Interactive Tutorial: Chest Trauma And Lung Transplant

Question 1

Classification of Chest trauma

Answer 1

• Common
• Account for ~25% of trauma deaths
• Overall chest trauma mortality is 10%
• <15% of patients with chest trauma require surgical intervention
• Inadequate / Delayed treatment —> Death
• Mortality
  —> Immediate deaths
  —> Deaths within a few hours
  —> Late deaths (days - weeks)

Classification based on ***Mechanism:

1. Blunt trauma
   - High velocity impact (e.g. RTA)
   - Low velocity impact (e.g. falling on level ground)
   - Crush injury (e.g. industrial accident)
2. Penetrating trauma
   - Sharps (e.g. knife)
   - Gun shot

Classification based on ***Anatomy:

1. Chest wall injury
   - Rib fracture
   - Sternal fracture
   - Clavicular fracture
   - Vertebral fracture
   - Scapular fracture
   - Soft tissue injury
2. Pleural cavity injury
   - Haemothorax
   - Pneumothorax
3. Parenchymal lung injury
   - Contusion
   - Laceration
   - Haematoma
4. Airway injury
5. Heat and Great vessel injury
   - Cardiac tamponade
6. Others
   - Diaphragmatic injury
   - Esophageal injury

Question 2

Investigations of Chest trauma

Answer 2

1. CXR
2. CT thorax
3. Angiography
4. Echocardiography
5. Bronchoscopy
6. MRI

Question 3

Management of Chest trauma

Answer 3

Initial management:

1. ABC
2. Early detection of life-threatening injuries
3. Assess as a whole
4. Identify indications for immediate operation

Treatment:

1. Simple therapeutic procedures (Non-operative)
   - majority of patients
   - Analgesia, Pulmonary hygiene, ETT intubation, Chest drain insertion, Physiotherapy
2. Thoracotomy / Sternotomy
   - <10% of blunt chest injuries
   - 15-30% of penetrating chest injuries

Question 4

***Indications for Immediate operation

Answer 4

1. Massive haemothorax
2. Ongoing bleeding from chest
3. Cardiac tamponade
4. Penetrating transmediastinal chest wounds
5. Chest wall disruption / Impalement wounds to chest
6. Massive air leak from chest tube
7. Major tracheobronchial injury
8. Great vessel injury with unstable haemodynamics

Question 5

Major thoracic injuries

Answer 5

1. Tension pneumothorax
2. Massive haemothorax
3. Flail chest
4. Pulmonary contusion
5. Tracheobronchial injuries
6. Cardiac tamponade
7. Traumatic aortic disruption

Question 6

1. Tension pneumothorax

Answer 6

• Air enters pleural space without a means of exit —> “one-way-valve” air leak
• Gradual increase in volume of air in pleural cavity
  —> Ipsilateral collapse of lung
  —> Pressure continue to develop
  —> Mediastinum displaced to opposite lung
  —> Impairing venous return (∵ kinking of SVC / IVC) + relaxation of heart
  —> Decreasing cardiac output

Causes:

1. Penetrating injury to chest
2. Blunt trauma with parenchymal lung injury
3. Mechanical ventilation with high airway pressure (Barotrauma)
4. Spontaneous pneumothorax

Diagnosis:

1. **Clinical (NOT wait for CXR)
   - Severe respiratory distress
   - **Unilateral absence of breath sounds
   - **Tracheal deviation
   - **Tachycardia / Hypotension
   - ***Neck vein distension
   - Cyanosis (late manifestation)
2. CXR
   - Large pneumothorax (from radiopaedia: visible visceral pleural edge seen as white thin line, no lung markings seen peripheral to this lung, radiolucent peripheral space)
   - Mediastinal shift

Treatment:
1. Immediate decompression
- Insertion of ***large bore needle into 2nd ICS along MCL
—> Convert Tension pneumothorax into Simple open pneumothorax

2. Chest drain insertion (Definitive)
   - After stabilisation by decompression

Algorithm:
Traumatic pneumothorax
—> Simple pneumothorax —> **Observation / **Chest drain insertion (depend on size)
—> Tension pneumothorax —> ***Urgent needle decompression followed by Chest drain insertion

Question 7

2. Massive haemothorax

Answer 7

• Common in penetrating trauma
• Each hemithorax can hold up to 3L of blood
• Intercostal / Internal mammary vessels most commonly injured
• Neck veins can be flat (hypovolaemia) / distended (mediastinal compression)
• Hilar / Great vessel disruption —> Severe shock

Diagnosis:

1. Clinical
   - Haemorrhagic shock
   - Flat neck veins
   - Unilateral absence / diminution of breath sounds
   - Unilateral dullness
2. CXR
   - Unilateral “white out” on CXR

Treatment:

1. Rapid fluid resuscitation
2. Decompression of chest cavity
3. Intubate a patient in shock / respiratory difficulty
4. Thoracotomy (Operative intervention)
   - if 1.5L blood evacuated initially
   - ongoing bleeding from chest drain of >200ml/hr for 2-4 hours
   - failure to achieve complete drainage / clotted haemothorax

