Feasibility and Safety of Controlled Active Hypothermia Treatment During Transport in Neonates With Hypoxic-Ischemic Encephalopathy

Abstract

Objectives: To evaluate the feasibility and safety of controlled active hypothermia versus standard intensive care during neonatal transport in patients with hypoxic-ischemic encephalopathy.

Design: Cohort study with a historic control group.

Setting: All infants were transported by Neonatal Emergency & Transport Services to a Level-III neonatal ICU.

Patients: Two hundred fourteen term newborns with moderate-to-severe hypoxic-ischemic encephalopathy. An actively cooled group of 136 newborns were compared with a control group of 78 newborns.

Interventions: Controlled active hypothermia during neonatal transport.

Measurements and main results: Key measured variables were timing of hypothermia initiation, temperature profiles, and vital signs during neonatal transport. Hypothermia was initiated a median 2.58 hours earlier in the actively cooled group compared with the control group (median 1.42 [interquartile range, 0.83-2.07] vs 4.0 [interquartile range, 2.08-5.79] hours after birth, respectively; p < 0.0001), and target temperature was also achieved a median 1.83 hours earlier (median 2.42 [1.58-3.63] vs 4.25 [2.42-6.08] hours after birth, respectively; p < 0.0001). Blood gas values and vital signs were comparable between the two groups with the exception of heart rate, which was significantly lower in the actively cooled group. The number of infants in the target temperature range (33-34°C) on arrival was 79/136 (58.1%) and the rate of overcooling was 16/136 (11.8%) in the actively cooled group. In the overcooled infants, Apgar scores, pH, base deficit, and eventual death rate (7/16; 43.8%) indicated more severe asphyxia suggesting poor temperature control in this subgroup of patients. Adverse events leading to pulmonary or circulatory failure were not observed in either groups during the transport period.

Conclusions: Therapeutic hypothermia during transport is feasible and safe, allowing for significantly earlier initiation and achievement of target temperature, possibly providing further benefit for neonates with hypoxic-ischemic encephalopathy.