Dexmedetomidine and 5-year Outcome in Elderly Patients After Surgery

Delirium is a frequent postoperative complication; a systematic review revealed that postoperative delirium occurs in 36.8% of surgical patients, and its prevalence increases with age. The occurrence of delirium is associated with worse long-term outcomes including worse functional recovery, decline in cognitive function, and increased mortality rate. Surgical stress, pain, and sleep disturbances are important factors leading to postoperative delirium in the elderly.

Dexmedetomidine is a highly selective alpha-2 adrenoreceptor agonist that provides anti-anxiety, sedation, and modest analgesia with minimal respiratory depression. For mechanically ventilated intensive care unit (ICU) patients, dexmedetomidine sedation improves the quality of sleep, decreases the incidence of delirium, and shortens the duration of ICU stay. For patients undergoing surgery, perioperative dexmedetomidine relieves the severity of stress response, decreases the requirement of anesthetics, and improves postoperative analgesia.

In the previous stage of the current study, 700 elderly patients who were admitted to the ICU after noncardiac surgery were recruited and randomized into two groups (dexmedetomidine group and placebo [normal saline] group). The results showed that prophylactic low-dose dexmedetomidine infusion during the early postoperative period ameliorated the subjective sleep quality and decreased the incidence of delirium (22.6% [79/350] with placebo vs. 9.1% [32/350] with dexmedetomidine; odds ratio 0.35, 95% confidence interval 0.22 to 0.54; p < 0.0001). The investigators hypothesize that low-dose dexmedetomidine infusion may also improve long-term outcome in this patient population.

The purpose of this 5-year follow-up study is to evaluate whether prophylactic low-dose dexmedetomidine infusion during the early postoperative period can improve the 5-year outcomes in elderly patients recruited in the previous randomized controlled trial.