Question 4

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 V_T - 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.

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