Evaluation of the Efficiency of the Atraumatic Endotracheal Tube in the Pulmonary-Gas Exchange: an Experimental Study

ABSTRACT OBJECTIVE: Mechanical ventilation is frequently necessary, in which case the use of an endotracheal tube is mandatory. The tube has an inflatable balloon in its distal extremity, whose aim is, among other functions, an efficient arterialization. However, serious injuries in the place of contact of the balloon with the trachea can be frequent. Some studies point out that balloons with permanent pressure may reduce this complication. Nevertheless, air scape, expressed by the inspiratory (IV) and expiratory volume (EV) variation (Δ IV-EV), may occur, possibly leading to hypoxemia. Thus, the goal of this study was to verify the efficiency of a modified endotracheal tube on arterializations compared to the traditional endotracheal tube. METHODS: The modified endotracheal tube presents intermittent insufflation, with three drillings in the internal region of the cuff, allowing for insufflation in the inspiratory phase of the mechanical ventilation. Three animals were used for the control group, with a cuff pressure of 30 cmH2O, and seven pigs had the modified endotracheal tube. Each animal was kept under mechanical ventilation (FIO2=0.21) for 6 hours. Arterial and venous gases were measured every three hours (T0; T3; T6). RESULTS: The gases confirmed the lack of hypoxia between the Groups, with a difference in the ΔIV-EV at T0 (P=0.0486). CONCLUSIONS: In this study, the lack of hypoxia showed the efficiency of the modified endotracheal tube. However, new studies are necessary, particularly in diseased lungs, in order to evaluate the real efficiency of the mentioned device on the pulmonary gas exchange.

Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects / Eficácia do balonete do tubo endotraqueal sobre a traqueia: aspectos físicos e mecânicos

Introduction: The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient. Objective: In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea. Methods: For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH2O. Results: We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models. Conclusion: We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken. .

Introdução: A pressão de insuflação do balonete (cuff) do tubo endotraqueal tanto pode causar isquemia de mucosa traqueal em pressões elevadas, e assim ocasionar morbidade traqueal importante, quanto pode causar microaspiração traqueal de secreção de orofaringe ou, ainda, ocasionar pneumonia associada à ventilação mecânica, caso a pressão do balonete seja insuficiente. Objetivo: A fim de investigar a eficácia do balonete do tubo endotraqueal RUSCH® 7,5mm, este estudo foi desenhado para investigar aspectos físicos e mecânicos do balonete em contato com a traqueia. Métodos: Para isto, foi desenvolvido modelo experimental in vitro para avaliar o escoamento de corante (azul de metileno) pelo balonete insuflado na parede de material artificial. Também foi desenhado estudo in vivo com 12 porcos da raça Large-White sob intubação endotraqueal. Foi instilado o mesmo corante na cavidade oral do animal e após óbito (sacrifício do animal) foi analisada a presença ou não de vazamento deste na traqueia pós-região do balonete. Todos os balonetes foram insuflados na pressão de 30 cmH2O. Resultados: Houve passagem de fluidos pelo balonete em todos os modelos experimentais in vitro e in vivo. Conclusão: Podemos concluir que, assim como diversos outros modelos de balonetes na literatura, balonetes do tubo RUSCH® 7,5mm também não são capazes de vedar completamente a traqueia e com isso prevenir aspiração de secreções orofaríngeas. Outras medidas para a prevenção devem ser tomadas. .