The effect of high-dose fentanyl anaesthesia (75 micrograms kg-1) on the metabolic and endocrine responses to cardiac surgery was compared with results obtained in similar patients who had received incremental doses of papaveretum. High-dose fentanyl anaesthesia prevented the increases in blood glucose, plasma cortisol and plasma growth hormone concentrations found before cardiopulmonary bypass, but during cardiopulmonary bypass was only effective in decreasing the hyperglycaemia. The continued administration of fentanyl following operation failed to suppress the hormonal and metabolic changes so that the total urinary excretion during the first 5 days after surgery was similar in both groups of patients. High-dose fentanyl anaesthesia was associated with only transient metabolic benefits confined to the period during operation.

The surgical treatment of giant intracranial aneurysms can be aided by using cardiopulmonary bypass to provide hypotension under hypothermic conditions. Cardiopulmonary techniques need to be modified to deal with the problems that arise during this type of neurosurgery.