Acute Pain Assessment in Prematurely Born Infants Below 29 Weeks: A Long Way to Go.

Objectives: Neonates born extremely prematurely are at high risk of acute and prolonged pain. Effective treatment requires reliable pain assessment, which is currently missing. Our study explored whether existing pain assessment tools and physiological indicators measure pain and comfort accurately in this population. Materials and Methods: We prospectively collected data in 16 neonates born at less than 29 weeks' gestational age during 3 conditions: skin-to-skin care, rest, and heelstick procedure for capillary blood sampling in the incubator. The neonates were video recorded in these situations, and recordings were coded using 5 observational pain assessment tools and numeric rating scales for pain and distress. We simultaneously collected heart rate, respiratory rate, arterial oxygen saturation, regional cerebral oxygenation, and the number of skin conductance peaks. All measures across the 3 conditions were compared using general linear modeling. Results: The median gestational age was 27.1 weeks (range: 24.1 to 28.7). Forty measurement periods across the 3 conditions were analyzed. Heart rate was significantly higher during heelstick procedures compared with during rest, with a mean difference of 10.7 beats/min (95% confidence interval [CI]: 2.7-18.6). Oxygen saturation was significantly higher during skin-to-skin care compared with during heelstick procedures with a mean difference of 5.5% (95% CI: 0.2-10.8). The Premature Infant Pain Profile-revised (PIPP-R) score was significantly higher during heelstick procedures compared with skin-to-skin care with a mean difference of 3.2 points (95% CI: 1.6-5.0). Discussion: Pain measurement in clinical practice in prematurely born infants below 29 weeks remains challenging. The included behavioral and physiological indicators did not adequately distinguish between a painful situation, rest, and skin-to-skin care in premature neonates.