Management of Bronchopleural Fistula 氣管肋膜廔管 Dr Grace SM Lam ICU Friday Lecture 16th January, 2009 支气管胸膜瘘

Bronchopleural Fistula Communication between the bronchial tree & pleural space Mortality varies between 18-67% Aetiology Postoperative 2/3 Non-postoperative 1/3

Post-operative BPF Most commonly follows pneumonectomy (0-9% v 0.5% in lobectomy) Predisposing factors: Rt pneumonectomy (shorter Rt main bronchus & single Rt bronchial artery) Uncontrolled preoperative pleural /pulmonary infection Preoperative irradiation Trauma Postoperative positive pressure ventilation Faulty closure of bronchial stump

Post-pneumonectomy CXRs Day 2 Day 14 Day 1 Day 30 Serial radiologic changes seen after pneumonectomy Radiographics 2006;26:1449-1468

Acute Post-pneumonectomy BPF Day 22 Tension pneumothorax & Pulmonary flooding Reappearance of air OR a drop in air-fluid level >1.5cm Mediastinal shift Subcutaneous or mediastinal emphysema Contralateral lung consolidation from transbronchial spill Radiographics 2006;26:1449-1468

Non-postoperative BPF Causes: Necrotizing pneumonia, TB, lung abscess & empyema ARDS Persistent spontaneous pneumothorax Thoracic trauma Iatrogenic (line placement, pleural biopsy, FOB) Irradiation & chemotherapy

Clinical Presentation Persistent air leak >24 hours after the development of pneumothorax Exclude other causes of persistent air leak An external air leak Extra-thoracic location of side holes Disconnections

Clinical Presentation Acute Sudden SOB, hypotension, coughing up of fluid & blood Subacute Insidious onset with fever, wasting, minimally productive cough Chronic Fibrosis of pleural space prevents mediastinal shift

Diagnosis Clinical Instillation of methylene blue through stump followed by its detection in chest tube Inhalation of different concentrations of oxygen and N2O followed by changes in gas concentration in post-pneumonectomy space CT scan to delineate the aetiology Bronchoscopy is both diagnostic & therapeutic

General Management Drainage of pneumothorax & infected pleural space with appropriate size chest tube(s) Pulmonary flooding: Airway control & position affected lung down Treat underlying cause, especially infection Maintain nutritional status Flow through a tube varies exponentially with the radius of the tube Flow varies with the 5th order of the tube radius in clinical situations due to turbulent flow of moist air (Fanning equation)

Mechanical Ventilation BPF offers a pathway of least resistance (or high compliance) Potential problems Significant loss of tidal volume (VT) ↓ CO2 excretion ↓Utilization of inspired O2 Failure to maintain PEEP Air flow through fistula delays healing Inappropriate cycling of ventilator

Conventional Ventilation Goal is to maintain adequate ventilation & oxygenation while↓fistula flow Minimize the pressure gradient between airway & pleural space Minimize mean airway pressure Lowest effective tidal volume Shorten inspiratory time Least number of mechanical breaths Limit PEEP Discontinue /minimize suction on chest tubes

Chest 1986; 90: 321-323 Persistent Bronchopleural Air Leak During Mechanical Ventilation. A Review of 39 Cases. A retrospective review Jan 1977 – Dec 1980 County hospital and regional trauma & burn center in Seattle Consecutive patients who received mechanical ventilation & developed persistent air leak >24hrs Patients after cardiac surgery or pulmonary resection were excluded

Non-traumatic Surgical Illness Chest 1986; 90: 321-323 Received MV 1700 Persistent Air Leak 39 (2%) Trauma 27 22 Chest Non-chest 5 Non-traumatic Surgical Illness 4 Abdominal 2 Burn Medical Illness 8 Pneumonia 4 TB 1 Near-drowning 1 Pancreatitis 1 Sepsis 1

Chest 1986; 90: 321-323 Overall mortality 67% Increased mortality in: Late air leak (94% v 45%; P=0.002) Diagnoses other than chest trauma (P<0.005) Maximum air leak >500ml/breath (100% v 57%; P<0.05) Pleural space infection (87% v 54%; P<0.05) Late air leak defined as air leak first appearing after 24hours after admission.

Chest 1986; 90: 321-323 Mode of MV Assist-control ventilation 33 Intermittent mandatory ventilation 6 Only 2 patients had persistent acidemia PH<7.30 despite adjustment of ventilatory settings BPF can usually be managed by conventional ventilation. The need for special ventilation techniques is uncommon.

Failure of Conventional Ventilation… Options: Chest tube manipulation Intermittent inspiratory chest tube occlusion Application of intrapleural pressure at expiration Independent lung ventilation High frequency ventilation Extracorporeal oxygenation

Intermittent Inspiratory Chest Tube Occlusion Synchronizing chest tube occlusion at inspiration Limit loss of tidal volume on inspiration Restores pulmonary gas exchange & promotes healing of BPF During Inhalation During Exhalation Chest 1990; 97: 1426-1430

Independent Lung Ventilation Indication Anatomical lung separation Massive hemoptysis Whole lung lavage for pulmonary alveolar proteinosis Copious secretions (e.g. bronchiectasis, lung abscess) Physiological lung separation Unilateral parenchymal injury Aspiration Pulmonary contusion Pneumonia Unilateral pulmonary edema Single lung transplant (post operative complications) Bronchopleural fistula Unilateral bronchospasm Severe bilateral lung disease failing conventional ventilationa Crit Care. 2005; 9(6): 594–600

