Flexible bronchoscopy in adults: Indications and contraindications

INTRODUCTION — Flexible bronchoscopy is a procedure that visualizes the lumen and mucosa of the trachea, proximal and distal airways. It can be used to diagnose or treat abnormalities within or adjacent to these airways.

The indications and contraindications of flexible bronchoscopy are discussed in this topic. The equipment, procedure and complications of flexible, fluorescence, and rigid bronchoscopy as well as endobronchial ultrasound and transbronchial needle aspiration techniques are discussed in detail elsewhere. (See "Flexible bronchoscopy in adults: Overview" and "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)" and "Detection of early lung cancer: Autofluorescence bronchoscopy and investigational modalities" and "Bronchoscopic laser in the management of airway disease in adults" and "Rigid bronchoscopy: Instrumentation" and "Bronchoscopy: Transbronchial needle aspiration" and "Endobronchial ultrasound: Indications, contraindications, and complications".)

INDICATIONS — Flexible bronchoscopy is indicated for diagnostic or therapeutic reasons. These are discussed in the following sections. Guidelines on the indications and contraindications of flexible bronchoscopy can be found at the British Thoracic Society.

Diagnostic indications — There are several diagnostic indications for flexible bronchoscopy. Common indications are discussed below (table 1):

●Evaluation of pneumonia or infiltrate of unclear etiology – Flexible bronchoscopy can obtain specimens as part of the evaluation for an infectious, opportunistic, or alternative etiology.

In suspected pneumonia or infection, microbiological specimen can be collected with bronchoalveolar lavage (BAL) or with bronchial washings via flexible bronchoscopy. Bronchoscopy is particularly helpful when pneumonia is suspected on the basis of an abnormal chest radiograph or CT scan with symptoms or signs of pneumonia (eg, fever, cough), but the patient cannot produce sputum for collection (eg, mycobacterial species) [1]. The value of bronchoscopic sampling in patients who can produce sputum for analysis is controversial and uncertain. (See "Basic principles and technique of bronchoalveolar lavage".)

Flexible bronchoscopy is used routinely to obtain specimens when an abnormal infiltrate is seen in immunocompromised (eg, long term steroid use, patients on chemotherapy, HIV, transplant recipients) host to rule out opportunistic infections (eg, PCP or fungal infections). (See "Pulmonary complications after allogeneic hematopoietic cell transplantation: Causes", section on 'Pulmonary infections'.)

In the intensive care unit (ICU), bronchoscopy with a BAL is often done on patients who are found to have a persistent lung infiltrate that is not responsive to antibiotics to rule out the infectious process or the cause of any post obstructive pneumonia.

Bronchoscopy is also useful for patients with slow or incomplete resolution of presumed pneumonia, despite treatment (eg, cryptogenic organizing pneumonia). The evidence suggests that among the persistent infiltrates that are eventually definitively diagnosed, most can be diagnosed by bronchoscopy [2]. (See "Role of bronchoalveolar lavage in diagnosis of interstitial lung disease" and "Nonresolving pneumonia", section on 'Bronchoscopy'.)

●Diagnosis of coronavirus disease 2019 (COVID-19) infection – Nasopharyngeal swab or saliva are considered the source specimen for detection of SARS-CoV-2 infection. Although bronchoscopy is not recommended as the primary mode of diagnosis of COVID-19 [3,4], limited evidence [5,6] and our experience suggest a possible role of BAL to confirm COVID-19 infection when the nasopharyngeal swab or saliva specimen is negative for SARS-CoV-2 and the suspicion of COVID-19 is high based on the clinical and radiologic presentation. In addition, BAL can identify an alternate etiologic agent such as bacterial coinfection in 27 to 56 percent [4,6]. In a multicenter retrospective study of 79 consecutive inpatients, two patients with negative nasopharyngeal swabs were found to have significantly detectable levels of SARS-CoV-2 RNA in BAL [6].

●Persistent atelectasis – Flexible bronchoscopy is warranted in patients who have persistent atelectasis that is either of unknown cause or suspected of being due to airway obstruction. The atelectasis often develops in the lower lobes as a result of poor cough or mucus plugging. The purpose of bronchoscopy is to identify (eg, malignant endobronchial obstruction) or remove any obstructing lesion (eg, mucus plug, foreign body). (See "Airway foreign bodies in adults".)

●Centrally located lung masses or nodules – Flexible bronchoscopy is a reasonable approach for the evaluation of large centrally located parenchymal masses discovered with chest imaging [7]. Diagnostic specimens can be collected for cytopathological analysis by washing, brushing, BAL, or biopsy. The extent of extrinsic compression of the airway from the mass if present can also be assessed as well as direct sampling of peribronchial masses with transbronchial needle aspiration (TBNA) can be performed. Transbronchial biopsy, biopsy of peripheral nodules and use of cryobiopsy are discussed separately. (See "Diagnostic evaluation of the incidental pulmonary nodule", section on 'Bronchoscopic techniques' and "Bronchoscopy: Transbronchial needle aspiration" and "Bronchoscopic cryotechniques in adults", section on 'Cryobiopsy' and "Image-guided bronchoscopy for biopsy of peripheral pulmonary lesions".)

●Peripheral lung mass or nodules – Flexible bronchoscopy with fluoroscopic guidance, electromagnetic navigation guidance, or radial probe ultrasound guidance can be used to access and obtain diagnostic tissue from the peripheral lung nodules. With an ultrathin bronchoscope (a variation of the flexible bronchoscope with an outer diameter of 2.8 to 3.5 mm) (picture 1) smaller peripheral airways can be accessed [8]. Because these bronchoscopes have a larger working channel (1.7 mm) unlike a pediatric bronchoscope, peripheral lung nodules or masses can be sampled with standard biopsy forceps or brushing. (See "Diagnostic evaluation of the incidental pulmonary nodule", section on 'Bronchoscopic techniques' and "Endobronchial ultrasound: Indications, contraindications, and complications", section on 'Sampling parenchymal pulmonary nodules'.)

