Abdominal Girth, Vertebral Column Length, and Spread of Spinal Anesthesia in 30 Minutes after Plain Bupivacaine 5 mg/mL

Published in Anesth Analg. 2014 Jul;119(1):203-6

Authors: Zhou QHt et al

BACKGROUND:

The spread of spinal anesthesia is highly unpredictable. In patients with increased abdominal girth and short stature, a greater cephalad spread after a fixed amount of subarachnoidally administered plain bupivacaine is often observed. We hypothesized that there is a strong correlation between abdominal girth/vertebral column length and cephalad spread.

METHODS:

Age, weight, height, body mass index, abdominal girth, and vertebral column length were recorded for 114 patients. The L3-L4 interspace was entered, and 3 mL of 0.5% plain bupivacaine was injected into the subarachnoid space. The cephalad spread (loss of temperature sensation and loss of pinprick discrimination) was assessed 30 minutes after intrathecal injection. Linear regression analysis was performed for age, weight, height, body mass index, abdominal girth, vertebral column length, and the spread of spinal anesthesia, and the combined linear contribution of age up to 55 years, weight, height, abdominal girth, and vertebral column length was tested by multiple regression analysis.

RESULTS:

Linear regression analysis showed that there was a significant univariate correlation among all 6 patient characteristics evaluated and the spread of spinal anesthesia (all P less than 0.039) except for age and loss of temperature sensation (P greater than 0.068). Multiple regression analysis showed that abdominal girth and the vertebral column length were the key determinants for spinal anesthesia spread (both P less than 0.0001), whereas age, weight, and height could be omitted without changing the results (all P greater than 0.059, all 95% confidence limits less than 0.372).

CONCLUSIONS:

Multiple regression analysis revealed that the combination of a patient’s 5 general characteristics, especially abdominal girth and vertebral column length, had a high predictive value for the spread of spinal anesthesia after a given dose of plain bupivacaine.