Postoperative pain assessment in the neonatal intensive care unit

To compare the convergent validity of two measures of pain (premature infant pain profile (PIPP) and crying, requires oxygen, increased vital signs, expression, and sleepless (CRIES)) in real life postoperative pain assessment in infants.

This study was a prospective, repeated measures, correlational design. Two staff nurses were randomly assigned either the PIPP or CRIES measure. An expert rater assessed each infant after surgery, and once a day using the visual analogue scale (VAS).

A level III neonatal intensive care unit in a metropolitan university affiliated paediatric hospital.

Pain was assessed in 51 neonates (28-42 weeks of gestational age) after surgery. There was no significant difference in the rates of change between the pain assessment measures across time using repeated measures analysis of variance (F(50,2) = 0.62, p = 0.540), indicating correlation between the measures. Convergent validity analysis using intraclass correlation showed correlation, most evident in the first 24 hours (immediately, 4, 8, 20, and 24 hours after the operation). Correlations were more divergent at 40 and 72 hours after surgery. No significant interactions were found between gestational age and measure (F(304,4) = 0.75, p = 0.563) and surgical group and measure (F(304,2) = 0.39, p = 0.680).

PIPP and CRIES are valid measures that correlate with pain for the first 72 hours after surgery in term and preterm infants. Both measures would provide healthcare professionals with an objective measure of a neonatal patient's pain.