Rigid bronchoscopy: Intubation techniques

INTRODUCTION — The rigid bronchoscope, which is a hollow stainless steel tube through which a rigid telescope is placed, provides access to the central airways. External diameters and lengths vary depending upon the manufacturer. The distal end of the rigid bronchoscope is usually beveled to facilitate intubation and lifting of the epiglottis; the proximal portion is equipped to accommodate attachments, provide side port ventilation, and permit insertion of ancillary instruments.

Issues relating to the general procedures surrounding the intubation techniques of rigid bronchoscopy will be reviewed here. The history of rigid bronchoscopy (including current instrumentation) and an overview of bronchoscopy (including indications and contraindications) are discussed separately. (See "Rigid bronchoscopy: Instrumentation" and "Flexible bronchoscopy in adults: Indications and contraindications".)

PATIENT PREPARATION — The following general preparative procedures should be performed prior to intubation using a rigid bronchoscope (see "Flexible bronchoscopy in adults: Indications and contraindications"):

●Patients are oxygenated by mask, and pharyngeal secretions are aspirated.

●Dentures are removed, and the teeth and gums are carefully inspected. The teeth may be protected with gauze pads, foam rubber, or plastic mouth guards.

●Some operators place a rolled blanket or towel between the shoulder blades in order to thrust the upper trachea forward and extend the cervical spine. Others extend the head of the operating room table to improve oropharyngeal and airway alignment.

●Depending upon the position of the glottis and the laryngotracheobronchial axis, it may be necessary to use one, two, or no pillows beneath the patient's head when it is resting on the table. Careful attention should be paid to patients with cervical spine disease.

ANESTHESIA — Anesthesiologists have become increasingly comfortable with intravenous general anesthesia, which avoids the administration of potentially noxious gases. Muscle relaxation and paralysis can be avoided with the use of assisted spontaneous ventilation, and wake-up time may be shortened. The combination of intravenous general anesthesia with propofol and assisted spontaneous ventilation is a commonly used anesthesia technique for rigid bronchoscopy [1-4].

Complete muscle relaxation is often desirable, since rigid bronchoscopy is stimulating, and particularly when work is being performed within the lower airways. When general anesthesia with inhaled gases is employed, it is essential to pack the nose and mouth to avoid gas leakage (picture 1) [2]. Packing, however, may impede manipulation of the rigid bronchoscope within the tracheobronchial tree. When packing is performed, Vaseline gauze is used in the nasal passages, and rolled gauze is placed in the mouth, firmly securing the rigid bronchoscope.

Ventilatory support can be provided using assisted spontaneous ventilation or closed-circuit positive pressure ventilation [1] as well as low- and high-frequency jet ventilation [5,6]. (See "Modes of mechanical ventilation", section on 'High frequency ventilation'.)

DIRECT INTUBATION — Direct intubation using a rigid telescope is the method of choice for rigid bronchoscopic intubation. With this technique, the rigid telescope is placed inside the bronchoscope, and the laryngeal structures are viewed directly through the telescope in a method that is quite similar to intubating with a Miller laryngoscope. Illumination is provided through the distal aspect of the rigid telescope, which is attached via a light cable to a cold light source. By comparison, if a rigid telescope is not used, the bronchoscope is introduced using only the naked eye. The following is a brief summary of the sequential steps required for direct intubation using a rigid telescope:

●The bronchoscopist stands directly behind the head of the supine patient.

●The rigid bronchoscope is held in the right hand with its tip uppermost. The middle finger of the left hand is used to protect the upper teeth and gums and to control head movements. The telescope should not extend beyond the edge of the rigid bronchoscope in order to prevent inadvertent injury to the oropharynx and larynx (picture 2).

●The bronchoscope is inserted with its tip facing forward and the bronchoscopist identifies the uvula posteriorly. The bronchoscope is advanced along the route of the tongue.

●The rigid bronchoscope is gently lifted upwards and the epiglottis is brought into view (movie 1 and picture 2). The anterior aspect of the beveled tip of the bronchoscope is then slid under the epiglottis in a manner similar to the Miller laryngoscope. Gentle advancement of the rigid tube provides further access to the larynx.

●After both arytenoids are identified, the rigid tube is lifted more anteriorly and the vocal cords are seen. As the vocal cords are approached, the tip of the bronchoscope is rotated 90 degrees laterally so that the beveled tip lies between them.

●The bronchoscope is advanced and rotated to enter the trachea without traumatizing the larynx.

●Once beyond the level of the cricoid cartilage, the bronchoscope may be rotated so that the beveled tip lies along the posterior wall of the trachea (movie 2).

