Bronchoscopy and Thoracentesis

In depth

The one-page summary above is what the PDF prints. These sections go further.

Flexible or rigid, and who should not be scoped

Flexible bronchoscopy does nearly all diagnostic work and most therapeutic work: inspecting the airways, lavage, brushings and biopsies, suctioning retained secretions, removing foreign bodies and guiding a difficult intubation. Rigid bronchoscopy is kept for work that needs its wider lumen and larger channels: brisk pulmonary hemorrhage, some aspirated foreign bodies in young children, obstructing lesions that need laser debulking or a stent, and dilation of a narrowed airway (Merck).

In massive hemoptysis the danger is blood spilling into the uninvolved lung, which can asphyxiate the patient, as well as blood loss. Rigid bronchoscopy is preferred because it controls the airway, gives a wider view and suctions better than a flexible scope. The rest of the plan: the bleeding lung down once the side is known, selective intubation of the uninvolved lung or blocking of the bleeding bronchus, correction of any coagulopathy, tranexamic acid, and bronchial artery embolization, the preferred way to stop the bleeding (success up to 90%); surgery is a last resort (Merck).

The contraindication is acute hypercapnic failure in a patient without a secured airway. Long-standing hypercapnia calls for caution with sedation, not automatic refusal: in a series of hypercapnic patients, most with COPD, bronchoscopy caused desaturation in 30% and was stopped early in 20% (BTS 2013).

Bronchoscopy to clear retained secretions is no substitute for chest physiotherapy, nebulized bronchodilators and suctioning; Merck reserves it for hypoxemia in a ventilated patient and for a lobe that stays collapsed behind impacted secretions despite those measures. BTS 2013 adds that a patient who needs noninvasive ventilation beforehand is scoped only where intubation and ventilatory support are readily at hand.

Preparation, sedation and topical lidocaine

Preparation (BTS 2013): no food for 4 hours and clear fluids until 2 hours before; IV access placed before sedation and kept until discharge; heart rate, respiratory rate, blood pressure and SpO₂ recorded before, during and after, with continuous pulse oximetry, and continuous ECG when the risk of arrhythmia is high. Supplemental oxygen is given (Merck). Coagulation studies, platelet count and hemoglobin are checked when there are clinical risk factors for bleeding; clopidogrel is stopped 7 days before a biopsy, and low-dose aspirin can continue.

Sedation is usually a short-acting benzodiazepine, an opioid or both (Merck), kept light enough that verbal contact is possible throughout (BTS 2013). Flumazenil reverses the benzodiazepine: 0.2 mg IV over 15 seconds, repeated at 60-second intervals to a total of 1 mg (label). It does not reverse opioids, and it can precipitate withdrawal seizures in patients who depend on benzodiazepines.

Topical lidocaine to the nose, pharynx, vocal folds and airways suppresses cough and lowers the sedation needed, but it is absorbed into the blood, with serum levels peaking 20–45 minutes after the dose (BTS 2013). Rare reactions to topical anesthesia are laryngospasm, bronchospasm, seizures, and cardiac arrhythmias or arrest (Merck). The risk of toxicity is higher with liver or heart dysfunction and significant renal impairment.

Count milligrams, not milliliters: a 1% solution holds 10 mg/mL, 2% holds 20 mg/mL and 4% holds 40 mg/mL, and the 10% spray gives 10 mg per actuation. BTS 2013 asks that the total delivered at all sites (nasal gel, throat spray, and doses through the scope) be monitored and documented, so one person keeps the running total. Once the limit is reached, no more is given at any concentration: 5 mL of 1% still adds 50 mg.

The sources differ on delivery: BTS 2013 advises against nebulized lidocaine, which showed no benefit and doubled the total dose in the largest trial, and prefers 1% solution sprayed through the scope; Merck lists nebulized or aerosolized lidocaine.

The scope in an artificial airway, and desaturation

A bronchoscope in the natural airway takes up only 10–15% of the tracheal cross-section. Inside a tube it takes far more: a 5.7 mm scope fills 40% of a 9 mm tube and 66% of a 7 mm tube, which can leave too little room to ventilate and can jam or damage the scope (BTS 2013). A tube of 8 mm or larger fits most adults and is preferred to a smaller one: resistance to airflow is lower, suctioning is easier, and a bronchoscope can pass through it (Merck).

On the ventilator (BTS 2013): give 100% oxygen before, during and just after the procedure; use a mandatory mode, because triggered modes do not ventilate reliably around the scope; raise the pressure limit so tidal volumes are still delivered, and the rate if needed; pass the scope through a swivel adapter with a sealing diaphragm so that PEEP is kept; watch tidal volume, SpO₂, ECG, blood pressure and end-tidal CO₂. Lavage on a ventilator worsens the PaO₂/FiO₂ ratio, and a pneumothorax can follow even when no biopsy was taken.

