Comparison of Surgical Pleth Index-guided Analgesia with Conventional Analgesia Practices in Children: A Randomized Controlled Trial.

Background: To compare surgical pleth index (SPI)-guided analgesia with conventional analgesia by evaluating intraoperative analgesic requirements, postoperative pain, and emergence agitation in children.

Methods: This study was designed as a parallel, two-arm, double-blind, randomized controlled trial. Forty-five children undergoing elective adenotonsillectomy were randomly allocated to SPI-guided group (SPI-guided analgesia group, n = 21) or control group (conventional analgesia group, n = 24). Anesthesia was maintained with sevoflurane 2 to 3 vol% in 50% nitrous oxide and oxygen to achieve state entropy between 40 and 60. Intraoperative fentanyl 0.5 μg/kg was administered for the first event persisting 3 min and subsequent events persisting 5 min. An event was defined as an SPI over 50 (SPI-guided group) or a blood pressure or heart rate 20% above the baseline (control group). The primary outcome was intraoperative fentanyl requirement. Secondary outcomes included intraoperative sevoflurane consumption, postoperative emergence agitation and pain score, and postoperative rescue analgesic requirements.

Results: Intraoperative fentanyl requirement was lower in SPI-guided group than in control group (0.43 ± 0.53 vs. 1.73 ± 0.59 μg/kg; P < 0.001). Intraoperative sevoflurane consumption was similar. The proportion of patients with high emergence agitation scores (4 to 5) was greater in SPI-guided group (61.9 vs. 25.0%; P = 0.01). The postoperative pain score and rescue fentanyl consumption were higher in SPI-guided group (7 [4.5; 9] vs. 3 [2; 6.75]; P = 0.002; 0.50 ± 0.34 vs. 0.29 ± 0.30 μg/kg; P = 0.04).

Conclusions: As currently constructed, SPI does not appear to be valid in children. This may be due to both differences in blood vessel distensibility and baseline increased heart rates in children versus adults.