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Performance of adjustable pressure-limiting (APL) valves in two different modern anaesthesia machines


Thomas, J; Weiss, M; Schmidt, A R; Buehler, P K (2017). Performance of adjustable pressure-limiting (APL) valves in two different modern anaesthesia machines. Anaesthesia, 72(1):28-34.

Abstract

The ability to gently ventilate a patient's lungs using a self-inflating bag requires a properly working adjustable pressure-limiting (APL) valve. We compared the performance of the APL valves of the GE Aisys CS(2) and the Draeger Fabius anaesthetic machines during closure and opening from 1-20 and from 20-1 cmH2 O, using standardised experimental baby and adolescent patient lung models. Airway pressures and inspiratory tidal volumes were measured using an ASL-5000 test lung and a GE Aisys CS(2) near-patient spirometry sensors. In both lung models, the GE Aisys CS(2) APL valves demonstrated non-linear behaviours for airway pressures and for inspiratory tidal volumes, with a sharp increase at set APL pressure levels of 8-10 cmH2 O. With further closure of the GE Aisys CS(2) APL valves up to 20 cmH2 O, inspiratory tidal volumes decreased to ~50% of the highest values measured. Airway pressures in the Draeger Fabius APL valves demonstrated a near linear increase and decrease. Airway pressure values measured in the Draeger Fabius were never higher than those set by the APL valves, whereas in the GE Aisys CS(2) , they considerably exceeded set pressures (by up to 27 cmH2 O). We conclude that the performance of the GE Aisys CS(2) APL valve does not allow safe bag-assisted ventilation of a patient's lungs.

Abstract

The ability to gently ventilate a patient's lungs using a self-inflating bag requires a properly working adjustable pressure-limiting (APL) valve. We compared the performance of the APL valves of the GE Aisys CS(2) and the Draeger Fabius anaesthetic machines during closure and opening from 1-20 and from 20-1 cmH2 O, using standardised experimental baby and adolescent patient lung models. Airway pressures and inspiratory tidal volumes were measured using an ASL-5000 test lung and a GE Aisys CS(2) near-patient spirometry sensors. In both lung models, the GE Aisys CS(2) APL valves demonstrated non-linear behaviours for airway pressures and for inspiratory tidal volumes, with a sharp increase at set APL pressure levels of 8-10 cmH2 O. With further closure of the GE Aisys CS(2) APL valves up to 20 cmH2 O, inspiratory tidal volumes decreased to ~50% of the highest values measured. Airway pressures in the Draeger Fabius APL valves demonstrated a near linear increase and decrease. Airway pressure values measured in the Draeger Fabius were never higher than those set by the APL valves, whereas in the GE Aisys CS(2) , they considerably exceeded set pressures (by up to 27 cmH2 O). We conclude that the performance of the GE Aisys CS(2) APL valve does not allow safe bag-assisted ventilation of a patient's lungs.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Children's Hospital Zurich > Clinic for Surgery
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:January 2017
Deposited On:14 Mar 2017 09:53
Last Modified:15 Mar 2017 09:05
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0003-2409
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1111/anae.13689
PubMed ID:27988964

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