Hypocarbia is associated with adverse outcomes in hypoxic ischaemic encephalopathy (HIE)

Abstract

Aim: Hypocarbia in the early postnatal period might exacerbate brain injury in babies with hypoxic ischaemic encephalopathy following birth asphyxia. This mini-review summarised studies on pCO2 values that were monitored periodically in term newborns with moderate/severe hypoxic-ischaemic encephalopathy and correlated with short or long-term outcomes.

Methods: We searched the databases MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), web of science and the Cochrane Library and identified nine studies.

Results: Among the nine included studies, therapeutic hypothermia was administered in seven studies. In most studies, blood pCO2 levels were measured from birth till 72 h of life or till the endpoint of therapeutic hypothermia. Eight studies showed that any hypocarbia (moderate or severe, or cumulative) was associated with an increased risk of adverse outcomes in the form of brain injury in MRI, death or neurodevelopmental disability.

Conclusion: Hypocarbia could lead to adverse short-term and long-term outcomes despite therapeutic hypothermia in neonates with HIE. Hence, it is vital to monitor pCO2 levels closely in these infants and consider strategies to maintain pCO2 levels in the normal range.

Keywords: asphyxia; hypocapnia; newborn; outcome; therapeutic hypothermia.