Vol .IX, No.1, Jan
15, 2003
Bronchopleural fistula (BPF) is an aberrant communication between the bronchial tree and the pleural space through which the inspired gas exits the lungs. It is a formidable therapeutic and management challenge especially in patients on mechanical ventilation. In empyema, which is almost a medical emergency, adequate and early pleural drainage is crucial. If the pleural fluid/pus is not drained exteriorly with a chest tube, it is likely to drain interiorly into the lungs producing an overwhelming pneumonia. BPF is involved not only in the drainage of the gas from the alveoli in the area of the fistula but also from the remote alveoli by pressure gradients created by it. It leads to decreased utilization of inspired oxygen before it escapes through the fistula and is also an efficient mechanism of carbondioxide removal.
Aetiology
In the west, approximately two-thirds of BPF cases occur following complicated lung surgery i.e. pneumonectomy (5-20%), lobectomy (1-5%), segmentectomy and wedge resection (0.5% each). The remaining one-third of BPF cases are related to pulmonary tuberculosis, necrotizing pneumonia, lung cancer, suppurative lung diseases, ventilator therapy in acute respiratory distress syndrome (ARDS), chest trauma (blunt or penetrating lung injury, thoracocentesis, pleural biopsy, chest tubes, CVP lines) and alveolar rupture which may be spontaneous or related to the ARDS treatment. In addition, lymphocytic empyema due to histoplasma capsulatum and pancreatic pleural effusion can also be complicated by BPF. In the developing countries, however tuberculosis remains the most important cause.
Clinical Features
Clinical presentation of BPF ranges from an incidental discovery on chest x-ray to a life threatening tension pneumothorax, however the most common presentation has been a chronic wasting illness that is fatal within a few months to years, if untreated. BPF should be suspected when a patient with pleural fluid collection expectorates more sputum than expected from the associated pulmonary disease or when a patient produces large amounts of sputum only when lying in one position. In acute presentation, large quantities of infected material can flood the airways of both ipsilateral and contralateral lung producing acute respiratory compromise. Early post surgery BPF can show a dramatic presentation because the mediastinum is mobile and predisposes to contralateral shift thereby compromising the remaining lung function. In contrast, late post surgery BPF arises in fibrotic space, thus impeding the development of tension pneumothorax due to the fixed mediastinum.
Diagnosis
Diagnosis of BPF is usually not difficult and is evident from clinical events. Upright chest x-ray showing an air-fluid level, particularly if the level fluctuates in serial films is highly suggestive of BPF. Sometimes, it is difficult to differentiate from a chest X-ray whether the air fluid level is in the lung parenchyma or the pleural space, a problem that is solved by investigations such as the ultrasound and the CT scanning. Thin section CT scan has been reported to be superior to standard CT especially for the diagnosis of peripheral fistulas. Bronchography documents the bronchopleural communication. Other highly useful investigations for diagnosis of BPF include intrapleural injection of methylene blue followed by bronchoscopy, xenon-ventilation nuclear scintigraphy and thoracoscopy.
Tubercular BPF
Tubercular BPF are uncommon these days because of the effective antitubercular treatment (ATT) and are usually seen in those patients who have taken inadequate treatment, in cases of cavity-rupture during the active disease and in old healed pulmonary tuberculosis with fibrothorax. The two important dangers of tubercular BPF are the propensity of mycobacteria in pleural space to become ATT resistant and occasional bacterial-super infection of the pleural space which may produce fulminant pneumonia. The incidence of this type of fistula is very high in India as compared to European countries and USA. However, exact figures for comparisons are not known. A conservative approach that includes ATT and chest tube drainage is preferred and may be sufficient in one-third of patients. Before definitive surgery is undertaken patient should ideally receive ATt for 3 to 4 months or until sputum is negative for the acid fast bacilli (AFB). Drainage of pleural space is the crucial first step for all patients to limit endobronchial contamination. By the time the BPF develops, the disease is so advanced as to preclude satisfactory re-expansion of lung thereby limiting surgical options to open thoracotomy or multiple stage thoracoplasty. Extensive disease may need decortication or pleuropneumonectomy. For surgically unfit patients, bronchoscopy related treatment to close down the fistula is preferred. Alternatively, long term chest tube drainage is advised.
