Comparison of the Newborn Infant Parasympathetic Evaluation (<scp>NIPE™</scp>) index to changes in heart rate to detect intraoperative nociceptive stimuli in healthy and critically ill children below 2 years: An observational study
Claudia Neumann, Tamara Babasiz, Nadine Straßberger‐Nerschbach, Ehrenfried Schindler, Christian Reuter, Leonie Weinhold, Mária Wittmann, Tobias Hilbert, Sven Klaschik
Abstract
BACKGROUND: The validity of current tools for intraoperative objective assessment of nociception/antinociception balance during anesthesia in young and very young surgery children is unknown. AIM: Primary aim of the study was to test the hypothesis that the Newborn Infant Parasympathetic Evaluation (NIPE) index performs better in indicating nociception in anesthetized children below 2 years than changes in heart rate. Secondary aims were to evaluate associations between intraoperative changes in NIPE index values and postoperative pain and emergence delirium. METHODS: Fifty-one children aged <2 years who underwent surgery were included in this prospective observational study. Patients were assigned to either group 1 (healthy children, n = 31) or group 2 (critically ill, ventilated premature infants and neonates, n = 20). The NIPE index and heart rate in response to three defined nociceptive stimuli were continuously recorded. Two different scales, Kindliche Unbehagens- und Schmerzskala (KUS) and Pediatric Anesthesia Emergence Delirium (PAED) as well as a Pain Questionnaire were used to assess postoperative pain levels and emergence delirium. RESULTS: In total, 110 nociceptive events were evaluated. The analysis revealed a statistically significant association between a decrease in the NIPE index and all nociceptive stimuli, with a sensitivity of 92% and a specificity of 96%. The mean percentage decrease ranged from approx. 15%-30% and was highly statistically significant in both groups and for each of the nociceptive events except for venous puncture (p = .004). In contrast, no consistent change in heart rate was demonstrated. The KUS and PAED scale scores were significantly associated with the duration of anesthesia (p = .04), but not with intraoperative NIPE depression. CONCLUSION: The NIPE index was reliable for assessing intraoperative nociception in children aged <2 years and was more reproducible for detecting specific nociceptive stimuli during general anesthesia than heart rate. An effect on postoperative outcome is still elusive.