Comparative effects of fentanyl versus sufentanil on cerebral oxygen saturation and postoperative cognitive function in elderly patients undergoing open surgery

This study was aimed to systematically evaluate the effects of fentanyl and sufentanil on intraoperative cerebral oxygen saturation changes and postoperative cognitive function in elderly patients undergoing open surgery. Ninety-six elderly patients who had undergone open surgery under general anesthesia were randomly divided into fentanyl group (F group, anesthesia by fentanyl, 4 g/kg) and sufentanil group (S group, anesthesia by sufentanil, 0.4 µg/kg). There were no significant differences between the F group and S group in the general characteristics of patients. Compared to the F group, the S group had a better effect on suppressing the stress response, maintaining a stable hemodynamic status and achieving better anesthesia effects. The anesthesia recovery time of the S group was significantly shorter than that of the F group. There was no significant difference between the two groups in the intraoperative and postoperative agitation. Patient’s waking time and extubation time were significantly shorter in the S group than the F group. The VAS scores in the S group were significantly lower than those in the F group at each time point. The Ramsay scores in the S group were significantly higher than those in the F group at each time point. The cerebral oxygen saturation (SctO2) levels in both groups were significantly increased following anesthesia induction and intubation compared to that of the awake state (P < 0.05), and SctO2 was significantly decreased during the surgery in both groups. The changes in SctO2 levels were not significantly different between the two groups (P > 0.05). The SctO2 level was significantly higher during surgery than that after intubation. Compared with the F group, the relative value of SctO2 decline in the S group was smaller. Compared to the day before surgery, the Montreal Cognitive Assessment (MoCA) scores of both groups were significantly reduced after surgery. At 1 day post-surgery, the MoCA scores of the S group were significantly higher and the incidence of postoperative cognitive dysfunction (POCD) was significantly lower compared to the F group. POCD occurred in three patients (6.2%) in the S group, and the ratio was significantly lower than that in the F group (11.9%) (P < 0.05). It showed a consistent trend with the SctO2 status during the surgery. The relative value of SctO2 decline in the S group was significantly smaller than that in the F group. The reduction of cognitive function in the S group was significantly lower than that in the F group. These results indicate that the changes in SctO2 are a good prediction of the incidence of POCD.