Journal article
Hypoxic guard systems do not prevent rapid hypoxic inspired mixture formation
Sofie De Cooman, Caroline Schollaert, Jan FA Hendrickx, Philip J Peyton, Tom Van Zundert, Andre M De Wolf
JOURNAL OF CLINICAL MONITORING AND COMPUTING | SPRINGER HEIDELBERG | Published : 2015
Abstract
Because a case report and theoretical mass balances suggested that hypoxic guard systems may not prevent the formation of hypoxic inspired mixtures (FIO2 ≤ 21 %) over the clinically used fresh gas flow (FGF) range, we measured FIO2 over a wide range of hypoxic guard limits for O2/N2O and O2/air mixtures. After IRB approval, 16 ASA I-II patients received sevoflurane in either O2/N2O (n = 8) or O2/air (n = 8) using a Zeus(®) anesthesia machine in the conventional mode. After using an 8 L/min FGF with FDO2 = 25% for 10 min, the following hypoxic guard limits were tested for 4 min each, expressed as [total FGF in L/min; FDO2 in %]: [0.3;85], [0.4;65], [0.5;50], [0.7;36], [0.85;30], [1.0;25], [1...
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Funding Acknowledgements
Jan Hendrickx has received lecture fees, travel support, equipment loans, and support for the NAVAT meetings from AbbVie, Acertys, Air Liquide, Allied healthcare, Armstrong Medical, Baxter, Draeger, GE, Hospithera, Heinen und Lowensein, Intersurgical, Maquet, MDMS, MEDEC, Micropore. Molecular, NWS, Philips, Quantum Medical.