A Surgical Pleth Index (SPI) target level lower than that reported in the current literature may be more appropriate in research studies examining SPI-guided anesthesia in pediatric patients, according to a study published in the British Journal of Anaesthesia.
In this trial, a total of 93 children (ages 2-16 years) who had received opioid-based plus sevoflurane anaesthesia for nonemergency surgery were included. SPI was found to be higher in patients who had rated pain as moderate to severe vs absent or mild in the postoperative acute care unit (P =.009).
Overall, a SPI target cutoff of 40 was shown to have the highest specificity and sensitivity. The negative predictive value “to exclude significant postoperative pain” for SPI ≤40 was 87.5%. A previous trial, which provided a cutoff value ≤50 for SPI, had a 24% sensitivity for moderate to severe pain in this patient cohort.
In children with moderate to severe pain treated in the postoperative acute care unit, investigators observed a negative association between SPI and age (P =.03). Patients who were 2 to 3 years of age and had moderate to severe pain had a higher SPI at the end of their surgery compared with patients who were between the ages of 4 and 8 years and 9 and 16 years (P =.04).
This pilot study included no standard sample size calculation, representing a potential study limitation. In addition, the investigators suggest that the categorization of patients into 3 subgroups may have reduced the ability to perform a detailed evaluation on the correlations between age and SPI.
Ledowski T, Sommerfield D, Slevin L, Conrad J, von Ungern-Sternberg BS. Surgical pleth index: prediction of postoperative pain in children? Br J Anaesth. 2017;119(5):979-983.