Effects of inhalation versus total intravenous anaesthesia on long-term mortality in older patients after noncardiac surgery: a retrospective observational study

Background Whether the anaesthetic agent used influences postoperative mortality in older patients remains unclear. We evaluated the effect of total intravenous anaesthesia (TIVA) vs inhalation anaesthesia on long-term mortality in older patients after noncardiac surgery. Methods We retrospectively analysed 45,879 patients aged ≥60 yr who underwent noncardiac surgery under general anaesthesia (for ≥2 h) between January 2011 and June 2019. They were divided into two groups according to the type of maintenance anaesthetic. The primary outcome was all-cause mortality within 1 yr after surgery. Secondary outcomes included postoperative complications (postoperative pulmonary complications, perioperative adverse cardiovascular events, and acute kidney injury), and 3-yr and 5-yr mortality after surgery. The stabilised inverse probability of treatment weighting method was used to adjust for potential confounders. Results Among 45,879 patients, 7273 (15.9%) patients received TIVA and 38,606 (84.1%) patients received inhalation anaesthesia. After adjustment with inverse probability of treatment weighting, there was no association between the type of anaesthetic agent and 1-yr mortality (hazard ratio=0.95; 95% confidence interval [CI] 0.84−1.08). Results for 3-yr and 5-yr mortality were similar. However, inhalation anaesthesia was associated with increased risk of postoperative complications (odds ratio [OR]=1.30; 95% CI 1.22−1.37 for postoperative pulmonary complications, OR=1.34; 95% CI 1.22−1.48 for perioperative adverse cardiovascular events, and OR=2.19; 95% CI 1.88−2.57 for acute kidney injury). In the subgroup analysis, the choice of anaesthetic agent showed differential effects on 1-yr mortality for female patients and emergency surgery. Conclusion The choice of anaesthetic agent during the intraoperative period was not associated with 1-yr mortality in older patients undergoing noncardiac surgery. Clinical trial registration Clinical Research Information Service of the Republic of Korea (KCT 0006363).