Distribution of methylene blue injected into the epidural space of anaesthetised sheep.

摘要

This study was conducted to determine the distribution of methylene blue injected into the epidural space of anaesthetized sheep. 15 sheep were anaesthetized and received 0.1, 0.2 or 0.3 ml/kg of a solution containing 0.12% methylene blue (MB) in 0.9% saline by lumbosacral epidural injection. 30 min after the epidural injection, the sheep were euthanized. After dorsal laminectomy, the extent of cranial and caudal migration of the dye within the epidural space from the injection site was measured. The mean (sd) number of stained spinal segments was 4.9 (0.9), 8.1 (0.9) and 10.1 (0.8), respectively, for 0.1, 0.2 and 0.3 ml/kg MB, with significant differences between the groups. A significant correlation between the injected volume and number of cranial stained spinal segments (R2=0.86) was observed. The results of the study could form the basis for determining and evaluating the pharmacodynamics of anaesthetics used in caudal epidural anaesthesia in sheep.