Therapeutic hypothermia on neonatal transport: 4-year experience in a single NICU

Abstract

Objective: Therapeutic hypothermia instituted within 6 h of birth has been shown to improve neurodevelopmental outcomes in term newborns with moderate-to-severe hypoxic-ischemic encephalopathy (HIE). The majority of infants who would benefit from cooling are born at centers that do not offer the therapy, and adding the time for transport will result in delays in therapy, that may lead to suboptimal or no neuroprotection for some patients. Our objective was to evaluate the effect of our center's experience with therapeutic hypothermia on neonatal transport.

Study design: Retrospective review of all cases of therapeutic hypothermia at a single neonatal intensive care unit from 2005 to 2009.

Result: Of 50 infants with HIE treated with hypothermia, 40 were outborn and 35 were cooled on transport. The majority of patients were passively cooled by the referring clinicians, then actively cooled by our transport team. Overcooling to <32 degrees C occurred in 34% of patients, but there were no significant differences in admission vital signs or laboratory values between overcooled and appropriately cooled infants. The average time after birth of initiation of passive cooling was 1.4 h and active cooling was 2.7 h compared with the time of admission to our unit of 5.9 h.

Conclusion: We discuss the important aspects of our program, including the education of referring and receiving clinicians and avoidance of overcooling.

Figures

Figure 1

Cooling start time and the University of Virginia (UVA) arrival time. A total of 50 infants underwent hypothermia therapy at the UVA Neonatal Intensive Care Unit from March 2005 to February 2009. Cooling start time is shown for inborn infants (hours after birth, n=10, filled squares). Of the 40 outborn infants, 35 were cooled before and during transport, and 5 were not cooled until arrival at UVA (filled triangles). Cooling was classified as passive (no external heat source, filled circles) or active (application of cool gel packs, filled diamonds). Some infants underwent passive followed by active cooling and both start times are included. The arrival time at UVA for all 40 outborn infants is shown (open diamonds). Horizontal lines represent mean hours after birth.

Figure 2

Comparison of temperature of 40 outborn neonates with hypoxic–ischemic encephalopathy (HIE) before and after neonatal transport. The rectal temperatures of 40 outborn infants on arrival of the University of Virginia (UVA) transport team to the referring hospital and on arrival of the patients to the UVA Neonatal Intensive Care Unit. Five patients were not cooled until after arrival to UVA, two patients underwent passive cooling only and thirty-three patients underwent active cooling during transport.

Figure 3

The University of Virginia (UVA) admission temperature for 35 outborn infants cooled on transport. The rectal temperatures of 35 outborn infants cooled during transport, recorded on admission to the UVA Neonatal Intensive Care Unit. Gray-shaded area represents target temperature (33 to 34 °C). Two patients with only passive cooling during transport (indicated with an open circle) had admission temperatures of 34.4 and 34.8 °C. All others were transported with active cooling.