Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1980
Nitroglycerin therapy for phenylephrine-induced hypertension in pregnant ewes.
Obstetrical situations in which endogenous or exogenous vasoactive amines precipitously increase maternal blood pressure and decrease uterine blood flow may be associated with increased maternal morbidity and mortality and with development of fetal acidosis and distress. We examined the effectiveness of nitroglycerin in lowering maternal blood pressure and increasing uterine blood flow during the infusion of the alpha-adrenergic agent phenylephrine. ⋯ While maintaining the phenylephrine infusion at a constant rate, the infusion of nitroglycerin rapidly returned maternal systemic pressure and pulmonary arterial pressure to control values, decreased total peripheral resistance to 18% above control, increased cardiac output to 12% below control, increased uterine artery blood flow to 30% below control, and increased the fetal arterial pH from 7.30 to 7.35 (p less than 0.05). It is concluded that maternal hypertension resulting from intense alpha-adrenergic stimulation may be treated rapidly and effectively by the intravenous infusion of nitroglycerin with a partial restoration (20%) of uterine artery blood flow toward control.