Intravenous Isosorbide Dinitrate in the Management of Acute Hypertension Following Cardiopulmonary Bypass

Twenty-one patients with acute systemic hypertension following cardiopulmonary bypass received isosorbide dinitrate intravenously in order to determine its effectiveness in managing this postoperative problem. Twenty patients underwent coronary artery bypass operation, and 1 patient had a pulmonary valvotomy. Bolus administration (0.25 to 2.5 mg [3.0 to 40.0 μg per kilogram]) decreased systemic systolic blood pressure 23% and diastolic blood pressure 25% (both, p < 0.01). Continuous controlled infusion (0.125 to 0.332 mg per minute [1.5 to 6.0 μg/kg/min]) caused a more modest drop in systemic blood pressure, with a 17% reduction in systolic blood pressure and an 11% drop in diastolic blood pressure (both, p < 0.05). Additional pressure reduction and maintenance therapy were provided by intermittent bolus administration or a continuous infusion. Moderate venodilation (decrease in central venous pressure) accompanied the systemic pressure response. The heart rate was not appreciably altered and, with the exception of 1 patient in whom systemic pressures were reduced to 105/60 mm Hg after bolus infusion, the desired level of systolic, diastolic, and mean arterial pressures were readily titrated and maintained in a stable, predictable manner. These observations suggest that intravenously administered isosorbide dinitrate is a practical, safe, and highly effective method of treatment of hypertension following cardiopulmonary bypass.