Effects of different anesthetic regimens on postoperative cognitive function of elderly patients undergoing thoracic surgery: a double-blinded randomized controlled trial

Postoperative cognitive dysfunction (POCD) is a serious surgical complication. We assessed the different POCD incidences between anesthesia using sevoflurane and sevoflurane combined with dexmedetomidine, with propofol-based sedation in elderly patients who underwent a thoracic surgical procedure.

A total of 90 patients aged 65 to 80 years old who underwent a thoracic surgical procedure at our hospital and 15 nonsurgical participants as controls, were enrolled in this study. Patients were divided in a randomized 1:1:1 ratio into 3 groups. All participants were randomized into a trial with three anesthesia groups (P, PS, PSD) or a control group (C) of healthy matches. All trial groups received distinct anesthetic combinations during surgery, while controls mirrored patient criteria.Group P (propofol and remifentanil were maintained during the surgery), Group PS (propofol, remifentanil, and sevoflurane were maintained during the surgery), and Group PSD (propofol, remifentanil, sevoflurane, and dexmedetomidine were maintained during the surgery).All participants were rated using a series of cognitive assessment scales before and three days after surgery. All participants were interviewed over the telephone, 7 days, 30 days, and 90 days postoperatively.

POCD incidences in the PSD (combined anesthetization with propofol, sevoflurane, and dexmedetomidine) group was significantly lower than that in the PS (combined anesthetization with propofol and sevoflurane) group, 1 day post-surgery (10.0% vs. 40.0%, P = 0.008), and the results were consistent at 3 days post-surgery. When the patients were assessed 7 days, 30 days, and 90 days postoperatively, there was no significant difference in POCD incidence among the three groups. Multivariate logistic regression analysis of POCD one day after surgery showed that education level was negatively correlated with incidence of POCD (P = 0.018) and single lung ventilation time was positively correlated with incidence of POCD (P = 0.001).

For elderly patients who underwent a thoracic surgical procedure, dexmedetomidine sedation shows an obvious advantage on improving short-term POCD incidence, which is caused by sevoflurane.