Question 8

3. Flail chest

Answer 8

• Results from direct high energy impact (blunt force)
• Multiple rib fracture
  —> >=2 ribs fractured in >=2 places
  —> A segment of chest wall separated from rest of bony chest wall
  —> Paradoxical motion of chest wall segment with inspiration and expiration
  —> Segment of lung not moving as intended (Inspiration —> alveoli collapse, Expiration —> alveoli expansion)
  —> Inefficient respiratory movement
  —> Effective lung volume reduced (patient has to take deeper / more rapid breaths —> more work for breathing)

Complications:

1. High risk for pneumothorax / haemothorax
2. Respiratory failure ∵
   - Paradoxical motion of chest wall
   - Underlying lung injury
   - Severe pain with restricted chest wall movement

Treatment:

1. Analgesia
2. Mechanical ventilation (usually necessary)
   - Immediately intubate for respiratory distress
   - Consider intubation for haemodynamic instability
3. Early surgery to restore integrity of ribcage

Question 9

4. Pulmonary contusion

Answer 9

• Most common potentially lethal chest injury
• Caused by haemorrhage into lung parenchyma
• Commonly associated with fractured ribs

Natural progression:
- Worsening hypoxaemia for first 24-48 hours

Diagnosis:

1. Clinical (can be difficult)
   - Few respiratory symptoms —> Main problem in diagnosis
   - Mainly Chest pain, SOB
   - Haemoptysis (rare)
2. CXR
   - Haziness in lung / Infiltration of lung segments + Rib fractures
   - Can be ***delayed (within 24-48 hours)
3. ***CT thorax
   - More accurate

Treatment (mainly ***supportive):

1. Supportive with supplemental O2
2. Physiotherapy
3. Mild analgesic
4. Broad spectrum antibiotics
5. Mechanical ventilation when necessary

Question 10

5. Tracheobronchial injuries

Answer 10

• Unusual (1%) but potentially fatal
• Frequently missed injury
• Result from Penetrating / Blunt trauma
• Most patients die at scene
• High mortality from associated injuries (in posterior mediastinum)

Classification:

1. Cervical tracheal injuries
   - ***Upper airway obstruction, Cyanosis
   - Dysphagia, Cough, Haemoptysis
   - Subcutaneous emphysema
2. Thoracic tracheal / bronchial injuries
   - **Intrapleural laceration
   —> Persistent SOB
   —> Massive air leak
   —> Massive pneumothorax
   - **Pneumomediastinum / Subcutaneous emphysema

CXR signs:

1. ***Peri-bronchial air
2. Deep cervical emphysema
3. Subcutaneous emphysema
4. Lung collapsed ***laterally with pneumomediastinum
5. Pneumothorax
6. Pleural effusion
7. Fallen lung sign

CT signs:

1. Fallen lung sign
   - bronchial fracture —> causing lung to collapse (∵ air leak) + fall to dependent part of chest
   - hanging onto hilum by vascular connections only

Treatment:

1. Secure airway
   - Intubation
   - Cricothyroidotomy / Tracheostomy
2. Immediate operation to primary repair

Question 11

6. Cardiac tamponade

Answer 11

• Penetrating (more common) / Blunt injury
• 75 to 100ml of blood can produce tamponade physiology in adult

Clinical features:

1. Beck’s triad
   - Hypotension
   - Distended neck vein
   - Muffled heart sound
2. Shock / Ongoing hypotension without obvious blood loss (more common) (i.e. Obstructive shock)

Diagnosis:
1. Transthoracic echocardiography

Treatment:

1. Emergency pericardiocentesis
   - catheter inserted subxiphoid area —> 45o from midline —> aiming left shoulder
2. Surgical pericardial drainage
   - through median sternotomy / subxiphoid incision

Question 12

7. Traumatic aortic disruption

Answer 12

• Tear in wall of aorta
• Mechanism: ***Rapid deceleration
• Usually located near ***ligamentum arteriosum
• Most die before reaching the hospital

Clinical signs:

1. Asymmetry in upper extremity BP
2. Widened pulse pressure
3. Chest wall contusion
4. Posterior scapular pain, intrascapular murmur

CXR:

1. Widened mediastinum (>8cm)
2. ***Loss of aortopulmonary window (notch between aortic arch and pulmonary artery)
3. ***Blurring of aortic knob
4. Deviation of trachea to right
5. Depression of left main stem bronchus
6. Fracture of first 3 ribs / scapula / sternum
7. Left pleural effusion

Diagnosis:

1. CT thorax with contrast
   - Valuable diagnostic tool for aortic injury
2. Aortography
   - Good standard for diagnosis
   - Useful for indeterminate cases / more detailed planning required

Treatment:

1. Urgent surgical repair
2. Endovascular aortic stent grafts (definitive treatment / buy time until definitive surgical repair)

Question 13

Pitfalls in Chest trauma

Answer 13

1. Simple pneumothorax can progress to Tension pneumothorax
2. Simple haemothorax can progress to a Clotted haemothroax —> ***Empyema
3. Undiagnosed diaphragmatic injury can result in Pulmonary compromise + Strangulation of peritoneal contents

