Passive induction of hypothermia during transport of asphyxiated infants: a risk of excessive cooling

Background: Induced mild hypothermia is an emerging therapy that has been shown to reduce the combined outcome of death or severe neurodevelopmental disabilities in asphyxiated full-term infants if started within 6 h after birth. Aim: To study the feasibility and safety of inducing hypothermia in asphyxiated infants already at the referring hospital by stopping active warming. Methods: Temperatures during passive induction of hypothermia were prospectively collected from transported asphyxiated infants. Results: Between December 2006 and April 2008, 37 infants of the total birth cohort of 40 350 fulfilled the criteria for hypothermia treatment. Eighteen of 34 infants treated with induced hypothermia were outborn. The rectal temperatures of the infants were 33.0-36.4 degrees C before transport and 31.0-36.5 degrees C on arrival. Six of the infants had a sub-therapeutic (< 33.0 degrees C) rectal temperature on arrival. Conclusion: Passive induction of hypothermia by turning off active warming devices is possible, making an earlier start of hypothermia achievable. However, there is a substantial risk of unintended excessive cooling; therefore, continuous monitoring of the central temperature is mandatory when such a strategy is used.