Endobronchial intubation is the placement of the endotracheal tube (ETT) in either the left or right mainstem bronchus. Unintentional endobronchial, or “mainstem,” intubation can lead to high peak inspiratory pressures during mechanical ventilation, hypoventilation, and hypoxemia. However, the ETT may also be placed into the mainstem bronchus intentionally for surgery. In addition, endobronchial intubation may be useful in managing patients with unilateral lung pathology and is essential in certain emergency situations.
Absolute indications for endobronchial intubation and subsequent one-lung ventilation (OLV) include:
Massive bleeding in one lung;
Infection with pus in one lung;
Lung bullae with/without pneumothorax;
Alveolar lavage (alveolar proteinosis or cystic fibrosis);
Minimally invasive cardiothoracic surgery.
On the other hand, relative indications for endobronchial intubation and subsequent OLV include:
The most frequent applications of OLV are for relative indications. Successful endobronchial intubation and ventilation depend primarily on the patient’s underlying pathology and the preferences and skill of the thoracic surgeon.
METHODS OF ENDOBRONCHIAL INTUBATION
Double-Lumen Endotracheal Tubes
The most widely adopted devices for achieving OLV by endobronchial intubation are the double-lumen ETTs. These tubes possess a fixed conformation that differentiates the left and right versions. Initially manufactured in red rubber, disposable double-lumen tubes (DLTs) are now produced using polyvinyl chloride with a blue cuff on the bronchial lumen for better fiberoptic identification. Sizes range from 35 to 42 French for adults. Smaller sizes of 28 and 32 French are also available for small-sized adults or pediatric population.
Placement of a DLT involves a number of steps. After the larynx is visualized with regular direct laryngoscopy, the DLT is introduced into the trachea, rotated 90 degrees toward the tracheal side (short lumen), then the stylet is removed, the tube rotated back 90 degrees, and advanced until resistance is felt. Since these tubes are preformed, they should allow correct endobronchial positioning in the vast majority of the cases (Figure 87-1).
Correct position of a left- and right-sided DLT. (Reproduced with permission from Butterworth JF, Mackey DC, Wasnick JD, Morgan and Mikhail’s Clinical Anesthesiology, 5th ed. McGraw-Hill; 2013.)
After inflation of the high volume, low pressure tracheal cuff, tracheal breath sounds should be checked immediately in both lung fields. The bronchial cuff should then be inflated gradually to avoid excessive pressure that can damage the bronchial mucosa. Since the bronchial cuff is not a high volume, low pressure cuff, generally no more than 2 mL of air is required. The chest should be auscultated again for bilateral breath sounds to rule out herniation over the tracheal carina of the bronchial cuff. Herniation of this cuff can compromise the ventilation ...