Bronchoscopy

Existentialism aside, there are three categories of indication for bronchoscopy on ICU.

Diagnosis

• Confirmation of endotracheal tube placement (or tracheostomy)
• Respiratory condition with intraluminal pathology
• Airway burns
• Airway trauma
• Lung cancer diagnosis and staging

Testing

• Bronchoalveolar lavage for sending samples
• Biopsies of masses
• Endobronchial ultrasound

Treatment

• Foreign body removal
• Secretion clearance and pulmonary toilet
• Awake tracheal intubation
• Airway stenting
• Massive haemoptysis

These patients are already the sickest patients in the hospital, with hypoxia, hypercapnia, metabolic and cardiovascular problems already and that's before you've decided to shove a periscope down their throat.

You need to know what physical and physiological effects the act of bronchoscopising has on a ventilated patient.

• The procedure can fail for whatever reason, as anything we do always can
• Hypoxia leads to increased myocardial work, with increased heart rate and blood pressure
• Hypercapnoea leads to acidosis and all of its ensuing changes in vascular resistance (systemic and pulmonary), myocardial output and intracerebral pressure
• Airway trauma can be direct from a clumsily-handled scope or indirect as a result of increased airway pressures from obstructing the trachea and bronchi
• Wild swings in intrathoracic pressure can have knock-on cardiovascular effects
• You can always trigger bronchospasm
• They can always get local anaesthetic toxicity as well

Don't suction for more than three seconds at a time, to prevent excessive atelectasis and hypoxia.

• Cardiovascular instability
• Acute myocardial ischaemia
• Coagulopathy
• Hypoxia
• Pneumothorax
• Bronchospasm

Preparation

• Check ID, consent and indications
• Ensure stability of unit appropriate for procedure to go ahead
• Rule out contraindications and correct reversible issues
• AoA monitoring
• Adjust ventilator/alarm settings as required
• Ensure NG feed stopped and NG tube aspirated if relevant
• Position patient and monitors appropriately to improve ergodynamics
• Select bronchoscope size (2mm smaller than tube)
• Ensure correct catheter mount on tube to facilitate bronchoscopy
• Emergency airway equipment
• Drugs (rocuronium and sedation)

Procedure

• Experienced operator and adequate assistance
• Check control and orientation of bronchoscope
• Monitor patient and ventilator throughout

Post-procedure

• Re-establish ventilator settings
• Disposal/cleaning of equipment where relevant
• Documentation
• Chest xray
• Review patient once settled

• Bronchoalveolar lavage
• 20% of intubated patients will get a VAP
• It's thought that aspiration of around 0.3 ml/kg (approx 25ml) of gastric content is enough to cause pneumonitis
• Most bugs can be detected in upper airway or tracheal secretions, but some prefer to dwell in the distance and need deeper sampling

e.g. Pneumocystis jiroveci, TB, other mycobacteria, fungi

• Bronchoalveolar lavage is the gold standard for Pneumocystis jiroveci pneumonia diagnosis, but PCR is increasingly used nowadays
• So you shove a load of 0.9% saline into the relevant segment of the lung and then suck it out again
• The hope is that whatever bug is causing your problem is then detected in these samples when you send it to the lab

If you use 50-60ml, you'll detect things in the more proximal airway branches. You'll need up to 200ml to ensure the whole segment and alveoli get a good washing.

The recommended amount for the exam is 60-180ml.

Endobronchial ultrasound.

This variant of flexible bronchoscopy incorporates an ultrasound probe rather than a camera.

One can take transbronchial needle aspirations of cysts, lumps and bumps

Have a guess.

It's just really slim, thus allowing for examination into the fourth generation of airway and potentially a bit beyond.

• Trachea ends after 12 cm at the carina at T4/5, branching into right and left main bronchi
• The carina looks slightly off centre because the right main bronchus is a couple of millimetres bigger than the left
• The trachealis muscle runs down the back of the trachea, and can be used as a visual reference during bronchoscopy

Head down the right

The right main bronchus is 25mm long.

The right upper lobe bronchus shoots off at 12 o'clock, and branches off to give three segments

• apical
• posterior
• anterior

The 30 mm right bronchus intermedius then continues before firing off the middle lobe bronchus, which has two branches:

• lateral
• medial

Finally we end up at the lower lobe bronchus, with five segments:

• apical
• posterior basal
• anterior basal
• lateral basal
• medial basal

Head down the left

The left main bronchus is 50mm long.

The left upper lobe has a superior division and lingular division.

The superior division has three segments

• apical
• posterior
• anterior

The lingular division also has two

• superior
• inferior

Finally the lower lobe has four segments

• apical
• lateral basal
• anterior basal
• posterior basal

Bronchi become bronchioles which become terminal bronchioles and then respiratory bronchioles and then alveoli.

• What the surgeon wants to do - flexible vs rigid
• How long it's likely to take
• What they want to achieve - quick look vs lots of biopsies
• Patient condition - physiological and psychological

TIVA

• No worries about being able to maintain anaesthesia
• No accidental anaesthesia for everyone else in the room
• Can use for MH patients or if volatiles not appropriate for other reasons

Volatile

• Bronchodilatory effect
• Automatic depth of anaesthesia monitoring
• Can keep the patient spontaneously breathing more easily

You can only really do this with jet ventilation, usually via the side port of a ventilating bronchoscope.

• High pressure (400kPa) jet of pure oxygen uses venturi effect to entrain room air at very high flow
• Can do high or low frequency jet ventilation
• Can be via supraglottic, subglottic or transtracheal
• Generally generates enough tidal volume with passive expiration*
• Can cause barotrauma so needs careful monitoring

*These are still small tidal volumes of up to 3ml/kg mind.

You strap high flow nasal oxygen to their face and hope that some of it ends up in the alveoli

• Also seems to slow the rate of CO2 rise
• Needs very careful patient selection
• Only acceptable for short procedures

• Sounds pretty ideal, as you would for a foreign body in a child
• Keep them breathing and avoid the trouble of ventilating them altogether
• Can do it with TIVA as well

Tough to get right because you often end up needing to give opioids and paralytics for the surgeon.

Many patients don't have the physiological reserve or body habitus to facilitate adequate spontaneous respiration under anaesthesia without obstructing their airway or desaturating rapidly.

Any tube can be obstructed by an extraluminal or intraluminal cause.

• Extraluminal - mediastinal tumour, thyroid goitre
• Intraluminal - bronchial carcinoma

Break this down into malignant and non-malignant.

Stenting for malignant causes is usually palliative.

• Malignant - primary cancer, metastasis
• Non-malignant - anastomotic strictures, tracheal stenosis, tracheobronchomalacia

Stents are avoided where possible in benign disease as they don't definitively fix the underlying problem and tend to move around and cause problems after a few years.