Surgery chapters
Pleural disease: pneumothorax, effusion and empyema
Pleural physiology, primary, secondary and tension pneumothorax with BTS-style management, chest drain insertion, transudate versus exudate and Light's criteria, malignant effusion, haemothorax, chylothorax, and the stages and surgery of empyema.
- Primary pneumothorax affects tall young men with apical blebs; secondary occurs in diseased lungs (COPD, TB) and is less well tolerated; tension pneumothorax is a clinical diagnosis needing immediate decompression.
- Effusions are transudates (protein under 30 g/L: heart, liver, kidney failure) or exudates (infection, cancer, TB), confirmed with Light's criteria.
- Empyema passes through exudative → fibrinopurulent → organising stages: antibiotics, then drainage, then VATS debridement or decortication.
On this page
Overview
The pleural space normally holds only a thin film of fluid (about 5–10 mL), although 1–2 litres pass through it each day. Fluid is made by parietal pleural capillaries and mostly reabsorbed by the visceral pleura and lymphatics.
Air (pneumothorax), fluid (effusion), blood (haemothorax), lymph (chylothorax) or pus (empyema) in this space collapses the lung. The surgeon's jobs are to drain, diagnose (biopsy) and stop recurrence (pleurodesis, decortication).
Pneumothorax
Types
| Type | Who and why |
|---|---|
| Primary spontaneous | Young (teens to late 20s), tall, thin men, often smokers; rupture of apical blebs/bullae; family history common |
| Secondary spontaneous | Underlying lung disease: COPD/emphysema, TB, cystic fibrosis, cavitating disease, necrotic tumour; older; poorly tolerated |
| Traumatic | Rib fractures, penetrating injury |
| Iatrogenic | Central line insertion, lung biopsy, positive-pressure ventilation |
| Tension | Any cause; a one-way valve lets air in but not out |
Tension pneumothorax
Air builds up under pressure: the lung collapses completely, the diaphragm flattens, the mediastinum shifts and venous return falls → shock.
Signs: severe distress, hypotension, tachycardia, distended neck veins, hyper-resonance and absent breath sounds on the affected side; tracheal deviation away is a late sign. Ventilated trauma patients are at particular risk.
Treatment: a clinical diagnosis – do not wait for an X-ray.
- Needle decompression with a large-bore cannula: classically the 2nd intercostal space, mid-clavicular line; current ATLS advice for adults favours the 5th space just anterior to the mid-axillary line (the chest wall is thinner there).
- Then insert a chest drain.
Tension pneumothorax = hypotension + distended neck veins + absent breath sounds + hyper-resonance on one side. Treat immediately; an X-ray only delays care.
Needle decompression converts a tension pneumothorax into a simple one. A chest drain must always follow.
Clinical features and imaging
- Sudden pleuritic pain and breathlessness. Small ones are often more painful; complete collapse is less painful but more breathless.
- Chest X-ray is the baseline test. UK practice measures the rim of air from chest wall to lung edge at hilum level: over 2 cm = large.
- CT is used if the X-ray is unclear or to look for underlying disease.
Physiology you are asked about
Pleural air is absorbed slowly because the total gas pressure in venous blood is below atmospheric. Nitrogen is absorbed slowest.
- High-flow oxygen lowers blood nitrogen and speeds absorption.
- Nitrous oxide is very soluble and diffuses into the air space, enlarging the pneumothorax – avoid it.
Management of spontaneous pneumothorax (BTS-based)
| Situation | Action |
|---|---|
| Bilateral or haemodynamically unstable | Chest drain |
| Primary, under 2 cm and not breathless | Observe; discharge with advice and review |
| Primary, over 2 cm and/or breathless | Needle aspiration (16–18 G cannula, up to 2.5 L). If it fails → small-bore drain and admit |
| Secondary, over 2 cm or breathless | Chest drain and admit |
| Secondary, 1–2 cm | Aspirate; if not under 1 cm afterwards → drain |
| Secondary, under 1 cm | Admit, high-flow oxygen (unless CO2 retainer), observe 24 hours |
Small-bore (about 8–14 Fr) Seldinger drains, ideally ultrasound-guided, are now standard for spontaneous pneumothorax.
Recurrence and advice
- About one-third recur after a first episode; about half of those with a second episode have a third.
- No flying until fully resolved (Kumar advises waiting about 1 week after resolution); no diving unless the patient has had surgical pleurodesis. Stop smoking (including cannabis).
Indications for surgery
- A second episode on the same side (ipsilateral recurrence).
- A first episode on the opposite side (contralateral).
- Both sides collapsed at once (bilateral).
