The impact of vasodilators on random-pattern skin flap survival in the rat following mainstream smoke exposure.

Abstract

This study demonstrates that acute mainstream cigarette smoke exposure is deleterious to dorsal random-pattern skin flap survival in the rat. Three vasodilators were also studied for their ability to mediate flap survival after smoke exposure. Sprague-Dawley rats (10 per group) were exposed to two cigarettes per day over a 14-day period. This is an exposure equivalent to that of an average cigarette smoker. Dorsal McFarlane caudally based random-pattern skin flaps (4 x 10 cm) were created on day 7 of the smoke exposure. Enteral phenoxybenzamine (0.56 mg per kilogram per day), enteral nifedipine (10 mg per kilogram per day), and topical nitroglycerin (1.3 cm or 7.5 mg per day) were administered after creation of the dorsal skin flaps in two doses daily during smoke exposure. Fluorescein was used to delineate areas of viability accurately. A pad digitizer was utilized to calculate designated skin flap areas to +/-1.0 mm2. Experimental animals demonstrated a 23% decrease (p < 0.01) in skin flap area survival compared with the control animals. The phenoxybenzamine group demonstrated a 5.5% increase in flap area survival (p=0.068), the nifedipine group demonstrated a 4.1% increase in flap area survival (p=0.049), and the nitroglycerin group demonstrated an 8.9% increase in flap area survival (p=0.049). These data suggest that phenoxybenzamine appears to affect skin flap survival marginally after smoke exposure. However, nifedipine and nitroglycerin improve random-pattern skin flap survival significantly after mainstream cigarette smoke exposure in the rat. These results imply that pharmacological intervention with vasodilators may ultimately prove clinically useful for random-pattern skin flap salvage in the cigarette-smoking patient.