Value of intracranial pressure monitoring of asphyxiated newborn infants.

Twenty-three infants suffering the effects of moderate or severe hypoxic-ischaemic encephalopathy were continuously monitored for intracranial pressure (ICP) by means of a subarachnoid catheter for a total of 1083 hours. Cerebral perfusion pressure (CPP) was also continuously monitored for 21 of the infants. The median age at the start of ICP monitoring was 17 hours, and the opening pressure correlated poorly with maximum sustained pressures. Maximum sustained ICP allowed the infants to be divided into three groups: (1) those with no elevation of ICP (nine), of whom two died and five had a normal outcome; (2) those with sustained rises in ICP which were resistent to treatment (nine), of whom seven died and two survivors are severely handicapped; and (3) those in whom the pressure was elevated but could be controlled medically (five), of whom two survived to be quite normal. No infant with a sustained elevation of ICP of 15mmHg or more survived to be normal, nor any who had had a CPP below 20mmHg for one hour or more. Hypotension was the cause of low CPP in most cases. There was a highly significant correlation between sustained elevation of ICP above 10mmHg and poor outcome, but no correlation between outcome and minimum CPP. It was not possible to predict clinically which infants would develop intracranial hypertension, and some infants with very severe perinatal asphyxia did not develop intracranial hypertension, and some infants with very severe perinatal asphyxia did not develop raised intracranial pressure at any time.