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.