Bronchoscope — 10 Marks Exam Answer

Definition

Historical Background

• 1897 — Gustav Killian performed the first bronchoscopy (rigid) to remove a pork bone from the right main bronchus; he is credited with invention of the rigid bronchoscope.
• Chevalier Jackson further developed and popularized rigid bronchoscopy in the United States.
• 1966 — Shigeto Ikeda introduced the flexible fiberoptic bronchoscope, revolutionizing the field.
• Subsequently, videobronchoscopes replaced fiberoptic systems, using a miniaturized camera at the tip to transmit images to a monitor.

Types of Bronchoscopes

1. Rigid Bronchoscope

• A straight metal tube that allows ventilation through the scope itself (closed circuit or open jet ventilation).
• Provides a secure airway — artificial breaths can be delivered through the scope.
• Has a large working diameter → multiple therapeutic instruments can be used simultaneously.
• Limited to the central airways (trachea and main bronchi).
• Modern systems are equipped with optical capabilities for magnified circumferential illumination and visualization.

2. Flexible (Fiberoptic/Video) Bronchoscope

• By far the more commonly used form.
• Enables access to more distal parts of the respiratory tract (up to 6th–8th generation bronchi with ultrathin scopes).
• Varies in diameter — from ultra-thin (≤3 mm external diameter) (for neonates and peripheral lung access) to larger therapeutic devices.
• A working channel allows insertion of biopsy tools, needles, brushes, and lavage instruments.
• Patient ventilation maintained by airflow around the scope.
• Fiberoptic (uses glass fibers to transmit image) → largely replaced by videobronchoscopes (chip-on-tip camera for superior electronic imaging).
• More fragile than rigid bronchoscopes; require careful maintenance and cleaning.

3. Ultrathin Bronchoscopes (≤3 mm)

• Developed originally for pediatrics; now used in adults for peripheral pulmonary lesions.
• Can reach 6th–8th generation bronchi under direct observation.
• Useful combined with navigational and radial EBUS techniques.

4. EBUS Bronchoscope (Endobronchial Ultrasound Scope)

• A specialized flexible bronchoscope with a convex ultrasound probe at the distal tip, plus a video camera.
• Used for real-time EBUS-guided transbronchial needle aspiration (EBUS-TBNA).

5. Robotic Bronchoscopy Systems (since 2018, FDA-approved)

• Integrate novel endoscopic design with navigation platforms.
• Improved articulation, stability, and biopsy instrument guidance in the distal lung.
• Use shape-sensing technology for peripheral lesion navigation.

6. Single-use Disposable Bronchoscopes

• Eliminates cross-infection risk (reusable scope carries ~2.8% cross-infection risk).
• Portable, no endoscopy staff needed; useful in emergencies and bedside procedures.

Accessories / Working Channel Instruments

Indications

Diagnostic Indications

1. Investigation of hemoptysis — to identify bleeding source
2. Evaluation of lung nodule / suspected malignancy — biopsy, brushings, TBNA
3. Bronchoalveolar lavage (BAL) — for microbiological, cytological, immunological analysis
4. Staging of lung cancer — EBUS-TBNA of mediastinal/hilar lymph nodes (sensitivity ~90% for epithelial malignancies)
5. Investigation of diffuse parenchymal/interstitial lung disease — transbronchial biopsy
6. Assessment of immunocompromised patients with lung opacities
7. Evaluation of persistent atelectasis, unresolved pneumonia
8. Diagnosis of sarcoidosis (EBUS-TBNA sensitivity >80%)
9. Assessment of tracheal/bronchial anatomy and central airway lesions
10. Diagnosis of tracheobronchial injuries

Therapeutic Indications

1. Foreign body removal — rigid bronchoscope preferred
2. Mucous plug clearance — reversal of atelectasis in ventilated patients
3. Endotracheal intubation guidance (difficult airway)
4. Stent placement for airway stenosis or tracheobronchomalacia
5. Laser photocoagulation (Nd:YAG) — >90% recanalization rate for central endobronchial obstruction
6. Electrocautery and argon plasma coagulation (APC) — thermal debulking
7. Cryotherapy — tumor debulking, foreign body removal
8. Balloon dilatation (tracheobronchoplasty) — for benign/malignant airway stenosis
9. "Coring out" of bulky central airway tumors — rigid bronchoscope preferred
10. Airway management and oxygenation during resuscitation (rigid scope)

Bronchoalveolar Lavage (BAL) — Key Diagnostic Technique

• Gold standard for obtaining respiratory secretions for hematologic, biochemical, microbiological, and cytologic analysis.
• Bronchoscope is wedged in a distal airway → 50 mL sterile saline instilled (1–3 aliquots) → aspirated back.
• Samples distal airways and alveoli not directly visualized.
• Avoids salivary contamination seen in sputum samples.
• Serial BAL from same site showing increasingly bloody returns suggests alveolar hemorrhage.

Biopsy Techniques

Contraindications

• Absolute: Uncorrectable severe hypoxemia, lack of patient cooperation (relative), unstable cardiovascular status
• Relative: Coagulopathy / thrombocytopenia (platelet <50,000 for biopsy), recent MI, severe airflow obstruction, uncorrected hypercapnia

Complications

Rigid vs. Flexible Bronchoscope: Quick Comparison

Advanced Bronchoscopy Techniques (Contemporary Relevance)

• Navigational bronchoscopy: Electromagnetic navigation (GPS-like feedback) + virtual bronchoscopy (CT-derived maps overlaid on live endoscopy)
• Radial EBUS: Thin ultrasound catheter advanced peripherally; concentric image = high diagnostic yield
• ROSE (Rapid On-site Cytologic Evaluation): Immediate cytotechnologist assessment of EBUS-TBNA adequacy during procedure
• Molecular testing: Transbronchial biopsy material can be used for immunostaining, genetic/mutation testing, and machine-learning-based UIP classifiers