Perfusion Index Predicts the Effectiveness of Supraclavicular Brachial Plexus Block in Children Under General Anesthesia: A Randomized Controlled Trial

Objectives: This study aimed to assess the predictive value of perfusion index (PI) in determining the effectiveness of supraclavicular block (SCB) in children under sevoflurane or propofol general anesthesia. Methods: In this randomized controlled study, 104 children who underwent elective upper extremity surgery under sevoflurane or propofol anesthesia were scheduled to be enrolled. The primary outcome was the effects of PI in predicting the effectiveness of SCB under general anesthesia. The PI value was obtained through pulse oximetries. Secondary outcomes include hemodynamic data, supplementary opioid doses, agitation score, pain score, and postoperative complications. Results: A total of 103 pediatric patients were analyzed. PI increased rapidly after anesthesia induction, and there was no significant difference in PI in the blocked side between the propofol group (PRO group) and sevoflurane group (SEV group). At 10 min after the block, PI in the blocked side was higher than that in the unblocked side in both groups ( p < 0.05). However, PI showed low sensitivity and specificity in predicting the effect of SCB at 10 min in both groups. At PACU, PI exhibited a high sensitivity (0.837 vs. 0.796) and specificity (0.721 vs. 0.898) for SCB at cutoff values of 5.91 and 6.67 in both PRO and SEV groups. The area under the receiver operating characteristic curve (AUROC) values were 0.834 (95% CI 0.750–0.918) and 0.895 (95% CI 0.832–0.959). Conclusion: PI demonstrates limited sensitivity and specificity in predicting the effect of SCB at 10 min after block under general anesthesia. However, PI may serve as a more appropriate indicator to guide the necessity for supplemental analgesia in PACU. Trial Registration: ClinicalTrials.gov identifier: NCT04216823