EFFECT OF TOPICAL DIPHENHYDRAMINE ON THE LARYNGEAL CHEMOREFLEX

Objective: To study diphenhydramine nebulization as a clinically appli cable method for blunting laryngeal chemoreflex (LCR)-associated apnea . Intervention: Fourteen piglets aged 15 to 18 days were studied. In 7 piglets, diphenhydramine hydrochloride (5.0 mg/kg) was nebulized onto the laryngeal mucosa after a baseline response was obtained. Results: After a 10-minute waiting period, the mean+/-SD LCR-induced apnea dur ation decreased from 29+/-13 seconds in the control animals to 15+/-5 seconds in the treated group (P=.02, 1-factor analysis of variance). A fter 1 hour, no treatment effect was seen. Conclusions: Nebulization o f diphenhydramine can effectively reduce LCR-induced apnea for a short time. Nebulization of longer-acting agents may provide an effective p rophylaxis of LCR-induced apnea.