Pharmacokinetics of inhaled anaesthetics in a clinical setting: comparisonof desflurane, isoflurane and sevoflurane

The pharmacokinetic characteristics of desflurane, isoflurane and sevoflura ne (16 patients for each anaesthetic) were estimated from measurements of i nspired and end-expired agent concentrations and ventilation. obtained duri ng routine anaesthesia in patients undergoing maxillofacial surgery (mean a ge 38 yr, duration of anaesthesia approximately 2 h). A two-compartment mod el described the data adequately. Although isoflurane and sevoflurane have almost the same tissue/blood partition coefficients, significant difference s between substances were observed for the peripheral volume of distributio n (medians and ranges: desflurane, 612 (343-1850) ml(vapour) kg(bw)(-1); is oflurane, 4112 (1472-9396) ml(vapour); kg(bw)(-1); sevoflurane, 1634 (762-8 843) ml(vapour) kg(bw)(-1)) and the transport clearance from the central to the peripheral compartment (desflurane, 7.0 (4.4-11.1) ml(vapour) kg(bw)(- 1) min(-1); isoflurane, 30.7 (15.9-38.7) ml(vapour) kg(bw)(-1) min(-1); sev oflurane, 13.0 (9.8-22.4) ml(vapour) kg(bw)(-1) min(-1)). Thus, during clin ical anaesthesia the important characteristics of the compounds could be ob tained and compared between substances from simple data.