Effect of inspired gas temperature on lung mechanics and gas exchange in neonates in normothermia or therapeutic hypothermia

Background Respiratory critical care guidelines suggest heating the air/oxygen mixture but do not recommend a specific temperature target. We aimed to clarify if inspired gas influences lung mechanics and exchange in intubated patients treated with whole body hypothermia (WBH) or normothermia (NT). Methods Prospective cohort study enrolling neonates ventilated for perinatal asphyxia resuscitation (no disease) acute hypoxemic respiratory failure. Patients were divided between those NT WBH. Compliance (Cdyn), airway resistances (Raw), oxygenation index (OI), PaO2/FiO2, A-a gradient, a/A ratio, estimated alveolar dead space (VDalv), ventilatory (VI) CO2 production (VCO2) registered at beginning (inspired 37°C). Then, was decreased (32 °C) variables recorded again after 1 3 h. Data analysed univariate multivariate repeated measures-ANOVA. Results Cdyn, Raw, OI, VDalv, VI VCO2 are similar WBH any timepoint (between-subjects effect); these results change adjusting presence of When this is considered ANOVA (within-subjects effect), Cdyn (p = 0.016), Raw 0.034) VDalv < 0.001) worse failure than without disease. Conclusions Decreasing from 37 °C 32 h does exchange, neither with, nor These findings fill knowledge gap regarding effect during WBH: they may inform future guidelines.