Objectives: To evaluate the effect of oral sucrose on skin blood flow (SBF; perfusion units; PU) measured by Laser Doppler Imager (LDI) in term newborns and pain response (Neonatal Infant Pain Scale score; NIPS score) during heel lance; (2) determine SBF changes during heel lance; and (3) the relationship between SBF and NIPS.
Materials and Methods: Term infants ≤7 days old (n=56) undergoing routine heel lance were randomized to pretreatment with 2.0 mL oral 24% sucrose (n=29) or sterile water (n=27) in a double-blinded, placebo-controlled trial. SBF was assessed by LDI scans and NIPS scores at 10 minutes before lance, immediately after lancing, and 5 minutes after blood extraction. Mean SBF and median NIPS scores were compared between groups using General Linear Model or Kruskal-Wallis. Regressions examined the relationship between SBF immediately after heel lance and NIPS score.
Results: Mean SBF and median NIPS scores immediately after heel lance were lower in sucrose-treated infants (167.9±15.5 vs. 205.4±16.0 PU, P=0.09; NIPS 1 [interquartile range 0 to 4] vs. NIPS 3 [interquartile range 0 to 6], P=0.02), although no significant difference in mean SBF. During heel lance NIPS score was predictive of SBF. An increase of 1 in NIPS score was associated with 11 PU increase in SBF (R2=0.21; P=0.09) for sucrose, and 16 PU increase for placebo-treated infants (R2=0.20; P=0.014).
Conclusions: Increased SBF assessed by LDI is a pain response among term neonates after routine heel lance, which was not completely attenuated by oral sucrose administration. Increased SBF is associated with NIPS scores. Sucrose analgesic efficacy evidenced by decreased NIPS scores for the sucrose group. Association of SBF with NIPS scores suggests that LDI is potentially useful for assessing newborn procedural pain.