The Effect of Desflurane Versus Sevoflurane on Postoperative Recovery

Background: Patients over the age of 65 years are at increased risk for developing delirium and cognitive complications in the immediate postoperative period after noncardiac surgeries, resulting in increased morbidity and mortality. Previous small studies have shown beneficial effects of desflurane on postoperative cognitive recovery, which has been explained by the more rapid onset and offset of anesthesia as compared to sevoflurane. However, there are very limited data on the effect of desflurane on postoperative recovery and time until criteria for discharge from post-anesthesia care unit (PACU) are fulfilled in elderly patients undergoing minor-to moderate-risk noncardiac surgery. Therefore, the investigators will test the primary hypothesis that general anesthesia with desflurane significantly reduces the time between discontinuation of volatile anesthetics after the end of surgery and reaching ready for discharge from PACU criteria, which are defined as reaching amodified Aldrete score ≥ 12, as compared to sevoflurane in patients ≥ 65 years of age undergoing minor-to moderate-risk noncardiac surgery.

Methods: The investigators will include 190 patients ≥ 65 years of age undergoing minor-to moderate-risk noncardiac surgery in this randomized, double-blinded clinical trial. Patients will be randomly assigned to receive desflurane or sevoflurane throughout surgery for maintenance of anesthesia. The primary outcome will be the time between discontinuation of desflurane until full postoperative recovery assessed via consecutive Aldrete Score assessments in the first 90 minutes after arrival at PACU. Aldrete Score will be assessed upon arrival at PACU and thereafter in five-minute intervals.

Statistics: The primary outcome, the time from discontinuation of volatile anesthetic agent to reaching discharge criteria from PACU assessed via Aldrete Score values,will be compared between both study groups using a Mann-Whitney-U test. Furthermore, the investigators will perform a median regression model for time to Aldrete score ≥ 12 points accounting for group as a factor as well as further covariables e.g. age, gender, weight.

Level of originality: Data regarding the effects of general anesthesia using desflurane in comparison to sevoflurane on postoperative recovery are mainly available from small studies. So far, there is very limited data on postoperative recovery and neurocognitive rehabilitation in elderly patients. However, this patient population is at a higher risk of developing postoperative neurocognitive complications, and could therefore, profit from a more rapid resurgence from anesthesia and postoperative recovery. Moreover, outpatient surgery will be becoming even more important. Therefore, reduction in postoperative PACU stay in combination with a decreased risk to develop postoperative delirium or cognitive dysfunction, might therefore improve outcome in this patient population as well.

Inclusion criteria

• ≥ 65 years of age at time of surgery
• Scheduled for elective minor- to moderate-risk noncardiac surgery with expected time of surgery ≤ 2 hours

Exclusion criteria

• Patients undergoing emergency surgery
• Patients undergoing bariatric surgery
• History of documented dementia / neurologic disorder
• Language, vision, or hearing impairments that may compromise cognitive assessments
• History of malignant hyperthermia
• History of structural muscle disease