Cooling Effect on Skin Microcirculation in Asphyxiated Newborn Infants with Increased C-Reactive Protein

Abstract

Background: Therapeutic hypothermia is presumed to suppress inflammatory processes after perinatal asphyxia. In a previous study of neonatal hypoxic-ischemic encephalopathy (HIE) we found altered skin microcirculation in about a third of the infants after rewarming. We speculated whether this could be linked to increased inflammatory responses, such as high C-reactive protein (CRP). The present study further explored this question. Objective: The aim of this study was to explore the differences in skin microcirculation and its oxygen delivery ability during cooling and after rewarming in HIE infants with or without high CRP. Methods: A previously studied population of 28 HIE infants was divided into two subgroups depending on low or high CRP (repeated values above 30 mg/l for more than 24 h). The differences between the two groups regarding laser Doppler perfusion measurements (LDPMs), computer-assisted video microscopy and diffuse reflectance spectroscopies during cooling on days 1 and 3 and after rewarming on day 4 were assessed. Results: After rewarming, infants with high CRP showed significantly higher skin LDPM perfusion, lower functional vessel density and larger heterogeneity of capillary flow velocities as compared to infants with low CRP, while no such differences were found during cooling. Conclusion: Skin microcirculatory responses differed significantly after rewarming, but not during cooling, between asphyxiated neonates with or without high CRP. We speculate whether cooling influences the inflammatory skin microcirculatory response and the ability of oxygen delivery to the cells. Further studies are needed to investigate this as well as its applicability to other vascular beds in the body.