Question 14

Lung transplantation

Answer 14

• Removal of one / both diseased lungs from patient —> Replacement with healthy lungs from a donor
• Accepted modality of treatment for ***End stage lung disease that is refractory to maximal medical treatment
• Poorest 5 year survival among all organ transplants: ~50%

Types:

1. Double transplant
2. Single transplant
3. Lobar transplant
4. Part of Heart-Lung transplant

Question 15

Indications of Lung transplant

Answer 15

1. Obstructive lung disease
   - ***COPD
   - Alpha 1 antitrypsin deficiency
2. Restrictive lung disease
   - ***Idiopathic pulmonary fibrosis
   - ILD
3. Septic lung disease
   - ***Cystic fibrosis
   - Bronchiectasis
4. Pulmonary vascular disease
   - Pulmonary hypertension

Question 16

Morbidity of Lung transplant

Answer 16

1. Use of Immunosuppressant / Steroid
   - Hypertension
   - DM
   - Hyperlipidaemia
2. Renal dysfunction
3. Bronchiolitis obliterans syndrome (after 5 years)
   - ∵ chronic rejection

Question 17

Candidacy considerations

Answer 17

1. High risk of death (>50%) due to lung disease within 2 years if lung transplantation not performed
2. High likelihood (>80%) of surviving >=90 days after lung transplantation
3. High likelihood (>80%) of 5-year post-transplant survival from a general medical perspective provided there is adequate graft function

Question 18

CI of Lung transplantation

Answer 18

Absolute CI:

1. Recent history of malignancy
   - 5-year disease free interval is prudent
2. Untreatable significant dysfunction of another major organ system (unless combined organ transplantation)
3. Uncorrected atherosclerotic disease with end-organ ischaemia / dysfunction / CAD not amenable to revascularisation
4. Acute medical instability
5. Uncorrectable bleeding diathesis
6. Chronic infection with highly virulent / resistant microbes that are poorly controlled pre-transplant
7. Active TB infection
8. Significant chest wall / spinal deformity expected to cause severe restriction
9. Class 2/3 obesity (BMI >35)
10. Current non-adherence to medical therapy / history of repeated / prolonged episodes of non-adherence
11. Psychiatric / Psychological conditions associated with inability to cooperate
12. Absence of an adequate / reliable social support system
13. Severely limited functional status with poor rehabilitation potential
14. Substance abuse / dependence (e.g. alcohol, tobacco, marijuana, other illicit substances) within last 6 months

Relative CI:

1. Age >65
2. Class 1 obesity (BMI 30-34.9)
3. Progressive / Severe malnutrition
4. Severe, symptomatic osteoporosis
5. Extensive prior chest surgery with lung resection
6. Mechanical ventilation / ECLS
   - however, carefully selected candidates without other acute / chronic organ dysfunction may be successfully transplanted

Question 19

Mechanical bridges to Lung transplantation

Answer 19

ECLS (Extracorporeal life support) recommended:

• Young age
• Absence of multiple-organ dysfunction
• Good potential for rehabilitation

ECLS not recommended:

• Septic shock
• Multi-organ dysfunction
• Severe arterial occlusive disease
• Heparin-induced thrombocytopenia
• Prior prolonged mechanical ventilation
• Advanced age
• Obesity

Question 20

Currently accepted “Ideal” donor

Answer 20

1. Age <55
2. ABO compatibility
3. Clear chest radiograph
4. PaO2 >300 on FiO2=100%, PEEP 5 cmH2O (P:F ratio —> reflect ability of oxygenation by lung)
5. Tobacco history <20 pack years
6. Absence of chest trauma
7. No evidence of aspiration / sepsis
8. No prior cardiopulmonary surgery
9. Sputum gram stain - absence of organisms
10. Absence of purulent secretions at bronchoscopy

Only 49% of donor lung satisfy above criteria, 51% are ***extended criteria donor lungs

Question 21

Absolute CI for donor lungs

Answer 21

1. Age >65
2. History of lung disease
3. History of prior cardiopulmonary surgery
4. History of severs chest trauma
5. Evidence of pulmonary edema
6. Long smoking history >20 pack years
7. Abnormal CXR
8. Fulminant pneumonia
9. HbsAg +ve, HCV Ab +ve
10. P/F radio <300 on FiO2=100%, PEEP 5 cmH2O
11. Evidence of aspiration clinically, on CXR / bronchoscopy

Question 22

Potential donor lungs are prone to injury

Answer 22

Inside in donor:
1. Cold ischaemia
2. Brain death
3. Hypotension
4. Trauama
5. Mechanical ventilation
6. Pneumonia
7. Aspiration
—> Activation of inflammation + coagulation in donor
—> ***Ischaemia-reperfusion induced lung injury after transplantation

Method to resolve:

1. Normothermic Ex Vivo lung perfusion (EVLP)
   - opportunity to salvage borderline lungs
   - increase donor lung supply
   - reduce transplant waiting list morbidity and mortality
2. Living donor lobar lung transplant (LDLLT)
   - possible serious complications in donor lobectomy —> LDLLT indicated only for critically ill patients who are unlikely to survive the long wait for cadaveric lungs

Monitor:
- CXR of explanted lung