Effect of freon inhalation on maximal expiratoryflows and heart rhythm after treatment with salbutamol and ipratropium bromide.

The purpose of this investigation was to determine whether inhalation of a freon gas mixture, the propellant of the commercial metered-dose aerosols, consisting of freon 11, freon 12, and freon 114, reduces the bronchodilating effects of inhaled salbutamol or ipratropium bromide or causes cardiac arrhythmias in control, asthmatic and bronchitic subjects. FEV1 and flows measured at different lung volumes on the maximal effort expiratoryflow-volume curve were measured during a period of 6 h. Inhalation of freon caused no significant overall reduction in the salbutamol and ipratropium bromide response in any group. Arrhythmias only occurred among the asthmatic and bronchitic patients, and were most frequent after salbutamol. Ventricular extrasystoles occurred in three cases, all after salbutamol and in two of these in combination with freon inhalation. In one patient there was furthermore hyposia and hypercapnia. The combination of the effects of hypoxia, hypercapnia, catecholamines and freon on the heart is therefore a more likely cause of arrhythmia than the effect of freon alone.