●Mediastinal lymphadenopathy or masses – Transbronchial needle aspiration (TBNA) performed through a flexible bronchoscope is used to sample enlarged mediastinal or hilar lymph nodes or masses, potentially eliminating the need for mediastinoscopy. Endobronchial ultrasound guided TBNA is a less invasive alternative in staging of lung cancer in addition to diagnosis [9,10]. (See "Bronchoscopy: Transbronchial needle aspiration", section on 'Mediastinal and hilar lymphadenopathy' and "Endobronchial ultrasound: Indications, contraindications, and complications", section on 'Mediastinal lymphadenopathy of unclear etiology'.)

●Hemoptysis – Flexible bronchoscopy is indicated in hemoptysis to identify and localize the cause of bleeding to direct appropriate therapy [11]. In mild or moderate hemoptysis, the bleeding may be controlled with local treatment using laser, APC, balloon tamponade, or selective occlusion of the suspected bronchus with a blockade catheter. Even if the source of bleeding cannot be identified, flexible bronchoscopy may localize the area of bleeding for angiographic embolization, or surgical resection [12]. Rigid bronchoscopy may be indicated in the management of massive hemoptysis that cannot be controlled with flexible bronchoscopy alone. (See "Evaluation of nonlife-threatening hemoptysis in adults", section on 'Initial evaluation' and "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)" and "Bronchoscopic argon plasma coagulation in the management of airway disease in adults" and "Evaluation and management of life-threatening hemoptysis".)

●Suspected airway obstruction – Airway obstruction may be expected on the basis of history (eg, aspiration), an abnormal physical examination finding (eg, focal wheezing or stridor), an abnormal pulmonary function test (eg, flattening of the inspiratory or expiratory limbs of the flow-volume loop) secondary to benign tracheal stenosis or malignant airway obstruction, or an abnormal radiographic finding (eg, focal hyperlucency on a chest radiograph suggesting postobstructive pneumonia). Flexible bronchoscopy is helpful in assessing the patency of the airways, confirming airway obstruction and identifying the cause. Ultrathin bronchoscopes (picture 1) can be used to examine the distal airways beyond a high grade obstruction without compromising the ventilation critically. (See "Clinical presentation, diagnostic evaluation, and management of malignant central airway obstruction in adults", section on 'Diagnostic evaluation and initial management' and "Airway foreign bodies in adults".)

●Evaluation of stridor – Flexible bronchoscopy is performed in the evaluation of stridor to determine if any vocal cord lesion or tracheal stenosis is present. After reviewing the chest computed tomography (CT) scan findings, the location and extent of tracheal stenosis is identified with bronchoscopy to plan appropriate therapy. It is also performed when airway narrowing (trachea or proximal bronchi) is suspected on chest CT and the patient has a history of previous intubation or tracheostomy. (See "Clinical presentation, diagnostic evaluation, and management of malignant central airway obstruction in adults".)

●Tracheobronchomalacia – Flexible bronchoscopy is used to examine the mechanical properties of the airways. Bronchoscopic documentation of dynamic airway collapse under moderate sedation in suspected patients is the gold standard for diagnosing tracheomalacia, tracheobronchomalacia, or excessive dynamic airway collapse (EDAC). Flexible bronchoscopy is indicated to examine the extent of the process and to evaluate candidacy for surgical intervention [13,14]. (See "Tracheomalacia in adults: Clinical features and diagnostic evaluation", section on 'Dynamic flexible bronchoscopy'.)

●Post-lung transplant evaluation – Flexible bronchoscopy with bronchoalveolar lavage and transbronchial biopsies is commonly performed in the posttransplant period to determine rejection and its severity or to rule out opportunistic infection such as pneumocystis jirovecii pneumonia (PJP), cytomegalovirus pneumonia (CMV), or aspergillus [15]. Flexible bronchoscopy is also done to evaluate the donor lung prior to harvesting to rule out any infection or laceration from trauma and can also be used to evaluate suspected tracheal stenosis at the anastomosis site. The value of surveillance bronchoscopy is controversial. (See "Lung transplantation: Procedure and postoperative management", section on 'Flexible bronchoscopy' and "Evaluation and treatment of acute cellular lung transplant rejection", section on 'Flexible bronchoscopy' and "Evaluation and treatment of acute cellular lung transplant rejection", section on 'Surveillance bronchoscopy'.)

●Toxic inhalation or burn injury – Flexible bronchoscopy is sometimes performed to assess the extent of smoke or chemical inhalation injury. Evidence of smoke inhalation includes carbonaceous debris, mucosal pallor, mucosal ulceration, and/or mucosal erythema [16]. Patients with smoke inhalation require close monitoring of their upper airway because obstruction due to edema is common. (See "Inhalation injury from heat, smoke, or chemical irritants".)

●Chest trauma – Blunt or penetrating trauma to the chest or neck can cause a laceration of the airway, which is generally suspected when a patient presents with pneumomediastinum or pneumothorax following trauma. Airway lacerations that follow blunt chest trauma generally involve the membranous distal trachea or proximal main stem bronchi. Bronchoscopy is done to localize and determine the severity of any airway laceration or injury [17]. Small injuries may be managed conservatively (ie, by placing the end of the endotracheal tube distal to the laceration under bronchoscopic guidance when the patient is intubated to minimize further damage of the injury), but severe injuries require surgical repair. (See "Initial evaluation and management of blunt thoracic trauma in adults", section on 'Tracheobronchial injury'.)

●Cough – Flexible bronchoscopy is usually one of the last diagnostic modalities employed in the evaluation of patients with subacute or chronic cough. It may occasionally identify a foreign body, airways disease, or endobronchial tumor as the cause of the cough [18-20]. (See "Causes and epidemiology of subacute and chronic cough in adults".)

●Tracheoesophageal fistula – Tracheoesophageal fistulae can be congenital, due to malignancy (eg, esophageal or lung cancer), or a complication of prolonged intubation or long-term tracheostomy. The initial diagnostic evaluation of a suspected tracheoesophageal fistula generally involves an upper gastrointestinal imaging series with contrast. However, flexible bronchoscopy is performed to confirm and identify the exact location and the extent of the fistula to determine appropriate management options. Administration of a contrast agent (eg, methylene blue) into the esophagus during bronchoscopy may help identify the tracheoesophageal fistula in certain cases [21]. (See "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Tracheoesophageal fistula and esophageal atresia'.)

