Effects of sevoflurane combined with dexmedetomidine or propofol on inflammation and postoperative cognitive dysfunction in elderly patients undergoing ear-nosethroat operation

Objective To explore the effects of sevoflurane combined with dexmedetomidine or propofol on inflammation and postoperative cognitive dysfunction in elderly patients undergoing ear-nosethroat operation. Methods A total of 90 patients aged 65-78 years old, undergoing ear-nosethroat operation in our hospital from April 2017 to January 2018, were enrolled and randomly divided into three groups: sevoflurane group (S group), sevoflurane combined with dexmedetomidine group (SD group), and sevoflurane combined with propofol group (SP group), 30 cases in each group. Sevoflurane of 1-1.5 minimum alveolar concentration (MAC) was maintained for the anesthesia in S group. Sevoflurane of 0.5 MAC was maintained for the anesthesia in SD group, meanwhile, dexmedetomidine with a load dosage of 1 μg/kg was pumped and finished within 10 min, and then dexmedetomidine with a dosage of 0.2 μg•kg-1•h-1 was intravenously pumped until 30 min before the end of the operation. Sevoflurane of 0.5 MAC was maintained for the anesthesia in SP group, and target control infusion (TCI) of propofol was performed and the plasma concentration of 2-3 μg/ml of propofol was kept. The levels of plasma interleukin 6, 8 (IL-6 and 8), tumor necrosis factor-alpha (TNF-alpha), and C-reactive protein (CRP) were detected before the operation and 24 hours after the operation in the three groups. Cognitive function test was performed on the patients of the three groups 1 d before the surgery and 7 d after the surgery, and the occurrence rate of POCD was calculated by the Z scoring method. Results There were no statistically significant differences in the levels of plasma IL-6 and 8, TNF-alpha, and CRP between S group and SP group 24 h after the surgery (P>0.05); the levels of plasma IL-6 and 8, TNF-alpha, and CRP in SD group were all lower than those in S group and SP group (P<0.05). As cognitive function test showed, compared with S group and SP group, the scores of Hopkins Verbal Learning Test (HVLT1) and digit span test (FSDT) were both higher in SD group (P<0.05). The occurrence rate of POCD was calculated by the Z scoring method: 9 cases had POCD in S group, and the occurrence rate was 30.0%, 8 cases had POCD in SP group, and the occurrence rate was 26.7%, and 2 cases had POCD in SD group, and the occurrence rate was 6.7%; compared with S group and SP group, the occurrence rate was lower in SD group (P<0.05). Conclusion Sevoflurane combined with dexmedetomidine can reduce inflammation and thus decrease the occurrence rate of POCD in elderly patients undergoing ear-nosethroat operation. Key words: Sevoflurane; Propofol; Dexmedetomidine; Inflammation; Postoperative cognitive dysfunction; Old age