Effect of Different Doses of Propofol and Nerve block Combined with General Anesthesia on The Intraoperative Anesthesia and Postoperative Awakening and Cognitive Function in Elderly Patients with Knee Osteoarthritis

Abstract

To explore the effect of different doses of propofol and nerve block combined with general anesthesia on the intraoperative anesthesia and postoperative awakening and cognitive function in elder patients with knee osteoarthritis (OA). Methods. According to the inclusion criteria for research object, we selected 98 elderly patients with knee OA who needed surgery and were admitted to our hospital from January 2019 to January 2021 for the study. Patients were divided into the low dose group (given 2 mg/kg propofol by pumping under constant speed during surgery) and the high dose group (given 4 mg/kg propofol by pumping during surgery) by the number table method to compare their indicators including the intraoperative anesthesia effect, with 49 cases in each group. Results. No between-group difference was shown in the anesthesia time and postoperative VAS scores, but the awakening time of the low dose group was significantly shorter than that of the high dose group (P<0.05); the differences in heart rate (HR) values at various time points between the two groups were not obvious, but the high dose group obtained significantly higher HR values at T₄ than the low dose group; the mean arterial pressure (MAP) values of both groups were significantly reduced at T₁ and then returned to the level before anesthesia (P>0.05); the bispectral index scores (BIS) of both groups experienced a marked drop at T₁ and then recovered gradually, but failed to return to the level at T₀ till the end, and a between-group difference in BIS indexes presented at T₁; the plasma corticosterone (CORT) concentration at T₁ of both groups were significantly lowered and then returned to the level at T₀, with no between-group difference; and compared with the low dose group, the high dose group achieved slightly lower mini-mental state examination (MMSE) scores at 24-72 h after surgery, with no significant difference between them (P>0.05). Conclusion. The therapy of different doses of propofol and nerve block combined with general anesthesia has no significant effect on the cognitive function in elderly knee OA patients after surgery. With the nerve block improving the analgesic effect, a low dose of propofol is good for the postoperative awakening of patients. Different doses of propofol inhibited the stress response to a different degree and produced good anesthesia outcomes in elderly patients, but comparatively speaking, a low-dose propofol ensures more smooth indexes and less effect on the intraoperative hemodynamics.