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).