●Bronchopleural fistula – When a post-lobectomy or postpneumonectomy patient develops a bronchopleural fistula, flexible bronchoscopy may be used to evaluate the integrity of the surgical stump and often to offer interventions such as endobronchial valve placement or closure [22,23]. In contrast, bronchoscopy may not be helpful in identifying the exact location of a fistula following transbronchial lung biopsy, thoracentesis, or attempted central venous catheter insertion because the injury in these cases is most likely along the pleural surface and the bronchoscope cannot visualize the peripheral airways or lung. However, in persistent air leak, bronchoscopy is still indicated to localize the involved lobe or subsegment with the help of selective balloon inflation to direct further intervention such as endobronchial valve placement or surgical intervention.

●Evaluate complications or placement of artificial airways – Flexible bronchoscopy is performed to assess any tracheal damage or ventilation difficulties (eg, obstruction from mucus or blood clot, ulceration, stenosis, cuff leaks, tube migration) in patients with tracheostomy or endotracheal tubes. It is also done to confirm tracheostomy tube placement when dislodged or inserted percutaneously. Bronchoscopic guidance is used commonly during percutaneous tracheostomy. (See "Tracheostomy: Rationale, indications, and contraindications" and "Complications of the endotracheal tube following initial placement: Prevention and management in adult intensive care unit patients".)

●Precancerous lesions – Flexible bronchoscopy with autofluorescence or narrow band imaging (NBI) (picture 2 and picture 3) can be used to diagnose and sample precancerous lesions in the trachea or proximal bronchi and to determine the extent of airway involvement prior to any surgical resection. Its use for the routine evaluation of precancerous lesions in populations at high risk of cancer is controversial. (See "Detection of early lung cancer: Autofluorescence bronchoscopy and investigational modalities", section on 'Proposed indications'.)

●Confocal microbronchoscopy – Real time noninvasive histologic imaging of the bronchial mucosa and alveoli can be obtained with probe-based confocal laser endomicroscopy. A 1.4 mm fiberoptic miniprobe is introduced through the working channel of the flexible bronchoscope. Using software to analyze the endogenous or exogenous fluorophores, the ultrastructure of the bronchi and alveoli can be visualized (image 1A-B) to assess alterations of the basement membrane to diagnose malignant, premalignant, or nonmalignant parenchymal lung diseases [24,25]. There are no universal indications for this type of bronchoscopy and it remains investigational. [26,27]

Therapeutic indications — There are numerous therapeutic indications for flexible bronchoscopy, including the following:

●Mucus impaction – Mucus accumulation in the airways may be severe enough to interfere with ventilation and/or oxygenation, or precipitate recurrent atelectasis. Flexible bronchoscopy is indicated in this situation to suction mucus (ie, pulmonary toilet) to remove the obstruction and open the airways.

●Foreign body removal – Most aspirated foreign objects specifically in the proximal airways can be removed from the tracheobronchial tree using a large variety of retrieval devices passed through the working channel of a flexible bronchoscope (eg, grasping forceps and baskets) [28]. However, when a foreign body gets impacted in the distal airways, rigid bronchoscopy with larger forceps may be needed for removal. (See "Airway foreign bodies in adults", section on 'Flexible bronchoscopy'.)

●Endotracheal tube placement – Flexible bronchoscopy may be used to guide the insertion of an endotracheal tube in a patient with difficult airway or to confirm the position of an endotracheal tube [29]. It is also used to guide the tip of an endotracheal tube into the left or right main stem bronchus for lung isolation in hemoptysis. Commonly, sedation is used during intubation which can exacerbate hypoxia in severely hypoxic patients with additional comorbidities. A study of nine patients showed that bronchoscopic intubation can be performed successfully in patients with pulmonary hypertension and right heart failure with severe hypoxia, who are at high risk of death or complications [30]. A small diameter flexible bronchoscope is used routinely by anesthesiologists to position the double lumen endotracheal tubes to achieve selective lung ventilation. (See "Flexible scope intubation for anesthesia".)

●Laser or argon plasma coagulation – A flexible laser fiber can be introduced through the working channel of a flexible bronchoscope with a ceramic tip to ablate endobronchial lesions [31]. These include neodymium-yttrium-aluminum-garnet (Nd:YAG) or neodymium yttrium-aluminum-perovskite (Nd-YAP) laser, which can desiccate and vaporize tumors or abnormal tissue occluding the airways. A flexible argon plasma coagulation (APC) probe can also be introduced through the bronchoscope to debulk an endobronchial mass. (See "Bronchoscopic laser in the management of airway disease in adults" and "Bronchoscopic argon plasma coagulation in the management of airway disease in adults".)

●Photodynamic therapy – Photodynamic therapy (PDT) can be provided with a flexible bronchoscope to destroy endobronchial tumors [31]. First, a photosensitizer drug (usually a hematoporphyrin derivative) is administered intravenously, which accumulates selectively within the neoplastic tissue. After 72 hours, a PDT probe is introduced through the working channel of the flexible bronchoscope into the endobronchial lesion that emits light at a wavelength of 600 to 800 nm to activate the photosensitizers in the target lesion, leading to the death of the neoplastic tissue. The dead tissue is usually debulked later with flexible or rigid bronchoscopy. (See "Endobronchial photodynamic therapy in the management of airway disease in adults".)

●Electrocoagulation – During electrocoagulation, a flexible electrocautery probe can be introduced through the working channel of a flexible bronchoscope. By applying electrical current through the probe, tracheobronchial tissue or endobronchial tumor can be coagulated within the airways. Some electrocautery probes have metallic wired snares to cut and cauterize polypoid endobronchial lesions simultaneously to minimize bleeding. (See "Endobronchial electrocautery".)

●Cryotherapy – A flexible cryoprobe can be inserted through the working channel of a flexible bronchoscope to freeze and destroy the endobronchial tumor or granulation tissue. As liquid nitrogen is passed through the catheter, the metallic tip of the probe is cooled. When placed in contact with the target tissue, this causes protein denaturation leading to cellular death. The tissue is destroyed by repeated freezing and thawing. Cryotherapy along with flexible bronchoscopy is often used to remove certain foreign bodies that have organic content. (See "Bronchoscopic cryotechniques in adults".)