Methods of Lung Separation Endobronchial Blockers Double Lumen ETT

Methods of Lung Separation Endobronchial Blockers Can be passed Along the side, or Into the lumen Of the single lumen ETT Final placement requires bronchoscopic guidance Does not allow ventilation of the obstructed lung (for anatomical lung separation)

Methods of Lung Separation Double Lumen ETT For independent lung ventilation

Size of double lumen ETT Appropriately sized to allow: Adequate functional separation of the lungs Access for suctioning and bronchoscopy Prevent migration of the tube Tube size (F) Circumference (mm) Lumen diameter (mm) Indication 35 38.0 5.0 Pediatrics 37 40.0 5.5 Small adults 39 44.0 6.0 Medium adults, usual female size 41 45.0 6.5 Large adults, usual male size

Double Lumen ETT Placement Confirming position by ascultation following sequential clamping is inaccurate in 38% Bronchoscopic confirmation is recommended For a left-sided double lumen ETT, bronchoscopy via: Tracheal port ~ Carina visualized, without herniation of bronchial cuff Bronchial port ~ LUL orifice visualized

Independent Lung Ventilation For unilateral BPF Unaffected lung: Conventional ventilation Affected lung: Conventional ventilation with lower mean airway pressure CPAP at pressure just below the critical opening pressure of BPF High frequency ventilation

High Frequency Ventilation High frequency oscillator

High Frequency Ventilation Conventional Ventilation High Frequency Ventilation Gas transport occurs by bulk flow /convection & molecular diffusion VA = f (VT – VDS) Delivery of small tidal volumes (VT≦VDS) at supra-physiologic frequencies Governs lung volume & oxygenation Frequency Tidal volume & CO2 elimination

Gas Transport in HFV Longitudinal gas transport : Coaxial flow Molecular diffusion Mixing of fresh & exhaled gas : Lateral diffusion Turbulent flow at airway bends & bifurcations Intra-alveolar pendelluft Most proximal alveoli by bulk flow

HFV in BPF Flow through an air leak is proportional to: Cross-sectional area of the leak Time held at high airway pressure ∴High frequency ventilation may reduce fistula leak

HFV in BPF Superior to conventional ventilation in controlling PCO2 & PO2 in proximal BPF & normal lung parenchyma Controversial in peripheral BPF with parenchymal disease (e.g. ARDS) Initial settings: Begin with MAP similar to or slightly lower than that of conventional ventilation Use higher frequency (13-15Hz) Amplitude to achieve minimal chest movement

Potential Complications of HFV Suboptimal humidification Inspissation of airway secretions Necrotizing tracheobronchitis Gas trapping

Treatment of BPF Operative Non-operative Drainage of infected pleural space, closure of BPF, and obliteration of dead space: Omental flap Transsternal transpericardial bronchial closure Eloesser muscle flap Thoracoplasty Conservative Chemical pleurodesis via chest drain Bronchoscopic methods 60cm Patient Underwater seal ANZ J Surg. 2006 Aug;76(8):754-6

Bronchoscopy in BPF Diagnostic: Therapeutic: Direct visualization of proximal fistula Distal fistula localized by systematically occluding bronchial segments by balloons Therapeutic: Distal small fistulas (~1mm) can be sealed by various agents: Glue, blood patch, coils, gel foams, lead shots No evidence to support the use of one over another

Bronchoscopy in BPF Amplatzer device Endobronchial valve (Emphasys) Commonly used for closure of atrial septal defects. For closure of larger BPF. Large range of device sizes & can be matched to size of fistula. Chest 2008; 133(6): 1481-4 Designed primarily for endoscopic lung volume reduction in emphysema. One-way valve that prevents entry of air but allows drainage of secretions. Thorax 2007; 62: 830-3

Bronchoscopy in BPF Endobronchial Watanabe Spigot (EWS) (Novatech, Grasse, France) A silicone-made bronchial filler for bronchial occlusion Flexible bronchoscope under LA J Bronchol 2003; 10: 264-7

Bronchial Occlusion With Endobronchial Watanabe Spigot J Bronchol 2003; 10: 264-7 63 cases in Japan between April 2000 and March 2002 40 intractable pneumothorax 12 pyothorax with bronchial fistula 7 pulmonary fistula, 1 bronchial fistula 1 bronchobiliary, 1 bronchoesophageal fistula, and 1 bronchogastric fistula

Bronchial Occlusion With Endobronchial Watanabe Spigot Technically successful bronchial occlusion In 58/60 (96.7%) Average 4 EWS/case used J Bronchol 2003; 10: 264-7

Take Home Messages BPF is an abnormal communication between bronchial tree & pleural space associated with significant mortality No established guidelines in the management of BPF Early recognition, drainage, & management of infection are critical Recognizes the potential problems with positive pressure ventilation, although conventional ventilation usually suffices List of available options represent personal experience not subjected to vigorous testing

References Radiographics 2006;26:1449-1468 Crit Care 2005; 9(6): 594–600 Chest 1986; 90: 321-323 Chest 1990; 97: 1426-1430 Chest 2005; 128(6): 3955-65 Chest 2008; 133(6): 1481-4 Thorax 2007; 62: 830-3 J Bronchol 2003; 10: 264-7

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