. Little is known about nurses' knowledge of pulse oximetry in the Middle East region. AIM To assess nurses' knowledge of pulse oximetry among emergency and critical care nurses and to explore predictors of nurses' knowledge of pulse oximetry. METHODS This is the second part of data analysis that was first presented in the 'proficiency in ECG' study conducted in Jordan. The original data used for both parts of analysis included a questionnaire with two tests; a knowledge of pulse oximeter test and an ECG proficiency test. Participants were asked to take, alone without receiving assistance, both tests. In this study, the second part of analysis, the focus is on the pulse oximeter test. The test consisted of 21 items that emphasize knowledge of basic physiological principles as well as device limitations; whether technical or interpretation. The test administration procedure also included asking participants to provide socio-demographic variables. In the original data collected in both parts of analysis, nurses working in the emergency department, cardiac care units or intensive care units from nine different hospitals (1 governmental, 6 private and 2 educational) and holding a bachelor degree or higher were asked to participate. RESULTS The total number of participating nurses was 210; out of 247 approached (response rate, 85%). The mean score in the nurses' knowledge of pulse oximetry test was 12.33 out of 21, corresponding to 58.7%. The clinical area currently working in predicted the knowledge of pulse oximetry test score after controlling for all other variables. Emergency department and intensive care unit nurses scored higher than cardiac care unit nurses by 1.86 and 1.63 points respectively (58.2% and 60% respectively). CONCLUSION Nurses consistently report inadequate education and training concerning pulse oximeter use and interpretation. A revision to hospital in-service education seminars and undergraduate nurses' curriculum to assure adequate preparation is needed. RELEVANCE TO CLINICAL PRACTICE Knowledge of pulse oximetry among emergency and critical care nurses is modest. This is a challenge worldwide. Predictors of nurses' knowledge of pulse oximetery are the clinical area currently working in (ICU and ED nurses are more knowledgeable than CCU nurses), proficiency in electrocardiography and taking an advanced cardiac life support course.
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Affiliation(s)
- Amer A Hasanien
- School of Nursing, Department of Clinical Nursing, The University of Jordan, Amman, Jordan
| | - Randa M Albusoul
- School of Nursing, Department of Clinical Nursing, The University of Jordan, Amman, Jordan
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de Oliveira DM, Lopes TR, Gomes FS, Rashid A, Silva BM. Ventilatory response to peripheral chemoreflex and muscle metaboreflex during static handgrip in healthy humans: evidence of hyperadditive integration. Exp Physiol 2023; 108:932-939. [PMID: 37036125 PMCID: PMC10988439 DOI: 10.1113/ep091094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 03/27/2023] [Indexed: 04/11/2023]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of peripheral chemoreflex and muscle metaboreflex integration on ventilation regulation, and what is the effect of integration on breathing-related sensations and emotions? What is the main finding and its importance? Peripheral chemoreflex and muscle metaboreflex coactivation during isocapnic static handgrip exercise appeared to elicit a hyperadditive effect with regard to ventilation and an additive effect with regard to breathing-related sensations and emotions. These findings reveal the nature of the integration between two neural mechanisms that operate during small-muscle static exercise performed under hypoxia. ABSTRACT Exercise augments the hypoxia-induced ventilatory response in an exercise intensity-dependent manner. A mutual influence of hypoxia-induced peripheral chemoreflex activation and exercise-induced muscle metaboreflex activation might mediate the augmentation phenomenon. However, the nature of these reflexes' integration (i.e., hyperadditive, additive or hypoadditive) remains unclear, and the coactivation effect on breathing-related sensations and emotions has not been explored. Accordingly, we investigated the effect of peripheral chemoreflex and muscle metaboreflex coactivation on ventilatory variables and breathing-related sensations and emotions during exercise. Fourteen healthy adults performed 2-min isocapnic static handgrip, first with the non-dominant hand and immediately after with the dominant hand. During the dominant hand exercise, we (a) did not manipulate either reflex (control); (b) activated the peripheral chemoreflex by hypoxia; (c) activated the muscle metaboreflex in the non-dominant arm by post-exercise circulatory occlusion (PECO); or (d) coactivated both reflexes by simultaneous hypoxia and PECO use. Ventilation response to coactivation of reflexes (mean ± SD, 13 ± 6 l/min) was greater than the sum of responses to separated activations of reflexes (mean ± SD, 8 ± 8 l/min, P = 0.005). Breathing-related sensory and emotional responses were similar between coactivation of reflexes and the sum of separate activations of reflexes. Thus, the peripheral chemoreflex and muscle metaboreflex integration during exercise appeared to be hyperadditive with regard to ventilation and additive with regard to breathing-related sensations and emotions in healthy adults.