Spray cryotherapy has been introduced to treat endobronchial lesions. A flexible bronchoscope is first positioned close to the target lesion in the airways. A special catheter that is connected to the source of liquid nitrogen is then introduced through the working channel of the bronchoscope and liquid nitrogen is sprayed on the target lesion. Once the lesion is frozen the tissue is devitalized. The process can be repeated several times [32,33]. (See "Bronchoscopic cryotechniques in adults".)

●Balloon dilation – Balloon catheters analogous to those used for endovascular angioplasty can be passed through the working channel of a flexible bronchoscope. After it is placed at the site of the airway stenosis, it is inflated to dilate the airway under direct bronchoscopic visualization. Serial dilations with smaller to larger size balloons are used to safely dilate without causing any damage. (See "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)".)

●Brachytherapy catheter placement – Using a flexible bronchoscope, a Brachytherapy catheter is placed and secured in the target airway with any endobronchial tumor (picture 4) and the bronchoscope is then removed. Radiation oncologists later insert the radioactive pellet through the catheter adjacent to the targeted malignant tissue during the treatment session. The radioactive pellets emit short range, high dose local radiotherapy to destroy the surrounding tumor cells in the airway without any significant damage to the lung parenchyma. Usually, three weekly sessions are planned. (See "Endobronchial brachytherapy".)

●Tracheobronchial stents – Expandable metallic stents and certain hybrid (silicone/metallic) stents can be placed with the help of a flexible bronchoscope in the airways occluded by tumor or stricture. Often rigid bronchoscopy is better to debulk the tumor first before placement of the stents. The stents are most commonly placed in conjunction with ablative therapies or balloon bronchoplasty. Rigid bronchoscopy is required for silicone stent placement and removal. During follow up after stent placement, surveillance flexible bronchoscopy is used periodically to clean both metallic and silicone stents and rule out stent migration. (See "Airway stents".)

●Bronchial thermoplasty – This procedure is done in severe asthmatics refractory to medical management with the goal of limiting bronchospasm by weakening the smooth muscles of the airway [34]. A special catheter with an expandable coil is passed through the working channel of a flexible ultrathin bronchoscope (to access smaller distal airways) (picture 5). The coil is placed in the airways in direct contact with the wall and thermal energy is applied to induce smooth muscle fibrosis which prevents bronchospasm. (See "Treatment of severe asthma in adolescents and adults", section on 'Bronchial thermoplasty'.)

●Facilitation of drainage catheter placement – Flexible bronchoscopy has been used to place long catheters in select patients to drain parenchymal abscess or to administer antibiotics locally [35,36] although it is not commonly performed in the US.

●Needle aspiration of mediastinal cysts – Some mediastinal cystic lesions (eg, bronchogenic cysts) can be therapeutically managed with transbronchial needle aspiration (TBNA) using a flexible bronchoscope or more commonly now with EBUS bronchoscope [37].

●Treatment of a bronchopleural fistula – In patients with persistent air leak or bronchopleural fistula (BPF) who have failed conventional therapy (ie, prolonged chest tube drainage or surgical closure), flexible bronchoscopy has been used to identify a bronchus leading to the leaking segment or surgical stump leaks. Endobronchial one-way valves or synthetic gels are then placed bronchoscopically to control the leak [38-40].

●Treatment of emphysema – The role of bronchoscopic one way valves and coils in managing emphysema as a mechanism of lung volume reduction is emerging, the details of which are discussed separately. (See "Bronchoscopic treatment of emphysema".)

CONTRAINDICATIONS

Overview — Bronchoscopy is contraindicated in conditions where the potential for a complication is high, either from the procedure itself or from the associated sedation. Absolute contraindications for bronchoscopy are absent informed consent, severe refractory hypoxia with inability to maintain adequate oxygenation during the procedure, or malfunctioning equipment. The common complications of flexible bronchoscopy are tachycardia, bronchospasm, hypoxemia, or bleeding. Sedation and partial airway occlusion with the bronchoscope can lead to hypoxia even in normal subjects. The contraindications discussed here are applicable to flexible bronchoscopy, BAL, brushing, transbronchial needle aspiration, and endobronchial or transbronchial biopsy. (See "Flexible bronchoscopy in adults: Overview".)

Inability to obtain an informed consent is an absolute contraindication to an elective procedure. Intolerance of sedation, due to compromised respiratory status requires specialized planning, such as general anesthesia with supported ventilation. For patients who are not sufficiently sedated with moderate sedation, may tolerate the procedure with general anesthesia

Risk-benefit analysis — A careful risk-benefit analysis prior to bronchoscopy is important to determine whether the information obtained from bronchoscopy will significantly influence the management decision. In certain circumstances, the risk factors may be optimized prior to the procedure to avoid any impending complications. For example, severe hypoxemia is a contraindication to bronchoscopy. However, a patient may be intubated specifically for bronchoscopy to minimize the risk of periprocedural hypoxemia at the known expense of exposing the patient to all the attendant complications of intubation and mechanical ventilation. The informed consent process should include a clear discussion of the available alternatives with possible outcomes and the risks. (See "Informed procedural consent".)

In most cases, bronchoscopic inspection of the airways, with or without BAL, may be safe but performing transbronchial biopsy, brushing or an advanced bronchoscopic intervention may be contraindicated to avoid a catastrophic outcome from asphyxia or bleeding. Specific contraindications of individual interventional procedures (eg, laser or stent placement) performed with flexible bronchoscopy are discussed separately. (See "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)", section on 'Complications' and "Bronchoscopic argon plasma coagulation in the management of airway disease in adults", section on 'Complications' and "Bronchoscopic laser in the management of airway disease in adults", section on 'Complications'.)

Specific contraindications

Patients at risk of pulmonary or cardiovascular complications — Patients considered at risk of decompensation during bronchoscopy include those with severe hypoxemia, current or recent myocardial ischemia, poorly controlled heart failure, significant hypotension or hypertension, exacerbation of asthma or chronic obstructive pulmonary disease, pregnancy, bradycardia or tachycardia, and life-threatening cardiac arrhythmias. Severe refractory hypoxia with inability to maintain adequate oxygenation during the procedure is a contraindication to bronchoscopy unless the bronchoscopic intervention is intended to relieve an obstruction or remove a foreign body that potentially could be therapeutic and can be done safely. An airway management plan should be in place before proceeding with bronchoscopy in such cases. Thus, nonemergent elective bronchoscopy should be avoided in patients who are currently having or have had any of the following events within the past six weeks: myocardial ischemia (ie, unstable angina, myocardial infarction), decompensated heart failure, an exacerbation of asthma or chronic obstructive pulmonary disease, or life-threatening cardiac arrhythmias.

