1-1-12 one-step wash-in scheme for desflurane-nitrous oxide low-flow anesthesia: rapid and predictable induction.

ABSTRACT: We propose a 1-1-12 wash-in scheme for desflurane-nitrous oxide (N2O) low-flow anesthesia. The objective of our study was to determine the time to achieve alveolar concentration of desflurane (FAD) at 1, 2, 3, 4, 5, and 6%.We enrolled 106 patients scheduled for elective surgery under general anesthesia. After induction and intubation, wash-in was started with a fresh gas flow (FGF) of N2O?:?O2 1?:?1?L?min(-1) and vaporizer concentration of desflurane (FD) of 12%. Ventilation was controlled to maintain PACO2 at 30-35?mmHg.The FAD rose rapidly from 0 to 4% in 2?min in a linear manner in 0.5?min increments. An FAD of 6% was achieved in 4?min in a linear fashion from FAD of 4% but in 1?min increments. An FAD of 1 to 6% occurred at 0.6, 1, 1.5, 2, 3, and 4?min. Heart rate during wash-in showed a statistically, albeit not clinically, significant pattern of increase. By contrast, blood pressure slightly decreased during this period.We developed a 1-1-12 wash-in scheme using a FGF of N2O?:?O2 1?:?1?L?min(-1) and FD of 12% for desflurane-nitrous oxide low-flow anesthesia. A respective FAD of 1, 2, 3, 4, 5, and 6% can be expected at 0.6, 1, 1.5, 2, 3, and 4?min.

SUBMITTER: Sathitkarnmanee T 

PROVIDER: S-EPMC4065730 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature