Isoflurane in a circle system with low gas flow.

Isoflurane was administered from a Goldman vaporizer to a circle breathing system with low fresh gas flows. The uptake and vapour concentration of isoflurane were compared in two groups of spontaneously breathing patients receiving oxygen alone (n = 19), or nitrous oxide and oxygen (n = 30). Anaesthesia was maintained successfully in all patients. The authors believe this to be a safe and economical way of delivering isoflurane.