Hypoxemia is common during bronchoscopy and usually transient. BTS 2013 calls a desaturation significant when SpO₂ changes by more than 4% or falls below 90%, and gives oxygen when that lasts more than 1 minute.

Sampling: lavage, biopsy, needle aspiration and EBUS

Not all of the lavage saline comes back. The lavaged segment is left with local pulmonary edema, which can cause transient hypoxemia, and cough may increase (Merck); desaturation below 90% is more frequent with lavage than with washings, brushings or biopsy, and oxygenation can stay lower for 2 hours or more (BTS 2013). When airway pressures and breath sounds are unchanged and no biopsy was taken, the response is more oxygen and monitoring, with a chest radiograph if the patient does not recover.

Fever follows about 5–10% of bronchoscopies and about 13% of lavages, typically starting about 8 hours later (range 4–24 hours) and lasting about 14 hours; it reflects an inflammatory response, usually without bacteremia, rarely comes with an infiltrate, and is not prevented by antibiotics (BTS 2013). Among 314 consecutive patients in one series, 14% developed fever in the first 24 hours, and a bacterial infection was proven in a quarter of those with fever; procalcitonin separated the two groups best (Hackner 2017). A stable patient with an early fever is therefore observed, not started on antibiotics at once; cultures, procalcitonin and treatment are for fever that persists or comes with dyspnea, hypoxemia or a new infiltrate.

Pneumothorax follows about 1 in 1,000 bronchoscopies overall but 1–6% of transbronchial biopsies, and about 40% appear late, up to 2 hours afterward (BTS 2013). A routine film after biopsy adds little in a patient without symptoms; new pleuritic chest pain, dyspnea, a falling SpO₂ or reduced breath sounds on the biopsied side calls for a chest radiograph. Treatment is on the Chest Tubes and Pneumothorax page.

Lavage also answers a diagnostic question in unexplained ARDS: when no predisposing cause is found, some experts advise bronchoscopy with lavage to rule out alveolar hemorrhage and eosinophilic pneumonia, followed by a lung biopsy if the lavage gives no answer (Merck). Diffuse alveolar hemorrhage is suspected in systemic rheumatic disease, such as lupus or vasculitis, and after bone marrow transplantation; it causes bilateral opacities, hypoxemia and a falling hemoglobin, and hemoptysis is absent in up to one-third of patients. Lavage fluid that becomes bloodier with each sequential sample confirms it, and the same fluid is sent for cultures and hemosiderin-laden macrophages. Treatment is high-dose glucocorticoids, often with cyclophosphamide or rituximab, and plasma exchange for anti-GBM disease.

Recovery after bronchoscopy

• Observation: patients who are not critically ill are observed for 2–4 hours; recovery is judged by the return of the gag reflex and by SpO₂ that holds without supplemental oxygen (Merck).
• Nothing by mouth until the gag reflex returns: topical anesthesia of the throat impairs swallowing and raises the risk of aspiration. Merck judges recovery by the return of the gag reflex; MedlinePlus allows no eating or drinking until the cough reflex is back, usually 1 to 2 hours; the lidocaine label says no food for 60 minutes after use in the mouth or throat.
• Expected: a scratchy throat, more cough after lavage, and a little blood-streaked sputum after a biopsy; fewer than 15% of patients have fever or minor bleeding from a biopsy site (Merck).
• Report: larger amounts of blood, pleuritic chest pain or dyspnea, a fever that persists, or returning drowsiness.
• After sedation: no driving, operating machinery or signing legal documents for 24 hours (BTS 2013).

Pleural effusion: when to tap

About 75 mL of fluid is enough to blunt the posterior costophrenic angle on an upright film; the lateral angle needs about 175 mL and sometimes up to 500 mL. A lateral decubitus film with the affected side down shows small, free-flowing effusions better (Merck). Ultrasound confirms the fluid and finds a safe site.

Thoracentesis is indicated for almost all patients whose pleural fluid is at least 10 mm thick on CT, ultrasound or a lateral decubitus film and is new or of uncertain cause (Merck). The usual exception is heart failure with symmetric effusions and no chest pain or fever: diurese first, and tap if the effusions persist for 3 days or more. A diagnostic tap removes about 50 mL; a therapeutic tap removes 500–1,500 mL to relieve dyspnea (BTS 2023).

