Background: Flexible fiberoptic bronchoscopy (FOB) plays an important role in the diagnosis of many pulmonary diseases. FOB allows for direct evaluation of the main airways and is helpful to obtain samples of bronchial and alveolar tissues and fluids. While often performed on an outpatient basis, FOB is also often required in the hospital to diagnose and sometimes treat tracheobronchial and pulmonary parenchymal problems in the critically ill patient. The indications and attendant risks of FOB performed on such critically ill patients are the focus of this section of the newsletter.

Indications: There are multiple uses for the performance of bronchoscopy in seriously ill patients. The primary indications for bronchoscopy in the critical care setting are listed in Table 1.

Tracheobronchial and pulmonary parenchymal infection/infiltrates
Community-acquired pneumonia is a common clinical problem managed by primary care physicians and pulmonologists. Most of these pulmonary infiltrative processes will respond to antibiotic therapy. In some instances, FOB may be helpful in the evaluation of patients whose pneumonia is severe or is worsening despite therapy. Biopsy sampling of the airway mucosa and pulmonary parenchymal tissues for pathologic review and culture by FOB may be helpful (Figure 1). Specifically, pneumonias persisting beyond 30 days in patients younger than 55 should be evaluated more fully with the use of FOB. We also recommend FOB in the evaluation of the critically ill patient with multilobar pneumonic infiltrates.

Pneumonia occurring in patients who are older than 55 and those patients with impaired immunologic function may take more time to improve from both a clinical and radiographical standpoint. The use of FOB for these latter patients may be delayed if their clinical condition is stable or continues to improve, as the time to resolution of the pneumonic process is known to be longer. The role of FOB in the evaluation of such chronic pulmonary infiltrative processes is toward the identification of possible endobronchial obstructive causes for the persistent infiltrate (e.g. endobronchial malignancy) or infectious etiologies that are resistant to the current antibiotic treatments being prescribed. However, in the critical care setting, more aggressive use of FOB is indicated to more accurately direct therapy for immunocompromised individuals with pulmonary infiltrates/pneumonia that may arise from a wide variety of opportunistic organisms (e.g. pneumocystis carinii, aspergillus fumigatus, atypical mycobacteria and tuberculosis). FOB can be used to obtain fluid from bronchoalveolar lavage (BAL) (the instillation of saline into the airway with collection via suctioning) and protected bronchial brush specimens for more accurate evaluation for the inflammatory and/or infectious etiology of the pneumonia (Figure 2). For example, BAL and transbronchial biopsies can provide nearly 100 percent sensitivity in the detection of pneumocystis carinii pneumonia, which is a common pathogen among patients with the acquired human immunodeficiency syndrome (HIV).

The etiology of diffuse pulmonary infiltrates of indeterminate etiology occurring in critically ill patients can also be identified with FOB. This is a reasonable, less invasive first alternative to surgical biopsy for the acquisition of potentially diagnostic tissues in these circumstances. Blood coagulation abnormalities and pulmonary arterial hypertension are contraindications for FOB biopsy in this setting. In these latter circumstances, or when the FOB biopsy results have been inconclusive, a decision to perform thoracoscopic or open surgical lung biopsy must be considered to determine the cause of the pulmonary infiltrative process.

Pulmonary atelectasis and retained bronchial secretions
Secretions retained within the airway may not be able to be mobilized despite the independent promotion of the patient's cough, nasopharyngeal suctioning, incentive spirometry and chest physiotherapy. Single lobar atelectasis due to retained secretions is usually not an indication for FOB, as the chest physiotherapy procedures mentioned above are usually adequate in the clearance of the atelectasis. In some instances (e.g. patients with very thick secretions, those with inspissated secretions or those with impaired cough ability), these routine measures do not result in adequate clearance of the secretions. For such patients, FOB is a useful modality for clearance of such tenacious secretions (Figure 3).

The performance of FOB is also useful in clearing secretions resulting in total lung atelectasis and in the immediate clearance of aspirated gastric contents. Clearance of the secretions is usually successful with direct instillation of saline followed by suctioning through the biopsy channel of the bronchoscope. In some instances, the use of a bronchial brush or biopsy forceps may be needed to dislodge the obstructing material. On rare occasions, FOB is not successful and conversion to rigid bronchoscopy for large channel access to the airway for secretion removal may be indicated.

Foreign body removal from the airway 
While in many patients, a clinical presentation consistent with pulmonary aspiration is very clear, this may not be the case among children or older individuals. The semi-comatose trauma patient sustaining significant injuries to the face and oral cavity may also be at risk for pulmonary aspiration of dislodged teeth. If foreign body aspiration is suspected, FOB can be helpful in determining this diagnosis. If a foreign body is found, the use of special "basket" devices that can be deployed through the biopsy channel of the bronchoscope can assist in the removal of the foreign body. As in the management of tenacious bronchial secretions, rigid bronchoscopy may be necessary to remove the foreign body if FOB snaring is unsuccessful. Rigid bronchoscopy also allows for the administration of general anesthesia as well as better control of any airway bleeding that may occur during removal of the foreign body.

