Prospective observational study to compare perfusion index and cremasteric reflex as indicators of onset of caudal block

Objectives: The aim of this study was to compare the efficacy of PI and cremasteric reflex (CR) in assessing the onset of caudal block. Material and Methods: Using convenience sampling, eligible participants as per the inclusion and exclusion criteria were enrolled. Baseline and post-sedation readings of mean arterial pressure (MAP), PI, and CR were taken, standard general anesthesia protocol was followed, and a caudal block was given. MAP, CR, and PI values were monitored and documented at 1 min intervals for 10 min. The loss of CR and doubling time from baseline PI were considered as the onset of caudal block, and the time required was compared. Results: The mean time to loss of CR and time required for PI to double were 7.17 min and 4.04 min, respectively. The average time of PI doubled post-caudal was significantly lower than the time to loss of CR ( P < 0.05). Conclusion: PI is a more efficacious, non-invasive, objective, and a feasible parameter that gives an earlier indication of caudal block onset. Change in MAP is not proven to be a reliable indicator of the onset of caudal block.