Background: Therapeutic hypothermia, a safe and effective treatment for neonatal encephalopathy in an intensive care setting, is not available in low-resource settings.
Aims/Methods: To assess two low-tech, low-cost cooling devices for use in low-resource settings: (i) commercially available water bottles filled with tepid water (25°C); (ii) a mattress made of phase changing material (PCM) with a melting point of 32°C (PCM works as a heat buffer at this temperature). Eleven anaesthetised newborn piglets were studied following transient hypoxia–ischaemia. The cooling device was applied 2–26 h after hypoxia–ischaemia with a target rectal temperature (Trectal) of 33–34°C. Trectal undershoot was adjusted using cotton blankets; the cooling device was renewed when Trectal rose above 35°C. Trectal data during cooling were dichotomised (within or without target) to assess: (a) the total period within the target Trectal range; (b) the stability and fluctuation of Trectal during cooling.
Results: Therapeutic hypothermia was achieved with both water bottles (n = 5) and the PCM mattress (n = 6). The mean (SD) time to reach target Trectal was 1.8 (0.5) h with water bottles and 1.9 (0.3) h with PCM. PCM cooling led to a longer period within the target Trectal range (p<0.01) and more stable cooling (p<0.05). Water bottle cooling required device renewal (in four out of five piglets).
Conclusion: Simple, low-tech cooling devices can induce and maintain therapeutic hypothermia effectively in a porcine model of neonatal encephalopathy, although frequent fine tuning by adjusting the number of blankets insulating the piglet was required to maintain a stable temperature. PCM may induce more stable cooling compared with water bottles.
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Competing interests: None.
Funding: This work was undertaken at UCLH/UCL who received a proportion of funding from the United Kingdom Department of Health’s NIHR Biomedical Research Centres funding scheme.
▸ Additional material is published online only at http://adc.bmj.com/content/vol94/issue5