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Affiliation(s)
- Diogo Machado de Oliveira
- Graduate Program in Translational MedicineFederal University of São Paulo (Unifesp)São PauloSPBrazil
| | - Thiago Ribeiro Lopes
- Graduate Program in Translational MedicineFederal University of São Paulo (Unifesp)São PauloSPBrazil
- Paulista Association for the Development of Medicine (SPDM)São PauloSPBrazil
| | - Felipe Silva Gomes
- Graduate Program in Translational MedicineFederal University of São Paulo (Unifesp)São PauloSPBrazil
| | - Anas Rashid
- Department of Neuroscience ‘Rita Levi Montalcini’University of TorinoTorinoItaly
- Graduate Program in Pulmonary MedicineUnifespSão PauloSPBrazil
| | - Bruno Moreira Silva
- Graduate Program in Translational MedicineFederal University of São Paulo (Unifesp)São PauloSPBrazil
- Graduate Program in Pulmonary MedicineUnifespSão PauloSPBrazil
- Department of PhysiologyUnifespSão PauloSPBrazil
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Comesaña-Campos A, Casal-Guisande M, Cerqueiro-Pequeño J, Bouza-Rodríguez JB. A Methodology Based on Expert Systems for the Early Detection and Prevention of Hypoxemic Clinical Cases. Int J Environ Res Public Health 2020; 17:E8644. [PMID: 33233826 PMCID: PMC7699904 DOI: 10.3390/ijerph17228644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/16/2020] [Accepted: 11/18/2020] [Indexed: 12/20/2022]
Abstract
Respiratory diseases are currently considered to be amongst the most frequent causes of death and disability worldwide, and even more so during the year 2020 because of the COVID-19 global pandemic. Aiming to reduce the impact of these diseases, in this work a methodology is developed that allows the early detection and prevention of potential hypoxemic clinical cases in patients vulnerable to respiratory diseases. Starting from the methodology proposed by the authors in a previous work and grounded in the definition of a set of expert systems, the methodology can generate alerts about the patient's hypoxemic status by means of the interpretation and combination of data coming both from physical measurements and from the considerations of health professionals. A concurrent set of Mamdani-type fuzzy-logic inference systems allows the collecting and processing of information, thus determining a final alert associated with the measurement of the global hypoxemic risk. This new methodology has been tested experimentally, producing positive results so far from the viewpoint of time reduction in the detection of a blood oxygen saturation deficit condition, thus implicitly improving the consequent treatment options and reducing the potential adverse effects on the patient's health.
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Affiliation(s)
- Alberto Comesaña-Campos
- Department of Design in Engineering, University of Vigo, 36208 Vigo, Galicia, Spain; (J.C.-P.); (J.-B.B.-R.)
| | - Manuel Casal-Guisande
- Department of Design in Engineering, University of Vigo, 36208 Vigo, Galicia, Spain; (J.C.-P.); (J.-B.B.-R.)
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Davies HJ, Williams I, Peters NS, Mandic DP. In-Ear SpO 2: A Tool for Wearable, Unobtrusive Monitoring of Core Blood Oxygen Saturation. Sensors (Basel) 2020; 20:E4879. [PMID: 32872310 PMCID: PMC7506719 DOI: 10.3390/s20174879] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [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] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023]
Abstract
The non-invasive estimation of blood oxygen saturation (SpO2) by pulse oximetry is of vital importance clinically, from the detection of sleep apnea to the recent ambulatory monitoring of hypoxemia in the delayed post-infective phase of COVID-19. In this proof of concept study, we set out to establish the feasibility of SpO2 measurement from the ear canal as a convenient site for long term monitoring, and perform a comprehensive comparison with the right index finger-the conventional clinical measurement site. During resting blood oxygen saturation estimation, we found a root mean square difference of 1.47% between the two measurement sites, with a mean difference of 0.23% higher SpO2 in the right ear canal. Using breath holds, we observe the known phenomena of time delay between central circulation and peripheral circulation with a mean delay between the ear and finger of 12.4 s across all subjects. Furthermore, we document the lower photoplethysmogram amplitude from the ear canal and suggest ways to mitigate this issue. In conjunction with the well-known robustness to temperature induced vasoconstriction, this makes conclusive evidence for in-ear SpO2 monitoring being both convenient and superior to conventional finger measurement for continuous non-intrusive monitoring in both clinical and everyday-life settings.
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Affiliation(s)
- Harry J. Davies
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, UK; (I.W.); (D.P.M.)
- Imperial Centre for Cardiac Engineering, Imperial College London, London SW7 2AZ, UK;
| | - Ian Williams
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, UK; (I.W.); (D.P.M.)
- Imperial Centre for Cardiac Engineering, Imperial College London, London SW7 2AZ, UK;
| | - Nicholas S. Peters
- Imperial Centre for Cardiac Engineering, Imperial College London, London SW7 2AZ, UK;
- National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London SW3 6LY, UK
| | - Danilo P. Mandic
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, UK; (I.W.); (D.P.M.)
- Imperial Centre for Cardiac Engineering, Imperial College London, London SW7 2AZ, UK;
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Maestri R, Robbi E, Lovagnini M, Bruschi C, La Rovere MT, Pinna GD. Arterial oxygen saturation during Cheyne-Stokes respiration in heart failure patients: does measurement site matter? Sleep Med 2019; 55:6-13. [DOI: 10.1016/j.sleep.2018.10.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/30/2018] [Accepted: 10/15/2018] [Indexed: 11/17/2022]
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Näslund E, Lindberg LG, Lund I, Näslund-Koch L, Larsson A, Frithiof R. Measuring arterial oxygen saturation from an intraosseous photoplethysmographic signal derived from the sternum. J Clin Monit Comput 2019; 34:55-62. [PMID: 30805761 PMCID: PMC6946764 DOI: 10.1007/s10877-019-00289-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/20/2019] [Indexed: 11/30/2022]
Abstract
Photoplethysmography performed on the peripheral extremities or the earlobes cannot always provide sufficiently rapid and accurate calculation of arterial oxygen saturation. The purpose of this study was to evaluate a novel photoplethysmography prototype to be fixed over the sternum. Our hypotheses were that arterial oxygen saturation can be determined from an intraosseous photoplethysmography signal from the sternum and that such monitoring detects hypoxemia faster than pulse oximetry at standard sites. Sixteen healthy male volunteers were subjected to incremental hypoxemia using different gas mixtures with decreasing oxygen content. The sternal probe was calibrated using arterial haemoglobin CO-oximetry (SaO2%). Sternal probe readings (SRHO2%) were then compared to SaO2% at various degrees of hypoxia. The time to detect hypoxemia was compared to measurements from standard finger and ear pulse oximeters. A significant association from individual regression between SRHO2% and SaO2% was found (r2 0.97), Spearman R ranged between 0.71 and 0.92 for the different inhaled gas mixtures. Limits of agreement according to Bland–Altman plots had a increased interval with decreasing arterial oxygen saturation. The sternal probe detected hypoxemia 28.7 s faster than a finger probe (95% CI 20.0-37.4 s, p < 0.001) and 6.6 s faster than an ear probe (95% CI 5.3–8.7 s, p < 0.001). In an experimental setting, arterial oxygen saturation could be determined using the photoplethysmography signal obtained from sternal blood flow after calibration with CO-oximetry. This method detected hypoxemia significantly faster than pulse oximetry performed on the finger or the ear.
