Effects of isoprenaline plus phenylephrine by pressurized aerosol on blood gases, ventilation, and perfusion in chronic obstructive lung disease.

The effects of a combined isoprenaline-phenylephrine inhalant in chronic obstructive lung disease were assessed in 23 patients. Significant changes occurred in blood gas tensions after inhalation, together with an overall improvement in ventilation/perfusion ratios. Cardiac output and physiological shunt were not significantly increased. Hence the addition of phenylephrine probably prevents the increase of hypoxaemia which may result from the disproportionate ventilation/perfusion ratio produced by sympathomimetics or xanthines used alone. The combination aerosol has a satisfactory bronchodilator effect, and is additionally safe if used by a severely hypoxic patient unaware of the seriousness of his condition.