COMBINED RESPIRATORY EFFECTS OF COLD AIR WITH SO2 OR NO2 IN REPEATED 10-MINUTE EXPOSURES OF HYPERVENTILATING GUINEA PIGS

Abstract

Previous studies in asthmatic subjects and guinea pigs have demonstrated attenuation of bronchoconstriction in repeated exposures to clean cold dry air. In the present animal study, we have simulated short-lasting human exposures to subfreezing urban air containing sulfur dioxide (SO2) and nitrogen dioxide (NO2). The anesthetized, paralyzed, and mechanically ventilated guinea pigs had 4 consecutive 10-min exposures either to clean cold dry air or to cold air with graded concentrations of SO2 (0-5 ppm) or NO2 (0-4 ppm). Peak expiratory flow (PEF) and tidal volume (V_T