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Affiliation(s)
- Erik Näslund
- Department of Surgical Sciences, Section of Anaesthesia & Intensive Care, Uppsala University, Uppsala, Sweden. .,Centre for Research & Development, Uppsala University/Region Gävleborg, Gävle, Sweden. .,Department of Anaesthesia, Gävle Hospital, 801 87, Gävle, Sweden.
| | - Lars-Göran Lindberg
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Iréne Lund
- Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | | | - Agneta Larsson
- Centre for Research & Development, Uppsala University/Region Gävleborg, Gävle, Sweden.,Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Robert Frithiof
- Department of Surgical Sciences, Section of Anaesthesia & Intensive Care, Uppsala University, Uppsala, Sweden
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Yossef Hay O, Cohen M, Nitzan I, Kasirer Y, Shahroor-Karni S, Yitzhaky Y, Engelberg S, Nitzan M. Pulse Oximetry with Two Infrared Wavelengths without Calibration in Extracted Arterial Blood. Sensors (Basel) 2018; 18:s18103457. [PMID: 30326552 PMCID: PMC6211094 DOI: 10.3390/s18103457] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/18/2018] [Accepted: 10/08/2018] [Indexed: 11/29/2022]
Abstract
Oxygen saturation in arterial blood (SaO2) provides information about the performance of the respiratory system. Non-invasive measurement of SaO2 by commercial pulse oximeters (SpO2) make use of photoplethysmographic pulses in the red and infrared regions and utilizes the different spectra of light absorption by oxygenated and de-oxygenated hemoglobin. Because light scattering and optical path-lengths differ between the two wavelengths, commercial pulse oximeters require empirical calibration which is based on SaO2 measurement in extracted arterial blood. They are still prone to error, because the path-lengths difference between the two wavelengths varies among different subjects. We have developed modified pulse oximetry, which makes use of two nearby infrared wavelengths that have relatively similar scattering constants and path-lengths and does not require an invasive calibration step. In measurements performed on adults during breath holding, the two-infrared pulse oximeter and a commercial pulse oximeter showed similar changes in SpO2. The two pulse oximeters showed similar accuracy when compared to SaO2 measurement in extracted arterial blood (the gold standard) performed in intensive care units on newborns and children with an arterial line. Errors in SpO2 because of variability in path-lengths difference between the two wavelengths are expected to be smaller in the two-infrared pulse oximeter.
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Affiliation(s)
- Ohad Yossef Hay
- Department of Physics/Electro-Optics Engineering, Jerusalem College of Technology, 21 Havaad Haleumi St., 91160 Jerusalem, Israel.
- Department of Electro-Optical Engineering, Ben-Gurion University of the Negev. 1 Ben-Gurion Blvd, 8410501 Beer Sheva, Israel.
| | - Meir Cohen
- Department of Physics/Electro-Optics Engineering, Jerusalem College of Technology, 21 Havaad Haleumi St., 91160 Jerusalem, Israel.
| | - Itamar Nitzan
- Department of Neonatology, Shaare Zedek Medical Center, Shmuel Bait St 12, 9103102 Jerusalem, Israel.
| | - Yair Kasirer
- Department of Neonatology, Shaare Zedek Medical Center, Shmuel Bait St 12, 9103102 Jerusalem, Israel.
| | - Sarit Shahroor-Karni
- Pediatric Intensive Care Unit, Shaare Zedek Medical Center, Shmuel Bait St 12, 9103102 Jerusalem, Israel.
| | - Yitzhak Yitzhaky
- Department of Electro-Optical Engineering, Ben-Gurion University of the Negev. 1 Ben-Gurion Blvd, 8410501 Beer Sheva, Israel.
| | - Shlomo Engelberg
- Department of Electrical and Electronics Engineering, Jerusalem College of Technology, 21 Havaad Haleumi St., 91160 Jerusalem, Israel.
| | - Meir Nitzan
- Department of Physics/Electro-Optics Engineering, Jerusalem College of Technology, 21 Havaad Haleumi St., 91160 Jerusalem, Israel.
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Salma RG, Abu-Naim H, Ahmad O, Akelah D, Salem Y, Midoun E. Vital signs changes during different dental procedures: A prospective longitudinal cross-over clinical trial. Oral Surg Oral Med Oral Pathol Oral Radiol 2018; 127:30-39. [PMID: 30219249 DOI: 10.1016/j.oooo.2018.08.002] [Citation(s) in RCA: 5] [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] [Received: 06/03/2018] [Revised: 07/13/2018] [Accepted: 08/03/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the magnitude of vital signs changes during 3 different dental treatments. STUDY DESIGN A prospective longitudinal multiarm cross-over clinical trial was conducted. Three dental procedures were performed on each participant: supragingival scaling, dental restoration under local anesthesia (LA), and exodontia under LA. The following parameters were recorded for in each dental procedure: body temperature (BT), respiratory rate (RR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), and peripheral oxygen saturation (SpO2). Three repeated measurements of each parameter were recorded at 3 phases of each procedure. RESULTS A total of 150 dental interventions were performed on 50 patients. Scaling caused a statistically significant rise in BT, RR, and SpO2, and a reduction in HR. Restorative treatment caused a statistically significant rise in SpO2 during LA. Exodontia caused a statistically significant rise in BT, RR, SBP (during the procedure), and SpO2 (during LA). CONCLUSIONS Scaling and restorative treatment did not significantly impact heart rate. The respiratory rate may temporarily rise during LA injection and some dental procedures, especially exodontia. Increase in systolic blood pressure and heart rate during exodontia was tolerated by healthy patients.
