Effect of auditory evoked potential-guided anaesthesia on consumption of anaesthetics and early postoperative cognitive dysfunction: a randomised controlled trial.

摘要

BACKGROUND: Post-operative cognitive dysfunction (POCD) after non-cardiac surgery is a well known problem in some categories of patients. This study aims to evaluate the influence of auditory evoked potential (AEP)-guided anaesthesia on the requirement for anaesthetic drugs and their influence on POCD. METHODS: Four hundred and fifty patients aged between 18 and 92 years scheduled for ophthalmic surgery under general anaesthesia were assigned randomly to one of two groups. In group A (AEP group), the depth of anaesthesia (DoA) was aimed at an AEP index (AAI) between 15 and 25. In group C (control group), DoA was guided by clinical signs. Hypotension was treated with fluids and vasopressors using a standardised algorithm. A mini-mental test and the Cognitive Failure Questionnaire were used to evaluate cognitive function. RESULTS: Anaesthetic drug requirements were significantly lower in group A than in group C: propofol 92.5 +/- 26.5 vs. 103.8 +/- 39.5 mg (P = <0.001) and desflurane end-tidal concentration 2.5 +/- 0.58 vs. 3.3 +/- 0.79% (P < 0.001). In group A, 36 patients (16%) received additional fluids and vasopressors compared to 65 patients (29%) in group C (P < 0.01). AAI values differed significantly between the groups: 18 (11-21) in group A vs. 12 (10-19) in group C (P < 0.001). The number of patients with POCD was 16 in group C compared to two in group A (P < 0.001) at day 1 post-operation. CONCLUSION: AEP monitoring allows dose reduction of anaesthetic agents, leading to better cardiovascular stability and decreased requirements for intra-operative fluids and vasopressors. Cognitive decline seen following minor ophthalmic surgery, even when anaesthesia is assessed clinically, is short-lived with no long-term sequelae.