CTVS 57 Empyema Thoracis

• Empyema is an infection of pleural space (purulent pleural effusion).
• Patients of all ages can develop empyema, but the frequency is increased in older or debilitated patients. 
• Pneumococci and staphylococci continue to be the most frequent causative organisms, but gram-negative aerobic bacteria and anaerobes are becoming more prevalent.

• Contamination from a source contiguous to the pleural space (50%–60%)
• Lung - Pneumonia, lung abscess
• Mediastinum
• Deep cervical area
• Chest wall and spine
• Subphrenic area

• Direct inoculation of the pleural space (30%–40%)
• Minor thoracic interventions
• Postoperative infections
• Penetrating chest injuries

Hematogenous infection of the pleural space from a distant site (<1%)

• American Thoracic Society described three stages in the natural course of empyema:
• - Exudative,
• - Fibrinopurulent, and
• - Organizing phases

During the exudative stage, sterile pleural fluid rapidly accumulates in the pleural space. The pleural fluid originates in the interstitial spaces of the lung and in the capillaries of the visceral pleura because of increased permeability. Thoracentesis at this stage yields fluid with a low white blood cell (WBC) count, a pH typically above 7.3, a glucose level greater than 60 mg/dL, and a low LDH level (<500 U/L). The pleural fluid glucose and pH levels are within the reference range. These effusions resolve with antibiotic therapy, and chest tube insertion is not required. This stage takes approximately 2-5 days from the onset of pneumonia.

In the second stage, or fibrinopurulent stage, bacterial invasion of the pleural sponuclear leukocytes, bacteria, and cellular debris. A tendency toward loculation and septation exists, pleural fluid pH (< 7.20) and glucose levels are lower (< 60 mg/dL), and the LDH levels increase. At this stage, bacteriological stains and/or cultures of the pleural fluid can be positive for microorganisms. This stage takes approximately 5-10 days after pneumonia onset.

In the last, or organization stage, fibroblasts grow into the exudates from both the visceral and parietal pleural surfaces, and they produce an inelastic membrane called a pleural peel. As the process progresses, a thick pleural rind may develop, leaving a trapped lung. Trapped lung is characterized by inability of the lung to expand and fill the thoracic cavity due to a restricting fibrous visceral pleural peel. Pleural fluid is thick. In an untreated patient, pleural fluid may drain spontaneously through the chest wall (ie, empyema thoracis necessitatis). Empyema thoracis may arise without an associated pneumonic process, such as from esophageal perforation, trauma, a surgical procedure in the pleural space, or septicemia. This last stage may take 2-3 weeks to develop.

• Symptoms of general malaise, fever, loss of appetite, and weight loss.
• Cough and dyspnea are common if lung infection is present

Chest x-ray— Most empyema are found in posterior lateral costophrenic angle (most dependent position)

Sonography– enables determination of exact location and guides diagnostic aspiration

Fluid analysis- pH, glucose level, LDH, Culture.

CT scan-differentiate between emppyema, lung abscess, ca bronchus,esophageal perforation

Bronchoscopy- Performed only in patients with high index of suspicion of bronchial obstruction d/t tumor.

• 1. Exudative stage 
• - Antibiotics alone.
• - May need thoracocentensis
• - Serial chest radiographs or ultrasound examinations to assess improvement.

• 2. Fibropurulent stage 
• - Antibiotic therapy
• - Chest tube drainage with closed system drainage

• 3. Organizing stage -
• - Intrapleural fibrinolytic therapy 
• - complete lung decortication by either thoracoscopy or thoracotomy would then be necessary

• 1. Control infection and sepsis by antibiotics
• - Community-acquired - third-generation cephalosporin or clindamycin
• - Hospital-acquired-- should guide by culture, empiric treatment should include coverage for MRSA and anaerobes.

• 2) Evacuation of pus from pleural space.
• A. Thoracocentesis (pleural tap) - use 18-gauge needle, send for Fluid analysis, repeat Chest x ray in 24 hours, Repeat thoracocentesis if volume is increased.

