Effect of whole body hypothermia on inflammation and surfactant function in asphyxiated neonates
T o the Editor: Hypothermia has become an evidence based treatment for neonates with hypoxic ischaemic encephalopathy (HIE) [1] The usefulness of hypothermia is due to several mechanisms and among these the reduction in inflammation seems to play a relevant role [2, 3] When applied as whole body hypothermia (WBH) cooling may affect other organs as well. Recent data showed better respiratory outcomes and trends towards lower inflammation in WBH treated preterm lambs [4] suggesting its possible usefulness to reduce lung injury through the modulation of the inflammatory pathway. By contrast, experiments with hibernating animals have shown that temperature induces significant adaptive changes to the surfactant composition and structure [5] Nevertheless, no data are currently available in humans. Two case reports have recently described an infant [6] and an adult [7] with severe lung injury, whose ventilation had been facilitated by concurrent hypothermia. Since hypothermia is an accepted therapy only for HIE, we designed a preliminary translational study to investigate the effect of WBH on inflammation and surfactant status in neonates with HIE unaffected by any pulmonary injury. Eligible babies were neonates with HIE who required WBH according to TOBY (total body hypothermia trial) criteria [8] Control babies were normothermic neonates matched for gestational age and SNAPPE II (Score for Neonatal Acute Physiology and Perinatal Extension II) score, born within 2 months of the HIE cases and needing intubation for surgical procedures during the first day of life. Both cases and controls had to be free from any pulmonary disease and fulfil the following criteria: 1) normal chest radiograph and auscultation; 2) inspiratory oxygen fraction of 0.21 to achieve arterial oxygen saturation =95% 3) normal amniotic fluid; 4) no signs of infection; and 5) no congenital lung disease or complex
European Respiratory Journal