Perfusion index as primary predictor of successful caudal block in infraumbilical and lower limb pediatric surgeries:...

Caudal block is a widely practiced regional anesthetic technique in pediatric patients undergoing infraumbilical and lower limb surgeries. However, assessing its effectiveness intraoperatively remains a challenge due to limitations in conventional clinical evaluation methods, especially under general anesthesia. The perfusion index (PI), a noninvasive indicator of peripheral perfusion, has emerged as a potential early marker of successful neuraxial block.

To evaluate the perfusion index as a primary predictor of successful caudal block in children undergoing elective infraumbilical and lower limb surgeries, and to compare it with traditional hemodynamic parameters.

This prospective observational study was conducted over two years at a tertiary care center. A total of 80 pediatric patients (ASA I-II, aged 1-8 years) undergoing elective surgeries under general anesthesia with caudal block were enrolled. PI, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded at baseline and at multiple time intervals post-block. The primary outcome was the change in PI; secondary outcomes included changes in hemodynamic parameters.

A significant increase in PI was observed as early as 3 minutes after caudal block, rising from a baseline of 1.55 ± 1.08 to 3.96 ± 1.94 (P < 0.001), with a peak at 30 minutes (5.23 ± 1.42). In contrast, SBP, DBP, and MAP showed significant reductions only after 15 minutes. SpO₂ remained stable throughout. The early rise in PI correlated with successful block onset and duration, making it a reliable early predictor compared to delayed hemodynamic changes.