Selective cerebralhypothermia for post-hypoxic neuroprotection in neonates using a solid ice cap

• Main Authors: Horn, A R, Woods,D L, Thompson, C, Els, I, Kroon, M
• Format: Article in Journal/Newspaper
• Language: English
• Published: University of Cape Town 2006
• Subjects: Mutton; Ice cap
• Online Access: http://hdl.handle.net/11427/24419; https://open.uct.ac.za/bitstream/11427/24419/1/Horn_Selective_2006.pdf

Objective. The main objective of this study was to study the safety and efficacy of a simple, cost-effective method of selective head cooling with mild systemic hypothermia in newborn infants with hypoxic ischaemic encephalopathy. Design. Ethical approval was obtained for a randomised controlled study in which 20 asphyxiated neonates with clinical signs of hypoxic ischaemic encephalopathy would be randomised into cooled and non-cooled groups. However, after cooling the first 4 babies, it was clear that repeated revisions to the cooling technique had to be made which was inappropriate in the context of a randomised controlled trial. The study was therefore stopped and the data for the 4 cooled infants are presented here in the form of a technical report. Hypothermia was achieved by applying an insulated ice cap to the heads of the infants and replacing it at 2 - 3-hourly intervals, aiming to achieve a target rectal temperature of 35 - 35.5°C and a target scalp temperature of 10 - 28°C. Setting. This study was carried out between July 2000 and September 2001 in the neonatal units of Groote Schuur Hospital and Mowbray Maternity Hospital, Cape Town. Subjects. Term infants with signs of encephalopathy were recruited within the first 8 hours of life if they had required resuscitation at birth and had significant acidosis within the first hour of life. Results. Target rectal temperature was achieved in all infants, but large variations in incubator and scalp temperatures occurred in 3 of the 4 infants. Reducing the target core temperature in a stepwise manner did not prevent excessive temperature variation and resulted in a longer time to reach target temperature. There was least variation in scalp temperature when the ice pack was covered in two layers of mutton cloth before application, but the resulting scalp temperatures were above the target temperature. The maximum scalp temperature variation was reduced from 22°C to 12°C using this method. Nasopharyngeal temperatures varied excessively within less than a minute, ...