Fig. 5.1.
Images of a 9-month-old female who presented with concern for foreign body aspiration. Air trapping on the left side (a) is noted on the decubitus films (b, c). Note the normal posteroanterior images; emphasize the importance of obtaining decubitus films.
Chest CT scans can be useful in the diagnosis of bronchial masses or foreign bodies, stenosis and intrinsic obstructions, or masses causing extrinsic compression of the airway.
Fluoroscopy with contrast imaging of the esophagus can also be useful in the diagnosis of congenital, recurrent, and acquired tracheoesophageal fistula.
Other Tests
Bronchoscopy itself is the most definitive technique in diagnosis of anatomic disorders of the airways. Other tests outside of those already discussed are infrequently useful in the diagnosis of pediatric surgical tracheobronchial disease.
Surgical Indications
Rigid and flexible bronchoscopies are indicated for examination of the airway in cases of suspected endoluminal diseases of the trachea and bronchi, airway foreign bodies, stenosis, fistula to the airway, obstructions, and hemorrhage. It is simultaneously a diagnostic and a therapeutic technique, useful for the treatment of endoluminal diseases. It permits clearance and collection of secretions (and blood), biopsy of tissue, removal of foreign bodies, dilation of strictures, destruction of endoluminal lesions, and treatment of some recurrent fistulas. Flexible bronchoscopy may be used to guide selective intubation of a main stem bronchus.
Technique
Bronchoscopy is divided into rigid and flexible types of bronchoscopy, which are complementary techniques.
Special Considerations
- 1.
Children requiring rigid bronchoscopy, especially for acute foreign body removal , usually require general anesthesia in order to tolerate the procedure and permit safe and effective examination. Flexible bronchoscopy may be performed under moderate sedation with topical airway anesthesia . Consultation with the anesthesiologist is required preoperatively when deciding to perform the procedure with or without spontaneous respiration (paralysis).
- 2.
Rigid bronchoscopy requires direct laryngoscopy to visualize the glottic opening and introduce the bronchoscope. Flexible endoscopy may be performed through a laryngeal mask airway , endotracheal tube, tracheostomy, or orally through a bite block. Additionally, a nasal approach may be adopted with the flexible endoscope inserted via the naris.
- 3.
Flexible bronchoscopy permits more distal examination of the airways, due to the smaller size and flexibility of the endoscope (Fig. 5.2). Subsequently, these pediatric bronchoscopes may be too small to have a working channel or have a small diameter channel that permits suctioning but limits instrumentation (graspers, biopsy forceps). The small size of the pediatric flexible bronchoscope may also limit image quality.
Fig. 5.2.
The tracheobronchial tree. The gray portions represent the areas which are beyond the limits of visualization by rigid bronchoscopy. A flexible bronchoscope is required to evaluate these areas. The figure is oriented to represent the anatomy as it is encountered via rigid bronchoscopy.
- 4.
Although both flexible and rigid pediatric bronchoscopies may be both diagnostic and therapeutic techniques , rigid bronchoscopy is more often used therapeutically in pediatrics. Most foreign bodies are removed with rigid bronchoscopy.
- 5.
Patients with bleeding in the airway should undergo rigid over flexible bronchoscopy due to its improved ability to achieve hemostasis and definitively secure the airway.
- 6.
Cervical instability and maxillofacial trauma or anomalies may make rigid endoscopy difficult or hazardous due to the need to extend the neck to allow a straight pathway for introduction of the rigid scope. In patients with head and neck trauma, flexible is preferred over rigid bronchoscopy. This is because the head and neck do not have to be manipulated as dramatically to insert the flexible bronchoscope. Similarly, in patients who are already intubated, flexible bronchoscopy is also preferred as the airway is already secured and the flexible scope may be inserted via the endotracheal tube. Patients with respiratory failure and significant ventilator support may not tolerate extubation and ventilation via the bronchoscope.
Anatomy
There are many important anatomic differences in the airways of adults and children which must be remembered when dealing with tracheobronchial disease. In children, several factors may make intubation of the airway more difficult. The jaw is smaller, the tongue is relatively larger, the epiglottis is larger, and the larynx is more anterior. The occiput is also relatively larger, causing neck flexion. The trachea is shorter and narrower, with the narrowest area in the subglottis.
In terms of physiology, the pediatric airway has a higher resistance to gas flow due to the smaller radius and cross-sectional area. For the same reason, the pediatric airway is more prone to obstruction by foreign bodies and secretions. Due to a relatively lower functional residual capacity and relatively higher rate of oxygen consumption, pediatric patients (and infants in particular) are less tolerant of apnea than adults.
Positioning
Proper setup of the operating room table and equipment facilitates performance of bronchoscopy (Fig. 5.3). For rigid bronchoscopy, the surgeon sits at the head of the bed, and the video monitor is placed at the foot. The anesthesia provider and anesthesia machine are situated to the left of the head of the bed. The instruments and the surgical assistant are to the right of the head of the bed.
Fig. 5.3.
Orientation of personnel and equipment during rigid bronchoscopy. (S) surgeon, (An) anesthesiologist, (Ae) anesthesia equipment, (N) assistant, (M) video monitor, (E) endoscopy equipment and instruments (light source, suction, bronchoscope, etc.).
The patient is placed in the supine position and a shoulder roll is placed to compensate for the large occiput and to straighten the airway. The cervical spine and the head are extended into the “sniffing position.” Eye protection should always be applied to the patient prior to commencing bronchoscopy. The index finger and thumb of the surgeon’s nondominant hand not only support the rigid scope but serve to protect the patient’s teeth and lips. The head is positioned such that it can be easily turned to the side during the procedure.
Children undergoing flexible bronchoscopy are generally sedated or anesthetized. They may be placed in the semi-recumbent or supine position. The surgeon stands at the head or to the side of the table with the monitor opposite him/her. The anesthesia provider and his/her equipment are to the side, cephalad to the surgeon, or at the foot.
Instruments
The basic requirements for rigid bronchoscopy are a light source, a rod-lens telescope , and the bronchoscope (Fig. 5.4). There are multiple styles and manufacturers of bronchoscopes, rod-lenses, and light sources, which are integrated with video equipment. Among telescopes, the Hopkins rod-lens style is the most popular. Telescopes have angles from 0° to 120°, and newer rigid telescopes have flexible tips allowing greater ranges of visualization up to 180°. A bite block, or similar device, may be used to protect the lips and teeth, as well as the endoscope.
