Spreading Pattern of Epidurally-Administered Contrast Media in Rabbits

토끼에서 경막외강으로 투여한 조영제의 분포양상

Background: The aim of this study was to examine the precise spreading pattern of contrast media in small increments in rabbits. Following pentobarbital anesthesia, the epidural puncture was done surgically with a blunt hook. Methods: The tip of epidural catheter was located at the mid-portion of T7 and T12, in the T7 group (n=7) and T12 group (n=8), respectively. Injection of the contrast media was started at 0.1 mL/kg and increased by 0.1 mL/kg up to a maximum of 0.6, mL/kg, under fluoroscopy. Results: In both groups, the extent of spread increased continuously as a Starling resistor with increasing injected volume(T7 group: $y=4.0+41.8x-28.1x^2$, T12 group: $y=0.2+57.7x-43.5x^2$) the total spread of contrast media was similar. The contrast media spread equally, both rostral and caudal, from catheter tip in T7 group; media spread approximately twice as far rostral as compared to caudal in T12 group (P<0.05). Conclusions: In rabbits, the position of epidural catheter tip should be positioned 2~3 segments below the aimed segment in lower thoracic or lumbar region, whereas in mid-thoracic region it should be positioned close to the level of aimed segment. Rabbits have relatively small epidural space therefore, the volume of injectant should be carefully determined with the suggested equations of this study.