Pulmonary artery pressure, reduction inhaled nitric oxide

We challenged 12 patients with congenital heart disease and pulmonary hypertension preoperatively in the cardiac catheterization laboratory and nine postoperative patients (after cardiopulmonary bypass) with a 2-min infusion of 10 M acetylcholine into the pulmonary artery. The nine postoperative patients received a 15-min trial of inhaled nitric oxide following the infusion of acetylcholine. The results are shown in Figs. 4 and 5. The decrease in pulmonary artery pressure and resistance in the preoperative patients in response to acetylcholine was markedly attenuated postoperatively. The percentage reductions in pulmonary artery pressure preoperatively were 27% 4% and 9% 2% P < 0.003) postoperatively. Similarly, pulmonary vascular resistance decreased by 46% 5% compared to 11% 4% P < 0.002). However, the response to inhaled nitric oxide in the postoperative patients was marked vasodilation contrasted with the blunted effect of acetylcholine. Mean pulmonary artery pressure (34.4 2.6 versus... 

FIGURE 6 Bedside monitor recording of systemic artery pressure (SAP) and pulmonary artery pressure (PAP) in a 7-month-old child with postoperative pulmonary hypertension refractory to treatment, including hyperventilation with oxygen, anesthesia, alkalosis, nitroprus-side, prostaglandin E, and acetylcholine. Administration of 80-ppm inhaled nitric oxide produced an immediate reduction in PAP, with little effect on SAP. 

FIGURE 10 Effects of nitric oxide (NO) inhalation on pulmonary artery (PA) pressure (PAp) and trapulmonary shunt fraction (Qs/Qt) in one patient during the first 36 hr after lung transplantation. PAp and Qs/Qt improved with NO and deteriorated during reductions in the NO dose. [Reproduced with permission from Adatia et al. (77).]... 

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