Transtracheal aspiration is a technique for the collection of lower respiratory tract and bronchial secretions for laboratory evaluation and culture.1,2 This technique is useful when standard sputum collection has not provided adequate material or determination of the infective agent(s). Specimens collected by this technique are free of contamination from nasal, oral, and pharyngeal secretions. This technique was first described in 1959.3 Several modifications to the original technique have been made.4-7 This technique may be more properly named transcricothyroid membrane aspiration. It is not used as much as in the past since the development of bronchoscopy. Despite this, it is safe, takes less preparation, takes less personnel, takes less equipment, and is much less expensive when compared to bronchoscopy.
ANATOMY AND PATHOPHYSIOLOGY
The most superficial portion of the cervical airway begins at the inferior thyroid cartilage and extends inferiorly to the thyroid isthmus (Figure 35-1). The inferior border of the thyroid cartilage is attached to the cricoid cartilage by the cricothyroid ligament. This is formed by a thicker central conus elasticus and laterally by thinner ligaments that are covered by the cricothyroid muscles (Figure 35-1B). The internal surface is covered by the mucous membrane of the larynx. Collectively, this is often referred to as the cricothyroid membrane or cricovocal membrane. The paired cricothyroid arteries cross from lateral to medial to form an arch that anteriorly crosses the upper one-third of the cricothyroid membrane. The pyramidal lobe of the thyroid occasionally extends superiorly to this level.
Anatomy of the airway structures of the neck. A. Topographic anatomy. B. The cartilaginous structures.
Transtracheal aspiration is indicated for the collection of tracheobronchial secretions for laboratory evaluation. Often, previous attempts to collect standard coughed and expectorated sputum samples have failed to yield adequate samples or reveal the etiology of a pulmonary infection. Patients who do not appear to be responding to the appropriate antibiotic regimen that was indicated by evaluation and culture of sputum samples may benefit from this technique to better determine the pathogen(s). This is particularly true in cases of atypical or mixed flora, as in suspected aspiration pneumonias, where this technique may yield superior culture results when compared to sputum samples.8
Patients who are unable to cooperate with or tolerate the required positioning should not be selected for this technique.9 Agitated patients requiring sedation that may affect respiratory effort should be avoided. Traumatically injured patients should have the cervical spine cleared for possible injury prior to performing the procedure. Patients with known or suspected blood dyscrasias (e.g., abnormal platelet counts, elevated prothrombin or partial thromboplastin times) should not be subjected to this technique due to the increased risk of tracheal hemorrhage. The Emergency ...