A comparison of postoperative pain scales in neonates

Practical, valid and reliable pain measuring tools in neonates are required in clinical practice for effective pain management and prevention of the evaluator bias.

This prospective study was designed to cross-validate three pain scales: CRIES (cry, requires O(2), increased vital signs, expression, sleeplessness), CHIPPS (children's and infants' postoperative pain scale) and NIPS (neonatal infant pain scale) in terms of validity, reliability and practicality. The pain scales were translated. Concurrent validity, predictive validity and interrater reliability in postoperative pain were studied in 22 neonates after major surgery. Construct validity and concurrent validity in procedural pain were determined in 24 neonates before and during frenulectomy under topical anaesthesia.

All scales had excellent interrater reliability (intraclass correlation >0.9). Construct validity was determined for all pain scales by the ability to differentiate the group with low pain scores before surgery and high scores during surgery (P<0.001). The positive correlations among all scales, ranging between r=0.30 and r=0.91, supported concurrent validity. CRIES showed the lowest correlation with other scales with correlation coefficients of r=0.30 and r=0.35. All scales yielded very good agreement (K>0.9) with routine decisions to treat postoperative pain. High sensitivity and specificity (>90%) for postoperative pain from all scales were achieved with the same cut-off point of 4. In terms of practicality, NIPS was the most acceptable (65%).

Based on our findings, we recommended NIPS as a valid, reliable and practical tool.