Comparing the washout profiles of desflurane in various anesthesia workstations

Background: Malignant hyperthermia can be induced by halogenated anesthetics that are inadvertently retained in the anesthetic circuit. Therefore, we compared the desflurane washout times of three different anesthesia workstations. Methods: The AisysTM, Fabius GSTM, and Pro-nextTM workstations were selected and each workstation was tested after connecting a 1-L test lung to the patient side and volume-controlled ventilation was performed with 500 mL tidal volume, a respiratory rate of 10/min, and O2 flow of 1.5 L/min. When the end-tidal concentration of desflurane reached 6%, the flow of desflurane was stopped and the time until desflurane had completely disappeared from the circuit under continuous gas flow was measured. Results: The mean washout times were 175 ± 5.5 s for the AisysTM system, 216 ± 13s for the Fabius GSTM system, and 254 ± 31 s for the Pro-nextTM system. The calculated washout times per circuit capacity were 175 ± 5.5 s/L for the AisysTM system, 216 ± 13 s/L for the Fabius GSTM system and 254 ± 31 s/L for the Pro-nextTM system. The AisysTM system provided significantly shorter times compared with the other systems. Conclusion: The AisysTM system provided the shortest washout time for desflurane. These findings may help prevent malignant hyperthermia among patients who are preparing to undergo anesthesia. Correspondence to: Shinsuke Hamaguchi, MD, PhD, Professor and Chairman, Department of Anesthesia and Pain Medicine, Dokkyo Medical University School of Medicine, 880 Kitakobayashi, Mibu, Tochigi 321-0293, Japan; Tel: +81282-86-1111 (ext. 2771); Fax: +81-282-86-0478; E-mail: [email protected]