Hypocapnia in early hours of life is associated with brain injury in moderate to severe neonatal encephalopathy.

Objective: To evaluate the association between hypocapnia within the first 24 h of life and brain injury assessed by a detailed MRI scoring system in infants receiving therapeutic hypothermia (TH) for neonatal encephalopathy (NE) stratified by the stage of NE. Study

Design: This retrospective cohort study included infants who received TH for mild to severe NE.

Results: 188 infants were included in the study with 48% having mild and 52% moderate-severe NE. Infants with moderate-severe NE spent more time in hypocapnia (PCO2 ≤ 35 mmHg) and presented with more severe brain injury on MRI compared to mild cases. The MRI injury score increased by 6% for each extra hour spent in hypocapnic range in infants with moderate-severe NE. There was no association between hypocapnia and injury scores in mild cases.

Conclusion: In infants with moderate-severe NE, the hours spent in hypocapnia was an independent predictor of brain injury.