Improved haemodynamics but reduced arterial blood oxygenation, at rest and during exercise after long-term oral prazosin therapy in chronic cor pulmonale.

The effect of vasodilator therapy in chronic obstructive lung disease with pulmonary hypertension was evaluated in eight patients during oral prazosin therapy (2-10 mg day-1). After one week, prazosin reduced mean pulmonary artery pressure and pulmonary and systemic vascular resistance, and increased cardiac index both at rest and during exercise. Similarly improved haemodynamics were observed after two months of therapy. Arterial PO2 and oxygen saturation fell significantly after two months both at rest and during exercise, but were not changed after one week. Lung function tests were not altered by prazosin. Thus, although prazosin improves the haemodynamics in patients with chronic obstructive lung disease, caution is advised in long-term therapy since prazosin worsens the arterial blood oxygenation.

Improved cardiac performance by salbutamol, a selective beta 2-agonist, in chronic cor pulmonale.

The effects of salbutamol, a relative specific beta 2-agonist, on hemodynamics and arterial blood oxygenation, were studied in 12 patients with chronic cor pulmonale. The studies were done during heart catheterization at rest (n = 12) and during arm bicycle exercise (n = 7) before and during salbutamol infusion of 0.2 microgram/kg/min. At rest, salbutamol significantly increased cardiac index on average by 31%, stroke volume index by 11%, and heart rate by 12 beats/min. Mean pulmonary artery pressure was not changed by salbutamol, whereas a small reduction in mean arterial pressure was observed. The vascular resistance was reduced by 15% in pulmonary and 24% in systemic circulation. Similar hemodynamic changes by salbutamol were observed during exercise. Arterial oxygen tension and saturation were not changed by salbutamol, but a significant rise in mixed venous oxygen saturation and oxygen delivery were observed both at rest and during exercise. Thus, salbutamol infusion improves the cardiac performance in patients with chronic cor pulmonale through a chronotropic effect combined with vasodilation in both the systemic and pulmonary circulation and thereby increased stroke volume. No deleterious effects on arterial blood oxygenation by salbutamol infusion were observed.

Bacteriological findings in the transtracheal aspirate from patients with acute exacerbation of chronic bronchitis.

Transtracheal aspirates from 87 patients with acute exacerbations of chronic bronchitis who had received no recent antibiotic treatment were examined. A single bacterial species was found in 83% of positive cultures. Predominant pathogens were Haemophilus influenzae and Streptococcus pneumoniae which occurred jointly or separately in 50% of positive cultures. Bacteria traditionally considered as non-pathogenic for the lower respiratory tract also appeared to play an aetiological role. Enterobacteriaceae and anaerobes were infrequent. No bacterial growth was found in 11 cases.