Avaliação da cera de osso como cofator na colonização de esternotomia em ratos

Abstract

INTRODUCTION: Bone wax is commonly used for sternum hemostasis after median sternotomy. Its use has been associated with increased incidence of infection in experimental and clinical studies. OBJECTIVE: To evaluate if bone wax acts as a promoting factor to the colonization of rats sternotomies using radiolabeled antibiotic scintigraphy. METHODOLOGY: Ninety Wistar rats were subjected to partial upper median sternotomy. The sternal wounds were treated or not with bone wax and contaminated with Staphylococcus aureus or not. The rats were divided into four groups, control (sternotomy), wax (sternotomy using bone wax), bacteria (sternotomy with bacterial contamination) and waxbacteria (sternotomy using bone wax and bacterial contamination). Eight days after the surgery, the animals were subjected to scintigraphy of the sternal region 210 and 360 minutes after infusion of ceftizoxime labeled with technetium-99m, followed by ex vivo radioactivity counting of the sternum. RESULTS: Quantitative analysis of the scintigraphic data showed no significant differences between the control vs. wax groups, suggesting that wax did not alter the uptake of the radiopharmaceutical. When comparing the control vs. bacteria groups (p = 0.03, p = 0.02, p = 0.04) and wax vs. waxbacteria group (p = 0.01 p = 0.02, p = 0.009), significant differences were found in all the scannings, respectively, at 210 and 360 minutes and ex vivo counting, indicating that scintigraphy using labeled ceftizoxime with technetium-99m had good accuracy in determining wich animals were infected. The waxbacteria and bacteria groups did not show significant differences in scintigraphy scanning data, meaning that bone wax did not facilitate colonization of sternal wound by the bacteria. CONCLUSION: Bone wax did not act as a promoting factor for the colonization of the sternal wounds in rats.