Clinical reliability and validity of the N-PASS: neonatal pain, agitation and sedation scale with prolonged pain

Abstract

Objective: To establish beginning evidence of clinical validity and reliability of the Neonatal Pain, Agitation and Sedation Scale (N-PASS) in neonates with prolonged pain postoperatively and during mechanical ventilation.

Study design: Prospective psychometric evaluation. Two nurses administered the N-PASS simultaneously and independently before and after pharmacologic interventions for pain or sedation. One nurse also administered the premature infant pain profile (PIPP) concurrently with the N-PASS. The setting consisted of 50-bed level III neonatal intensive care unit. Convenience sample of 72 observations of 46 ventilated and/or postoperative infants, 0 to 100 days of age, gestational age 23 to 40 weeks was used. Outcome measures comprised convergent and construct validity, interrater reliability and internal consistency.

Result: Interrater reliability measured by intraclass coefficients of 0.85 to 0.95 was high (P<0.001 to 0.0001). Convergent validity was demonstrated by correlation with the PIPP scores (Spearman's rank correlation coefficient of 0.83 at high pain scores, 0.61 at low pain scores). Internal consistency, measured by Cronbach's alpha, was evident with pain scores (0.82), and with sedation scores (0.87). Construct validity was established via the Wilcoxon signed-rank test, comparing the distribution of N-PASS scores before and after pharmacologic intervention showing pain scores of 4.86 (3.38) and 1.81 (1.53) (mean (s.d.), P<0.0001) and sedation scores of 0.85 (1.66) and -2.78 (2.81) (P<0.0001) for pre- and postintervention assessments, respectively.

Conclusions: This research provides beginning evidence that the N-PASS is a valid and reliable tool for assessing pain/agitation and sedation in ventilated and/or postoperative infants 0 to 100 days of age, and 23 weeks gestation and above.