●Severe hypoxemia – Hypoxemia is common during bronchoscopy and results from sedation and partial occlusion of the airways from the bronchoscope. It can also trigger arrhythmias. Nonemergent bronchoscopy should be avoided in patients with severe hypoxemia, which is defined as resting arterial oxygen tension (PaO₂) <60 mmHg or an oxyhemoglobin saturation (SpO₂) <90 percent while receiving an FiO₂ ≥60 percent. Although severe hypoxemia has been considered an absolute contraindication, if the treatment decision is felt to significantly depend on the results of the bronchoscopy or if it is considered to be therapeutic (eg, mucus plug removal), bronchoscopy may be performed either on noninvasive ventilation or with laryngeal mask airway (LMA) placement with the informed consent clearly stating the risk of impending respiratory failure [41]. Alternatively, bronchoscopy can be performed after elective intubation with the attendant complications of intubation and mechanical ventilation clearly outlined to the patient.

In critically ill patients with acute hypoxemic respiratory failure requiring noninvasive ventilation (NIV), bronchoscopy is occasionally performed by some clinicians, although these patients have a high likelihood of subsequent endotracheal intubation due to failure of NIV. A prospective study of 40 subjects requiring noninvasive ventilation at baseline median fraction of inspired oxygen (FiO₂) of 0.5 reported a statistically significant rise in the partial pressure of carbon dioxide (pCO₂) and worsening in oxygenation requiring an increase the FiO₂ post bronchoscopy. Although no one required intubation immediately after bronchoscopy, 10 percent were intubated in the subsequent eight hours and 45 percent within 48 hours. The contribution of the bronchoscopy to subsequent intubation is unknown [42].

In patients with central airway obstruction from tracheal stenosis or endobronchial malignant lesions, the risk of hypoxia is high during bronchoscopy. There may be complete obstruction of ventilation when a bronchoscope is passed through the obstructed airway. However, if an intervention is planned to treat the condition, bronchoscopy can and should be performed provided adequate pre-procedure planning is done to address any procedural complications. Limiting the duration of bronchoscopic examination or intervention will also permit adequate ventilation and oxygenation.

●Severe pulmonary hypertension – Bronchoscopy, and in particular, transbronchial biopsy, in patients with severe pulmonary hypertension (PH) is traditionally considered high risk. Risks include bleeding from transbronchial biopsy as well as hemodynamic compromise secondary to both sedation and increased mean pulmonary arterial pressure during bronchoscopy and possible requirement for mechanical ventilation post procedure. PH is defined as mean pulmonary arterial pressure (mPAP) ≥20 mmHg. This assessment is largely based upon clinical experience and the logic that capillary pressure is constantly elevated in this group. There is no absolute cut-off point in pulmonary pressure over which bronchoscopy becomes unsafe. However, in general, we prefer to avoid bronchoscopy in patients with untreated PH. (See "Treatment and prognosis of pulmonary arterial hypertension in adults (group 1)", section on 'Surgical or periprocedural care'.)

While data largely report no increased risk of bleeding, they are limited by their observational design and inclusion of mostly patients with mild PH [43-46]. For example, a systematic review of nine studies totaling 1699 patients with PH undergoing transbronchial biopsy reported no increased risk of bleeding with this procedure, although there was an increased risk of hypoxemia [46]. However, most patients had mild or moderate PH and the risk in those with severe disease was not studied.

●Unstable or severe obstructive airways disease – Bronchoscopy to obtain bronchoalveolar lavage or transbronchial lung biopsy is usually safe in patients with stable obstructive airways disease (eg, asthma, chronic obstructive pulmonary disease [COPD], bronchiectasis). However, there is a potential for bronchospasm and/or drop in FEV₁ or FVC in patients with severe asthma or COPD [47]. Premedication with nebulized bronchodilator and optimization of asthma control can minimize the risks of bronchospasm or hypoxia. Patients may benefit from CPAP or positive pressure ventilation during recovery from sedation. Transbronchial biopsy should be avoided in COPD patients with bullous disease due to the higher than usual risk of pneumothorax. Nonemergent elective bronchoscopy should be avoided in patients who are currently having or have had an exacerbation of asthma or chronic obstructive pulmonary disease in the prior six weeks. Oxygen supplementation during bronchoscopy should be avoided or used with caution in those where the pre-bronchoscopy partial arterial pressure of carbon dioxide is raised. Some clinicians advocate spirometry followed by arterial blood gas analysis (in those found to have a forced expiratory volume in one second [FEV₁] <40 percent) prior to bronchoscopy, especially in patients suspected to have severe obstruction at baseline. In a prospective study of 151 patients who had bronchoscopy performed, the patients with COPD were compared with those without COPD [48]. The patients with COPD were significantly more likely to have fewer BAL and transbronchial biopsies done compared with those without COPD. Similarly, during moderate sedation the patients with COPD were given lower doses of midazolam and fentanyl. There was no significant difference in major complications such as pneumothorax or respiratory failure [48].

●Hemodynamic instability and myocardial ischemia – Systemic cardiovascular effects of bronchoscopy include increased mean systemic pressure, increased cardiac index, and decreased oxygenation. Consequently, bronchoscopy should be avoided in patients with acute ongoing myocardial ischemia and elective bronchoscopy should be deferred for six weeks after an acute myocardial infarction (MI) or unstable angina. In addition, bronchoscopy should not be performed in patients with severe hypertension/hypotension or uncontrolled rhythm disturbances (tachycardia/bradycardia) in the outpatient setting.

However, major complications are uncommon such that when clinically indicated and the benefits outweigh the risk, a recent myocardial infarction should not always preclude bronchoscopy particularly when results/therapies might significantly impact the management (eg, massive hemoptysis, pre-cardiac transplant evaluation for infection). In a retrospective study of bronchoscopy to evaluate suspected pneumonia in 21 patients with acute MI in a coronary care unit, it was found to be safe [49]. One patient had bleeding and another required intubation within 24 hours of bronchoscopy. The risk of chest pain or post procedure MI was not increased in this population. However, therapy was changed in 64 percent of the patients based on the acquired information.