• B.  Chest tube drainage -  Indications of chest tube drainage are 
• 1.Frankly purulent/turbid /cloudy pleural fluid
• 2.Presence of organism identified by gram stain and/or culture.
• 3.Pleural fluid pH <7.2
• 4.Poor clinical progress with antibiotics
• 5.Loculated pleural collection
• Removal after radiological confirmation of successful drainage and evidence of sepsis resolution

• C. Intrapleural fibrinolytic agent
• - For physical decompression of multiloculated collection.
• - Fibrinolysis agent like streptokinase, urokinase, and tissue plasminogen activator are commonly used. 
• - DNA is a main contributor to the viscosity of empyema fluid - intrapleural administration of the enzyme deoxyribonuclease (DNase) might reduce empyema fluid viscosity and thus improve the efficacy of pleural drainage. 

• D. Video-Assisted Thoracoscopy (VATS)
• - Primary modality for treating complicated empyema after initial therapy.
• - Adhesiolysis and débridement with better exposure and mini-thoracotomy, decortication for lung expansion.
• - Higher successful rate (90%), shorter hospital stay, less cost.

E. Decortication — Pleural fibrosis generally begins to regress once the pleural infection is adequately controlled. However, when visceral pleural fibrosis does not regress and limits reexpansion of the lung, the resulting pulmonary restriction may be clinically significant. In this situation, a total pleurectomy/decortication may be indicated to achieve lung reexpansion.

3) Obliteration of empyema cavity

• Pleurodesis is a procedure in which the pleural space is artificially obliterated.
• Pleurodesis is used to prevent the re-accumulation of pleural effusions. It involves the adhesion of the two pleurae.

• It can be done chemically or surgically.
• A. Chemical - bleomycin, tetracycline, povidone-iodine, or a slurry of talc can be introduced into the pleural space through a chest drain. The instilled chemicals cause irritation between the parietal and the visceral layers of the pleura which closes off the space between them and prevents further fluid from accumulating. Chemical pleurodesis is a painful procedure, and so patients are often premedicated with a sedative and analgesics. A local anesthetic may be instilled into the pleural space, or an epidural catheter may be placed for anesthesia.
• B.  Surgical pleurodesis - may be performed via thoracotomy or thoracoscopy. This involves mechanically irritating the parietal pleura, often with a rough pad. Moreover, surgical removal of parietal pleura is an effective way of achieving stable pleurodesis.

• Indications -
• - Recurrent benign transudative pleural effusion (e.g hypoproteinemia, Renal failure and heart failure)
• - Proven recurrent malignant effusions 

• Contraindicatios -
• - Greater than 150ml drainage per day ongoing through chest drain or chest x-ray that shows a large  residual fluid volume.
• - Suspicion of pleural infection

•  Ensure the chest drain (already in place) is correctly positioned with a 3-way tap on the end
•  Place sterile dressing under ICD 3-way tap, remove cap to 3-way tap and clean.
•  Insert local anaesthetic syringe into 3-way tap and only rotate tap to “open” when syringe is in place. Opening the tap with the bung removed and no syringe in its place can lead to the introduction of air into the chest cavity
•  Instil lignocaine (3mg/kg) into chest drain and turn 3-way tap off. 
•  Mix 40ml of Normal saline with 4g of talc. Agitate the solution. It is very difficult to dissolve the talc and once the slurry is made so do not stop moving the syringe or the talc will precipitate out.
•  Instil the talc slurry into the pleural cavity via the ICD 3 way tap and flush immediately with 10ml of saline
•  Close the drain and leave closed for 1 hour

• Video-assisted thoracoscopic surgery (VATS) is minimally invasive thoracic surgery that does not use a formal thoracotomy incision. 
• VATS provides adequate visualization despite limited access to the thorax, allowing the procedure to be performed in a state of debilitation and for patients who have marginal pulmonary reserve.
• In VATS the patient is placed in a lateral decubitus position under general anaethesia with one lung ventilation and the lung on the operative side being collapsed.

