Midazolam-flumazenil versus propofol anaesthesia for scoliosis surgery with wake-up tests

Background : Wake-up tests may be necessary during scoliosis surgery to ensure that spinal function remains intact.
Methods : Intra- and postoperative wake-up tests were performed together with somatosensory cortical evoked potentials (SCEPs) monitoring in 40 patients randomized to either midazolam (M) or propofol (P) infusions for scoliosis surgery. Other anaesthetic medication was similar in both groups. At the surgeon's request, N₂O was turned off and midazolam or propofol infusions were discontinued. In the M group, flumazenil was given in refracted doses. Patients were asked to move hands and feet. The test was repeated immediately after the end of surgery.
Results : The median intraoperative wake-up times were 2.9 min in the M group and 16.0 min in the P group. The respective postoperative wake-up times were 1.8 and 13.9 min. The quality of both intra- and postoperative arousals was significantly better in the M group. Twelve patients in the P group could not be awakened intraoperatively within 15 min and were given nalox-one. One of these patients woke up violently and dislodged the endotracheal tube. Another patient in the P group had explicit recall of the test, but no pain. Five patients in the M group became resedated in the recovery room. Cost of anaesthetic drugs was similar in both groups. Satisfactory intraoperative SCEPs were recorded from 17 patients in each group. There were no neurological sequelae.
Conclusions : Wake-up tests can be conducted faster and better with midazolam-flumazenil sequence compared with propofol.