COMPARISON OF THE EFFECT OF INHALED NITRIC-OXIDE AND INTRAVENOUS NITROGLYCERINE ON HYPOXIA-INDUCED PULMONARY-HYPERTENSION IN PIGS

Pulmonary hypertension is usually treated with intravenous (i.v.) vaso dilators, but their use is limited by systemic effects. In the current study, we compared the effects of inhaled nitric oxide and intravenou s nitroglycerine on pulmonary and systemic haemodynamic responses as w ell as on gas exchange measurements in anaesthetized pigs whose pulmon ary pressure was increased by hypoxia (FiO(2)=15%). Both treatments re duced pulmonary pressure to the control level. Inhaled nitric oxide di d not affect systemic arterial pressure but intravenous nitroglycerine decreased it from 126.2 to 108.8 mmHg (P=0.04). Unlike intravenous ni troglycerine, inhaled nitric oxide increased arterial PaO2 from 5.3 to 5.9 kPa (P=0.02). Both treatments diminished central venous pressure and left atrial pressure, suggesting a possible cardiac effect. Inhale d nitric oxide was shown to be a potent pulmonary vasodilator which at tenuated pulmonary hypertension and improved arterial oxygenation with out important direct effects on systemic pressure in porcine hypoxia-i nduced pulmonary hypertension.