Although atelectasis can often be successfully managed with chest physiotherapy and airway clearance techniques, hemoptysis requires airway inspection to localize the source of bleeding. Coagulation parameters should be checked, and flexible bronchoscopy (FB) with diagnostic and therapeutic intent performed. FB may allow for the visualization of the source of bleeding, identification of the reason for right lung atelectasis, therapeutic suctioning of blood clots from the airway, foreign body removal, placement of endobronchial blocker balloon, or selective intubation of one lung (Table 46-1).

Prior to bronchoscopy, reversal of any coagulopathy should be initiated, and hypoxia should be corrected to the maximal degree possible using increased fraction of inspired oxygen (Fio₂) and end-expiratory pressure. There should be consideration of chest physio­therapy and blind endobronchial suctioning; the lumen of a Ballard suction catheter is much larger than the working channel of a bronchoscope, so it may be easier to remove a large occluding central mucus plug or blood clot with a directional suction catheter than with a bronchoscope.

Bronchoscopy, especially when a large therapeutic bronchoscope is used, impairs ventilation. For this reason it is crucial to monitor the end-tidal CO₂ level during the procedure in any patient with a CNS mass lesion or elevated intracranial pressure (ICP). Airway occlusion will frequently result in low lung volumes when pressure-limited modes of ventilation are employed, leading to hypoventilation, cerebral vasodilation, increased intracranial volume, and a concurrent surge in ICP. For this reason, ICP and the maximal concentration of CO₂ (ETCO₂) must be strictly monitored, and care should be taken not to precipitate an ICP crisis or herniation event.

The flexible bronchoscope was introduced by Ikeida in 1968.¹ Since then it has served as an alternative and adjunct to rigid bronchoscopy, obviating its need under most circumstances. Increased in the utility and indications for flexible bronchoscopy have been manifold since its introduction. In this chapter, bronchoscopy refers to flexible bronchoscopy unless otherwise stated. Advances in optical technology and signal processing have led to miniaturization of the imaging channels and removal of delicate fiberoptics in the scope, which allow for a larger working channel and increased flexibility. Bronchoscope outer diameters range from 4 to 7 mm, and working channel diameters are 2.0 to 2.8 mm (Figure 46-2).

Flexible bronchoscopy is a valuable tool for airway management.^2-8 The bronchoscope can be used as an intubating stylet for nasal intubation, when a difficult airway is expected, or if patient factors do not allow for optimal positioning of an endotracheal tube (ETT) under direct visualization, such as in patients with cervical, oral, or facial trauma.^5,8 A bronchoscope can be used for confirmation of placement of single lumen as well as dual lumen ETTs^7-9 or to troubleshoot ETT malfunction. Awake intubation can be performed with assistance of bronchoscope and topical anesthesia, minimizing need for sedation.^10,11 Use of medications such as dexmedetomidine, as well as other instruments such as Glideoscope, intubating LMA (laryngeal mask airway), and the Bullard laryngoscope have been described as well.^12-15 Bronchoscopic intubation is an important rescue technique, but takes additional time and should only be used if intubation cannot be performed safely by other methods.³ The operator should be familiar with maneuvering the bronchoscope to the trachea and upper airway anatomy. A smaller bronchoscope is preferred for nasotracheal intubation as the ETT typically has a smaller diameter.^2,3 For urgent intubations, portable bronchoscopes or laryngoscopes with built-in video or fiberoptic displays may expedite the process.

Bronchoscopic Intubation

An appropriate-sized ETT should be loaded over the bronchoscope prior to insertion. The bronchoscopist should ensure the ETT moves freely over the scope prior to inserting it into the airway. A lubricated scope is then introduced and advanced through the vocal cords to mid-trachea. The ETT is advanced over the bronchoscope into the trachea, and placement is confirmed visually at the desired level. If there is resistance to insertion of the tube, it should be withdrawn gently and swiveled 90° to prevent it from “hanging up” on the arytenoids or vocal cords. Use of force is contraindicated as it can lead to upper airway injury. If there is a tracheal lesion or stenosis, the bronchoscope is used to advance the tube beyond the obstruction under direct visualization. A bite lock or oral airway should be used when orotracheal intubation is performed to avoid the risk of damaging the scope. A bronchoscope can also be used for tube replacement or exchange. For tube exchange, the cuff of the existing ETT is deflated, and the preloaded bronchoscope advanced along the side of existing tube into the trachea. The old tube is removed, and the new tube can be positioned in trachea as described above.

