Randomized comparison between sevoflurane anaesthesia and unilateral spinal anaesthesia in elderly patients undergoing orthopaedic surgery.

BACKGROUND AND OBJECTIVE

This prospective, randomized study was conducted to compare unilateral spinal block using small doses of hyperbaric bupivacaine and single-agent anaesthesia with sevoflurane in elderly patients undergoing hip surgery.

METHODS

Thirty patients (> 65 yr) undergoing hip fracture repair were randomly allocated to receive unilateral spinal anaesthesia with hyperbaric bupivacaine 7.5 mg 0.5% (Group Spinal, n = 15) or volatile induction and maintenance anaesthesia with sevoflurane (Group SEVO, n = 15). General anaesthesia was induced by increasing the inspired concentration to 5%. A laryngeal mask airway was placed without muscle relaxants, and the end-tidal concentrations of sevoflurane were adjusted to maintain cardiovascular stability. Hypotension (decrease in systolic arterial pressure > 20% from baseline), hypertension or bradycardia (heart rate < 50 beats min(-1)) requiring treatment, and the length of stay in the postanaesthesia care unit was recorded. Cognitive functions were evaluated the previous day, and 1 and 7 days after surgery with the Mini Mental State Examination test.

RESULTS

Hypotension occurred in seven patients of Group Spinal (46%) and in 12 patients of Group SEVO (80%) (P = 0.05). Phenylephrine was required to control hypotension in three spinal patients (21%) and four SEVO patients (26%) (n.s.). SEVO patients had lower heart rates than spinal patients from 15 to 60 min after anaesthesia induction (P = 0.01). Bradycardia was observed in three SEVO patients (22%). Discharge from the postanaesthesia care unit required 15 (range 5-30) min in Group Spinal and 55 (15-80) min in Group SEVO (P = 0.0005). Eight patients in Group Spinal (53%) and nine patients in Group SEVO (60%) showed cognitive decline (Mini Mental State Examination test decreased > or = 2 points from baseline) 24 h after surgery (n.s.). Seven days after surgery, confusion was still present in one patient of Group Spinal (6%) and in three patients of Group SEVO (20%) (n.s.).

CONCLUSIONS

In elderly patients undergoing hemiarthroplasty of the hip, induction and maintenance with sevoflurane provide a rapid emergence from anaesthesia without more depression of postoperative cognitive function compared with unilateral spinal anaesthesia. This technique represents an attractive option when patient refusal, lack of adequate co-operation or concomitant anticoagulant therapy contraindicate the use of spinal anaesthesia.