Objective: To describe the development of a silicone stent and perform in vivo testing for biocompatibility/applicability in the normal canine trachea. Methods: Four different densities were tested in order to obtain the silicone prototypes. The pressure required for compression considering a contact area of 1 cm2, and a 30% reduction in diameter was calculated for each density. The best density was 70-75 Shore A hardness. Powdered barium sulfate was added to the silicone to make the stent radiopaque and easily identifiable in radiological imaging. This novel stent presents a corrugated external surface with discontinuous and protruding arcs resembling the tracheobronchial rings (for intercalation and fixation in the lumen of the lower airways), a highly polished inner surface and smooth extremities (to prevent friction-related damage). The prototype considered most appropriate in terms of rigidity and flexibility was bronchoscopically implanted in normal canine tracheas. After eight weeks, the animals were euthanized, and the tracheas were removed for anatomopathological analysis. Results: There were no postimplantation complications, and none had to be removed. After eight weeks, the devices were found to be well-positioned. Histopathology revealed a well-preserved epithelial basal membrane, foci of denuded epithelium, mild submucosal inflammatory infiltrate with scattered granulation tissue, vascular neoformation, and no microorganisms. Conclusions: The stent developed proved resistant to mechanical stress, biocompatible in the canine trachea and well-preserved at the study endpoint.

Keywords: Implants, experimental; Silicones; Biocompatible materials.

Objective: To evaluate the influence of the surgical team (general surgery or thoracic surgery) and the surgical technique (with or without isthmectomy) on the incidence of postintubation injuries in the airways of tracheostomized patients. Methods: Between January 1st and August 31st, 2007, 164 patients admitted to the adult intensive care unit and tracheally intubated for more than 24 h were studied prospectively at the Sumaré State Hospital, located in the city of Sumaré, Brazil. When tracheostomy was necessary, these patients were randomly assigned to thoracic or general surgery teams. All of the patients were submitted to fiberoptic tracheoscopy for decannulation or late evaluation of the airway. Results: Of the 164 patients in the study, 90 (54.88%) died (due to causes unrelated to the procedure), 67 (40.85%) completed follow-up, and 7 (4.27%) were lost to follow-up. Of the 67 patients who completed follow-up, 32 had undergone tracheostomy (21 by the general surgery team and 11 by the thoracic surgery team), and 22 had been submitted to isthmectomy (11 by the general surgery team and 11 by the thoracic surgery team). There was no difference between the surgical teams in terms of the incidence of stoma complications. However, there was a significant difference when the surgical techniques (with or without isthmectomy) were compared. Conclusions: Not performing isthmectomy in parallel with tracheostomy leads the surgeon to open the tracheal stoma more distally than expected. In such cases, there were more stoma complications.

Keywords: Tracheostomy; Intensive care units; Tracheal stenosis.