Therapeutic Effect of Perioperative Mild Hypothermia on Postoperative Neurological Outcomes in Patients with Acute Stanford Type A Aortic Dissection.

Abstract

Background: Postoperative patients of acute Stanford type A aortic dissection (AAAD) often experience complications consisting of nervous system injury. Mild hypothermia therapy has been proven to provide the therapeutic effect of cerebral protection. We aimed to investigate the therapeutic effects of perioperative mild hypothermia on postoperative neurological outcomes in patients with AAAD.

Methods: A prospective randomized controlled study was conducted on adult patients undergoing aortic dissection surgery between February 2017 and December 2017. Patients in the treatment group underwent mild hypothermia (34° to 35°C) immediately after surgery, and in the conventional therapy group, patients were rewarmed to normal body temperature (36° to 37°C). Postoperative time to regain consciousness, postoperative serum neuron-specific enolase (NSE) and S-100β levels, cerebral tissue oxygen saturation, presence of delirium or permanent neurological dysfunction, intensive care unit (ICU) and hospital stay duration, and 28-day mortality were compared.

Results: We enrolled 55 patients who underwent AAAD surgery and were randomly allocated into to 2 groups, 27 patients in the treatment group and 28 patients in the conventional therapy group. Compared with the conventional therapy group, postoperative time to regain consciousness was much shorter for patients in the mild hypothermia group (12.65 hours, interquartile range [IQR] 8.28 to 23.82, versus 25.80 hours, IQR 14.00 to 59.80; P = .02), and the rate of regaining consciousness in 24 hours after surgery was much higher (74.07% versus 46.42%; P = .037). At the same time, the ICU stay of patients in the mild hypothermia therapy group was significantly shorter than that in the conventional therapy group (5.53 ± 3.13 versus 9.35 ± 8.76 days; P = .038). Cerebral tissue oxygen saturation, incidence of delirium or permanent neurological dysfunction, duration of hospital stay, and 28-day mortality showed no statistical difference. Postoperative serum NSE and S-100β levels increased compared with preoperative baseline values in both groups (P < .05), and the serum NSE levels of patients in the mild hypothermia therapy was significantly lower than the conventional therapy group 1 hour (P = .049) and 6 hours (P = .04) after surgery. There was no difference in the chest drainage volume or shivering between the 2 groups 24 hours after surgery.

Conclusions: Perioperative mild hypothermia therapy is able to significantly reduce brain cell injury and shorten the postoperative time to regain consciousness, thus improving the neurological prognosis of patients with AAAD.