Another retrospective study of 21 bronchoscopies in 20 patients reported one death in a patient with ongoing ischemia but found it to be safe when performed on average of about 12 days after an acute MI [50]. In these situations, it is preferred by some clinicians that careful attention to sedation and oxygenation, as well as minimizing distress during bronchoscopy, avoids excessive increases in heart rate or decreases on oxygenation to minimize the risk of precipitating an acute myocardial event.

The safety of EBUS bronchoscopy within one year of percutaneous coronary intervention (PCI) was examined in a retrospective study of 24 patients [51]. There was no significant bleeding while one patient developed atrial fibrillation with rapid ventricular rhythm.

A study evaluated the clinical course and complications following diagnostic BAL in critically ill mechanically ventilated patients [52]. Although there was a significant decline in PaO₂/FiO₂ ratio from 29 to 25 kPa after one hour of bronchoscopy, there was no significant decrease in hemodynamic parameters such as mean arterial pressure, heart rate, requirement of pressor use, or cardiac rhythm abnormalities at 1 and 24 hours following bronchoscopy.

Patients at risk of bleeding — Bronchoscopic procedures such as brushing, biopsy, or needle aspiration as opposed to airway inspection or obtaining a BAL place patients at higher risk of bleeding during bronchoscopy. Examples of those at higher than usual risk of bleeding in whom bronchoscopic procedures (not necessarily bronchoscopy per se) are contraindicated include patients on antiplatelet agents (eg, aspirin, clopidogrel, ticlopidine), oral or parenteral anticoagulant therapy, or patients with thrombocytopenia, coagulopathy, or with chronic renal insufficiency. We prefer a minimum platelet count of 30,000/microL to perform a bronchoscopy for inspection or BAL and at least 50,000/microL to perform any other elective diagnostic procedures. In patients with thrombocytopenia or those at risk for bleeding, we avoid nasal insertion and prefer to insert the bronchoscope orally to minimize the risk of epistaxis from scope trauma. However, in cases of emergency, the decision to perform bronchoscopy should be individualized and will depend on the skills and experience of the operator.

●Anticoagulants/coagulopathy – Nonemergent brushing, biopsy, and EBUS or needle aspiration should preferably be avoided in patients who have taken an antiplatelet agent within the past four to five days or subcutaneous low molecular weight heparin in the past 12 hours, or who have a platelet count of 50,000 platelets/mm³ or lower, an international normalized ratio (INR) of 1.3 or greater, or an elevated partial thromboplastin time (PTT) 1.5 times baseline [53,54]. In general, bronchoscopy with bronchoalveolar lavage may be performed safely in those with platelet counts between 30,000 and 50,000 platelets/mm³ but entry via the nasal passage should be avoided in all patients with counts ≤50,000/mm³ due to the higher risk of epistaxis [54]. For patients who receive platelets or fresh frozen plasma (FFP) to correct an abnormality, the relevant laboratory study can be repeated to confirm that the abnormality has been corrected, before proceeding with a non-emergent procedure.

The recommendation to hold antiplatelet agents prior to bronchoscopy is supported by a prospective cohort study of 604 patients who underwent flexible bronchoscopy with transbronchial biopsy [53]. The study found that the risk of bleeding was significantly higher among patients taking clopidogrel alone (89 percent) and clopidogrel plus aspirin (100 percent), compared to the control (3.4 percent). However, the possibility that the bleeding risk associated with antiplatelet medications is agent-specific cannot be excluded, since another study found no increased risk of bleeding among patients taking aspirin [55].

EBUS bronchoscopy performed within one year of percutaneous coronary intervention (PCI) while on anti-thrombotic agents in 24 patients found that, while aspirin or clopidogrel were held for at least three days prior to the procedure in five patients after a careful cardiac evaluation, the EBUS bronchoscopy was performed on 19 patients on aspirin and clopidogrel or other anti-thrombotic agents without any significant bleeding [51].

Certain chemotherapy agents such as sunitinib or bevacizumab may increase the risk of bleeding. A careful review of all medications prior to bronchoscopy is important and should be held prior to bronchoscopy with biopsy or any other intervention.

The risk of bleeding can be minimized by holding oral warfarin for 3 to 5 days and Clopidogrel for five to seven days prior to the procedure, having an INR <1.3, holding low molecular weight heparin for 24 hours, holding IV heparin for two to four hours, and possibly the administration of platelets in those with thrombocytopenia. Blood tests for coagulation and platelet count should be done in those with known risk factors or those requiring biopsy.

●Renal insufficiency – Bronchoscopy with biopsy in uremic patients can increase the risk of bleeding because of dysfunctional platelets. However, a recent retrospective study of 25 patients who underwent bronchoscopic biopsy with underlying uremia and end stage renal failure requiring dialysis, reported a bleeding complication rate of 8 percent [56]. No complication was noted in patients requiring dialysis. Bronchoscopic biopsy may be performed without an increased risk if additional bleeding disorders are screened and addressed appropriately.

In patients with blood urea nitrogen (BUN) >30 mg/dL or serum creatinine >2 mg/dL, administration of desmopressin (DDAVP) approximately 30 minutes before the procedure will minimize risk of bleeding when brushing, biopsy, or needle aspiration is anticipated.

Most of flexible bronchoscopy is done under moderate sedation. Patients on dialysis could have adverse effects of sedative effects from altered clearance of drugs used for moderate or deep sedation. In a retrospective study of eight patients on dialysis, who received moderate doses of pethidine intravenously or hydroxyzine intramuscularly, no significant respiratory depression was noted. However, the procedure provided a diagnosis of cancer in three out of four patients with suspected lung cancer [57].

●Superior vena cava syndrome – When superior vena cava (SVC) is stenotic or compressed by an intrathoracic mass, it can lead to collateral vessel formation. Enlarged vasculature can potentially lead to bleeding if biopsy is planned. However, a retrospective study of bronchoscopy in 11 out of 18 patients with SVC syndrome did not report any complication [58].

