Influence of Height and Vertebral Length on Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine / 대한마취과학회지

ABSTRACT

BACKGROUND: Many factors determine the distribution of local anesthestics in the subaracnoid space. Especially, patient's height is considered an important determinant of the dose of spinal anesthesia. However, the relationship between height and the level of analgesia has not been clearly documented. We studied the correlation between vertebral lengths measured from C7 to the level of the iliac crest (C7-IC), to the sacral hiatus (C7-SH) and to the coccyx (C7-CX) and the level of analgesia injected a fixed amount of local anesthetic in spinal anesthesia. METHODS: Fifty six healthy patients who consented to spinal anesthesia for elective operation were studied. All patient were administered 0.5% hyperbaric bupivacaine 11 mg in the lateral decubitus position on a horizontal operation table. Immediately after drug injection, the patients were turned to the supine horizontal position. For the first 30 minutes, we measured the level of analgesia to pinprick every two minutes. RESULTS: The average of maximum cephalad spread of analgesia was T7.0 1.6. There were weak correlations between patient's height or C7-IC and the level of analgesia. However a significant correlation existed between vertebral length measured from C7 to SH and the level of analgesia. CONCLUSIONS: It is concluded that vertebral length (C7-SH) provides a more meaningful approach to dose selection than height.