Respiratory

Pleural disease and Infections

Pleural effusion

Introduction

  • Collection of fluid within the pleural space restricts lung inflation and so impairs lung function. It may be a manifestation of local or systemic disease. Divide them into exudates and transudates depending on their protein content

Clinical

  • Symptoms may depend on how quickly the fluid collects and underlying cardiorespiratory function causing increasing breathlessness and possibly pleuritic type chest pain
  • Exam shows reduced chest wall movement, Stony dull percussion note, Decreased vocal resonance, absent breath sounds. Bronchial breath sounds and whispering pectriloquy at top of effusion with overlying consolidation. A massive effusion pushes lung and trachea and mediastinum away

Investigations

  • See fluid on CXR before clinically detectable ( needs > 300 mls). On occasions the fluid can become loculated and ultrasound can be useful to mark the effusion for aspiration
  • Pleural aspiration of fluid for
    • Biochemistry - protein, glucose, LDH, pH, Amylase (A low glucose < 3.3 mmol/L suggests infection, tumour, RA, mesothelioma. Milky fluid suggests a chylothorax which may be due to damage to the thoracic duct)
    • Cytology - FBC (Increased WCC suggests infection, Raised HB with a bloody effusion) , malignant cells
    • Bacteriology for culture and microscopy
    • Immunology - Selected cases rheumatoid factor, ANA, Complement
  • In selected cases HRCT with contrast can identify some potential causes

Light's criteria for an Exudate

  • Pleural protein > 50% of serum protein
  • Pleural LDH > 60% serum LDH
  • Pleural LDH > 66% upper limit of normal for serum

Causes of a Transudate

  • Cardiac failure
  • Nephrotic syndrome
  • Liver failure
  • Myxoedema
  • Hypoalbuminaemia
  • Meigs's syndrome with ovarian tumour and right pleural effusion

Causes of an Exudate

  • Pneumonia, Tuberculosis , Empyema
  • Cancers (blood stained) - Bronchogenic, Mesothelioma, Lung metastases, Ovarian tumours
  • Pulmonary infarct - bloody
  • Pancreatitis ? raised amylase
  • Connective tissue disease - SLE, RA
  • Drugs - methysergide, nitrofurantoin
  • Radiotherapy
  • Trauma, Post cardiac surgery
  • Asbestosis (blood stained)
  • Yellow nail syndrome - impaired lymph drainage with yellow nails, effusion and lymphoedema
  • Post myocardial infarction
  • Familial Mediterranean fever
  • Constrictive pericarditis
  • Oesophageal rupture ? raised amylase

Management

  • Aspiration initially usually 1000-2000 mls can provide symptomatic relief and provide fluid for analysis. Aspirating larger volumes can cause pulmonary oedema.
  • Pleurodesis in which an inflammatory reaction is caused in the pleural space. Usually talc is used. Useful palliative measure with malignancy.

Empyema

Introduction

  • A collection of pus in the pleural space often seen post bacterial pneumonia.

Aetiology

  • The aetiology is usually secondary to a "parapneumonic" effusion post bacterial pneumonia which suppurates
  • Increased incidence with Diabetes, alcohol abuse, IVDU, GORD

Clinical

  • Persisting fever post pneumonia. May have pleuritic chest pain

Investigations

  • Raised WCC and ESR/CRP and Pleural effusion on CXR
  • Aspiration shows a yellow exudate which may be thick and viscous with raised protein and white cells
  • Pleural aspirate pH acidic < 7.2 and LDH > 1000 IU/L. (pH > 7.8 suggests Proteus)

Management

  • Radiologically guided drainage either USS or HRCT
  • Prolonged antibiotics based on sensitivity of culture.