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Affiliation(s)
- Ra'ed Ghaleb Salma
- Assistant Professor, Department of Oral and Maxillofacial Surgery, Riyadh Elm University, Riyadh, Saudi Arabia.
| | - Horiyah Abu-Naim
- Teaching Assistant, Arab American University, Jenin, State of Palestine
| | - Osama Ahmad
- General practice, New You Medical Center, Riyadh, Saudi Arabia
| | - Doa'a Akelah
- General practice, Riyadh Elm University, Riyadh, Saudi Arabia
| | - Yasmin Salem
- General practice, Riyadh Elm University, Riyadh, Saudi Arabia
| | - Essma Midoun
- General practice, Riyadh Elm University, Riyadh, Saudi Arabia
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Long B, Koyfman A, Vivirito MA. Capnography in the Emergency Department: A Review of Uses, Waveforms, and Limitations. J Emerg Med 2017; 53:829-842. [PMID: 28993038 DOI: 10.1016/j.jemermed.2017.08.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 08/11/2017] [Indexed: 01/12/2023]
Abstract
BACKGROUND Capnography has many uses in the emergency department (ED) and critical care setting, most commonly cardiac arrest and procedural sedation. OBJECTIVE OF THE REVIEW This review evaluates several indications concerning capnography beyond cardiac arrest and procedural sedation in the ED, as well as limitations and specific waveforms. DISCUSSION Capnography includes the noninvasive measurement of CO2, providing information on ventilation, perfusion, and metabolism in intubated and spontaneously breathing patients. Since the 1990s, capnography has been utilized extensively for cardiac arrest and procedural sedation. Qualitative capnography includes a colorimetric device, changing color on the amount of CO2 present. Quantitative capnography provides a numeric value (end-tidal CO2), and capnography most commonly includes a waveform as a function of time. Conditions in which capnography is informative include cardiac arrest, procedural sedation, mechanically ventilated patients, and patients with metabolic acidemia. Patients with seizure, trauma, and respiratory conditions, such as pulmonary embolism and obstructive airway disease, can benefit from capnography, but further study is needed. Limitations include use of capnography in conditions with mixed pathophysiology, patients with low tidal volumes, and equipment malfunction. Capnography should be used in conjunction with clinical assessment. CONCLUSIONS Capnography demonstrates benefit in cardiac arrest, procedural sedation, mechanically ventilated patients, and patients with metabolic acidemia. Further study is required in patients with seizure, trauma, and respiratory conditions. It should only be used in conjunction with other patient factors and clinical assessment.
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Affiliation(s)
- Brit Long
- Department of Emergency Medicine, San Antonio Military Medical Center, Fort Sam Houston, Texas
| | - Alex Koyfman
- Department of Emergency Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Michael A Vivirito
- Department of Emergency Medicine, Joint Base Elmendorf-Richardson Medical Center, Joint Base Elmendorf-Richardson, Alaska
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O'Driscoll BR, Howard LS, Earis J, Mak V. BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax 2017; 72:ii1-ii90. [DOI: 10.1136/thoraxjnl-2016-209729] [Citation(s) in RCA: 316] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/03/2017] [Accepted: 02/12/2017] [Indexed: 12/15/2022]
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Torres-Peralta R, Losa-Reyna J, Morales-Alamo D, González-Izal M, Pérez-Suárez I, Ponce-González JG, Izquierdo M, Calbet JAL. Increased PIO2 at Exhaustion in Hypoxia Enhances Muscle Activation and Swiftly Relieves Fatigue: A Placebo or a PIO2 Dependent Effect? Front Physiol 2016; 7:333. [PMID: 27582710 PMCID: PMC4987359 DOI: 10.3389/fphys.2016.00333] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/20/2016] [Indexed: 12/30/2022] Open
Abstract
To determine the level of hypoxia from which muscle activation (MA) is reduced during incremental exercise to exhaustion (IE), and the role played by PIO2 in this process, ten volunteers (21 ± 2 years) performed four IE in severe acute hypoxia (SAH) (PIO2 = 73 mmHg). Upon exhaustion, subjects were asked to continue exercising while the breathing gas mixture was swiftly changed to a placebo (73 mmHg) or to a higher PIO2 (82, 92, 99, and 142 mmHg), and the IE continued until a new exhaustion. At the second exhaustion, the breathing gas was changed to room air (normoxia) and the IE continued until the final exhaustion. MA, as reflected by the vastus medialis (VM) and lateralis (VL) EMG raw and normalized root mean square (RMSraw, and RMSNz, respectively), normalized total activation index (TAINz), and burst duration were 8–20% lower at exhaustion in SAH than in normoxia (P < 0.05). The switch to a placebo or higher PIO2 allowed for the continuation of exercise in all instances. RMSraw, RMSNz, and TAINz were increased by 5–11% when the PIO2 was raised from 73 to 92, or 99 mmHg, and VL and VM averaged RMSraw by 7% when the PIO2 was elevated from 73 to 142 mmHg (P < 0.05). The increase of VM-VL average RMSraw was linearly related to the increase in PIO2, during the transition from SAH to higher PIO2 (R2 = 0.915, P < 0.05). In conclusion, increased PIO2 at exhaustion reduces fatigue and allows for the continuation of exercise in moderate and SAH, regardless of the effects of PIO2 on MA. At task failure, MA is increased during the first 10 s of increased PIO2 when the IE is performed at a PIO2 close to 73 mmHg and the PIO2 is increased to 92 mmHg or higher. Overall, these findings indicate that one of the central mechanisms by which severe hypoxia may cause central fatigue and task failure is by reducing the capacity for reaching the appropriate level of MA to sustain the task. The fact that at exhaustion in severe hypoxia the exercise was continued with the placebo-gas mixture demonstrates that this central mechanism has a cognitive component.
