Effect of Different Volumes of Bupivacaine 0.25% Caudal Block on Cardiac Index Measured by Ultrasonic Cardiac Output Monitor in Children Undergoing Elective Lower Abdominal Surgery: A Double-Blind Randomized Controlled Trial

Abstract

Background: Caudal block with bupivacaine is widely used for analgesia in pediatric lower abdominal surgery, but its effects on cardiac index (CI) require further evaluation. This study assessed changes in CI following caudal bupivacaine 0.25% using non-invasive Ultrasonic Cardiac Output Monitoring (USCOM).
Methods: This double-blind randomized clinical trial included 33 children undergoing lower abdominal surgery. Participants were randomized into three groups (n=11 each): caudal bupivacaine 0.25% at 0.8 mL/kg (Group A), 1.2 mL/kg (Group B), or general anaesthesia alone (Group C). CI was measured using USCOM at baseline and serially after induction up to 30 minutes. Between-group differences were analyzed statistically.
Results: CI differed significantly among the three groups at baseline and throughout the observation period (p<0.05). At baseline, mean CI was 4.53, 5.12, and 5.79 L/min/m² in Groups A, B, and C, respectively (p=0.022). At 30 minutes, mean CI decreased to 3.97, 3.99, and 4.92 L/min/m² in Group A, B, and C, respectively (p=0.017). CI decreased progressively over time in all groups, with lower values observed in the caudal block groups.
Conclusions: Caudal bupivacaine 0.25% was associated with a significant decrease in CI in children undergoing lower abdominal surgery. The decrease was greater with increasing bupivacaine volume, although CI remained within age-appropriate clinical ranges.