Pneumothorax

Introduction

  • Air within the pleural space

Aetiology

  • The lung is surrounded by a visceral pleura, a pleural space and the parietal pleura which is in contact with the thoracic wall
  • The negative intrapleural pressure sucks the lung to the chest wall which moves and is inflated during ventilation.
  • If air gets in here the lung basically collapses as there is no force adhering it to the chest wall.
  • Air can enter from outside such as due to trauma from the lung via a tear in the lung and visceral pleura
  • When air enters the pleural space this causes the lung to collapse and does not expand during inspiration

Principles of management

  • Treatment is to remove the air either by aspiration or chest drain and allow the defect to heal. The lung can then reexpand.
  • Normal inspiratory mechanism fail to work and the lung collapses air in the space prevents expansion. Lung function compromised.
  • Those with underlying lung disease are less able to tolerate a Pneumothorax and so must be treated more aggressively/cautiously.

Primary Pneumothorax (no apparent lung disease)

  • Usually occurs where an apical bleb or bulla has popped often in a tall thin smoker
  • Most often recur within 1st year in those who are tall and continue to smoke - 40% in 2 years.

Secondary causes (underlying lung disease)

  • High positive end expiratory pressure ventilation (consider in any ventilated patient who deteriorates)
  • Asthmatics, Cystic fibrosis, Emphysema, Lung abscess, PCP pneumonia, Idiopathic pulmonary fibrosis, Sarcoidosis
  • Endometriosis/catamenial pneumothorax - occurs within 72 hours of menses
  • Oesophageal rupture, Lymphangioleiomyomatosis, tuberous sclerosis, Lung carcinoma
  • Histiocytosis X, Eosinophilic granuloma
  • Marfan's syndrome and homocystinuria, lung biopsy
  • Central venous line insertions near pleura(subclavian and rarely internal jugular)

Clinical

  • Suspect this in any acutely breathless patient.
  • Side affected is hyperresonant with decreased air entry, decreased chest movements
  • Shifted trachea always from hyperresonant side and extremis suggests tension pneumothorax
  • There may be a clicking sound with auscultation "Hamman's sign"
  • Tracking of escaped air into subcutaenous tissues - surgical emphysema

Investigations

  • CXR which shows an absence of lung markings between the ribs and a rim of lung edge may be seen (Expiratory films not needed). A rim of 2 cm differentiates it into a large or small pneumothorax.
  • Lateral CXR may help if PTX suspected and PA chest not definitive
  • HRCT - In some cases where it is difficult to differentiate a Bulla from a PTX then old CXR images for comparison and CT imaging may be useful
  • Any pneumothorax with a rim of greater than 2 cm suggests a lung volume decrease of up to 50%.
  • HRCT scan is becoming used for decisions on best place to place drain in complex cases and in detecting small pneumothoracies
  • Scanners are now so much faster with a complete scan in less than a minute
  • ABG - may show Type 1 or Type 2 Respiratory failure (where COPD coexists usually)

Management of Primary Pneumothorax

  • If not SOB and rim < 2 cm then consider discharge with advice for outpatient follow up
  • If breathless aspirate and repeat CXR and assessment - if successful consider discharge with advice for outpatient follow up
  • if rim > 2cm aspirate and if successful consider discharge
  • if aspiration fails to improve situation then chest drain
  • Put patient on high FiO2 oxygen as this helps reabsorption of pleural air by dropping partial pressure of nitrogen in blood encouraging its movement into plasma and excretion

Management of Secondary PTX (mortality 10%)

