Tracheal injury is a well-known complication of tracheal intubation. Tracheal tubes may cause direct single trauma at intubation or repetitive friction trauma once in place. However, the most important mechanism responsible for the injury is the reduction of mucosal blood flow caused by compression from the endotracheal tube cuff.1 Injury mainly involves the mucosa, but damage could penetrate deeply through the cartilage if the ischemic insult is sustained. Tracheal stenosis is a frequent long-term consequence of mucosal ischemia due to tracheal intubation2; nevertheless, other type of lesions could also be seen before fibrotic narrowing occurs.3
A 73-year-old man without previous relevant history was admitted to our emergency room with right brachial paresis and dysarthria that rapidly evolved into unconsciousness. Computed tomography of the head revealed parenchymal hemorrhage involving the left hemisphere, extending to the lateral ventricles with significant mass effect that displaced the midline. The patient underwent left parietal craniotomy with drainage of the hematoma and was transferred to the intensive care unit (ICU) intubated with a 7.5 mm internal diameter endotracheal tube. The outcome was favorable with spontaneous eye opening and obeying commands with movement of the left side of the body. After 8 days in the ICU on mechanical ventilation, bronchoscopy-guided dilational percutaneous tracheostomy was performed. During the procedure, tracheal exploration revealed ulcerative lesions on tracheal rings, third to sixth on the anterior tracheal wall, surrounded by inflamed mucosa, on the site that corresponded to the endotracheal tube cuff (Fig. 1). A tracheostomy cannula was inserted by percutaneous technique between the second and third tracheal rings without complications. The patient was disconnected from mechanical ventilation on the next day and discharged from the ICU 6 days later.
Postintubation tracheal injury is the most common origin of benign tracheal stenosis.2 Other problems secondary to intubation that could involve the trachea are tracheomalacia, tracheal rupture, and fistula formation. Injury to the tracheal mucosa could be found in different stages considered as prestenotic lesions that include edema, ulceration, granulation, and fibrotic scarring.3 Injury may appear at the tracheal tube cuff pressure area or less frequently over the friction zones above or below the tracheal tube cuff. The frequency of laryngotracheal lesions in the ICU after extubation seems to be quite frequent.4 Tracheal cuff pressure is the main risk factor for the development of tracheal injury during intubation; if it is too high (>30 cm H2O), ischemia of the mucosa would occur.1 In contrast, if cuff pressure is too low (<20 cm H2O), aspiration of pharyngeal and subglottic secretions would increase the risk of ventilator-associated pneumonia.5 Several techniques are used for monitoring and adjusting endotracheal tube cuff pressure within these safe limits, including estimation by pilot balloon palpation, intermittent measurement by manometry or continuous measurement by a transducer, and the use of automatic devices.
The reported incidence of tracheal cuff over inflation in the ICU is between 55% and 90%,6,7 with high morbidity associated to airway problems, especially those related to tracheal damage.4,8 In our ICU, the protocol of tracheal cuff monitoring and adjustment is made by respiratory therapists every 2 hours using a manometer (graduated in centimeters of water) designed for this purpose. Other mechanisms that could lead to tracheal injury secondary to tracheal intubation are the friction produced by patient movement and, if the tracheal tube diameter is too large for tracheal lumen diameter, the friction caused by tube segments above or below the cuff. Thus, implementation of protocols for measuring and adjusting tracheal cuff pressures is justified. Direct visualization is the only method to detect tracheal injury from tracheal cuff in its earlier stages. Besides avoiding risks, an advantage of performing percutaneous tracheostomy with bronchoscopy guidance is that it allows for tracheal examination.
The authors thank all members of ARUAL Medicina de Reanimación, S.C.
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