[Atraumatic endotracheal tube for mechanical ventilation].

BACKGROUND AND OBJECTIVES Patients who need to stay under endotracheal intubation for long periods or when undergoing general anesthesia may develop tracheal lumen injuries due to pressure from distal cuff. In some cases, these injuries may evolve to stenosis or, occasionally, necrosis. The objective of this study was to present a modified endotracheal tube (METT) in which the cuff pressure is variable according to the cycle of mechanical ventilation (MV), which was tested on a lung simulator and animal model. METHODS Two models of endotracheal tubes, a modified (METT) and a conventional (CETT), number 7.5 mm and 8.0 mm, were connected to a lung simulator in a mechanical ventilator adjusted with two tidal volumes (TV) of 10 and 15 mL.kg(-1) and a compliance of 60 mL.cmH(2)O to evaluate the ventilatory efficiency of METT. Both models were also compared in Large-White pigs under general anesthesia and MV for 48 consecutive hours. Subsequently, animals were sacrificed for histopathological analysis of their tracheas. RESULTS Both METTs (#7.5 and 8.0) presented air leaks in lung simulator. The smallest air leak (13%) was observed in METT #7.5 with TV = 15 mL.kg(-1), while the largest air leak (32%) was observed in METT #8.0 with TV = 10 mL.kg(-1). Nevertheless, both METTs showed good efficiency on the lung simulator. In animals, on histopathological analysis of their tracheas, it was found that METT caused less trauma to the epithelium when compared to CETT. CONCLUSION The use of a new model of ETT may decrease the risks of tracheal injury without hindering respiratory mechanics.