Hypothermia in the newborn

Abstract

With induced hypothermia, body temperature can go down to about 17°C and tissue metabolic needs are reduced to a bare minimum; circulatory arrest can be tolerated for 60 minutes in this temperature range, and the procedure offers a blood- less field of particular value in cardiac surgery. One disadvantage with hypothermia is redistribution of blood flow causing certain organs such as skeletal muscle to be poorly perfused and therefore warmer than other parts with a consequent intolerance of oxygen deprivation. Other problems include acid- base disturbances and possible neurologic defect directly related to the duration of the period of circulatory arrest. (Tyson, 1975). In the newborn, however, hypothermia is likely to produce catastrophic sequelae with a high fatality rate, particularly with temperatures below 32"C in the first day of life.(Arniel and Kerr, 1963). There is an increased mortality rate when temperatures drop below 36°C but the reasons for this are not clear. (Sinerman 58, 1963). Thermoregulation breaks down below 32° and may not recover for a few days, during which time the infant, readily assumes the environ- mental temperature and may also develop a bleeding tendency. (Cockburn & Drillien, 1974).