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Affiliation(s)
- Rafael Torres-Peralta
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas, Spain; Research Institute of Biomedical and Health Sciences, Instituto Universitario de Investigaciones Biomédicas y SanitariasLas Palmas, Spain
| | - José Losa-Reyna
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas, Spain; Research Institute of Biomedical and Health Sciences, Instituto Universitario de Investigaciones Biomédicas y SanitariasLas Palmas, Spain
| | - David Morales-Alamo
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas, Spain; Research Institute of Biomedical and Health Sciences, Instituto Universitario de Investigaciones Biomédicas y SanitariasLas Palmas, Spain
| | | | - Ismael Pérez-Suárez
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas, Spain; Research Institute of Biomedical and Health Sciences, Instituto Universitario de Investigaciones Biomédicas y SanitariasLas Palmas, Spain
| | - Jesús G Ponce-González
- Department of Physical Education, University of Las Palmas de Gran Canaria Las Palmas, Spain
| | - Mikel Izquierdo
- Department of Health Sciences, Public University of Navarra Tudela, Spain
| | - José A L Calbet
- Department of Physical Education, University of Las Palmas de Gran CanariaLas Palmas, Spain; Research Institute of Biomedical and Health Sciences, Instituto Universitario de Investigaciones Biomédicas y SanitariasLas Palmas, Spain
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Abstract
Gastrointestinal endoscopic sedation has improved procedural and patient outcomes but is associated with attendant risks of oversedation and hemodynamic compromise. Therefore, close monitoring during endoscopic procedures using sedation is critical. This monitoring begins with appropriate staff trained in visual assessment of patients and analysis of basic physiologic parameters. It also mandates an array of devices widely used in practice to evaluate hemodynamics, oxygenation, ventilation, and depth of sedation. The authors review the evidence behind monitoring practices and current society recommendations and discuss forthcoming technologies and techniques that are poised to improve noninvasive monitoring of patients under endoscopic sedation.
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Affiliation(s)
- Nadim Mahmud
- Department of Internal Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Tyler M Berzin
- Center for Advanced Endoscopy, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA, USA.
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Iyer NS, Koziel JR, Langhan ML. A qualitative evaluation of capnography use in paediatric sedation: perceptions, practice and barriers. J Clin Nurs 2015; 24:2231-8. [PMID: 25926380 DOI: 10.1111/jocn.12848] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2015] [Indexed: 11/30/2022]
Abstract
AIMS AND OBJECTIVES We explored perceptions about capnography for procedural sedation and barriers to use in a paediatric emergency department. BACKGROUND Capnography is a sensitive monitor of ventilation and is increasingly being studied in procedural sedation. While benefits have been found, it has not gained wide acceptance for monitoring of children during sedation. DESIGN A qualitative exploratory study was performed. METHODS Using a grounded theory approach, physicians and nurses from the paediatric emergency department participated in one-on-one interviews about their experiences with and opinions of capnography. An iterative process of data collection and analysis was used to inductively generate theories and themes until theoretical saturation was achieved. RESULTS Five physicians and 12 nurses were interviewed. Themes included: Experiences: Participants felt that procedural sedation is safe and adverse events are rare. Normal capnography readings reassured providers about the adequacy of ventilation. Knowledge: Despite experience with capnography, knowledge and comfort varied. Most participants requested additional education and training. Diffusion of Use: While participants expressed positive opinions about capnography, use for sedation was infrequent. Many participants felt that capnography use increased in other paediatric populations, such as patients with altered mental status, ingestions or head trauma. Barriers: Identified barriers to use included a lack of comfort with or knowledge about equipment, lack of availability of the monitor and cannulas, lack of inclusion of these supplies on a checklist for procedural sedation preparedness, and lack of a policy for use of capnography during sedation. CONCLUSION Capnography use during sedation in the paediatric emergency department is limited despite positive experiences and opinions about this device. Addressing modifiable barriers such as instrument availability, continuing education, and inclusion on a checklist may increase use of capnography during sedation. RELEVANCE TO CLINICAL PRACTICE Despite the perceived benefits, a broad implementation plan is required to introduce capnography successfully to the paediatric emergency department.
