Can anesthesia ventilators provide high-frequency ventilation?
We measured the tidal volumes (VT) delivered by two anesthesia ventilators (the Narkomed 2B and the Ohmeda 7800) to a model lung at frequencies of 60 breaths/min and 99-100 breaths/min under two conditions of compliance and resistance designed to mimic mild and severe adult respiratory distress syndrome (ARDS) (mild ARDS = S1 and severe ARDS = S2). The VT produced were measured with a pneumotachometer at the ventilator outflow and distal to the anesthesia circuit. With the Narkomed 2B, the VT measured at the entrance to the model lung decreased from 216 mL to 129 mL in S1, and from 152 mL to 88 mL in S2 as the ventilatory frequency increased from 60 to 99 breaths/min. With the Ohmeda 7800, the VT decreased from 213 mL to 118 mL in S1, and from 134 mL to 73 mL in S2 when the frequency was changed from 60 to 100 breaths/min. Since the delivered VT are similar to those previously reported to maintain adequate ventilation at these rates using standard high-frequency ventilation (HFV), it may be possible to use these newer anesthesia ventilators for this purpose.
Tessler
M J
MJ
Department of Anaesthesia, Jewish General Hospital, Montréal, Québec, Canada.
Ruiz-Neto
P P
PP
Finlayson
R
R
Chartrand
D
D
D000758:Anesthesia; D006612:High-Frequency Ventilation / Q000295:instrumentation*; D006801:Humans