A Thoroughbred stood 65 minutes after inhaled anesthesia ended during recovery from fracture repair. That interval describes one milestone in a multi-drug veterinary case. Midazolam had been given before induction, and the report did not measure when its effect wore off.
The three-year-old horse received midazolam intravenously along with medetomidine and butorphanol before induction. Guaifenesin and alfaxalone were used for induction. The maintenance regimen then used sevoflurane with alfaxalone and medetomidine infusions. Surgery lasted 180 minutes and inhaled anesthesia lasted 230 minutes. The team used mechanical ventilation and administered dobutamine to support arterial pressure, so the recorded vital signs reflect the regimen and its supportive care.
The authors reported that spontaneous breathing appeared 10 minutes after inhalation ended and the tube was removed at 15 minutes. The horse received three additional medetomidine doses during recovery and stood with some ataxia on its second attempt at 65 minutes. The report also describes assisted recovery using ropes. A time to standing under those conditions cannot serve as a midazolam clearance measurement or isolate the effect of any single drug.
This report documents how the team managed one prolonged procedure and how it timed recovery. Without a comparison regimen or drug concentrations, it cannot establish the contribution of midazolam, the frequency of complications, or the expected recovery time in another horse. When comparing reports, identify both ends of the interval and what happened between them. See also how another racehorse study used shared midazolam premedication.
Source: Wakuno A, Maeda T, Kodaira K, Kikuchi T, Ohta M. Journal of Equine Science. 2017, 28:111–115.