Effects ofSublingual Nitroglycerin on Resting Pulmonary GasExchange andHemodynamics inMan

SUMMARY Simultaneous hemodynamic, ventilation and bloodgas measurements were performed in 19 males during cardiaccatheterization for evaluation ofchest painsyndromebefore and3 to 5 min after 0.4 mg sublingual nitroglycerin. Pulmonary arterialpressures and total pulmonaryvascular resistancefell (P < 0.001 forboth), and mean systemic arterial pressure decreased (P < 0.05).However, peripheral vascular resistance, cardiac output, andmixedvenous PG2 did not change.Total and tidal ventilation, PCO2, pH,andbase excess remained VASODILATORSare being used with increasing frequen-cy for thetreatment of patients withcongestiveheartfailureofvarious etiologies in addition to their usual indication forthe therapy ofangina pectoris and hypertension. In a recentwork from this institution it was demonstrated that in 16patients with advanced congestive heart failure to whomsodium nitroprusside was administered intravenously, there was a reduction in systemicarterial oxygen pressure (PaO2) and an increase in