Total intravenous anesthesia combined with epidural eptazocine

To reduce the doses of intravenous anesthetics (ketamine, diazepam, droperidol, and vecuronium) used in total intravenous anesthesia (TIVA), epidural administration of a ϰ-stimulating opioid, eptazocine, was combined with TIVA in 115 patients. Surgical procedures were uneventful under TIVA plus epidural eptazocine; significant depression of EEG and somatosensory-evoked potentials during anesthesia were observed without delay in recovery. The circulatory response and blood glucose level during and after anesthesia and surgery were stable, and there was no postanesthetic respiratory depression. On the other hand, in 46 patients given TIVA only, hypertension, tachycardia, and elevated blood glucose during and after anesthesia were observed: in 25 (54.3%) patients, a vasodepressor was required, and in 18 (39.1%) patients, nitrous oxide was needed. Therefore, epidural eptazocine may make it possible to use lower doses of anesthesia in TIVA, thus reducing the adverse effects associated with TIVA such as hypertension during surgery, intraoperative awareness, postanesthetic respiratory depression, delayed recovery from anesthesia, and neurological signs after anesthesia. This may be due to the ϰ-stimulating action of epidural eptazocine on the spinal cord and its σ-blocking action, as well as its lack of μ-action on the brain.