From the Guidelines
Hypothermia in a neonate is defined as a body temperature below 36.5°C (97.7°F), with moderate hypothermia being a temperature less than 36°C, and it is a significant risk factor for mortality and morbidity in premature infants. According to the 2015 guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care 1, it is recommended that the temperature of newly born nonasphyxiated infants be maintained between 36.5°C and 37.5°C after birth through admission and stabilization. Newborns are particularly vulnerable to hypothermia due to their large surface area relative to body weight, limited subcutaneous fat, immature temperature regulation mechanisms, and limited ability to generate heat through shivering.
Classification and Prevention
Hypothermia can be classified as mild (36.0-36.4°C), moderate (32.0-35.9°C), or severe (below 32.0°C) 1. Prevention is crucial and includes drying the baby immediately after birth, delaying the first bath, maintaining a warm delivery room, using hats and warm blankets, and practicing skin-to-skin contact. Strategies to minimize heat loss, such as the use of occlusive wrapping, exothermic warming mattress, warmed humidified resuscitation gases, polyethylene caps, and increasing delivery room temperature, have been introduced to prevent hypothermia in preterm infants 1.
Treatment and Complications
Treatment involves immediate warming through skin-to-skin contact with the mother (kangaroo care), wrapping the baby in pre-warmed blankets, using radiant warmers or incubators set to 36.5-37.5°C, and ensuring the room temperature is at least 25°C (77°F) 1. For moderate to severe cases, warming should be gradual to avoid complications, although the optimal rate of rewarming is not well established, with some guidelines suggesting either rapid (0.5°C/h or greater) or slow rewarming (less than 0.5°C/h) may be reasonable 1. Hypothermia can lead to serious complications including hypoglycemia, metabolic acidosis, respiratory distress, and increased mortality, so prompt recognition and intervention are essential.
Resource-Limited Settings
In resource-limited settings, maintaining body temperature or preventing hypothermia during transition (birth until 1 to 2 hours of life) in well newborn infants can be achieved by putting them in a clean food-grade plastic bag up to the level of the neck and swaddling them after drying, or through skin-to-skin contact or kangaroo mother care 1. These methods may be reasonable alternatives to more advanced warming techniques, highlighting the importance of adapting guidelines to the available resources while prioritizing the prevention of hypothermia and its associated morbidities and mortalities.
From the Research
Definition of Hypothermia in Newborns
- Hypothermia in newborns is defined as a drop in the newborn's core temperature less than 36.5°C 2
- It is a significant concern in neonatal care, particularly in preterm infants, and is associated with increased morbidity and mortality 2, 3
Causes and Risk Factors
- Neonates are vulnerable to hypothermia due to a low temperature environment, physiological function, and many other factors 4
- Risk factors for hypothermia include lower gestational age, increased multiples, lower APGAR score, lower birth weight, and lack of antenatal steroids 2
- Hypothermia is also associated with deliveries from outside hospitals, operative or instrumental delivery, prematurity, low birth weight babies, time taken to transfer the baby, and inadequate clothing after delivery 3
Detection and Prevention
- Thermal care is a critical part of caring for neonates, and simple, affordable, and effective tools for detecting hypothermia are needed, especially in resource-poor countries 5
- Devices such as ThermoSpot can be used to detect hypothermia, but their sensitivity and accuracy need to be improved 5
- Skin-to-skin care is an effective method for preventing hypothermia, but when it is not feasible, other warming devices such as radiant warmers, conductive warmers, and incubators can be used 6
Consequences of Hypothermia
- Hypothermia is associated with increased mortality and morbidity rates in affected neonates, including prolonged need for respiratory support, higher rates of pulmonary hemorrhage, sepsis, intraventricular hemorrhage (IVH), and necrotizing enterocolitis, longer hospital stay, and mortality 2
- Hypothermic infants have a three-fold higher mortality and morbidity, and a longer stay in the unit, and are more likely to have post-natal weight loss 3