- Persistent air leak or failure to re-expand despite drainage (seek a surgical opinion at about 3–5 days).
- Spontaneous haemothorax.
- At-risk professions (pilots, divers) and pregnancy (as planned care).
A first uncomplicated primary pneumothorax is not itself an indication for surgery (unless the patient is a pilot/diver or it fails to settle).
Surgery
Done by VATS (usual) or thoracotomy. Three aims:
- Seal leaks.
- Staple or remove blebs and bullae.
- Stick the lung to the chest wall so it cannot collapse completely again: pleurectomy (stripping the parietal pleura), pleural abrasion or talc pleurodesis.
Inserting and managing a chest drain
Safe triangle: bounded by the lateral edge of pectoralis major, the lateral edge of latissimus dorsi and a line at nipple level (5th intercostal space), with its apex below the axilla. In practice: anterior to the mid-axillary line, at or above the nipple level, which usually finds the 5th space.
Key steps:
- Full asepsis; local anaesthetic down to the pleura.
- Cut the skin only; then blunt dissection through muscle with artery forceps.
- Pass just over the top edge of the lower rib, keeping clear of the vessels and nerve that run under the rib above.
- A slightly oblique track reduces air entry.
- Aim towards the apex for air, towards the base for fluid.
- Connect to an underwater seal (acts as a one-way valve); keep the bottle below the chest.
- Check position with a chest X-ray.
Safe practice:
- Never clamp a bubbling drain (risk of tension).
- Suction is not routine: if the lung is reluctant to expand it can shift the mediastinum, and with fragile lung it may worsen the leak.
- For trauma haemothorax in adults use a large tube (28 Fr or bigger).
- Remove the drain when it has done its job.
"Pec, Lat, Nipple" – the drain goes between the two muscle edges, no lower than the nipple line, and always over the top of the rib.
Surgical emphysema
Air in the soft tissues; needs a breach of an air-containing organ plus positive pressure. Causes: pneumothorax with a leaking drain site, ruptured oesophagus (most serious), asthma, barotrauma from ventilation.
Pleural effusion
Detection
- Seen on an erect chest X-ray (blunting of the costophrenic angle) from about 300 mL; clinically detectable from about 500 mL (stony dullness, reduced breath sounds).
- Ultrasound confirms fluid, shows loculations and guides aspiration.
Mechanisms
- Raised pulmonary capillary pressure (heart failure, fluid overload).
- Low plasma oncotic pressure (nephrotic syndrome, cirrhosis, malnutrition).
- Blocked mediastinal lymphatics (lymphoma, breast and other cancers).
- Leaky capillaries (infection, inflammation, autoimmune disease).
Transudate or exudate?
| Feature | Transudate | Exudate |
|---|---|---|
| Protein | Under 30 g/L | Over 30 g/L |
| Typical causes | Heart failure, nephrotic syndrome, cirrhosis, hypothyroidism, constrictive pericarditis, Meigs' syndrome (ovarian fibroma; usually right-sided) | Pneumonia, lung cancer, metastases, TB, pulmonary infarction, autoimmune disease, pancreatitis (high amylase), mesothelioma |
| Side | Often bilateral, larger on the right | Often unilateral |
Light's criteria – the effusion is an exudate if any one is met:
- Pleural fluid protein ÷ serum protein > 0.5
- Pleural fluid LDH ÷ serum LDH > 0.6
- Pleural fluid LDH > two-thirds of the upper limit of normal for serum LDH
One positive Light's criterion is enough to call the fluid an exudate. Light's criteria are most useful when the protein level is close to 30 g/L.
Pleural protein 40 g/L, serum protein 70 g/L → 40 ÷ 70 = 0.57 (> 0.5)
Pleural LDH 300 IU/L, serum LDH 400 IU/L → 300 ÷ 400 = 0.75 (> 0.6)
At least one criterion is met → exudate (look for infection, cancer, TB).
Other useful fluid tests: pH and glucose (low in empyema, also rheumatoid and TB), Gram stain and culture, cytology, amylase, adenosine deaminase for TB, triglycerides for chylothorax.
Fluid that is bloody in a smoker suggests malignancy (or infarction/trauma). Pleural fluid in lung cancer usually means the tumour is beyond surgical cure.
Malignant pleural effusion
Causes: lung cancer, pleural metastases (especially adenocarcinoma, breast), mediastinal lymphatic blockage, and mesothelioma (almost always asbestos; presents with effusion and persistent chest wall pain).
The surgeon has two roles:
- Diagnosis – pleural fluid cytology (low yield), Abrams needle biopsy (low yield in malignancy), CT-guided biopsy, or VATS biopsy (most common and best yield).
