RESUMO
PURPOSE: The heart rate variability-derived Newborn Infant Parasympathetic Evaluation (NIPE) monitor is an objective, non-invasive tool for the assessment of pain in children under 2 years of age. The aim of this study was to objectively compare pain in infants undergoing open and laparoscopic inguinal hernia surgery using the NIPE monitor. METHOD: This prospective observational study included neonates and infants (<2 years of age) undergoing elective open inguinal herniotomy and laparoscopic inguinal hernia repair under general anaesthesia with a caudal block. The NIPE monitor was connected to the electrocardiogram monitor with continuous monitoring performed intraoperatively, and postoperatively in the Post Anaesthesia Care Unit. The NIPE index was recorded at different intraoperative steps. The median NIPE index (NIPEm) was calculated for the entire procedure and postoperative period. The NIPE index ranges from 0 to 100; lower values indicate greater levels of pain, values < 50 indicate severe pain. P values < 0.05 were considered significant. RESULTS: There were 40 infants recruited: 27 underwent open herniotomy and 13 underwent laparoscopic repair. Intraoperatively, NIPEm was found to be significantly lower in the laparoscopic group (59.00 vs. 77.00, p = 0.0018). Postoperatively, NIPEm was also found to be significantly lower in the laparoscopic group (49.00 vs. 57.50, p = 0.0001). CONCLUSION: This is the first study to objectively demonstrate that laparoscopic inguinal hernia repair is more painful intraoperatively and leads to greater levels of pain in the early postoperative period compared to open inguinal herniotomy. This difference might explained by painful stimuli in anatomical areas not covered by the caudal block. TYPE OF STUDY: Treatment Study/Prospective Study. LEVEL OF EVIDENCE: Level II.
RESUMO
BACKGROUND: Pain assessment is essential for the administration of appropriate analgesia. Currently, clinicians use surrogate methods, such as heart rate or behavioural pain scales, to estimate pain in neonates and infants. The Newborn and Infant Parasympathetic Evaluation (NIPE™) monitor aims to provide an objective numeric value (NIPE index) of pain through a continuous assessment of the patient's parasympathetic activity. The aim of this study was to determine if the intraoperative NIPE index monitoring could predict postoperative pain in neonates and infants. METHODS: This prospective observational pilot study included neonates and infants undergoing elective day-surgical procedures (n = 50). Intraoperatively, NIPE indices at 0 (NIPE0), 10 (NIPE10), 20 (NIPE20), 30 (NIPE30) minutes and at completion of surgery (NIPEe), were recorded; the median NIPE index (NIPEm) was calculated for the entire procedure. Postoperative Face, Legs, Activity, Cry, Consolability (FLACC) scale scores were calculated by the nursing staff blinded to the intraoperative NIPE indices. RESULTS: Linear regression documented an association between the NIPEm and postoperative FLACC score at 0 (r = 0.31, p = 0.03) and 10 min (r = 0.36, p = 0.01). No significant associations were observed for FLACC scores at 20 (r = 0.21, p = 0.2) and 30 min (r = 0.36, p > 0.9). Multiple regression analysis revealed that intraoperative NIPE10, NIPE20, NIPE30 and NIPEe also predicted the FLACC score at 0 min (p = 0.003). CONCLUSION: The intraoperative NIPE index is predictive of pain in the immediate postoperative period. This association was lost at 20 min likely due to nursing intervention to administer analgesia. NIPE monitoring could be useful in facilitating postoperative pain management in infants. LEVEL OF EVIDENCE: II. TYPE OF STUDY: Study of Diagnostic Test.