Most Hemodynamically Stable Method for Change From High to Low Anesthesia Flow: A Randomized Controlled Trial Comparing State Entropy, High Fresh Gas Flow for 10 Minutes, and 0.8 Ratio of End-Expired Agent Concentration to Inspired Agent Concentration.

This study was undertaken to determine the most hemodynamically stable method to low-flow anesthesia (LFA) between 10-minute administration of high fresh gas flow, 0.8 equilibration ratio (Fe/Fi), and state entropy (SE) between 40 and 60, a marker for adequate depth of anesthesia. Change from high fresh gas flow to LFA was done in 3 groups of 30 patients each: group T (time): 10 minutes; group R (ratio): Fe/Fi = 0.8, and group SE: SE = 40 to 50. A decrease in mean blood pressure or heart rate was treated with ephedrine or atropine, with study termination at more than 2 boluses of either. In group SE, no patient required ephedrine or atropine. The requirement for ephedrine was statistically higher in groups R and T than group SE. Atropine requirement was statistically higher in group R vs groups T and SE. In group R, the mean (SD) time to LFA was 43.9 (20.37) minutes, and in group SE was 151.9 (74.4) seconds. Hypotension or bradycardia did not occur when LFA was started at SE of 40 to 50 after anesthesia induction compared with LFA at 10 minutes, which caused hypotension, and Fe/Fi of 0.8, which caused hypotension and bradycardia. PMID: 31612844 [PubMed - in process]
Source: AANA Journal - Category: Anesthesiology Authors: Tags: AANA J Source Type: research