Prognosis of BPF
Prognosis depends primarily on the nature and the extent of the underlying lung disease, presence or absence of pleural space infection and associated comorbid conditions such as the poorly controlled diabetes, chronic renal failure, decompensated liver disease, immunodeficiency, etc. The size of the
air-leak is an independent vital prognostic factor - leaks exceeding 500 ml/breath carry almost 100% mortality whereas lesser leaks have a mortality rate of nearly 57%. Similarly, in chest trauma patients, leaks appearing within the first 24 hours of injury have a relatively better prognosis (45% mortality) as against leaks appearing after that (90% mortality). Overall, the patient survival depends on a high index of suspicion, early diagnosis and aggressive surgery.
Management
Best management of BPF is prevention including meticulous surgery and liberal prophylactic use of pedicled muscle flaps for patients at increased risk. Equally important is the treatment of the underlying lung disease, appropriate antibiotics and good nutritional status of the patient. Initial treatment includes drainage to prevent flooding of bronchial tree with the pus. Increased flow through fistula is an important factor that delays healing and is decreased when the side with the fistula is placed in a dependent position.
Chest tube (C.T.) has far more important role than that of a passive conduct in BPF and can be both useful and detrimental. It not only draws pleural air due to fistula but also decreases the air leak, thereby promoting fistula repair. Efficient drainage is very crucial since air leaks may be as forceful as 16 litres per minute. Small diameter C.T. can lead to lung collapse and tension pneumothorax in the setting of a mobile mediastinum. Large diameter C.T. is particularly needed for high flow BPF and infected pleural space. Amount of suction applied via C.T. is individualized since the requirements vary from no suction to intermediate suction (10-15 cm H2O) to high suction (25 cm H2 0). The negative effects of C.T. include a loss of the tidal volume, altered PaO2 and PaCO2 and interference with ventilator cycling.
Mechanical Ventilation and BPF
In case of an inoperable BPF, all techniques of ventilation (and pleural drainage system) should be tried since there is no consensus about the effects of ventilatory adjustment on duration and healing of air leak. Management of a large BPF in a ventilated patient is different because it presents problems in achieving adequate ventilation while allowing repair of the fistula. The amount of air leak is inversely related to the patient survival since the leak via fistula delays its healing. The main threat is that of hypoxia and not hypercarbia because the air that leaves BPF has CO2 level comparable to that in the mixed expired air.
The targets of conventional ventilation (C.V.) in BPF management include lowest effective tidal volume and PEEP coupled with lowest possible number of mechanical breaths and decreased inspiratory time-the goals which are met more accurately with SIMV rather than ACMV mode. Pressure control ventilation (PCV) has been successfully used treating BPF that develops in the setting of polytrauma related ARDS. By allowing lower inspiratory airway pressure, PCV promotes fistula closure.
High frequency jet ventilation (HFJV) is an United States FDA approved method for ventilation. It is generally superior to C.V. in maintaining PO2 and PaCO2 it is particularly recommended for managing proximal tracheal or bronchial fistulas with normal lung parenchyma. HFJV decreases flow through BPF, an effect seen more constantly in infants and young children than in adults and is usually accompanied by a drop in PaO2.
In ARDS, BPF typically occurs after 1-2 weeks of illness and is associated with poor prognosis. Fistula flow increases significantly with each increment of PEEP irrespective of the method of ventilation (CV versus HFJV). Therefore, HFJV is justified in ARDS only if C.V. fails in managing associated BPF. In ARDS related BPF, the HFJV does not provide adequate gas exchange and the leak itself is not affected because of the peripheral location of the fistula and the decreased lung compliance.
Other ventilaroty options that are helpful during both C.V. and HFJV in managing patients with BPF include : 1) selective intubation and C.V. of unaffected lung; 2) Independent lung ventilation, wherein two ventilators are used - C.V. to normal lung and HFJV to BPF lung, and 3) Ultra high frequency Jet Ventilation applied to BPF lung and C.V. to normal lung.
Bronchoscopic applications
Fiberoptic bronchoscopy (FOB) has got both diagnostic and therapeutic role in BPF. It can be used to directly visualize and treat particularly the proximal fistulas to assess the length of the bronchial stump harbouring the fistula and being a relatively noninvasive treatment option, it is highly valuable in poor surgical conditions. Distal BPFs not visualized directly by FOB, require passage of an occluding balloon and a decrease in air leak localizes the bronchial segment leading to fistula. For directly visualized proximal BPFs, the sealant is directly applied through a catheter in the working channel of FOB, whereas for a distal BPF, a multiple lumen Swan Gauz catheter is used both to localize the fistula and to pass the occluding material of choice.
