Comparison of auditory evoked potential index and heart rate variability for monitoring the level of sedation and analgesia during PCEA / 中华麻醉学杂志

ABSTRACT

Objective To compare auditory evoked potential index (AEPI) , BIS , heart rate variability (HRV) and spectral edge frequency (SEF) for monitoring the level of analgesia and sedation produced by different analgesic mixture of PCEA. Methods Thirty ASA Ⅰ-Ⅱ patients undergoing upper abdominal surgery under general anesthesia were enrolled in the study.Patients with mental or hearing disorders were excluded. The patients were randomly divided into three groups . The basic analgesic mixture for PCEA was 0.2% ropivacaine + 0.01% morphine in the 3 group and the PCEA regimen was loading dose 5ml , background infusion 1ml?h-1, bolus dose 1ml and lock-out interval 10 min. The difference among the 3 groups was that the 5ml loading dose contained clonidine l00?g in group Ⅱ or midazolam 2mg in group Ⅲ. The patients were premedicated with phenobartital and scopolamine. Epidural catheter was placed at T9-10 , a test dose of 1 % lidocaine 3-5ml was given to confirm the correct placement of the epidural catheter. General anesthesia was induced with midazolam 0.06mg?kg-1, fentanyl 4?g?kg-1, propofol 0.5mg?kg-1 and vecuronium 0.1mg?kg-1. Anesthesia was maintained after tracheal intubation with isoflurane inhalation and propofol infusion. Patients were transported to PACU after operation.PCEA was started after extubation when the patients was awake and complained of pain. The AEPI, BIS , HRV and SEF values and VAS, OAA/S scores were recorded before induction of anesthesia (T0 ) at the end of surgery (T1), 5, 15, 30 , 60 , 90 min and 2h, 4h, 8h, 20h, 24h after loading dose (T2-12). Results (1) AEPI was significantly higher than the baseline value when the patient was awake and feel pain ( P