• Indications of VATS - 
• Stapled lung biopsy
• Lobectomy or pneumonectomy
• Resection of peripheral pulmonary nodule
• Evaluation of mediastinal tumors or adenopathy
• Pleural biopsy
• Bullectomy
• Treatment of recurrent pneumothorax
• Management of loculated empyema
• Pleurodesis of malignant effusions
• Repair of a bronchopleural fistula

• Absolute contraindications
• Markedly unstable or shocked patient
• Extensive adhesions obliterating the pleural space
• Prior talc pleurodesis

• Relative contraindications 
• Inability to tolerate single-lung ventilation
• Previous  thoracotomies
• Extensive pleural diseases
• Coagulopathy

Bronchopleural fistula (BPF) refers to communication between the pleural space and the bronchial tree.  Bronchopleural fistulas occurring within one week of surgery are not necessarily associated with an empyema, whereas those occurring more than two weeks after surgery are associated with an empyema.

• Causes
• - Post-operative complication of pulmonary resection: considered by far the most common cause
• - Lung necrosis complicating infection
• - Persistent spontaneous pneumothorax chemotherapy or radiotherapy (for lung cancer) 
• - Tuberculosis

• Risk factors for formation of a bronchopleural fistula after pneumonectomy -  
• - Right-sided procedures
• - Large diameter (>25 mm) bronchial stump
• - Residual tumor
• - Concurrent radiation therapy or chemotherapy
• - Age greater than 60 years
• - Poor wound healing
• - Prolonged postoperative mechanical ventilation

Signs and symptoms - Fever, productive cough, hemoptysis, subcutaneous emphysema, and persistent air leak from a chest tube.

Radiology -  Chest radiographs frequently demonstrate a new air-liquid level in the PPS, multiple air-liquid levels in the postpneumectomy space (PPS), or a change in a preexisting air-liquid level.

Treatment - drainage of the pleural space, systemic antibiotics, and then repair of the air leak once the PPS has been sterilized. Bronchopleural fistulas that occur within one week of surgery and are not associated with an empyema can be surgically closed.

Definition - Obstruction of the pulmonary artery or one of its branches by material (eg, thrombus, tumor, air, or fat) that originated elsewhere in the body. 

Risk factors - condition of hypercoagulable states

• Pathophysiology - Virchow's triad
• 

• Types 
• 1. Acute - Massive (BP < 90/40 for >15 minutes)
• 2. Chronic
• 3. Saddle PE - embolus lodges at main PA bifurction 

• Clinical features - 
• •dyspnea
• • Pleuritic chest pain 
• • cough 
• • Hemoptysis
• • Syncope.

• Features of massive Pulmonary Embolism 
• •collapse/hypotension
• •unexplained hypoxia
• •engorged neck veins
• •Acut right heart failure

• Physical Signs
• •Normal
• •Tachypnea (respiratory rate >16/min) 
• •Rales 
• •Accentuated second heart sound 
• •Tachycardia (heart rate >100/min)
• •Fever (temperature >37.8°C) 
• •Diaphoresis 
• •S3 or S4 gallop
• •Clinical signs and symptoms suggesting thrombophlebitis
• •Lower extremity edema
• •Cardiac murmur
• •Cyanosis 

Clinical probability of PE - Wells' criteria is used for predicting the probability of PE. 

• Laboratory investigations - 
• - ABG - hypoxemia, hypocapnia, respiratory alkalosis. If there is massive embolism, then there is hypercapnia and respiratory acidosis. 
• - Troponin - Elevated in moderate to severe PE.
• - D-Dimer - increased 
• - ECG - sinus tachycardia. Classical finding is S₁Q₃T₃ pattern, [@ सुकुटी] RV strain and new incomplete RBBB. 
• - Chest x-ray - atelectasis, effusion 
• - CTPA - high specificity for main, lobar and segmental vessels

• Management - 
• - Acute - anticoagulation with UFH and LMWX
• - Chronic - Warfarin, target INR - 2-3 
• - Thrombolysis - Indication of thrombolysis are massive PE (SBP <90 mmHg for >15 minutes)
• - Surgical embolectomy - requires cardiopulmonary bypass

Prevention - Inferior vanacava filter (Filter out large emboli)