The result decides the next step. Light's criteria separate exudate from transudate (see the Chest Tubes and Pneumothorax page). In a parapneumonic effusion, a pH below 7.20, glucose below 60 mg/dL, a positive Gram stain or culture, or loculation means the fluid should be drained completely, by thoracentesis or a chest tube (Merck).

• No absolute contraindications (Merck). Relative: a bleeding disorder or anticoagulation; altered chest wall anatomy; cellulitis or herpes zoster at the puncture site; lung disease severe enough that a complication would be life-threatening; uncontrolled coughing or an uncooperative patient.
• BTS 2023 adds: no ultrasound available, or no safe site on ultrasound (a very small or posterior collection).

Thoracentesis: position, needle site and drainage

The preferred position for thoracentesis is sitting upright, leaning slightly forward, with the arms supported (Merck); leaning forward with the arms raised and resting on a table widens the rib spaces (BTS 2023). Lying on the side is an alternative. A recumbent or supine tap, as in a ventilated patient, is possible but is best guided by ultrasound or CT (Merck).

Ultrasound is used for every pleural fluid tap: it raises the success rate and lowers the pneumothorax rate (Merck, BTS 2023). Merck's entry point is in the mid-scapular line, one intercostal space below the top of the effusion and over the upper border of the rib, so the needle meets fluid, not lung. The upper border matters because the intercostal vein, artery and nerve run along the lower edge of each rib. BTS 2023 prefers a site as lateral as possible, in the triangle of safety, because close to the spine the neurovascular bundle may not be covered by the rib.

A ventilated patient is tapped recumbent or supine under ultrasound or CT guidance and has chest imaging afterward even when the tap went well (Merck). BTS 2023 lists a symptomatic effusion in a ventilated patient among the indications for a chest drain.

Fluid is removed slowly, by syringe or gravity; vacuum bottles and wall suction are not used (BTS 2023). BTS 2023 advises a maximum of 1.5 L in one attempt; Merck notes that some clinicians remove no more than 1.5 L in 24 hours, although the evidence that the risk of re-expansion pulmonary edema rises with the volume removed is weak. Blood pressure and symptoms are monitored once more than 500 mL is out (Merck).

Cough during drainage is read differently by the two sources. Merck's procedure page calls coughing normal, a sign of the lung re-expanding, and stops drainage for chest pain, dyspnea or hypotension; its Pleural Effusion page continues until chest tightness, chest pain or severe coughing develops. BTS 2023 stops for chest tightness, pain, persistent cough or worsening breathlessness, because these can mark re-expansion edema or a lung that cannot expand. Taken together: a brief cough with no other symptom is watched, and a persistent or severe cough, or any of the other signs, ends the procedure.

After thoracentesis: imaging and complications

Pneumothorax is the most common complication: from a punctured lung, from air drawn in through the device, or from a lung that cannot re-expand; ultrasound guidance lowers the rate (BTS 2023). Others are bleeding from an intercostal vessel, re-expansion pulmonary edema (symptomatic after fewer than 1% of taps, usually within the first hour), hypotension, vasovagal syncope, infection, pain, and puncture of the liver or spleen. Site soreness is treated with acetaminophen or an oral NSAID, and the patient is told to report new dyspnea or chest pain (Merck).

Compressive atelectasis: when drainage is the treatment

The film helps tell them apart: a lung collapsed behind an obstructed bronchus loses volume and pulls the trachea and mediastinum toward the affected side, while a large effusion pushes them toward the unaffected side (Marchiori 2017).

When a large effusion is compressing the lung, therapeutic thoracentesis relieves the dyspnea, and lung expansion therapy and airway clearance do not remove the cause (Merck, BTS 2023). In a malignant effusion, if thoracentesis relieved the dyspnea and the fluid returns, the next step is an indwelling pleural catheter or pleurodesis; pleurodesis is not used when the lung is trapped and cannot expand (Merck).

Exam pearls

• Absolute contraindications to bronchoscopy: acute hypercapnic failure without intubation, inability to oxygenate, high-grade tracheal obstruction, untreatable life-threatening arrhythmia.
• Topical lidocaine is absorbed: total every dose in milligrams and stop at the limit.
• Desaturation or arrhythmia during the scope: scope out, oxygen on.
• After lavage: transient hypoxemia and an early fever are expected; after transbronchial biopsy: think pneumothorax.
• Nothing by mouth until the gag reflex returns; after flumazenil, watch for resedation for up to 120 minutes.
• Thoracentesis: upright and leaning forward, ultrasound, one space below the top of the fluid, over the rib.
• Image after a tap for ventilation, aspirated air, more than one pass or symptoms; not routinely otherwise.