Assistance in endotracheal intubation and endotracheal tube positioning
Laryngoscopic visualization of the airway is the usual means of directing the insertion of an endotracheal tube when ventilatory assistance is required. FOB may be a necessary alternative to this direct visualization approach for patients who have sustained a cervical spine injury requiring intubation. This approach may be necessary for intubation of patients who have large tongues, redundant posterior pharyngeal tissue or small oral apertures. Patients with large pharyngeal or anterior mediastinal tumors may require FOB to assist in an "awake" intubation procedure.

FOB is also a particularly helpful asset in ensuring proper positioning of the endotracheal tube itself. In some centers, a single channel fiberoptic instrument is placed into the endotracheal tube immediately after intubation, and the position of the tip of the endotracheal tube is directly assessed. This may obviate the need to obtain a chest roentgenogram to check for tube position. FOB is also an important means of evaluating sudden increases in peak airway pressure during mechanical ventilation. FOB may help rule out a mainstem bronchial intubation, severe mucus plugging of the airways, or occlusion of the tube itself due to secretions.

Evaluation of potential tracheobronchial trauma
Blunt and penetrating chest trauma is another potential indication for FOB. Direct visualization of the airway is necessary in the case of blunt chest trauma when tracheobronchial disruption is suspected. Care must be undertaken to evaluate the areas closest to the carina and proximal mainstem bronchi, as bronchial tears are often seen in these areas. The mucosal changes associated with a bronchial tear may be subtle, and a physician experienced in airway disruption should assist in such an evaluation. Direct visualization should also be done in a patient with penetrating chest trauma when the hilar and/or mediastinum has been potentially injured. The physicians in charge should make preparations for immediate thoracotomy to repair the airway if a significant direct injury is encountered.

Inhalational injury to the airway 
Inhalation of thermal or chemical toxins can result in airway injury at any level of the airway from the larynx to the peripheral bronchial tree. Reliance on clinical criteria (e.g. carbonaceous sputum, singed nasal hairs and wheezing) will not accurately diagnose tracheal or bronchial involvement from the inhaled toxin(s). The presence of airway injury is associated with significant complication and mortality rates; thus, early evaluation of the airway through FOB is helpful in overall patient management. Repeated FOB during the next several days may be necessary to assist in clearance of airway debris (e.g. secretions and sloughed airway mucosa) from the airway.

Evaluation of hemoptysis 
Hemoptysis is another indication for the performance of FOB in the intensive care setting. The purpose of FOB in this situation is to determine the cause and the site of bleeding. In most in- stances, large channel bronchoscopes can effectively clear the airway of significant amounts of blood. In some instances, in which the hemoptysis is truly massive, rigid bronchoscopy may be necessary to afford adequate clearance of the blood from the airway. The rigid bronchoscopic procedure is ideally performed in the operating room with preparation for thoracotomy and lung resection if such an intervention is indicated.

It is often helpful to intubate the patient who is having significant active hemoptysis prior to performing the FOB to allow for adequate control of the airway. This allows for ease of passage of the bronchoscope on repeated attempts to remove a clot from the airway and also allows for the administration of high-flow oxygen directly into the trachea during the procedure.

While useful to diagnose the cause and to localize the site for the bleeding, FOB can also be helpful in controlling the bleeding itself. The latter can be done with the administration of various medications (e.g. thrombin and epinephrine) directly onto the bleeding site or with the use of balloon catheters to occlude the bronchus from which the blood is arising. Such control of the bleeding may prevent blood aspiration to other areas of the lung, which can lead to further respiratory compromise and subsequent asphyxiation.

Performance of bronchoscopy: Performance of FOB in patients who are seriously ill can be done safely. It is particularly important to maintain adequacy of the airway and to ensure that high-flow oxygen is administered. Adequate patient sedation and comfort should be ensured, and electrocardigraphic monitoring of cardiac rhythm is essential. Careful monitoring of the oxyhemoglobin saturation via pulse oximetry and the general status are performed by members of the bronchoscopy team (e.g. respiratory therapists, nurses and cardiopulmonary technicians).

Specific contraindications for FOB must be considered (Tables 2 and 3). Care must be given to those patients who are uncooperative and for patients with unstable angina pectoris. Elderly individuals and others with resting severe hypoxemia or hypercarbia must have adequate control of the airway and careful monitoring if FOB is being considered.

Additional care must also be given when considering FOB in a patient who has a bleeding diathesis (e.g. platelet dysfunction in a patient with renal disease or a patient treated with systemic anticoagulation). This is of particular importance if a bronchial brush or bronchial biopsy sampling is being considered. Adequate assessment of the patient's coagulation status should be performed prior to the procedure. Appropriate informed consent must be obtained from the patient and/or family prior to the procedure. Attention to such details will afford the patient a safe procedure.

Conclusion: Fiberoptic bronchoscopy is a useful adjunct to many patients who are seriously ill and who have pulmonary processes attendant with their underlying illness. The FOB procedure can be easily and safely performed in patients who are extremely ill. Valuable information, which could otherwise not easily be obtained, can be gained from direct visualization and sampling of airway tissue via FOB. Appropriate therapy can then be based upon these results.

Suggested reading

Campbell GD, Niederman MS, Broughton WA, et al. Hospital acquired pneumonia in adults. Am J Respir Crit Care Med. 1996;153:1711.

Brandstetter RD. Flexible fiberoptic bronchoscopy in the intensive care unit. J Intensive Care Med. 1989;4:428.