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Affiliation(s)
- Neel S Iyer
- Lake Erie College of Osteopathic Medicine, Lake Erie, PA, USA.,Yale School of Public Health and Epidemiology, New Haven, CT, USA
| | - Jeannette R Koziel
- Department of Pediatrics, Section of Emergency Medicine, Yale-New Haven Hospital, New Haven, CT, USA
| | - Melissa L Langhan
- Department of Pediatrics, Section of Emergency Medicine, Yale University School of Medicine, New Haven, CT, USA
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15
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ElMoaqet H, Tilbury DM, Ramachandran SK. Effect of concurrent oxygen therapy on accuracy of forecasting imminent postoperative desaturation. J Clin Monit Comput 2015; 29:521-31. [PMID: 25326787 DOI: 10.1007/s10877-014-9629-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/12/2014] [Indexed: 10/24/2022]
Abstract
Episodic postoperative desaturation occurs predominantly from respiratory depression or airway obstruction. Monitor display of desaturation is typically delayed by over 30 s after these dynamic inciting events, due to perfusion delays, signal capture and averaging. Prediction of imminent critical desaturation could aid development of dynamic high-fidelity response systems that reduce or prevent the inciting event from occurring. Oxygen therapy is known to influence the depth and duration of desaturation epochs, thereby potentially influencing the accuracy of forecasting of desaturation. In this study, postoperative pulse oximetry data were retrospectively modeled using autoregressive methods to create prediction models for [Formula: see text] and imminent critical desaturation in the postoperative period. The accuracy of these models in predicting near future [Formula: see text] values was tested using root mean square error. The model accuracy for prediction of critical desaturation ([Formula: see text] [Formula: see text]) was evaluated using meta-analytical methods (sensitivity, specificity, likelihood ratios, diagnostic odds ratios and area under summary receiver operating characteristic curves). Between-study heterogeneity was used as a measure of reliability of the model across different patients and evaluated using the tau-squared statistic. Model performance was evaluated in [Formula: see text] patients who received postoperative oxygen supplementation and [Formula: see text] patients who did not receive oxygen. Our results show that model accuracy was high with root mean square errors between 0.2 and 2.8%. Prediction accuracy as defined by area under the curve for critical desaturation events was observed to be greater in patients receiving oxygen in the 60-s horizon ([Formula: see text] vs. [Formula: see text]). This was likely related to the higher frequency of events in this group (median [IQR] [Formula: see text] [Formula: see text]) than patients who were not treated with oxygen ([Formula: see text] [Formula: see text]; [Formula: see text]). Model reliability was reflected by the homogeneity of the prediction models which were homogenous across both prediction horizons and oxygen treatment groups. In conclusion, we report the use of autoregressive models to predict [Formula: see text] and forecast imminent critical desaturation events in the postoperative period with high degree of accuracy. These models reliably predict critical desaturation in patients receiving supplemental oxygen therapy. While high-fidelity prophylactic interventions that could modify these inciting events are in development, our current study offers proof of concept that the afferent limb of such a system can be modeled with a high degree of accuracy.
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Pretto JJ, Roebuck T, Beckert L, Hamilton G. Clinical use of pulse oximetry: official guidelines from the Thoracic Society of Australia and New Zealand. Respirology 2013; 19:38-46. [PMID: 24251722 DOI: 10.1111/resp.12204] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 09/18/2013] [Indexed: 11/29/2022]
Abstract
Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and critical-care medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of age-specific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations. Pulse oximetry does not provide information about the adequacy of ventilation or about precise arterial oxygenation, particularly when arterial oxygen levels are very high or very low. Arterial blood gas analysis is the gold standard in these settings. Pulse oximetry may be inaccurate as a marker of oxygenation in the presence of dyshaemoglobinaemias such as carbon monoxide poisoning or methaemoglobinaemia where arterial oxygen saturation values will be overestimated. Technical considerations such as sensor position, signal averaging time and data sampling rates may influence clinical interpretation of pulse oximetry readings.
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Affiliation(s)
- Jeffrey J Pretto
- Department of Respiratory & Sleep Medicine, John Hunter Hospital, Newcastle, New South Wales, Australia; School of Medicine & Public Health, University of Newcastle, Newcastle, New South Wales, Australia
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17
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Mohr NM, Wessman B. Continuous capnography should be used for every emergency department procedural sedation. Ann Emerg Med 2013; 61:697-8. [PMID: 23684325 DOI: 10.1016/j.annemergmed.2012.11.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 10/31/2012] [Accepted: 11/09/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Nicholas M Mohr
- Department of Emergency Medicine, Division of Critical Care, Department of Anesthesia, University of Iowa College of Medicine, Iowa City, IA, USA
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18
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De Jong MJ, Schmelz J, Evers K, Bradshaw P, McKnight K, Bridges E. Accuracy and precision of buccal pulse oximetry. Heart Lung 2011; 40:31-40. [DOI: 10.1016/j.hrtlng.2009.12.002] [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] [Received: 10/12/2009] [Accepted: 12/10/2009] [Indexed: 11/26/2022]
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Choi SJ, Ahn HJ, Yang MK, Kim CS, Sim WS, Kim JA, Kang JG, Kim JK, Kang JY. Comparison of desaturation and resaturation response times between transmission and reflectance pulse oximeters. Acta Anaesthesiol Scand 2010; 54:212-7. [PMID: 19719816 DOI: 10.1111/j.1399-6576.2009.02101.x] [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] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In general, there is a response time between actual arterial hypoxemia and its detection by pulse oximeters. We compared the desaturation and resaturation response times between two types of pulse oximeters, transmission and reflectance pulse oximeters, to find out which oximeter has a more rapid response time. METHODS Thirty-three ASA 1 or 2 patients were enrolled in this study. A transmission pulse oximeter was placed on the index finger and a reflectance pulse oximeter was placed on the forehead and monitored simultaneously. After the induction of general anesthesia without pre-oxygenation, we waited until the oxygen saturation value of any of two pulse oximeters declined to 90%, and then mask ventilation was started with 100% oxygen. Oxygen saturation was recorded at an interval of 2 s during this time. RESULTS The desaturation response time of SpO(2) to 95% after apnea was 82.0 s (interquartile range: 67.0-98.5 s) vs. 94.0 s (interquartile range: 84.0-106.5 s) (P<0.001) and SpO(2) to 90% was 94.0 s (interquartile range: 75.5-109.5 s) vs. 100.0 s (interquartile range: 84.5-114.5 s) (P<0.001) in the reflectance and transmission oximeters, respectively. The resaturation response time from mask ventilation to 100% SpO(2) was 23.2+/-5.6 vs. 28.9+/-7.6 s (P<0.001) in the reflectance and transmission oximeters, respectively. CONCLUSION In clinical situations in which rapid changes in oxygen saturation are expected, we recommend the forehead reflectance pulse oximeter because it responds more quickly in detecting oxygen desaturation and resaturation compared with the transmission pulse oximeter.