The various materials that have been used to effect the closure of BPF include cyano acrylate based agents, fibrin agents, silver nitrate, tetracycline, gel foam and lead shots in addition to balloon occlusion. However, these materials are not useful in large proximal tracheal or bronchial ruptures and multiple distal parenchymal defects. Immediately, the agent seals the leak by acting as a plug and subsequently close the fistula by inducing fibrosis and mucosal proliferation.
Recent Advances in BPF Management
1. Sclerotherapy which is carried out by bronchoscopic submucosal injection of polidocanal around BPF. It is technically easy and highly successful in treating fistulas complicating pleuropneumonectomy for lung cancer. It is safer, simple and inexpensive and can be prescribed as the first therapeutic step.
2. Nd-YAG laser is an attractive endobronchial treatment option for small (<2mm) proximal BPFs. Laser beam is directed through FOB to bronchial mucosa surrounding the fistula. This procedure has about 80% success rate in closing fistulas which have no tumour or infection at the bronchial stump.
Dr. Javed A. Malik, MD (Med.),
Senior Resident,
Pulmonary Medicine,
PGIMER, Chandigarh.
Introduction
Smoking is the most common preventable cause of death and disease. Lung is the most common target of smoke related diseases such as Chronic Bronchitis, Emphysema and Lung cancer. 70% of the smokers want to quit smoking, but only 46% try to quit each year and they fail more often than succeeding. Most of the people who quit, do on their own. There is little support from health care providers. This is mainly because of the lack of an effective treatment untill recently.
GLOBAL INITIATIVE FOR CHRONIC OBSTRUCTIVE LUNG DISEASE (NIH & WHO) Programme
Reduce Risk Factors of COPD
(Smoking Cessation)
Smoking cessation is the single most effective - and cost effective - intervention to reduce the risk of developing COPD and slow its progression.
· Even a brief, 3-minute period of counselling to urge a smoker to quit can be effective, and at a minimum this should be done for every smoker at every visit. More intensive strategies increase the likelihood of sustained quitting (see the strategy).
· Pharmacotherapy (nicotine replacement and/or bupropion) is recommended when counseling is not sufficient to help patients stop smoking. Special consideration should be given before using pharmacotherapy in people smoking fewer than 10 cigarettes per day, pregnant women, adolescents, and those with medical contraindications (unstable coronary artery disease, untreated peptic ulcer, and recent myocardial infarction or stroke for nicotine replacement; and history of seizures for bupropion).
Role of Physician in Smoking
cessation
70% of smokers visit health care settings each year for some or other health related problems. So, health care workers can identify these smokers much before they develop smoking related diseases. Moreover, the long-term success in quitting is only 7% if smokers try on their own. This success rate goes up to 15-30% if a physician assists in quitting.
Effects of Nicotine on Human
Brain
Nicotine increases levels of noradrenaline, dopamine and serotonin in the brain by reducing reuptake. This causes mood elevation, increased mood, better concentration and decreased anger. These effects are seen within 10 seconds of taking a puff. So, smokers become dependent on nicotine.
Tobacco Dependence
DSM IV defines tobacco dependence as withdrawal symptoms on cessation of smoking or tolerance for nicotine or persistent desire or unsuccessful desire to cut down smoking. The other way of assessing dependence is by a questionnaire termed as Fagerstorm Test for Nicotine dependence (FTND). Based on scores in FTND tobacco dependence is graded into three categories:
« Profound dependence - FTND score of 7 or more.
« Moderate dependence - FTND score of 4-7.
« Mild dependence - FTND score of 3 or less
Simply, any person who smokes a cigarette within 5 minutes of waking up from bed or smokes more than 30 cigarettes a day is considered to have profound dependence. Tobacco dependence behaves like a chronic disease. Only a minority of the patients go into remission (i.e. successful quitting) whereas the majority will have multiple episodes of relapse and remission.
Strategy to Help a Patient Quit Smoking
1. ASK: Systematically identify all tobacco users at every visit. Implement an office-wide system that ensures that, for EVERY patient at EVERY clinic visit, tobacco-use status is queried and documented.
