title: Accuracy of ten isoflurane vaporisers in current clinical use.
abstract: There is a lack of independent data regarding the accuracy of isoflurane vaporisers in current clinical use. We studied the accuracy of 10 isoflurane vaporisers (six Penlon Sigma Delta, four Datex-Ohmeda Isotec 5) taken from our operating theatres and anaesthetic rooms. Isoflurane output was measured at a range of fresh gas flow rates using both 100% oxygen and a 1:2 oxygen:nitrous oxide mixture as carrier gas. Within a clinical range of fresh gas flow rates (1-6 l.min(-1)) the worst relative output deviation of each vaporiser was at least ±20%, with under-delivery of isoflurane being commoner than over-delivery. Relative output deviation ranged from -62% to +21%, which could lead to a risk of awareness or overdose. Despite the existence of an in-house calibration schedule, the vaporisers we found in current clinical use under- or occasionally over-delivered isoflurane to a dangerous and unpredictable extent.
authors.affiliation: Department of Anaesthesia, Queen Elizabeth Hospital Birmingham, Edgbaston, UK. johnmatthewkelly@doctors.net.uk
authors.forename: J M
authors.initials: JM
authors.lastname: Kelly
authors.forename: K-L
authors.initials: KL
authors.lastname: Kong
mesh_terms: D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004337:Drug Carriers; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage*; D009330:Nebulizers and Vaporizers / Q000592:standards*; D010100:Oxygen / Q000008:administration & dosage
chemical_list: D018685:Anesthetics, Inhalation; D004337:Drug Carriers; D007530:Isoflurane; D010100:Oxygen