- Palliation – drain the fluid and prevent reaccumulation with talc pleurodesis (at VATS or through a drain).
Drain large effusions slowly. Rapid removal can cause pain, mediastinal shift and re-expansion pulmonary oedema.
Haemothorax
- Blood in the pleura; most often from chest trauma (intercostal or internal mammary vessels).
- Massive haemothorax: shock, flat neck veins, dull percussion, absent breath sounds.
- Treat: resuscitation and a large-bore drain (28 Fr or more).
- Urgent thoracotomy if 1500 mL drains at once or bleeding continues at over 200 mL/h for 3–4 hours.
- Remove all blood early; retained clot leads to empyema or fibrothorax. Do not clamp the drain to "tamponade" bleeding.
"1500 now or 200 an hour" – the thoracotomy rule.
Chylothorax
Lymph (chyle) in the pleura, usually from thoracic duct injury (trauma, oesophageal or cardiac surgery) or malignant infiltration (lymphoma). The fluid is milky and rich in triglycerides/chylomicrons.
Empyema
Pus in the pleural space, the end stage of pleural infection.
Causes
- Pneumonia (commonest) and lung abscess, bronchiectasis, TB.
- After thoracic surgery or chest drains, infected haemothorax.
- Oesophageal perforation, penetrating trauma.
- Spread from a subphrenic abscess or rib/vertebral osteomyelitis.
Organisms: Streptococcus milleri group, anaerobes, Staph. aureus; Haemophilus influenzae in children.
Clinical clues
Pneumonia that is not settling: persistent or swinging fever and raised inflammatory markers despite antibiotics. Aspirate under ultrasound: pH below 7.2, low glucose, high LDH, or frank pus = needs drainage.
Stages and treatment
| Stage | Pleural findings | Treatment |
|---|---|---|
| 1. Exudative | Thin, protein-rich fluid | Antibiotics ± aspiration or drainage to dryness |
| 2. Fibrinopurulent | Thicker fluid, loculation | Chest drain; if loculated → VATS debridement |
| 3. Organising | Thick peel (cortex) traps the lung | Decortication (usually posterolateral thoracotomy, sometimes VATS) |
An empyema that does not respond to antibiotics and drainage, with a trapped lung, needs decortication – stripping the fibrous peel off the visceral pleura so the lung can re-expand.
Antibiotics alone rarely cure an established (fibrinopurulent) empyema. Pus must be drained.
Postoperative drains should exit anterior to the mid-axillary line so the patient does not lie on them.
Expect: the typical patient with primary spontaneous pneumothorax; tension pneumothorax as a clinical diagnosis with immediate needle decompression then drain; indications for surgery after pneumothorax (second ipsilateral, first contralateral, bilateral, persistent leak, professions at risk); VATS pleurectomy and talc pleurodesis; the safe triangle and passing over the upper rib border; never clamping a bubbling drain; nitrous oxide danger; transudate versus exudate and Light's criteria; Meigs' syndrome; pH under 7.2 in empyema; the three empyema stages and decortication for a trapped lung; and the 1500 mL / 200 mL per hour rule for haemothorax.
Quick revision
- Primary pneumothorax: tall young men, apical blebs; secondary: COPD, TB, older.
- Tension: shock, distended neck veins, absent breath sounds → decompress first, then drain.
- Surgery: second ipsilateral, first contralateral, bilateral, persistent leak, pilots/divers.
- Drain: safe triangle, 5th space, over the upper rib border, underwater seal, never clamp if bubbling.
- Exudate if protein over 30 g/L or Light's criteria met.
- Malignant effusion: VATS biopsy and talc pleurodesis.
- Haemothorax: thoracotomy if 1500 mL at once or 200 mL/h for 3–4 h.
- Empyema: exudative (antibiotics) → fibrinopurulent (drain/VATS) → organising (decortication).
Written by The House Job from standard references (Bailey & Love; Kumar and Clark's Clinical Medicine).
FAQ
Is a first spontaneous pneumothorax an indication for surgery?
Usually not; surgery is offered for a second episode on the same side, a first on the other side, bilateral disease, a persistent air leak, or high-risk jobs such as pilots and divers.
Why should a chest drain pass over the top of the rib?
The intercostal vein, artery and nerve run in the groove under each rib, so staying close to the upper border of the rib below avoids them.
What does a pleural fluid pH below 7.2 mean in pneumonia?
It strongly suggests an infected (complicated) effusion or empyema, which needs drainage rather than antibiotics alone.
What is decortication?
An operation that peels the thick fibrous layer off a lung trapped by organised empyema or old haemothorax so that the lung can expand again.