Other Uses of Bronchoscopy for ICU Airway Management

A smaller bronchoscope such as a pediatric scope can be used in similar fashion to assist with double-lumen endotracheal tube placement—a common method to isolate large-volume hemoptysis and prevent asphyxia. The scope can be used for insertion and also to guide placement into either mainstem bronchus. A small bronchoscope can then be passed through the tracheal lumen to confirm optimal positioning of the bronchial cuff. Left-sided double-lumen ETTs (the dual lumens are in the L mainstem bronchus and trachea) are preferred because the right mainstem bronchus tends to be smaller, with an increased likelihood of right upper lobe occlusion and atelectasis.^5,7,9

A bronchoscope can be used during extubation as well for assessment of upper airway in patients where upper airway injury or edema is suspected or if stridor is noted following extubation.⁵ Risk factors for postextubation stridor and upper airway edema include prolonged intubation, traumatic intubation, overinflation of the ETT cuff, absence of a “cuff leak,” female gender, and self-extubation.^16,17

Another common use of bronchoscopy in the ICU is to facilitate percutaneous dilatational tracheostomy (see Chapter 45, Percutaneous Tracheostomy).^18-20 Percutaneous tracheostomy is cost effective and safe compared with surgical tracheostomy and can be performed at the bedside in the ICU.^20,21 Furthermore, risks associated with photodynamic therapy (PDT), such as paratracheal insertion or posterior wall puncture, can be minimized under direct visualization with aid of a bronchoscope.^19,20 Bronchoscopic PDT requires two operators, one to operate the bronchoscope and the other to perform the procedure. In this technique the bronchoscope is advanced just proximal to the tip of the ETT, and the ETT is pulled back under direct visualization. Tracheal puncture and wire positioning can be visualized in real time, and thus inadvertent posterior wall puncture is avoided. The bronchoscope can be used to provide additional confirmation of tracheostomy tube placement as well as suctioning of any endobronchial blood after tracheostomy. Attention should be paid to physiological parameters while using the bronchoscope to assist in airway procedures to minimize the physiological effects of airway occlusion, as discussed below.

Equipment

The bronchoscopist must be familiar with modern bronchoscopy equipment and instruments. The proximal end of a modern video bronchoscope has an angulation control lever, suction valve, proximal opening of working channel (usually 2.0 or 2.8 mm in diameter), buttons to freeze or capture images, and a button to change the display output or light input (such as narrow-band imaging). The proximal end is connected to the light source via a flexible tube. The distal end of bronchoscope has a light source, and imaging/an image capture device such as a CCD sensor, while the distal end of the working channel is usually at the 3 o’clock position. Most bronchoscopes used in the ICU are forward-viewing with 0° angulation. The scope connects to a center console that processes the image and displays it on a monitor. Portable bronchoscopes without a console and with a built-in display are also available. A suction control valve and biopsy valve are attached to the proximal end of the scope in order to use suction and the biopsy channel. An assistant generally helps with central controls, hold the ETT, hands instruments or attaches the sputum trap while the bronchoscopist controls the scope. Bronchoscopes by convention are designed to be held in the left hand, but can be held in the right hand if that is the nondominant hand, which leaves the dominant hand free for using tools in the working channel.

The usual three positions for a bronchoscopist to stand during the procedure are behind the patient’s head, at his side, or facing the patient. Any of these positions can be used, but standing behind the head provides anatomical correlation with the bronchoscopic view and is easier for visual correlation in beginners. The patient can be supine, semi-upright, or even in a sitting position for the procedure. In patients with elevated ICP, the monitor might need to be adjusted according to the patient’s position to ensure correct measurement and monitoring. A bite-block should be used whenever oral route of bronchoscopy is used even if the patient has an ETT. An adapter is inserted between the ventilator circuit and ETT, through which the bronchoscope can be introduced. A variety of instruments are available to the bronchoscopist for diagnostic and therapeutic purpose. We recommend simulation training if available prior to bronchoscopy. The equipment and bronchoscope should be cleaned according to infectious disease control standards after each use.