2. ADVICE: Strongly urge all tobacco users to quit. In a clear, strong, and personalized manner, urge every tabacco user to quit.
3. ASSESS : determine willingness to make a quite attempt. Ask every tobacco user if he or she is willing to make a quite attempt at this time (e.g. within the next 30 days).
4. ASSIST : Aid the patient in quitting.
Help the patient with a quit plan; provide practical counseling; provide intra-treatment social support; help the patient obtain extra treatment social support; recommend use of approved pharmacotherapy if appropriate; provide supplementary materials.
5. ARRANGE : Schedule follow-up contact.
Schedule follow-up contact, either in person or via telephone.
Steps in Smoking Cessation:
A physician should adopt a step care approach in smoking cessation attempts.
1. Identify the smokers: Most of the smokers will visit health care settings. Identify them by a good history taking.
2. Stratify them according to their current smoking status.
* Current smokers who are willing to quit(A)
* Current smokers who are not willing to quit (B)
* Former smokers - recently quit (C)
* Extended abstinence (D)
3. Intervene-based on their currect smoking status.
a) Group A : Current smokers who are willing to quit :
* Ask systematically about nicotine use, precipitating factors, difficulty in quitting etc.
* Advice to quit
* Assess-willingness to quit
* Assist- in quitting - psychotherapy, pharmacotherapy etc.
* Arrange - follow up visit.
b) Group B : Current Smokers
who are not willing to quit :
Explain the importance of quitting to the patient -5R
* Relevance of quitting - health, financial benefits of quitting
* Risks of smoking-to self and to the environment
* Rewards of quitting - better health, increased appetite, model for children,
saving money
* Roadblocks in quitting - fear of failure, withdrawal symptoms, weight
gain, depression
* Repetition - repeat the above measures till patient is willing to quit. Once
willing, adopt the strategy as for group A
c) Group C : Recently Quit :
In this group, the aim is to prevent relapse
* Support by regular follow up, telephone calls and organizationsl help
* Treat depression by suitable antidepressant
* Treat withdrawal symptoms
* Prevent weight gain - increase activity, no dieting, delay weight gain
* Flag the motivation
d) Group D - Quit in the remote past
These patients are unlikely to relapse. Encourage continued abstinence in
this group of patients.
Non - Pharmacological Management
1. Establish a therapeutic alliance
2. Intervention - 5A plan (see 3b)
3. Cessation can be achieved by two methods (abrupt and gradual). Studies
have shown that both of these methods are of equal efficacy. Gradual method is better for the heavily dependent patients for the fear of withdrawal symptoms. But, set a definitive date for stopping while adopting the gradual cessation method.
4. Delay weight gain by increasing activity and drug therapy such as
bupropion and nicotine gums. There is no role of strict dieting.
5. Take care of other substance abuse such as alcohol, narcotics etc.
6. Behavioral therapy -
* Avoid stimulus-smoking friends, ashtrays, parties etc.
* Social support from friends and family members
* Reward/punishment
* Relaxation exercises
Pharmacological Therapy
The drugs used in smoking cessation can be broadly divided into four
different groups. They are
1 Nicotine replacement therapy
2 Drugs mimicking nicotine -
bupropion, clonidine
3 Antagonist therapy
4 Aversive therapy
1. Nicotine Replacement Therapy
Nicotine replacement therapy is the most commonly used pharmacological method in smoking cessation. There are four different types of nicotine preparations.
a. Nicotine Gum
Nicotine gum is absorbed in the buccal mucosa and bypasses hepatic first pass metabolism. Gums are available in strength of 2 and 4 mg. The usual dose is one piece every 1-2 hrs with a miximum of 30 pieces per day. Gums have to be chewed slowly and intermittently to avoid overdose. Peak effect is seen after 30 minutes. Gums alone cannot alleviate withdrawal symptoms, as the immediate effects of smoking are not produced. Gum is the best nicotine preparation for delaying weight gain. Adverse reactions such as sore jaw, mouth irritation are seen in 0.1-1% of patients. This preparation is not available in India.
b. Nicotine Patch
Each patch releases 1.5 mg/hr. Two doses are available (16 hr/day-15mg, 24hr/day-21mg). Patch is applied once daily to a clean, dry site on arm or trunk. Application site is not reused for at least 1 week. Peak effect is seen after 6-10 hrs of application and steady levels are seen throughout the day. Local skin irritation is seen in 2-3% of patients. This preparation is available in India.