  • If SOB aspirate and if successful consider home after 24 hrs monitoring
  • If rim < 1cm and comfortable then monitor, give high FiO2 if safe. Consider aspiration.
  • If rim < 2cm aspirate and if successful consider home after 24 hrs monitoring
  • IF rim > 2cm or aspiration fails to improve situation then chest drain
  • Aspiration
    • Discuss, explain, consent, IV cannula, sit upright forward leaning on pillow
    • Double check side to aspirate on CXR. Percuss and listen.
    • Mark 2nd ICS in midclavicular line. Infiltrate down to pleura with local anaesthesia
    • Prepare skin, Asepsis, Gloves, gown and skin prep
    • Check 3 way tap and 50 ml syringe. Plan to aspirate via needle to syringe and then expel air. Check it.
    • Check air aspiration with green needle and then insert cannula over edge of 2nd rib aspirating
    • Remove inner cannula needle and connect 3 way tap and begin repeated aspiration counting.
    • Aspirate up to 2.5 L only - any more suggest big leak and chest drain
    • Once done remove needle and repeat CXR to see if fully re-expanded and reassess clinically
    • A second attempt may be considered with a primary pneumothorax. Otherwise failure suggests a chest drain.
  • Chest drains

    Introduction

    • For air fine bore tubes are more commonly used and can be inserted using seldinger technique
    • Should be done by experienced operator or with good close supervision.

    Choice of tube

    • Small seldinger tubes for pneumothoracies
    • Larger tubes in ventilated patients or large air leaks - avoid using trocar for insertion.

    Valve types

    • Tube attached to portable one way Heimlich flutter valve
    • Air/water drain stops bubbling when hole has healed and no more air enters pleural spaces

    Method

    • Explain and consent. IV Cannula. Good positioning - sitting forward on pillow on table
    • Sedation where required IV Midazolam or even Diamorphine. Avoid with respiratory depression. Monitor O2 sats.
    • Decide where usually midaxillary line at 5th rib space. Last axillary hair (or male nipple level) was told to me by one chest surgeon.
    • infiltrate deeply with 10 mls of 1% lignocaine aspirating on the way. Should finally aspirate air.
    • Some patients have deep levels of subcutaneous fat here and can be quite a distance to the pleural space.
    • Gloves, gown, skin preparation, strict asepsis
    • Large drain inserted by horizontal incision with mattress stich and blunt forceps and finger dissection down. Trocar can guide drain but no force to be used or use forceps to grip drain and place into pleural space. Ensure drainage side holes all lie in the pleural space or surgical emphysema will happen
    • Seldinger - use introducer needle to enter pleural space, place guide wire, remove needle and use dilator over wire and then pass drain. Ensure all side holes within cavity.
    • Connect to drain and check bubbling and secure. Get check CXR.

    Removing drains

    • Never clamp as can cause tension pneumothorax
    • However prove drain not blocked or moved by watching movements with respiration
    • Remove drain 24 hrs after air leak is presumed to have healed

    Complications

    • Tube blocked - small drains should be flushed routinely with sterile saline
    • Persisting air leak after several days suggests hole not healing and perhaps a bronchopleural fistula. Consider CT to check position of tube and pneumothorax.
    • May consider negative pressure on drain or a larger chest drain but best to speak to thoracic surgeons. The hole may need to be closed surgically.

    Removal

    • Everyone says something different. Just pull out quickly and smoothly. Tie suture if one. Apply dressing. Repeat CXR.

    Advice

    • Smoking cessation is very important and often forgotten in the young patient
    • No flying 6 weeks or longer. Can be assessed at chest follow up.
    • No diving - consider surgical referral.
    • Come back if breathless/pain
    • Never clamp a chest drain

    Tension Pnemothorax

    Introduction

    • Treat immediately - penetrating knife wound, chest trauma, ventilated patient
    • Increasing intrathoracic pressures will compromise cardiac function

    Mechanism

    • Due to a valve like mechanism air is sucked into pleural space and can?t escape.
    • The pleural space is ?pumped up? and displaces the mediastinal and prevents cardiac venous right atrial filling which leads to cardiovascular collapse

    Clinical

    • Presents with acutely worsening breathlessness and circulatory collapse
    • Context important - post CVP insertion or chest trauma or on a ventilator.

    Investigations

    • One should treat immediately without a CXR.

    Management

    • Treat immediately with urgent decompression with a venflon or other needle in the 2nd space midclavicular line (unlikely to be harmful if wrong)
    • Then a timely insertion of a chest drain