Bronchoscopy





Background


Bronchoscopy is an endoscopic technique used to visualize the tracheobronchial tree for diagnostic and therapeutic purposes. The word “bronchoscopy” is derived from Greek words by combining the prefix “broncho” meaning “bronchus” and the verb “skopía” meaning “to view.” Rigid bronchoscopy, which was first used in the 1920s, is less commonly used now, as it uses a more rigid piece of equipment that can only access the proximal airway. Flexible bronchoscopy is also known as standard white light bronchoscopy. Bronchoscopy is sometimes referred to as a “bronch.”


How to Use It


Bronchoscopy is used to examine a patient’s airways and obtain samples of bronchoalveolar fluid or lung tissue using a cytology brush or transbronchial needle aspiration (TNA) from the upper and lower respiratory tract. Theses samples can diagnose respiratory tract infections, lung cancer or other cancer types that metastasize to the lungs, and diffuse parenchymal lung diseases. Diffuse parenchymal lung diseases can be idiopathic, secondary to occupational exposures, as part of a generalized autoimmune disease such as connective tissues diseases, or caused by medications. Examples of causative medications include chemotherapy agents (bleomycin, gemcitabine, epidermal growth factor receptor [EGFR]-targeted agents, mechanistic target of rapamycin protein [MTOR] inhibitors, immune checkpoint inhibitors), rheumatological therapies (methotrexate, leflunomide, biologic disease-modifying antirheumatic drugs), antibiotics (nitrofurantoin and daptomycin), and amiodarone. Bronchoscopy is used to remove foreign bodies or mucus plugs from the airways, evaluate and manage hemoptysis and airway bleeding, destroy large central airway tumors, apply tracheal stents, or facilitate endotracheal intubations and percutaneous tracheostomy procedures. Post lung transplant, bronchoscopy may help determine rejection and its severity and rule out opportunistic infection. Endobronchial ultrasound (EBUS) uses ultrasound waves along with bronchoscopy to examine and sample mediastinal lymph nodes and surrounding structures. It is used to diagnose conditions affecting lymph nodes such as sarcoidosis, lymphoma, or malignancy. It assists in the staging of lung cancer.


How It Is Done


Pulmonologists, intensivists, anesthesiologists, and surgeons can perform bedside emergent bronchoscopy under conscious sedation or general anesthesia. Bedside procedures are performed in the emergency room, intensive care unit, or step-down unit, usually to obtain lower airway specimens, facilitate intubation, or remove foreign body or mucus plugs. A physician, a nurse, and a respiratory therapist are usually present. Specialized bronchoscopies with adjunct procedures such as TNA, lung biopsies, and EBUS are performed by pulmonologists in designated endoscopy areas or operating rooms. These procedures require the presence of well-trained staff and are performed under conscious sedation or general anesthesia. In nonemergent situations, patients should withhold food and liquids for the appropriate amount of time prior to the procedure to reduce the risk of aspiration. See Chapter 6: Introduction to Anesthesia for details about withholding food and liquid. The test entails using a bronchoscope, video monitor, light source, and image processor. The bronchoscope consists of the control handle, a flexible shaft, and camera. The flexible shaft has the working channel in it. The cytology brush, biopsy forceps, and needles are usually inserted through the working channel. After sedating the patient using general anesthesia for rigid bronchoscopy or conscious sedation (benzodiazepines [e.g., midazolam] and analgesics [e.g., fentanyl]) for flexible bronchoscopy, the physician passes the scope through the nasal cavity or mouth, into the larynx, vocal cords, trachea, and right and left bronchial segments. Occasionally, bronchoscopy is performed under monitored anesthesia care in the presence of an anesthesiologist, so if necessary, the bronchoscopy may be converted to using general anesthesia with propofol without intubation. To anesthetize the airways and minimize cough, 1% lidocaine solution is used. A normal test shows a normal airway. Abnormal exams include findings such as excessive or discolored airway secretions, distorted anatomy of the bronchial tree, bronchial hemorrhage, foreign body, tracheomalacia, mucosal lesions, endobronchial lesions, or extrinsic compression. Procedure-related mortality is extremely rare (0.01%), and reported complication rates are 0.08%–6.8%. Most complications occur during or in the first few hours following the procedure. They are mostly related to sedation (transient hypotension or hypoxemia) or due to associated procedures such as TNA or transbronchial biopsies (bleeding and pneumothorax). Bleeding rate after a transbronchial lung biopsy is approximately 2.8%. Most bleeding is usually mild and resolves spontaneously. In those with continued bleeding, epinephrine can be sprayed onto the bleeding lesion to induce vasoconstriction. The pneumothorax rate following transbronchial biopsy is 2%–4%. Many cases are managed conservatively, while the remainder require chest tube placement. Minor complications include sore throat and minor hemoptysis in the first 1–2 days following the procedure. Other rare complications include bronchospasm, epistaxis, cardiac arrhythmias, laryngeal injury, and methemoglobinemia from excessive lidocaine use.


Medication Implications





  • Balancing bleeding and thrombosis risk :




    • To minimize bleeding, correct platelet count <50,000/mm 3 , international normalized ratio (INR) >1.5, or activated partial thromboplastin time (aPTT) >50 seconds prior to bronchoscopy if there is a possibility of biopsy.



    • Aspirin is safe and does not increase bleeding during bronchoscopy. It may be continued.



    • In addition to bleeding risk related to specific bronchoscopic procedures, risk of thrombotic events as defined by the American College of Chest Physicians (ACCP) must be considered. Patients are considered low risk (using antiplatelet therapy for primary prevention of myocardial infarction or stroke) or high risk (placement of coronary stent within previous 3–6 months or myocardial infarction within previous 3 months). ACCP further states that patients receiving dual antiplatelet therapy for coronary stents defer procedures like bronchoscopy for at least 6 weeks (bare metal stent [BMS]) and 6 months (drug-eluting stent [DES]).




      • For low-risk patients, P2Y 12 inhibitors (e.g., clopidogrel, ticlopidine, ticagrelor, prasugrel) should be stopped 7 days before the procedure. If not on aspirin, aspirin therapy can be considered while the P2Y 12 inhibitor is held. Resume P2Y 12 inhibitors 24 hours after the procedure.



      • For high-risk patients, consult cardiology. P2Y 12 inhibitors may be stopped if >6 weeks since BMS or >6 months since DES. The risks and benefits of the bronchoscopy should be considered for individual patients. Aspirin should be continued. Intravenous bridging using reversible glycoprotein inhibitors (e.g., eptifibatide or tirofiban) may be considered. Cangrelor, an intravenous P2Y 12 inhibitor, may also be used. Clopidogrel may be resumed 24 hours after the procedure. Ticagrelor and prasugrel have a rapid onset of action, so caution should be used when resuming these agents. See Chapter 20: Coronary Artery Bypass Grafting for more details about P2Y 12 inhibitors.




    • In addition to bleeding risk related to specific bronchoscopic procedures, risk of thromboembolism must be considered. According to ACCP, annual thromboembolism risk determines overall risk (high [>10%], moderate [5%–10%], or low [<5%]).


Nov 21, 2021 | Posted by in PHARMACY | Comments Off on Bronchoscopy
Premium Wordpress Themes by UFO Themes
%d bloggers like this: