[APN: evaluation behavioral scale of acute pain in newborn infants]

This study was designed to validate a behavioral acute pain rating scale for term and preterm neonates (APN).

From January through June 1996, neonates requiring a heel lance or a venous puncture for blood sampling at the intensive care unit and the nursery of Poissy Hospital were recruited into the study. After a pilot study, a pain rating scale was developed. The scale score pain ranged from 0 to 10 and it evaluated three items: facial expression, limb movements, and vocal expression with ratings per item ranging from 0 to 4, 0 to 3 and 0 to 3, respectively. Two observers evaluated independently each infant during a painful procedure (puncture for a blood sample) and during a dummy procedure (rubbing the thigh softly).

Forty-two neonates born between 25 and 41 weeks gestational age were included in the study. Medians (quartiles) of gestational age, birth weight, and corrected postmenstrual age at time of investigation were 34 (29-39) weeks, 1,850 (1,055-3,093) g, and 35.5 (31-39) weeks, respectively. Ten infants were intubated. The scale showed to be sensitive because all possible scores were obtained; during painful procedures scores ranged from 1 to 10, with 95% of scores > or = 3 while during dummy procedures they ranged from 0 to 5, with 88% of scores < or = 2. The medians (95% confidence interval) of scores were for painful procedures 5 (5 to 7) and for dummy procedures 1 (0 to 1). This indicates a good specificity of the scale. High intercorrelation of items (internal consistency) was confirmed by a Cronbach's coefficient alpha of 0.88. Inter-rater agreement was high since the Krippendorff R test was 91.2.

This behavioral acute pain rating scale for newborns demonstrated a good specificity and sensitivity, internal consistency and inter-rater reliability. This scale could be used to test the analgesic effects of different therapies during painful procedures.