Special populations — Flexible bronchoscopy is a high-risk procedure in select populations but can be performed safely with certain provisions. As examples:

Bronchoscopy in COVID-19 patients — Bronchoscopy is an aerosol-generating procedure and may expose the bronchoscopist or other health care workers to potential infection. Initial guidelines from North America and Europe recommended delaying or avoiding elective bronchoscopy in COVID-19-positive patients or in patients with unknown COVID-19 status [3,59-61]. As the disease transmission process is better understood, we believe that bronchoscopy can be done without a prolonged delay, after the indication and risk of exposure versus benefit is carefully evaluated [59,60]. However, bronchoscopy should not be considered a primary mode to diagnose COVID-19 infection.

●Testing prior to bronchoscopy – Although specific guidelines for bronchoscopy or aerosol-generating procedures are yet to be updated, we believe an elective bronchoscopy should not be delayed for more than two weeks after a positive SARS-CoV-2 test in asymptomatic patients, provided that the indication for bronchoscopy is still present. A repeat SARS-CoV-2 or negative test is not mandatory [62].

A SARS-CoV-2 test (reverse transcription polymerase chain reaction [RT-PCR] or antigen based) prior to bronchoscopy or within 72 hours of scheduled elective bronchoscopy, in addition to screening for symptoms or exposure history, should be performed. Targeted SARS-CoV-2 testing in patients to identify asymptomatic or presymptomatic SARS-CoV-2 infection can further reduce the risk for exposure during the bronchoscopy, in addition to the use of universal personal protective equipment (PPE) and infection control in health care settings. (See "COVID-19: General approach to infection prevention in the health care setting".)

●Timing – Flexible bronchoscopy can be performed emergently (on the same day) in SARS-CoV-2-positive patients, if deemed therapeutic (such as in mucus plug impaction or central airway obstruction from tumor or foreign body causing acute respiratory distress), and for evaluation of moderate or massive hemoptysis. Bronchoscopy should be performed urgently (within one to three days) in immunocompromised cases with persistent infiltrate or in lung transplant patients with clinical decline, where bronchoscopy with BAL or biopsy can guide appropriate therapy.

Bronchoscopic evaluation of lung mass or mediastinal adenopathy for diagnosis and staging in suspected malignancy is crucial and may be delayed for two to three weeks in SARS-CoV-2-positive patient.

A comprehensive stratified approach to delay bronchoscopy is described [59]; however, we feel that bronchoscopy can be done safely if the COVID-19 test is negative and the suspicion for COVID-19 infection is minimal, based on clinical and radiologic presentation, and in SARS-CoV-2 positive patients with appropriate precautions.

●Procedure – For patients considered infectious, all bronchoscopies should be done in a negative-pressure room to minimize droplet spread. The risk of aerosolization can be further reduced if the patient is intubated for the procedure or is already on mechanical ventilation (eg, intensive care unit [ICU]). If a negative-pressure room is not readily available, a portable high-efficiency particulate air (HEPA) filtration system can be placed in the room to filter pathogens [63,64]. Entry and exit to the room during the procedure should be strictly avoided.

In SARS-CoV-2-positive cases, the bronchoscopy is preferable under deep sedation or general anesthesia with a short-acting paralytic to minimize cough reflex.

●PPE – The rate of healthcare worker exposure in this population is unknown. Nonetheless, in the absence of full powered air purifying respirator (PAPR), we recommend wearing an N-95 mask with a face shield, cap, impermeable gown with gloves, knee-high shoe covers, and follow strict donning and doffing of PPE to avoid cross contamination. Restricting the number of personnel in the room is also important as most procedures can be done with two health care personnel (bronchoscope operator and an assistant). A nurse can administer and monitor sedation remotely in the ICU where the sedation can be administered from outside using a long intravenous tubing. Additionally, if the procedure is performed in the bronchoscopy suite, an anesthesiologist or a nurse (or both) may need to be present. Similar precautions should be observed during the preprocedure evaluation and recovery.

●Equipment – Use of disposable bronchoscopes, if available, can minimize the risk of cross contamination and avoid exposure to health care personnel, especially during the cleaning. Although routine procedures such as a BAL can be performed easily with disposable scopes, they are not as robust and procedures other than BAL may require a regular non-disposable flexible bronchoscope. The bronchoscopy tower with monitor can be covered in plastic wrap and cleaned thoroughly with standard high-level disinfectants. Precautions are needed for specimen handling according to local infection control protocols. All specimens acquired are placed in a double biohazard bag and handled using double gloves.

Raised intracranial pressure — Intracranial pressure (ICP) rises during flexible bronchoscopy. Thus, we avoid bronchoscopy with conscious sedation in this population. However, it is often performed safely without any adverse neurologic effects using either deep sedation with propofol or general anesthesia [65-67].

As an example, safety of bronchoscopy has been documented in a study of 15 intubated patients with severe head injury who were paralyzed during the procedure with continuous ICP monitoring [65]. Although ICP almost doubled during bronchoscopy, it returned to baseline post bronchoscopy without any changes in Glasgow coma score or neurological examination. Another prospective study of 26 flexible bronchoscopies in 23 patients with brain injury performed under general anesthesia did not report any acute neurologic event due to bronchoscopy. Despite adequate sedation, analgesia, and paralysis a transient rise in ICP and mean arterial pressure occurred during the bronchoscopy, without a substantial change in the cerebral perfusion pressure (CCP) [66].

Mechanical ventilation — A bronchoscopy for bronchoalveolar lavage (BAL) or airway inspection can be performed on mechanical ventilation with moderate or high ventilatory settings (FiO₂ 100 percent and positive end expiratory pressure [PEEP] >10). The vitals should be monitored closely, so the procedure could be aborted or held when a significant oxygen desaturation develops. Elevations in mean airway pressure are frequent but are rarely associated with barotrauma. Additional procedures such as transbronchial or endobronchial biopsy may increase the risk of complications, particularly, pneumothorax.

Transbronchial biopsy should be done with caution in patients with emphysematous bullous disease who are on a mechanical ventilator requiring high PEEP (>10) to avoid a pneumothorax. In intubated patients, the endotracheal tube may be shortened by cutting the proximal end of the tube, to allow the bronchoscope to reach the peripheral airways. The suction time should be limited to less than two to three seconds to minimize loss of tidal volume.

