Effects of dexmedetomidine on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing minimally invasive coronary artery bypass surgery

Abstract

OBJECTIVE:

This study aimed to investigate the effects of dexmedetomidine on cerebral oxygen saturation [Sct(O₂)] and postoperative cognitive function in elderly patients undergoing minimally invasive coronary artery bypass graft surgery.

METHODS:

Sixty elderly patients who received minimally invasive coronary artery bypass graft surgery were randomly equally divided into dexmedetomidine group (group D) and control group (group N). The patients in group D were pumped with 1 μg/kg dexmedetomidine for 15 min before incision, followed by continuous pumping at 0.3–0.5 μg/(kg·h) till the end of the operation. The patients in group N received same dose of normal saline during the operation. Sct(O₂) was monitored at pre-induction (T0), post-induction (T1), 30 min (T2) after single-lung ventilation, and after surgery (T3). Mini-mental state examination (MMSE) was used to assess the cognitive function at 1 day before, 72 hour and 7 days after surgery.

RESULTS:

Sct(O₂) level in group D was significantly higher than that in group N at T2 (P < 0.05). Sct(O₂) level was statistically lower at T2 than that at T0, T1 and T3 in the same group N (P < 0.05). At 72 h and 7d after operation, the incidence of cognitive dysfunction in group D was markedly lower than that in group N (P < 0.05), the MMSE score in group D was markedly higher than those in group N, but was significantly lower than that before surgery (P < 0.05).

CONCLUSION:

Dexmedetomidine can alleviate the decrease of Sct(O₂) during single-lung ventilation, improve postoperative cognitive function, and reduce the incidence of POCD in elderly patients with minimally invasive coronary artery bypass surgery.