c. Nicotine Nasal Spray
Each spray contains 0.5mg nicotine. Dose is 1 or 2 sprays in each nostril every hour with a maximum of 5/hour or 40/day. Rapid effect (<10 min) is seen in this preparation and hence can alleviate withdrawal symptoms immediately. While spraying, head should be tilted backward. Do not sniff, swallow, or inhale while spraying. Adverse reactions are nasal and throat irritation, watering eyes, cough, headaches and dizziness. Not available in India.
d. Nicotine Inhaler
Each puff contains 13 micrograms and 80 inhalations over 20 minutes is the dose. Nicotine is actually absorbed through the buccal mucosa. Adverse reactions are mouth and throat irritation, cough, rhinitis, pharyngitis and stomatitis.
e. Combination Therapy
Combination therapy is more efficacious than individual preparations as these preparations differ in their onset and duration of action. The reommended doses of combination therapy are given below.
Adverse Efects of Nicotine Preparations
· Headache, palpitation, nausea, arrhythmias-mainly due to ongoing smoking or improper chewing of gums
· Local reaction
Contraindications to Nicotine
· Absolute : pregnancy, acute MI, arrhythmia, unstable angina, dermal reaction and smoking <10 cig/day.
· Relative : chronic stable uncontrolled hypertension, active GI bleed, LVF, thyrotoxicosis etc.
2. Drugs mimicking Nicotine
1. Bupropion is the first non-nicotine - containing agent to be approved by the FDA for smoking cessation. Studies have proven that Bupropion in a dose of 300mg per day is better than nicotine replacement therapy or placebos in successful quitting at 6 weeks and one year. The various possible mechanisms of action of bupropion in smoking are :
· Smokers are more likely to have a history of major depression than non-smokers.
· Nicotine may act as an antidepressant in some smokers.
· The development of depressed affect or depression after smoking cessation may lead to relapse.
· Both nicotine and bupropion have similar effects in brain-increasing nor epinephrine, dopamine and serotonin levels in brain.
· The dosage is 150 mg daily for 3 days followed by 150 mg twice daily. Therapy should be stopped if patients smokes at 7 weeks of therapy. This drug is now available in India. Side effects are insomnia, headache, dry mouth, dizziness, nausea, polyuria, rhinitis, back pain urticaria, anxiety and bronchospasm. The drug is contraindicated in patients with seizure disorder, pregnancy. Burpropion is used for a period of six months and tapered after that. However, it can be used for longer periods if depressive symptoms persist.
The other drugs, which have nicotine like effects, are clonidine and nortryptiline. These drugs are used only, if bupropion is contraindicateded or not tolerated.
3. Antagonistic
Therapy:
Macamylamine and Naltrexate are non-competitive blocker of CNS/PNS nicotine receptors. Some workers have used these drugs and their efficacy has not been proven. Patient can hike smoking to overcome the antagonistic effect and withdrawal symptoms can be dangerous because of the antiinicotinic action of these drugs.
4. Aversive Therapy:
Silver acetate had been tried in the past in nicotine cessation. Silver reacts with nicotine and products a unpleasant taste while smoking. The compliance is poor because of the unpleasant taste. Argyrism is a concern with this therapy
.
Smoking
Prevention:
Prevention is the best way of controlling nicotine use in the community. Adolescents should be targeted for prevention as 90% of the smokers start smoking in the adolesent age group. This can be better achieved by anti-smoking messages in all possible media, legislation for smoke free public places and prventive strategies as a part of the school curriculum.
Further reading
1. A clinical practice guidelines for treating tobacco use and dependence JAMMA 2000;283: 3244-3254
2. prochazka AV. New developments in smoking cessation. Chest 2000:117:1695-1755
3. Hanstein KO. Pharmacotherapy of nicotine dependence. Int. J Clinical Pharmacology and Therapeutics 2000:6: 273-290.
4. Practice guideline for the treatment of patients with nicotine dependence. Am J Psychiatry 1996; 153: Suppl 1-25.
Dr. Mahendran Chetty, MD, DM
Senior Resident, Pulmonary, Medicine
PGIMER, Chandigarh.