Use of a microprocessor in the control of malignant hypertension with sodium nitroprusside

In a malignant hypertensive, steady control of blood pressure at a pre-determined level has been achieved with the continuous intravenous infusion of sodium nitroprusside. A microprocessor was programmed to assess the patient's blood pressure and adjust the rate of nitroprusside infusion so that a mean pressure of 106 mmHg was achieved. Brief interruption of the nitroprusside infusion allowed the effectiveness of changes in oral therapy to be evaluated. Thiocyanate concentrations were measured throughout as an index of potential nitroprusside toxicity. After six days, blood pressure control was maintained with oral therapy alone and papilloedema had almost resolved.