Study of the endotracheal tube cuff on the trachea and its physical and mechanical aspects

Orientadores: Álfio José Tincani, Marcos Mello MoreiraTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: Introdução: A pressão de insuflação do balonete do tubo endotraqueal tanto pode causar isquemia da mucosa traqueal sob pressões elevadas, quanto pode ocasionar microaspiração de secreções orofaringeas caso a ela seja insuficiente ¿ o que eleva o risco para a pneumonia associada à ventilação mecânica. Objetivo: Discutir os aspectos físicos e mecânicos do balonete do tubo endotraqueal da marca RUSCH® formato globular de PVC (cloreto de polivinil) através de medições diretas do balonete insuflado e observar se há ocorrência de escoamento de solução através do balonete. Métodos: Para estudar os aspectos físicos foram feitas medições diretas (diâmetro e comprimento) do balonete insuflado a uma pressão de 30cmH20 com um paquímetro de precisão. As medidas indiretas foram obtidas a partir dos primeiros resultados (perímetro, área e peso). Para estudar os aspectos mecânicos através da análise do escoamento de solução através do balonete, foram desenvolvidos modelos experimentais in vitro e in vivo para avaliar a ocorrência de escoamento de secreções de maneira transversal e qualitativa. No estudo in vitro foram instilados 3ml de solução de azul de metileno e observada a presença de escoamento da mesma através do balonete insuflado em 20 tubos em modelo de traqueia artificial. No estudo in vivo 3ml da mesma solução foram instilados na rima oral 12 porcos da raça Large-White sob intubação endotraqueal. Imediatamente após o sacrifício a traqueia foi dissecada com o balonete ainda na mesma posição e foi avaliada presença ou não de tingimento na traqueia distal ao balonete. Todos os balonetes foram igualmente insuflados na pressão de 30cm H2O. Resultados: Quanto aos aspectos físicos, a uma pressão de 30 cmH20, há 640,8g de peso sendo exercido sobre a traqueia. Ainda sob essa pressão os canais longitudinais puderam ser demonstrados e observados nos estudos in vitro e in vivo. Em relação aos aspectos mecânicos, houve passagem de solução através dos balonetes em todos os modelos experimentais tanto in vitro como in vivo. Conclusões: O balonete dos tubos endotraqueais de PVC RUSCH® 6,0 e 7,5mm não foram capazes de impedir o escoamento das soluções instiladas. Novos estudos que associem a custo-efetividade podem justificar a substituição do uso dos balonetes de PVC por modelos de balonetes com desempenho superior já existentes no mercadoAbstract: Introduction: The inflation pressure of the endotracheal tube cuff can either cause ischemia of the tracheal mucosa at high pressures or, if the cuff pressure is insufficient, tracheal microaspiration of the oropharyngeal secretion, increasing the risk of ventilator-associated pneumonia. Objectives: This study was designed to discuss the physical and mechanical aspects of the endotracheal tube cuff RUSCH® globular shaped in PVC (polichloride vynil) material through direct measurements of the inflated endotracheal tube cuff and to observe if leakage of solutions around de cuff do occur. Method: To study the physical aspects, direct measurements (diameter and length) were taken with a precision pachimeter with the cuff inflated at a 30cmH20 pressure. The indirect measurements (perimeter, surface area and weight) were obtained using the first results. In order to study the mechanical aspects, in vitro and in vivo experimental models were developed. In the in vitro study 3ml of a methilene blue solution were instilled and it was observed the presence of leakage across the inflated cuff inside an artificial tracheal model. In the in vivo study, 3ml of the same solution were instilled in the oral cavity of 12 Large White pigs under endotracheal intubation. Imediately after the sacrifice, the tracheas were dissected with the cuff still in the same position so the presence or abscence of blue dye below the cuff region on the tracheal wall could be investigated. All cuffs were equally inflated at the pressure of 30cmH2O. Results: Physical aspects ¿ at a 30cmH20 pressure there is a 640,8g weight over the tracheal wall. Still under this pressure it was observed and demonstrated the presence of longitudinal channels in both in vitro and in vivo studies. Mechanical aspects: It was observed leakage of fluids through the cuff in all the 20 in vitro and 12 in vivo experiments. Conclusions: We conclude that the RUSCH®6.0 and 7.5mm endotracheal tube cuffs were not capable to develop a satisfactory seal of the trachea and thus not able to prevent aspiration of the instilled dye above the cuff. New studies relating the cost-effectiveness might justify the substitution of the PVC globular models for cuffs with superior seal capacity already availableDoutoradoFisiopatologia CirúrgicaDoutora em Ciência

Preservation of the External Jugular Vein in Bilateral Radical Neck Dissections: Technique in Two Cases and Review of the Literature

Context. The possibility of cephalic venous hypertension with the resultant facial edema and elevated cerebrospinal fluid pressure continues to challenge head and neck surgeons who perform bilateral radical neck dissections during simultaneous or staged procedures. Case Report. The staged procedure in patients who require bilateral neck dissections allows collateral venous drainage to develop, mainly through the internal and external vertebral plexuses, thereby minimizing the risks of deleterious consequences. Nevertheless, this procedure has disadvantages, such as a delay in definitive therapy, the need for a second hospitalization and anesthesia, and the risk of cutting lymphatic vessels and spreading viable cancer cells. In this paper, we discuss the rationale and feasibility of preserving the external jugular vein. Considering the limited number of similar reports in the literature, two cases in which this procedure was accomplished are described. The relevant anatomy and technique are reviewed and the patients’ outcomes are discussed. Conclusion. Preservation of the EJV during bilateral neck dissections is technically feasible, fast, and safe, with clinically and radiologically demonstrated patency

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.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 a294552558SEM INFORMAÇÃOSEM INFORMAÇÃODobell, A.R., The origins of endotracheal ventilation (1994) Ann Thorac Surg, 58 (2), pp. 578-584Mehta, S., Tracheal tube cuff pressure (1989) Anaesthesia, 44 (12), pp. 1001-1002Mehta, S., Mickiewicz, M., Pressure in large volume, low pressure cuffs: Its significance, measurement and regulation (1985) Intensive Care Med, 11 (5), pp. 267-272Luna, C.M., Legarreta, G., Esteva, H., Laffaire, E., Jolly, E.C., Effect of tracheal dilatation and rupture on mechanical ventilation using a low-pressure cuff tube (1993) Chest, 104 (2), pp. 639-640Bernhard, W.N., Yost, L., Turndorf, H., Danziger, F., Cuffed tracheal tubes--physical and behavioral characteristics (1982) Anesth Analg, 61 (1), pp. 36-41Nordin, U., The trachea and cuff-induced tracheal injury. 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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