Effect of Side-Stream Smoking on Random-Pattern Skin Flap Survival in Rats Anajara Gazzalle, MD,* Lourenc ¸o Frigeri Teixeira, MD,* Alice Cardoso Pellizzari,Þ Fernanda Cocolichio,Þ Juliana Tonietto Zampieri,Þ Daniel Rauber,Þ Luı ´se S. Pezzin,Þ Vanessa D. Zago,Þ and Jefferson Luis Braga-Silva, MD, PhD* Abstract: The secondhand exposure to cigarette smoke is being considered evil, and damage caused by this passive exposure has been proven by several studies. To investigate the effects of sidestream smoke exposure on random- pattern skin flap survival, 20 female rats were separated into 2 groups: group A (n = 10) was exposed 6 weeks to the smoke from the burning cigarette (passive smoking) and group B (n = 10) was the control group. After 6 weeks of exposition, a dorsal McFarlane flap of 4 Â 10 cm was performed in all rats. Two weeks after this procedure, the ratio of necrotic and total areas was calculated using computer programs. The median area of necrosis in group A was 29.5%, significantly higher than that in group B with 17.5% (P G 0.024). In conclusion, this study suggests increased risk of random-pattern skin flap necrosis after sidestream exposure to cigarette smoke. Key Words: passive smoke, secondhand smoke, rat, random flap (Ann Plast Surg 2014;72: 463Y466) T he effect of smoking has been widely studied, with recognized cardiovascular and neoplastic adverse effects and macrovascular and microvascular endothelial dysfunction. 1Y3 Despite the increased efforts by the public health system to in- crease the awareness regarding the ill effects of smoking, the use of tobacco is widespread, including indoors. The secondhand exposure to cigarette smoke is also being considered evil, and damage caused by this passive exposure has been proven by several studies. Even younger patients can have hemodynamic changes after short periods of passive exposure. 1Y4 Passive smoking is the inhalation of indirect smoke, called sec- ondhand smoke or environmental tobacco smoke, which is defined as the smoke to which a nonsmoker is exposed. Currently, the health risks of secondhand smoke are a matter of scientific consensus, and these risks have been a major motivation for smoking bans in work- places and indoor public places, including restaurants, bars and night clubs, as well as some open public spaces. Lee et al 5 reported a study with both mainstream and sidestream smoke. They stated that the indirect smoke is divided into sidestream (from the burning tip) or mainstream (exhaled by the smoker). Experimentally, several studies evaluated the influence of pas- sive smoking in various systems, such as oropharynx, kidney, bone, and intervertebral discs, most pointing to dysfunction after passive exposure. 6Y11 Studies with active smoking on rats resulted in circulatory def- icit and necrosis of skin flaps. 12Y16 There is lack of data on the effects of secondhand smoking on skin flaps. Smoking complicates the healing process, causing imbalance in the normal physiological response, a fact of particular interest in plastic and reconstructive surgery. 12,13,16Y18 The objective of this experimental study was to investigate the effects of sidestream smoke exposure on random-pattern skin flap survival on rats. MATERIALS AND METHODS After the institution’s ethics committee approval, experiments were carried out on 20 healthy female Wistar rats, weighting 200 to 250 g. Rats were housed in an environmentally controlled room and offered standard rat chow and water ad libitum. The animals were separated in 2 groups with 10 rats each: group A was exposed to side- stream smoke 6 weeks preoperatively, and group B underwent inside the apparatus this same period but without the smoke. Study Groups and Sidestream Smoke Exposure Protocol The animals were exposed to passive cigarette smoke with the Braga-Gazzalle 19 smoke exposure system (Fig. 1). The system built for smoke inhalation consists of a 40 Â 33 Â 17-cm polypropylene box divided into 2 chambers by a perforated screen (Fig. 1). The larger chamber was used for the rats (up to 5) and the smaller for the cigarettes, coupled in a metal base with holes. At the opposite end of the device, a fan (0.14-A computer cooler) was installed. This gen- erates a continuous airflow inside the box: the smoke is aspirated from the smaller chamber and leaves through the opposite side. The volume of the drawn smoke is composed basically of the burning tip (sidestream) as the cigarette filter tip is coupled to the metal base and hermetically isolated from the ambient air. During the experi- ment, the apparatus is kept closed by a wood cover. One-week gradual acclimation of the rats to cigarette smoke was used, with 1 h/d. 15 The final standardized maximum exposure was reached with 8 cigarettes per 2 h/d, for 6 weeks and not on week- ends. The cigarettes used were Marlboro, which have high levels of tar (10 mg), carbon monoxide (10 mg), and nicotine (0.8 mg). Surgical Technique At the end of the sixth week of the experiment, after exposure, both groups underwent surgery. Dorsal McFarlane (4 Â 10 cm) cau- dally based random-pattern skin flaps 12,13,15,18 created on day 42 (6 weeks) of the sidestream smoke exposure. The flap skin and underling panniculus carnosis to fascia were incised and raised. The flap was then sutured back in place using interrupted mononylon 5.0 sutures. We used a plastic mold to standardize the incisions. The rats were housed individually after surgery. Carboxyhemoglobin Assay On day of surgery, blood was taken from one tail artery approx- imately 5 minutes after the smoke session. 12,13,15 The carboxyhem- oglobin (CoHb) content was measured using spectrophotometry. RESEARCH Annals of Plastic Surgery & Volume 72, Number 4, April 2014 www.annalsplasticsurgery.com 463 Received January 24, 2012, and accepted for publication, after revision, May 29, 2012. From the *Division of Hand Surgery and Reconstructive Microsurgery, Hospital Sa ˜o Lucas, and †School of Medicine at the Pontifı ´cia Universidade Cato ´ lica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil. Conflicts of interest and sources of funding: none declared. Reprints: Anajara Gazzalle, MD, Av. Ipiranga, 6690, sala 220, Porto Alegre, RS, Brazil, CEP 90.610-000. E-mail: anajaragazzalle@gmail.com. Copyright * 2013 by Lippincott Williams & Wilkins ISSN: 0148-7043/14/7204-0463 DOI: 10.1097/SAP.0b013e318262395c Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.