Contemporary anesthesia ventilators incur a significant "oxygen cost".
OBJECTIVE
Anesthesia ventilators use oxygen or oxygen/air mixtures to drive the bellows during controlled ventilation. As a practitioner may find himself in a situation that the only available oxygen source is a compressed oxygen cylinder, it is important to know the oxygen consumption of anesthesia ventilators during controlled ventilation.


METHODS
We tested the Datex-Ohmeda 7900 ventilator mounted on an Excel 210 anesthesia machine under a variety of conditions. For comparison, we also tested the Ohmeda 7800 and the Dräger AV-2 ventilator under control conditions. All experiments were performed using a test lung.


RESULTS
The oxygen consumption of the AV-2 and the Datex-Ohmeda ventilators averaged 302 +/- 17 L x hr(-1) and 564 +/- 68 to 599 +/- 56 L x hr(-1), respectively (P < 0.01 AV-2 vs 7800 and 7900). When using an E-type cylinder, this would result in a mean time to alarm of 93 min and 54 to 57 min, respectively. Decreased lung compliance increased the oxygen consumption to 848 +/- 16 L x hr(-1).


CONCLUSIONS
Machine-driven mechanical ventilation incurs a significant "oxygen cost." We show that the amount of oxygen consumed by mechanical ventilation with contemporary anesthesia ventilators is influenced by patient-dependent factors and may greatly exceed the amount of oxygen delivered to the patient.
Klemenzson
Gudmundur K
GK
Department of Anesthesia and Critical Care, Landspitalinn University Hospital of Iceland, Reykjavik, Iceland.
Perouansky
Misha
M
D000403:Airway Resistance / Q000502:physiology; D000769:Anesthesia, Inhalation / Q000295:instrumentation*; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D008170:Lung Compliance / Q000502:physiology; D010100:Oxygen / Q000008:administration & dosage; D010101:Oxygen Consumption / Q000502:physiology; D011312:Pressure; D012121:Respiration, Artificial / Q000379:methods; D013990:Tidal Volume / Q000502:physiology; D013997:Time Factors; D012122:Ventilators, Mechanical
D010100:Oxygen