Relationship between volatile anesthetics and functional outcomes in patients with subarachnoid hemorrhage

Volatile anesthetics have been suggested to exert neuroprotective effects in patients with subarachnoid hemorrhage caused by a ruptured cerebral aneurysm. However, their effects on functional outcomes remain unverified. We assessed the association between volatile anesthetics and functional outcomes in patients with subarachnoid hemorrhage.

Using data from the Japanese Diagnosis Procedure Combination inpatient database, patients with subarachnoid hemorrhage, aged = 18 years, and undergoing any procedures for aneurysm treatment were selected. Patients were categorized into those who received volatile anesthetics and those who did not. The primary outcome was a composite of in-hospital death or impaired functional outcome at discharge. The secondary outcomes included in-hospital mortality, postoperative cerebral infarction, postoperative acute hydrocephalus, tracheostomy, hospital stay, and total healthcare costs. After 1:1 propensity-score matching, a generalized linear model or linear model was applied for each outcome, with cluster-robust standard error adjustment. Interaction analysis was also conducted for the primary outcome and in-hospital mortality.

Overall, 35,097 matched pairs were generated. No significant difference was noted in the primary outcome between the two groups (total intravenous anesthetics: 44.5%; volatile anesthetics: 44.1%; odds ratio 0.99, 95% confidence interval [CI] 0.93-1.06, p = 0.84). However, in-hospital mortality differed significantly between the groups (total intravenous anesthetics: 9.3%; volatile anesthetics: 8.7%; odds ratio 0.89, 95% CI 0.82-0.97, p < 0.01). Other secondary outcomes showed no significant group differences. Interaction analysis indicated that volatile anesthetics worsened outcomes among patients with impaired consciousness at admission.

Volatile anesthetic use was not associated with improved functional outcomes in patients with subarachnoid hemorrhage. In patients presenting with impaired consciousness, volatile anesthetics were associated with poorer outcomes, although this finding should be interpreted with caution, given the observational nature of the study.