Chest
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The experience we describe derives from the short-term administration of isoproterenol in 15 patients with ventricular septal defect (VSD) and severe pulmonary artery hypertension (PAH). For the whole study group, mean pulmonary artery pressure (PAP) was 68.5 +/- 2.6 mm Hg, pulmonary vascular resistance (Rp) was 11.6 +/- 0.9 U/m2, pulmonary vascular resistance/systemic vascular resistance ratio (Rp/Rs) was 0.9 +/- 0.03, and the pulmonary vascular gradient (PAd-PWP) was 45 +/- 3.5 mm Hg. Infusions of isoproterenol decreased PAP, Rp, Rp/Rs ratio, and PAd-PWP an average of 10.2 mm Hg, 2.88 U/m2, 0.13 and 6.6 mm Hg, respectively, for the whole group (P less than 0.001). ⋯ Group A patients underwent VSD repair, and the mean average postoperative decrease in PAP was 31 mm Hg (P less than 0.001). Our findings suggest that in patients with VSD and severe PAH, in whom surgical treatment is controversial, a trial with isoproterenol should be routinely attempted. If the preceding hemodynamic parameters improve significantly, the VSD repair should be performed.
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An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (133Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. ⋯ Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal.