Special considerations in the premature and ex-premature infant

Abstract

The premature infant is defined as a live birth of less than 37 weeks' gestation. In the UK, premature babies account for 13% of registrable births and 47% of neonatal deaths. There is an increased association with congenital abnormalities, particularly in babies who are small for gestational age. Specific problems include perinatal asphyxia, hyaline membrane disease, bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, jaundice, intraventricular haemorrhage, retinopathy of prematurity, hypoglycaemia, haemorrhagic disease, increased susceptibility to infection and lack of thermoregulation. Anaesthesia for the premature infant is challenging. Many of these babies have multi-system pathology and require meticulous preoperative assessment. Vascular access is often problematic. Drug metabolism may be reduced and excretion impaired due to immature renal function. Ventilation should be adjusted with changing lung compliance to minimize barotrauma and high oxygen concentrations. Fluids should be administered cautiously, but fluctuations in blood pressure should be avoided to reduce the possibility of ischaemic and haemorrhagic cerebral injury. All neonates feel pain. Adequate analgesia improves surgical outcome and is essential to suppress the stress response and reduce variations in blood pressure. Postoperative apnoea is a common complication. The main predictors are gestational age, postconceptional age, previous apnoeic episodes and anaemia. There is some evidence that caffeine, 10 mg/kg, may reduce this incidence.