Outline the principles of, and strategies for management of a persisting broncho-pleural fistula (BPF) in a mechanically ventilated patient.

Include in your answer the advantages and disadvantages of each strategy.

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College Answer

Principles of Management:
1. Drainage
 Adequate drainage of the fistula with an intercostal catheter of adequate size to manage a large air leak.
 May require multiple catheters, and ability to manage large flow rates.
 Minimise suction.

2. Ventilatory management
 Aim is to reduce mean airway pressure to reduce flow through fistula tract.
 Low tidal volume and PEEP.
 Low mandatory breath rate.
 Permissive hypercapnoea.
 Short inspiratory time.
 Attempt to wean to spontaneous breathing mode from mandatory ventilation as soon as practicable and preferably from ventilatory support altogether.

3. General measures
 Standard ICU supportive management
 Broad spectrum antibiotic cover
 Attention to nutritional requirements – patients usually catabolic.

Strategies for Managing Large Leaks:
1. Independent Lung Ventilation
 Advantages: - May minimise leak in injured lung whilst preserving gas exchange with conventional parameters in normal lung.
 Disadvantages: -requires some form of double lumen tube – difficult to place and secure.
 May not be tolerated in hypoxic patients.
 Requirement for two ventilators –either synchronous or asynchronous – technically demanding and complex.

2. High Frequency Ventilation
 Advantages are that it may reduce peak air pressures and theoretically reduce air leak.
 Disadvantages - not widely available. Recent evidence suggesting an increase in mortality for this ventilatory technique in ARDS patients.

3. Surgery
 Advantages – Definitive management strategy. May be only option to seal leak.
 Disadvantages – Patient may not be fit enough to tolerate.

4. Endobronchial Occlusion
 Advantages – Widely available, can be definitive treatment.
 Disadvantages – may be technically challenging, not feasible with multiple leaks.

5. Application of PEEP to intercostal catheter
 Advantages – may decrease leak volume and maintain intra-thoracic PEEP.
 Disadvantages – compromise drainage, risk of tension, not feasible with multiple tubes.

6. ECMO
 Advantages – may be only option to treat hypoxia.
 Disadvantages – not widely available, complex, little experience.

Examiners' comments: Overall, candidates had poor knowledge of this topic.

Discussion

This answer would benefit from a tabulated format:

Management Strategies for Bronchopleural Fistula
Strategy Advantages Disadvantages
Drainage
- large-bore drain
- or, multiple drains
- minimise suction
  • easy and readily available
  • Usually well tolerated
  • Does not interfere with weaning of ventilation
  • Risk of damaging more lung and creating larger leaks
  • Potentially, perpetuates the fistula by negative pressure suction
  • Invasive
Ventilator strategy:
- low VT
- low PEEP
- low resp rate
- short insp. time
- tolerate high PCO2
- wean rapidly
- extubate early
 
  • easy and readily available
  • Usually well tolerated
  • Early extubation is the ideal step to aim for, as spontaneous negative pressure breathing is better for BPF healing than positive pressure ventilation.
  • The BPF itself may frustrate weaning off ventilation
  • Mandatory mode may prolong ventilation time
  • Permissive hypercapnea may lead to respiratory acidosis, which is not ideal for the patient with traumatic brain injury
Independent lung ventilation
- dual-lumen tube
- or, bronch blocker
 
  • Isolation of one lung permits the selective low-volume low-pressure ventilation of the affected lung, and more rapid higher volume ventilation of the unaffected lung.
  •  PCO2 levels may be easier to control in this manner
  • Technically difficult: DLT insertion is one thing; running two ventilators is another.
  • There may be leak of gas and pressure from one lung to another if the seal is imperfect
  • Sedation requirements will  be higher, to tolerate the larger tube and the very unnatural respiratory pattern
  • Local pressure effects of the DLT are also more problematic
     
Surgical repair
  • The affected lung can be surgically repaired. USually, this means segmental lobectomy (for alveolar leaks) or patching and oversowing of the bronchial leak
  • Apparently, success rates are between 80 and 95%
  • It may be impossible to find the leak intraoperatively
  • It may be unfeasible to remove so much lung
  • It may be impossible if there are multiple leaks
  • The patient must tolerate one-lung ventilation
  • This approach requires thoracotomy
Bronchial stenting
  • The affected bronchus can be stented over bronchoscopically, thereby blocking the leak.
  • This is a minimally invasive alternative to surgical patch repair
  • You need to be sure of where the leak is
  • The leak must be in an accessible bronchus.
  • This may not work if there are multiple leaks
  • The procedure requires technical expertise
  • The patient must be fit to tolerate the bronchoscopy
Bronchial occlusion
  • Similarly to surgery, the affected pronchus is blocked with either a one-way valve or a plug. In fact, the Lois article lists options such as blood clot, cyanoacrylate glue, fibrin, lead shot,  gel foam, calf bone, and various others.
  • You need to be sure of where the leak is
  • The leak must be in an accessible bronchus
  • A major part of the lung may be sacrificed
  • The atelectatic lung may develop infection
Application of PEEP to the ICC
  • The equal intra and extrathoracic PEEP decreases the leak volume
  • Maintained intra-thoracic PEEP permits higher PEEP levels to be used
  • Drainage is compromised
  • There is a major risk of rapid tension pneumothorax
HFOV
  • May reduce peak pressures
  • Certainly reduces tidal volume (to ~50ml)
  • Thus, theoretically reduces flow across the BPD, allowing it to heal
  • This is avery unnatural form of ventilation, and may be poorly tolerated
  • Large amounts of sedation or paralysis will be required
ECMO
  • This may be the only option for severely hypoxic patients
  • With ECMO, one can limit or totally abolish gas flow through the BPF
  • All the risks of ECMO apply, as it is a maximally invasive therapy
  • It is not widely available.
  • There is little experience with this in BPF.