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Affiliation(s)
- S J Choi
- Department of Anesthesiology and Pain Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-Ku, Seoul, Korea
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20
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Abstract
Pulse oximetry, a straightforward method for estimating arterial oxygen saturation, can detect hypoxemia early; it's used often and in a variety of settings. But what's not always clear is how frequently-or even whether-patients should be monitored, and unless guidelines are understood and followed, pulse oximetry can be misused or overused. This article reviews the technology and its limitations and discusses current guidelines and their implications for nurses.
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22
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Hetzler RK, Stickley CD, Kimura IF, LaBotz M, Nichols AW, Nakasone KT, Sargent RW, Burgess LPA. The effect of dynamic intermittent hypoxic conditioning on arterial oxygen saturation. Wilderness Environ Med 2009; 20:26-32. [PMID: 19364183 DOI: 10.1580/08-weme-or-218.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Increases in arterial oxygen saturation (SaO2) in response to intermittent hypoxic exposure (IHE) are well established. However, IHE protocols have historically involved static hypoxic environments. The effect of a dynamic hypoxic environment on SaO2 is not known. OBJECTIVE The purpose of this study was to examine the effect of dynamic IHE conditioning on SaO2 using the Cyclical Variable Altitude Conditioning Unit. METHODS Thirteen trained participants (9 males, age 30.1 +/- 9.2 years; 4 females, age 30.3 +/- 8.9 years) residing at or near sea level were exposed to a 7-week IHE conditioning protocol (mean total exposure time = 30.8 hours). Participants were exposed to a constantly varying series of hypobaric pressures simulating altitudes from sea level to 6858 m (22 500 feet) in progressive conditioning tiers, creating a dynamic hypoxic environment. SaO2 was evaluated using pulse oximetry (SpO2) 4 times: at 2740, 3360, and 4570 m, prior to and following the first 3 weeks of IHE, and at 4570, 5490, and 6400 m at the start and end of the final 4 weeks. RESULTS SpO2 improved 3.5%, 3.8%, and 4.1% at 2470, 3360, and 4570 m, respectively (P < .05), and 3.3%, 3.4%, and 5.9% at 4570, 5490, and 6400 m, respectively (P < .05). At 4570 m, SpO2 increased from 81.7% +/- 6.5% to 89.1% +/- 3.2% over the entire 7-week conditioning period. DISCUSSION The dynamic intermittent hypoxic conditioning protocol used in the present study resulted in an acclimation response, such that SpO2 was significantly increased at all altitudes tested, with shorter exposure times than generally reported.
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Affiliation(s)
- Ronald K Hetzler
- Department of Kinesiology and Rehabilitation Science, College of Education, University of Hawaii, Honolulu, HI 96822, USA
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23
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Abstract
This study compares resting arterial oxygen saturation as measured by pulse oximetry (Sp(O2)) among 818 Tibetans and 668 Han who were born and raised at altitudes between 3200 and 4300 m in Qinghai Province, Western China. Both Tibetans and Han show an increase in Sp(O2) values between the ages of 5 and 19 yr, and both groups show a decline after the third decade. However, mean, age-adjusted Sp(O2) values at rest do not differ significantly among growing Tibetans and Han aged 5 through 19 yr or among Tibetans and Han aged 20 through 51 yr. Therefore, the results of this study do not support the hypothesis that indigenous groups possess a superior arterial saturation while awake and at rest compared to lowlanders who have been born and raised at high altitude. Differences between adult Tibetan males and females approach statistical significance (females show higher values than males), while differences between adult Han males and females are not statistically significant. A review of the literature indicates that substantial interstudy variation exists in resting Sp(O2) values among Tibetans residing at high altitudes (between 2% and 4%, depending on the age of individuals measured) and may reflect differences in sample size, health of participants, instruments, probe location, and measurement protocols.
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Affiliation(s)
- Charles A Weitz
- Department of Anthropology, Temple University, Philadelphia, Pennsylvania 19122, USA.
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24
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Iobbi MG, Simonds AK, Dickinson RJ. Oximetry feedback flow control simulation for oxygen therapy. J Clin Monit Comput 2007; 21:115-23. [PMID: 17205376 DOI: 10.1007/s10877-006-9064-6] [Citation(s) in RCA: 12] [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: 09/14/2006] [Accepted: 11/26/2006] [Indexed: 11/28/2022]
Abstract
OBJECTIVES For many with Chronic Obstructive Pulmonary Disease (COPD), arterial oxygen saturation while receiving Long-Term Oxygen Therapy (LTOT) falls below an acceptable threshold (SpO(2) < 90%) for extended periods during routine daily activities. Using a closed-loop controller, we have evaluated a simulated method to automatically regulate the oxygen flow-rate in response to the measured oxygen demand. METHODS The closed-loop control scheme was implemented in a computer simulation on Simulink. Feedback from a pulse oximeter was used to maintain a target SpO(2) of 91% by changing the oxygen flow-rate to the patient. The controller was evaluated using a model to approximate the patient's arterial oxygen saturation response, including hypoxic events from artificial disturbances as well as recorded patient oximetry data. RESULTS The simulated controller produced improvement in arterial oxygen saturation throughout a wide range of disturbance frequencies. It suppressed disturbances with periods greater than a couple of minutes by more than -10 dB. When evaluated with patient oximetry recordings, the controller on average reduced the time spent with arterial blood saturation below threshold by 76%. Given the same volume of oxygen, the closed-loop controller also produced a 63% improvement compared to fixed flow-rate LTOT. CONCLUSIONS The simulation findings indicate an optimized matching between oxygen supply and demand, maintaining SpO(2) above threshold to improve therapeutic efficacy compared to standard LTOT.
