Anatomical dead space and airway resistance after glycopyrrolate or atropine premedication

The effects of atropine and glycopyrrolate on anatomical dead space, one and three second forced expiratory volume, maximal expiratory flow rate, and total forced expiratory volume were determined in ten healthy volunteers. Using Fowler's single breath nitrogen analyzing technique, atropine was found to increase dead space by 19.2 per cent at one hour, declining to 11.02 per cent at four hours. Glycopyrrolate increased dead space by 21.57 per cent at one hour, 29.28 per cent at two hours, and 26.65 per cent at four hours. When compared to the effects of saline control injection, the dead space increases are significant. The difference between glycopyrrolate and atropine is significant only at four hours. Increases in maximal expiratory flow rate induced by atropine and glycopyrrolate were significant at one-half hour, while atropine alone induced a significant increase in one second forced expiratory volume. Three second forced expiratory volume and total forced expiratory volume were not significantly altered.