HEMODYNAMIC MEASUREMENTS DURING CONTROLLED HYPOTENSION BY NITROGLYCERIN

  • 1 January 1980
    • journal article
    • research article
    • Vol. 29  (10) , 542-546
Abstract
In 9 patients undergoing neurosurgical operations for cerebral aneuryms hemodynamic measurements were made before, during and after continuous i.v. administration of nitroglycerin at a mean dose of 6.5 .mu.g/kg .cntdot. min during 60 min. Within 15 min of the start of the infusion mean arterial pressure fell from 94.2 .+-. 10.5 to 73.4 .+-. 11.1 mm Hg. A further decrease of mean arterial pressure even by a substantial raising of the nitroglycerin dose was not possible. Fifteen minutes after the discontinuation of nitroglycerin administration mean arterial pressure rose to the preinfusion level. The decrease of stroke volume index from 40.8 .+-. 9.0 to 31.0 .+-. 7.3 ml/m2 was partially compensated by an increase of heart rate from 65.9 .+-. 9.6 to 77.7 .+-. 19.4 beats/min. Consequently cardiac index fell only slightly from 2.9 .+-. 0.6 to 2.5 .+-. 0.5 ml/min .cntdot. m2. The right atrial pressure decreased to 3.3 .+-. 2.9 mm Hg, the mean pulmonary arterial pressure to 6.3 .+-. 1.9 mm Hg and the pulmonary capillary wedge pressure to 2.3 .+-. 2.1 mm Hg. The significant fall of total peripheral resistance to 983 .+-. 194 dyn .cntdot. s/cm5 (P < 0.05) and the decrease of left ventricular stroke work index to 34.7 .+-. 11.5 g .cntdot. m/m2 contributed to reduce myocardial O2 consumption. Due to its effect on blood pressure, its reversibility of action and its absence of adverse side effects nitroglycerin is a valuable agent for controlled hypotension.