Halothane and Phaeochromocytoma. a Case Report.

SUMMARY A further instance of the successful removal of a phaeochromocytoma is reported and it is suggested that halothane, despite theoretical contraindications, may be the anaesthetic agent of choice for this procedure. The possible value of (a) prolonged pre-operative preparation with either oral phentolamine or phenoxybenzamine with or without pronethalol, (b) pre-operative blood volume studies, and (c) central venous pressure recordings during the operative procedure, should be investigated. It may be that, with these precautions, the choice of anaesthetic agent and technique will require further evaluation. Phaeochromocytomas are tumours of the sympathetic nervous system which secrete excessive quantities of the catecholamines, adrenaline and noradrenaline, and occasionally dihydroxytyra-mine and other related compounds, in varying proportions into the blood stream and the abnormalities presented by the patient can be accounted for by the known physiological effects of these amines. Some phacochromocytomas discharge catechol-amines continuously resulting in sustained hypertension^ while others do so intermittently giving rise to paroxysms of hypertension. Clinical confirmation of the diagnosis in these cases may be afforded by means of the phentolamine test (Helps, Robinson and Ross, 1955) and the demonstration of excess catecholamines in the urine (Hingerty, 1957). The phentolamine test, unfortunately, gives so many spurious positive results that some regard it as wellnigh useless (Frazer, S. C, personal communication, 1963). A small proportion of patients, however, with a secreting phaeochromocytoma are normotensive when under observation and give no history of attacks, but a histamine provocation test may provide clinical confirmation of the diagnosis (Roth and Kvale, 1945), although this test is now seldom used. These cases are 3 indeed, the ones which the anaesthetist should be particularly aware of, for they may first reveal themselves during elective surgery. It has been estimated that 6-8 of every 2,000,000 patients anaesthetized in this country may have an unsuspected phaeochromo-cytoma (Ainley-Walker, 1962). As 90 per cent of these tumours are reputed to be benign, the majority of these patients should be completely curable. Anaesthetists should, therefore, be able to suspect the diagnosis in the first place and have that discipline of reaction necessary to avoid a fatal outcome from cerebral haemorrhage, acute pulmonary oedema or ventricular fibrillation. Much has been written regarding the anaesthetic management of patients with phaeochro-mocytoma but most of the anaesthetic techniques employed have been associated with violent blood pressure swings, in spite of the aid of phentolamine. Although concern has been expressed regarding the use of …