In support of this approach, a retrospective study of 38 patients who underwent BAL and transbronchial biopsy on mechanical ventilation to evaluate pulmonary infiltrate, reported etiologic diagnosis obtained in 63 percent with an increased rate of pneumothorax (9 of 38) without any fatalities [68].

Large anterior mediastinal masses — Bulky lymphadenopathy or large masses of the anterior mediastinum may compress and block the airway during sedation. It may be difficult to ventilate these patients during the procedure or post recovery resulting in respiratory failure and intubation. While some clinicians prefer deep sedation or general anesthesia in such cases, one case report describes the use of dexmedetomidine (avoids muscle relaxation; awake intubation) for the performance of bronchoscopic procedures on anterior mediastinal masses [69]. Thus, in this population we prefer performing bronchoscopy in a sitting position with spontaneous respiration. An awake bronchoscopy with topical sedation or regional anesthesia (glossopharyngeal block) may also be an acceptable alternative.

Pregnancy — Decrease in residual volume and expiratory reserve volume along with an increased demand of oxygen by the fetus and the placenta during pregnancy may lead to rapid oxygen desaturation during bronchoscopy. Medications used for sedation also may pose an adverse risk to the fetus. Nonemergent bronchoscopy should be postponed until delivery or at least after 28 weeks of pregnancy [70]. However, if it is considered lifesaving (acute airway obstruction or massive hemoptysis) and needs to be performed during pregnancy, bronchoscopy should be preferably done in the operating room with anesthesia and an obstetrician available with continuous fetal monitoring. Placement in the left lateral decubitus position and oral approach (if not intubated) will minimize risks.

Older patients — Flexible bronchoscopy is safe in the older adult population. The predominant risk may be oversedation. A retrospective study showed that the use of supplemental oxygen, rate of fever, hypertension, or bleeding were not significantly different between those >75 years and those between 50 and 75 years of age [71].

Another retrospective study compared the safety and utility of flexible bronchoscopy outside the intensive care unit, among patients 85 years or older with those ages 65 to 79 years old. Although the older adult population had a higher American Society of Anesthesiologists (ASA) class compared with the younger group there was no significant difference in complication rates, diagnostic yield or indications between the two groups suggesting that the flexible bronchoscopy is safe among those older than 85 years old compared with the younger cohort [72].

Patients requiring prophylactic antibiotics — The value of prophylactic antibiotics in patients who typically require them for other procedures is unknown. Some clinicians advocate for their use in patients who are asplenic, have a mechanical heart valve prosthesis, or who have a history of endocarditis [73]. In some patients with artificial prosthesis (eg, hip or knee replacement), some clinicians use prophylactic antibiotic to prevent a transient bacteremia and potential seeding of the prosthetic with bacteria. However, the value of the practice is of unclear benefit.

Miscellaneous — Inability to obtain an informed consent is an absolute contraindication to an elective procedure. Intolerance of sedation, due to compromised respiratory status requires specialized planning, such as general anesthesia with supported ventilation. Other relative contraindications include an inability to cooperate with the procedure or malfunctioning equipment. We generally avoid flexible bronchoscopy in those with an unstable cervical spine, unless the spine is stabilized. For those with temporomandibular joint dysfunction who cannot open their oral orifice wide enough for insertion of the scope, a small bronchoscope can be easily inserted through the nasal orifices.

SUMMARY AND RECOMMENDATIONS

●Common diagnostic indications for bronchoscopy include the evaluation of pneumonia or infiltrates of unclear etiology as well as the evaluation of hemoptysis, sampling of lung masses, nodules, or mediastinal lymph nodes to diagnose malignancy, the evaluation and diagnosis of endobronchial foreign bodies, tracheoesophageal fistula, tracheobronchomalacia, and endobronchial lacerations, and the evaluation of cough and airway complications of artificial airways. (See 'Diagnostic indications' above.)

●Common therapeutic uses include the removal of excess mucus or foreign body from the airways; endotracheal tube placement in difficult airways; endoluminal tumor debulking with laser, APC, cryotherapy, or electrocautery; balloon bronchoplasty; surveillance of tracheobronchial stents; bronchial thermoplasty; or endobronchial valve placement. (See 'Therapeutic indications' above.)

●Absolute contraindications for bronchoscopy are absent informed consent (for an elective procedure), severe refractory hypoxia with inability to maintain adequate oxygenation during the procedure, or malfunctioning equipment. Other contraindications to flexible bronchoscopy include those at risk of respiratory and cardiovascular decompensation as well as those at risk of bleeding during bronchoscopy. (See 'Overview' above.)

•Urgent bronchoscopy can be done safely in COVID-19 patients with full powered air-purifying respirator (PAPR) or appropriate personal protective equipment (PPE) and infection control in a negative-pressure room. Elective bronchoscopy can be performed two to three weeks after a SARS-CoV-2-positive test in asymptomatic patients. (See 'Bronchoscopy in COVID-19 patients' above.)

•Specific contraindications to flexible bronchoscopy include those with severe hypoxemia (but responsive to increasing fraction of inspired oxygen), exacerbation of asthma, exacerbation of chronic obstructive pulmonary disease, severe pulmonary hypertension, current or recent myocardial ischemia, poorly controlled heart failure, life-threatening cardiac arrhythmias. (See 'Patients at risk of pulmonary or cardiovascular complications' above.)

•Flexible bronchoscopy is also contraindicated in those patients who are at risk of bleeding including those on anticoagulants or who have a coagulopathy that cannot be reversed, patients with renal insufficiency, and occasionally those with superior vena cava syndrome. (See 'Patients at risk of bleeding' above.)

•Flexible bronchoscopy is a high risk procedure in select populations, but can be performed safely with certain provisions. As examples, flexible bronchoscopy can be performed in patients with raised intracranial pressure preferably under deep sedation or general anesthesia. Non-emergent bronchoscopy should be delayed in pregnancy until after delivery or at least after 28 weeks of gestation but can be performed for emergent indications preferably under general anesthesia. Additional precautions should be considered in those on mechanical ventilation, in those with large anterior mediastinal masses, and in older adults. (See 'Special populations' above.)

•Other miscellaneous contraindications include intolerance of sedation, inability to cooperate with the procedure, and malfunctioning equipment. (See 'Miscellaneous' above.)