Does Repeated Painful Stimuli Change Cerebral Near-Infrared Spectroscopy Response in Healthy, Term, Large for Gestational Age Newborns?

Abstract

The objective of this study was to evaluate the effect of repeated painful stimuli on short-term pain response in healthy, term, large for gestational age newborns by measuring the regional cerebral oxygen saturation (rScO2), and behavioral and physiological responses. We compared term large for gestational age infants who received repeated painful stimuli (study group) with term, appropriate for gestational age infants (control group). A pulse oximeter and a near-infrared spectroscopy probe were connected to babies during the study period, and the responses of the babies were recorded by video, from which the crying time and the Neonatal Infant Pain Scale were obtained. The heart rate, peripheral oxygen saturation (SpO2), and rScO2 data were sampled every 1 second and exported to a personal computer via digital output during the study period. The maximum heart rate, the minimum SpO2, and peak, baseline, and mean rScO2 measurements following skin puncture were recorded. Data were compared within 1 group and between the 2 groups. After the heel prick, crying time (P<0.001) and Neonatal Infant Pain Scale scores (P=0.024) increased, and SpO2 levels decreased significantly (P=0.012) in the study group versus the control group. Although mean rScO2 increased significantly within 1 group (P<0.001), it was not significant between the 2 groups. The percent change in rScO2 was greater in the study group (5.2 [2.5 to 9.3]) compared with the control group (2.8 [1.1 to 8.2], P=0.037). We showed that rScO2 values changed significantly within the first few days of life in babies who received more painful stimuli compared with the control group, similar to behavioral and physiological responses.