Abstract
BACKGROUND AND AIMS: Studies assessing caudal block's effects on children's cardiac output are scarce. We aimed to estimate the effects of the caudal block using different volumes of plain bupivacaine 0.25% on the cardiac index assessed by electrical cardiometry. METHODS: Children aged 1-8 years undergoing minor lower abdominal surgeries were randomly assigned to one of three equal groups: The 0.8 group received general anaesthesia (GA) along with caudal block with 0.8 mL/kg of bupivacaine 0.25%, the 1.2 group received GA along with caudal block with 1.2 mL/kg of bupivacaine 0.25%, and the control group received GA only. The primary outcome was the percentage of change in the cardiac index from the baseline 10 minutes after the caudal block. Continuous variables were analysed using the ANOVA test, while categorical data was analysed using a chi-squared test with the significance level set at P < 0.05. RESULTS: The mean percentage of change of cardiac index from baseline 10 minutes after caudal block was significantly lower in the 0.8 and 1.2 groups (-11.4 (standard deviation (SD): 12.5%) and -17.1 (SD: 15.5%), respectively) compared to the control group (-0.7 (SD: 11.5%), (P = 0.007 and P = 0.0001). Mean differences were -11 (0.8 vs control, 95% confidence interval (CI): -18.7, -3.3%, and -15.2 (1.2 vs control, 95% CI: -23, -7.5%). CONCLUSION: The cardiac index progressively decreased with the increase in the volume of the caudal block with plain bupivacaine at 0.25% compared to the baseline. However, this decrease was not clinically significant, suggesting that the cardiac index remained within an acceptable range after the caudal block. Nevertheless, caution is warranted due to the increased incidence of hypotension with increasing volumes of plain local anaesthetics in the caudal block.