Prior to the Procedure

Hemodynamic and ventilatory parameters should be noted prior to starting the procedure. Appropriate changes to the ventilator settings such as increasing Fio₂, increasing ventilator rate, decreasing peak flow, and adjusting pressure alarms should be made as appropriate.²² Ensure that the internal diameter of the ETT is large enough to allow for ventilation with the bronchoscope inserted; an ETT ≥ 7.5 is generally sufficient, as long as a small scope is utilized. Hypoxemia during bronchoscopy can be avoided by preoxygenation, and Fio₂ is typically increased to 1.0 a few minutes before starting the procedure. End-tidal CO₂ monitoring can be used, but the accuracy is affected by use of suction and leaks in the circuit; dynamic adjustments to maximize exhaled tidal volumes might be a better strategy to ensure adequate ventilation. Hemodynamic measurements at brief intervals and continuous cardiac telemetry are advised. Sedation should be readily available, as well as emergency drugs if needed. Depending on the choice of sedation and patient’s baseline hemodynamics, appropriate intravenous fluids and medications should be available to control hypotension if it occurs. The use of a local anesthetic such as lidocaine is recommended even in sedated patients.²³ Drugs used for sedation are operator dependent and are beyond the scope of this discussion. We use a combination of a short-acting opiate and a benzodiazepine or in intubated patients, an up-titration of sedative and analgesic agents already in use,²⁴ with care not to disrupt cerebral hemodynamics or ventilation.²⁵ The operator or supervising physician should be trained in conscious sedation methods and medications. In nonintubated patients, a sedation assessment including an airway assessment, should be performed prior to the procedure.

Taking care to avoid the camera lens, the distal portion of a clean bronchoscope is lubricated using a silica-based product and is introduced by nose, mouth, or the artificial airway. An assessment of the larynx and vocal cords should be made if the patient is not intubated, noting secretions, blood, edema, vocal cord motion, and any mucosal lesions. Local anesthetic should be administered above the vocal cords. The scope is then gently passed through the vocal cords to avoid trauma. If the patient is intubated, the scope is advanced to the distal endotracheal tube. Once the scope is in the trachea, local anesthetic should again be instilled into the trachea. The scope should be centered in the airway to prevent rubbing against the tracheobronchial mucosa, which elicits the cough reflex and will drive up ICP. Prior to any diagnostic procedure, airway inspection is recommended. Normal airway anatomy is shown in Figure 46-3, but anatomical variations in this schematic are common. Based on clinical data and inspection findings, appropriate sampling procedure and location should be chosen. Excessive suctioning must be avoided, and hemodynamics are closely monitored.

Diagnosing Infection

Ventilator-associated pneumonia (VAP) can be challenging to diagnose and treat as the clinical signs and symptoms of VAP are neither sensitive nor specific among the critically ill. Bronchoscopy can be used to diagnose VAP.^26-30 Protected brush sampling and bronchoalveolar lavage (BAL) are commonly used to obtain specimens for quantitative microbiological analysis.^31,32 Current guidelines recommend obtaining a lower-respiratory specimen to guide antibiotic therapy in VAP, but not delaying antimicrobial therapy,²² because a delay in antibiotic therapy while awaiting results of respiratory cultures is associated with increased mortality.²⁹ Nonbronchoscopic techniques such as endotracheal aspiration and mini-BAL can be used to obtain specimens, but a large randomized trial recently showed a mortality benefit when invasive quantitative cultures were used to guide therapy compared with cultures of endotracheal aspirates in patients with VAP.²⁶ Although data are conflicting regarding the benefits of bronchoscopic sample acquisition, bronchoscope-assisted cultures are associated with a change to more appropriate antibiotics.^26,29,31,32 Culture results from BAL and protected specimen brush (PSB) show good agreement.³² BAL is the preferred method for obtaining a lower respiratory specimen in the immunocompromised patient,^33-35 and bilateral BAL might offer better yield for Pneumocystis carinii and cytomegalovirus in immunocompromised patients.³⁶