Background and aim Compound A generation and accumulation in sevoflurane anaesthesia is dependent on fresh gas flow. We investigated the extent of generation of compound A.
Methods After Institutional Review Board approval and informed consent, patients with normal renal function were randomized to receive either sevoflurane (n = 33) or isoflurane (n = 43) minimal flow anaesthesia (0.5 L min−1) for at least 2 h under standardized conditions. Compound A concentrations were quantified and blood and urine samples were taken to assess renal involvement. Both groups were comparable.
Results No significant differences concerning blood chemistry and urine measurements were found. The maximum mean compound A concentration was observed 90 min after flow reduction being 40±9p.p.m. at a corresponding mean sevoflurane concentration of 2.1 ±0.5 vol%. Mean inspiratory compound A exposure was 102±l33p.p.mh−1.
Conclusion Compound A concentrations using 0.5 L min−1 fresh gas flow and a heated absorber were higher than previously published values using an inflow of 1 Lmin−1. Compound A exposure was similar to other clinical studies which did not show changes in renal and hepatic function.