Features
Implications
- Young children have an undeveloped hypothalamus
- Ability to regulate temperature is impaired
- Large surface area to weight ratio
- Increased thermal conductance
- Subcutaneous tissue is 20-30% thinner than adults
- Poorly developed shivering, sweating and vasoconstriction mechanisms
- Prone to excessive heat loss and thermoregulation easily overwhelmed by environmental conditions
- Requires higher optimal ambient temperature in neonates and young infants
- In neonates and young infants, heat production occurs through metabolism of brown fat (located in small amounts around the scapulae, the mediastinum, the kidneys and adrenal glands) - known as non-shivering thermogenesis
- Brown fat metabolism occurs at the expense of increased oxygen consumption
- Volatile agents inhibit brown fat metabolism further affecting temperature regulation during general anaesthesia
- Neonates and young infants have limited glycogen stores and rely heavily on gluconeogenesis for maintenance of glucose levels
- Hypoglycaemia is common in the stressed neonate and young infant
- Glucose levels should be monitored regularly in the neonatal period
- Infusions of 10% glucose may be required to prevent hypoglycaemia and resultant neurological damage
- Fat tissue as a proportion of body weight is higher in infants, peaking between 3–6 months of age
- Altered body composition may affect volume of distribution of certain drugs