EFFECT OF INHALED NITRIC OXIDE (NO) AND pH ON PULMONARY VASCULAR RESISTANCE(PVR) IN THROMBOXANE INDUCED PULMONARY HYPERTENSION. 1974

We investigated whether the effect of inhaled Nitric oxide (NO) is modified by acid base status. In 10 piglets (7-24 days), 3 levels of respiratory acid base condition (pH: 7.35-7.42 [EUCP], < 7.15 [ACID], >7.50 [ALK]) were tested at similar levels of ventilatory support (mean airway pressure:11 cm H₂O and 40% FiO₂), by the creation of a variable size dead space. Mean pulmonary artery pressure (mPAP) was doubled by the continuous infusion (0.06-0.187 μg/kg/min) of a thromboxane mimetic (U46,619). Thereafter, inhaled NO was tested at 40 and 80 ppm for 20 minutes at each pH. The order of interventions was randomized. Results are shown as mean ± s.e.m. Inhaled NO reduced PVR and improved oxygenation by a similar degree at all pH. Table

Table 1