This study examined the effect of positive end-expiratory pressure (PEEP) on sevoflurane washout from anesthesia workstations using a test lung model. Two workstations (Perseus A500 and Carestation 650) were tested with fresh gas flows (FGF) of 2-8 L / min at PEEP levels of 0 and 8 cmH2O. Washout time was the interval for sevoflurane concentration to fall from 8% to 0%. In the Perseus A500, PEEP prolonged washout at 2 L / min (2562 92 s vs. 2266 17 s, p = 0.027), 4 L / min (1397 36 s vs. 1275 32 s, p = 0.012), and 6 L / min (756 8 s vs. 533 34 s, p = 0.006), but not at 8 L / min (115 2 s vs. 113 2 s, p = 0.23). In the Carestation 650, washout was prolonged at 2 L / min (5254 229 s vs. 4447 113 s, p = 0.013), 4 L / min (3597 101 s vs. 2911 230 s, p = 0.022), and 6 L / min (1816 94 s vs. 1492 115 s, p = 0.021), but not at 8 L / min (252 3 s vs. 212 35 s, p = 0.187). Our findings indicated that PEEP delayed anesthetic washout most at lower FGFs, which warrants caution in low-flow anesthesia. J. Med. Invest. 73 : 111-115, February, 2026.
Ishikawa et al. (Thu,) studied this question.