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Affiliation(s)
- Mario G Iobbi
- Department of Bioengineering, South Kensington Campus, Imperial College London, London, SW7 2AZ, UK
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25
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Abstract
STUDY OBJECTIVES Current Medicare guidelines include an apnea-hypopnea index (AHI) > or = 15 events per hour, in which all hypopneas must be associated with 4% desaturation, to qualify for reimbursement for therapy with continuous positive airway pressure (CPAP). The present data demonstrate the effect of pulse oximeter differences on AHI. DESIGN Prospective study, blinded analysis. SETTING Academic sleep disorder center. PATIENTS One hundred thirteen consecutive patients (84 men and 29 women) undergoing diagnostic sleep studies and being evaluated for CPAP based on the Medicare indications for reimbursement. INTERVENTIONS Patients had two of four commonly used oximeters with signal averaging times of 4 to 6 s placed on different digits of the same hand during nocturnal polysomnography. MEASUREMENTS AND RESULTS Apneas and candidate hypopneas (amplitude reduction, > 30%) were scored from the nasal cannula airflow signal without reference to oximetry. Candidate hypopneas then were reclassified as hypopneas by each oximeter if they were associated with a 4% desaturation. Although the use of three oximeters resulted in a similar AHI (bias, < 1 event per hour), the fourth oximeter showed an overall increase in AHI of 3.7 events per hour. This caused 7 of 113 patients to have an AHI of > or = 15 events per hour (meeting the Medicare criteria for treatment) by one oximeter but not when a different oximeter was used. More importantly, when our analysis was limited to those patients whose number of candidate hypopneas made them susceptible to the threshold value of 15 events per hour, 7 of 35 patients who did not meet the Medicare AHI standard for treatment by one oximeter were reclassified when a different oximeter was used. CONCLUSION In the present study, oximeter choice affected whether the AHI reached the critical cutoff of 15 events per hour, particularly in those with disease severity that was neither very mild nor very severe. As oximetry is not a technique that produces a generic result, there are significant limitations to basing the definition of hypopnea on a fixed percentage of desaturation in determining the eligibility for CPAP therapy.
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Affiliation(s)
- Subooha Zafar
- New York University School of Medicine, New York, NY, USA
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Kolb JC, Farran P, Norris SR, Smith D, Mester J. Validation of Pulse Oximetry During Progressive Normobaric Hypoxia Utilizing a Portable Chamber. ACTA ACUST UNITED AC 2004; 29:3-15. [PMID: 15001800 DOI: 10.1139/h04-001] [Citation(s) in RCA: 16] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Validation of pulse oximetry in commercially available normobaric hypoxic chambers (NHC) has not been previously reported. The present study examined the validity of pulse oximetry (SpO2) against direct measurements of arterial oxygen saturation (SaO2) via co-oximetry (AVOXimeter 4000) in 13 young adults age 21.3 ± 0.6 years. Over a period of 2.5 hrs, the inspired fraction of oxygen inside a NHC (Hypoxico, Inc.) was progressively reduced from 20.9% to 11.5%. Measurements of SaO2 at baseline and at 15, 30, 60, 90, 120, and 150 min during the hypoxic exposures were compared with SpO2 estimates of oxygen saturation (Nellcor 295) using reflectance (RS-10, temporal) and transmission (D-25, finger) sensors. Regression analysis and methods for assessing agreement (bias, b; precision, p) of SaO2 with SpO2 were similar (R2 = 0.92, 0.89; b = 0.016, −0.47; p = 2.47, 3.03; RS-10 and D-25, respectively). When SaO2 < 85%, RS-10 had greater validity than D-25 (R2 = 0.73, 0.56; b = 1.38, 1.13; p = 2.72, 4.34; RS-10 and D-25, respectively). In light of these findings, caution should be exercised when monitoring individuals with pulse oximetry during desaturation episodes below 85%. When employing frequent NHC exposures, a priori validation of SpO2 utilized to assess blood oxygen status appears warranted. Key words: oxygen saturation, co-oximetry, altitude
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Affiliation(s)
- Jon C Kolb
- Faculty of Kinesiology, Univ. of Calgary, Canada
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Abstract
During exercise, pulse oximetry is problematic due to motion artifact and altered digital perfusion. New pulse oximeter technology addresses these issues and may offer improved performance. We simultaneously compared Nellcor N-395 (Oxismart XLTM) pulse oximeters with an RS-10 forehead sensor (RS-10), a D-25 digit sensor (D-25), and the Ivy 2000 (Masimo SETTM)/LNOP-Adt digit sensor (Ivy) to arterial blood oxygen saturation (Sa(O(2))) by cooximetry. Nine normal subjects, six athletes, and four patients with chronic disease exercised to maximum oxygen consumption (VO(2 max)) under various conditions [normoxia, hypoxia inspired oxygen fraction (FI(O(2))) = 0.125; hyperoxia, FI(O(2)) = 1.0]. Regression analysis for normoxia and hypoxic data was performed (n = 161 observations, Sa(O(2)) = 73-99.9%), and bias (B) and precision (P) were calculated. RS10 offered greater validity than the other two devices tested (y = 1.009x - 0.52, R(2) = 0.90, B+/-P = 0.3 +/- 2.5). Finger sensors had low precision and a significant negative bias (D-25: y = 1.004x - 2.327, R(2) = 0.52, B+/-P = -2.0 +/- 7.3; Ivy: y = 1.237x - 24.2, R(2) = 0.78, B+/-P = -2.0 +/- 5.2). Eliminating measurements in which heart rate differed by >10 beats/min from the electrocardiogram value improved precision minimally and did not affect bias substantially (B+/-P = 0.5 +/- 2.0, -1.8 +/- 8.4, and -1.25+/-4.33 for RS-10, D-25, and Ivy, respectively). Signal detection algorithms and pulse oximeter were identical between RS-10 and D-25; thus the improved performance of the forehead sensor is likely because of sensor location. RS-10 should be considered for exercise testing in which pulse oximetry is desirable.
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Affiliation(s)
- Yoshiki Yamaya
- Department of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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