Comparison of effects of spinal anesthesia and general anesthesia on early postoperative cognitive function in elderly patients undergoing hip replacement

Abstract

Objective To compare the effects of spinal anesthesia and general anesthesia on early postoperative cognitive function in elderly patients undergoing hip replacement. Methods One hundred and four elderly patients of both sexes, aged ≥ 60 yr, with body mass index of 18.5-24.0 kg/m2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective unilateral hip replacement, were randomized into 2 groups (n = 52 each) using a random number table method: general anesthesia group (group G) and spinal anesthesia group (group S). Total intravenous general anesthesia was adopted to maintain the bispectral index value at 40-60 during surgery in group G. In group S, spinal anesthesia was applied by injecting 0.5% bupivacaine 1.5-3.0 ml at the L3-4 vertebral interspace, and the level of anesthesia was regulated and maintained at T10.Mini-Mental State Examination scale was used to evaluate the cognitive function on 1 day before surgery (T0) and 7 days after surgery (T1). Difference value method, 1 standard deviation method and Z score method were applied to diagnose postoperative cognitive dysfunction.Patients′ spouses in two groups were recruited as control group (group C) according to the Z-scoring method. Results There were 47 and 49 cases in G and S groups, respectively, and 33 cases in group C. Compared with group C, the memory score was significantly decreased at T1 (P 0.05). The memory score was significantly higher at T1in group S than in group G (P 0.05). Conclusion Spinal anesthesia and general anesthesia exerts no effect on early postoperative cognitive function in elderly patients undergoing hip replacement. Key words: Anesthesia, spinal; Anesthesia, general; Cognition disorders; Aged; Arthroplasty, replacement, hip