The effect of cardiac output changes on end-tidal volatile anaesthetic concentrations.
Cardiac output is a major determinant of the rate of uptake of volatile anaesthetic agents. Theoretical work suggests a 30% change in cardiac output will produce a measurable change in end-tidal volatile agent. We present three patients in whom significant changes in haemodynamic parameters, consistent with a large fall in cardiac output, were accompanied by an increase in end-tidal volatile agent concentrations. The changes in end-tidal volatile agent concentrations were comparable in magnitude but in the opposite direction to the changes in end-tidal CO2. Clinically, an unexplained change in end-tidal concentration of a volatile agent may signify a large change in cardiac output.
Kennedy
R R
RR
Department of Anaesthesia, The Christchurch School of Medicine, New Zealand.
Baker
A B
AB
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018685:Anesthetics, Inhalation / Q000493:pharmacokinetics; D002302:Cardiac Output; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000493:pharmacokinetics; D008738:Methyl Ethers / Q000493:pharmacokinetics; D000077149:Sevoflurane; D013990:Tidal Volume
D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D007530:Isoflurane