Effects of oral and inhaled salbutamol and oral pirbuterol on right and left ventricular function in chronic bronchitis.

In many patients with chronic bronchitis and emphysema right and left ventricular ejection fractions (RVEF and LVEF) are reduced. A study was conducted using multiple gated equilibrium radionuclide ventriculography to compare the effects of oral salbutamol 4 mg and pirbuterol 15 mg on cardiac function in 12 patients with chronic bronchitis (forced expiratory volume in one second 0.86 (SEM 0.12) 1; arterial oxygen pressure 8.2 (SEM 0.5) kPa (61.7 (SEM 3.8) mm Hg)). Different doses of nebulised salbutamol (500 microgram and 5 mg) were also compared in nine of the patients. Both oral salbutamol and oral pirbuterol produced significant increases in RVEF and LVEF at 60 and 90 minutes after drug ingestion (p less than 0.01 in each case). There were no significant differences between salbutamol and pirbuterol in their effects on RVEF and LVEF. Inhaled salbutamol at doses commonly prescribed had no significant effect on RVEF and LVEF after 20 and 60 minutes. Salbutamol and pirbuterol given by mouth have similar actions on RVEF and LVEF. Further studies are necessary to assess the effects of long term B2 agonists in this group of patients.