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Updated: Jun 2, 2026
Electrophysiological Measurements and Analysis of Nociception in Human Infants
Published on: December 20, 2011
A comparison of pain measures in newborn infants after cardiac surgery
Linda S Franck1, Deborah Ridout, Richard Howard
1University of California, San Francisco, San Francisco, CA 94143, USA University College London (UCL), Institute of Child Health, London, UK Great Ormond Street Hospital for Children NHS Trust, London, UK University College London Hospitals, London, UK.
Insights
Accurate pain assessment in neonates is crucial. The COMFORT score effectively measured pain in critically ill infants after cardiac surgery, outperforming other scales.
Area of Science:
- Neonatal intensive care
- Pediatric surgery
- Pain management
Background:
- Lack of validated pain assessment tools for critically ill neonates postoperatively.
- Need for reliable methods to evaluate pain in neonates undergoing cardiac surgery.
Purpose of the Study:
- To compare the efficacy of various pain assessment indices in critically ill neonates after cardiac surgery.
- To identify the most accurate tool for postoperative pain evaluation in this population.
Main Methods:
- Studied 81 full-term infants during the first 48 postoperative hours.
- Measured heart rate, blood pressure, heart-rate variability, cortisol levels, and four composite pain scales (CHIPPS, CRIES, COMFORT, PIPP).
- Utilized regression models to analyze relationships between pain indices, procedural intensity, and opioid levels.
Main Results:
- The COMFORT score demonstrated the best performance, showing a significant difference between procedures with and without tissue damage (27% difference, P<0.001).
- The COMFORT score correlated inversely with opioid dose and plasma levels, explaining 52% of the variance in morphine levels at 24 hours (P<0.001).
- Both behavioral (45%) and physiological (15%) components of the COMFORT score significantly contributed to pain assessment (P<0.001).
Conclusions:
- The COMFORT score is a superior tool for assessing postoperative pain in critically ill neonates undergoing cardiac surgery.
- Both behavioral and physiological measures within the COMFORT score are vital for accurate pain evaluation.
- Further research should focus on integrating validated tools like the COMFORT score into clinical practice for improved neonatal pain management.
Abstract:
Accurate pain assessment tools to evaluate pain in critically ill neonates in the postoperative period are lacking. Therefore, we compared a number of potentially useful indices of pain in critically ill neonates following cardiac surgery. Eighty-one full-term infants were studied during the first 48 postoperative hours and the following indices were measured: heart rate, mean arterial blood pressure, heart-rate variability, urinary and plasma cortisol, and 4 composite pain measurement scales: Children's and Infants' Postoperative Pain Scale (CHIPPS), CRIES, COMFORT, and Premature Infant Pain Profile (PIPP). Regression models were used to investigate relationships between individual pain indices or composite pain assessment scales with respect to procedural intensity and opioid dose and plasma levels. COMFORT score performed best, with a 27% difference in score between procedures causing tissue damage and those that did not (P<0.001). COMFORT score and the high-frequency component of heart-rate variability showed inverse correlations with opioid dose and plasma levels over the first 48 hours postoperatively, but after accounting for clinical variables, only COMFORT score remained significant (eg, 52% of variance in morphine level at 24 hours, P<0.001). The factor structure of the COMFORT score revealed that both behavioural and physiological variables account for a significant proportion of the variance (45% and 15%, respectively; P<0.001). Plasma concentrations of cortisol increased postoperatively but urinary cortisol excretion did not change significantly. Of the pain indices studied, the COMFORT score performed best, with both behavioural and physiological components providing significant contributions.