INTUBATION WITH LARYNGOSCOPY — For operators who are uncomfortable with direct intubation but who are adept at laryngoscopy, the vocal cords may be visualized using the laryngoscope alone. Either straight or curved instruments may be used with intubation during rigid laryngoscopy:

●With the laryngoscope in the midline and after the epiglottis has been lifted, the rigid bronchoscope is inserted into the lateral aspect of the mouth and directed toward the larynx.

●As the bronchoscope is inserted between the vocal cords, it is rotated slightly and kept in the midline to avoid striking the beveled edge of the bronchoscope against the lateral wall of the subglottis.

●Once the bronchoscope is inserted through the cords, the laryngoscope is removed, and the rigid telescope can be placed into the rigid bronchoscope. The bronchoscope is then advanced further into the tracheal lumen.

INTUBATION VIA TRACHEOSTOMY — Intubation through a tracheostomy is a relatively simple technique. After topical anesthesia with viscous lidocaine applied to the edges of the tracheostomy, the rigid bronchoscope can be inserted directly through the stoma from a lateral position.

Tracheostomy intubation is easiest if the bronchoscopist stands behind the patient and slightly to the patient's left or right. Care is taken in order to avoid striking the beveled edge of the rigid bronchoscope against the posterior wall of the trachea.

COMPLICATIONS — Expertise in rigid bronchoscopy requires a long apprenticeship. It should be noted that only part of becoming a skilled rigid bronchoscopist is intubation. The other, perhaps more important, aspects lie in the procedures performed in patients with critical central airway obstruction. In addition, bronchoscopists must never forget that they share the airway with the anesthesiologist. Oxygenation and ventilation must always take priority over any manipulations of the rigid bronchoscope.

Most complications of rigid bronchoscopy are related to poor insertion technique, prolonged trauma of the larynx and vocal cords, hypercapnia, hypoxemia, or hemodynamic instability. Specific complications include damage to structures of the mouth and oropharynx, laryngeal swelling, spinal cord injury, and airway perforation and injury to the vocal cords and arytenoids.

Damage to structures of the mouth and oropharynx — Careful inspection of the mouth and teeth is essential to avoid dislodging a loose tooth. In addition, the gums should not be traumatized, and the lips should not be injured by accidentally pulling them into the mouth above or below the rigid bronchoscope. Precautions should also be taken in patients who may have herpes infections of the oropharyngeal airway.

Laryngeal swelling — Laryngeal swelling may occur during or immediately following rigid bronchoscopy. It is unclear, however, whether either inhalation of beta agonists prior to procedure or the administration of intravenous corticosteroids before and after rigid bronchoscopy may be beneficial in preventing this problem.

Spinal cord injury — Spinal cord injuries are possible in patients with cervical spine disease and severe osteoporosis. In selected cases, the presence of either of these diseases is a contraindication to rigid bronchoscopic intubation.

Airway perforation and injury to the vocal cords and arytenoids — Two major complications that must be avoided are airway wall perforation (particularly of the posterior wall of the trachea and the subglottic region) and luxation or laceration at the level of the vocal cords and arytenoids. Such injuries may occur because of faulty intubation technique or if intubation is attempted before a patient is fully asleep or sufficiently anesthetized.

SUMMARY AND RECOMMENDATIONS

●The rigid bronchoscope is a potentially dangerous instrument. It consists of a hollow stainless steel tube that provides access to the central airways and through which a rigid telescope is placed. External diameters and lengths vary depending upon the manufacturer. The distal end of the rigid bronchoscope is usually beveled to facilitate intubation and lifting of the epiglottis, while the proximal portion is equipped to accommodate attachments, provide side port ventilation, and permit insertion of ancillary instruments. (See 'Introduction' above.)

●The technique of rigid bronchoscopic intubation is one that is gradually perfected over time. Direct intubation using a rigid telescope is the method of choice for rigid bronchoscopic intubation. With this technique, the rigid telescope is placed inside the bronchoscope, and the laryngeal structures are viewed directly through the telescope. For operators who are uncomfortable with direct intubation but who are adept at laryngoscopy, the vocal cords may be visualized using a standard laryngoscope alone. (See 'Direct intubation' above and 'Intubation with laryngoscopy' above.)  

●The bronchoscope can and should be introduced gently, delicately, and with substantial care. Most complications of rigid bronchoscopy are related to poor insertion technique, prolonged trauma of the larynx and vocal cords, hypercapnia, hypoxemia, or hemodynamic instability. Specific complications include damage to structures of the mouth and oropharynx, laryngeal swelling, spinal cord injury, and airway perforation and injury to the vocal cords and arytenoids. (See 'Complications' above.)