Flail Chest

Last updated 20/08/19

Definition

• Segment of thoracic cage seperated from rest of chest wall due to underlying rib fractures in at least 2 parts of single rib in at least 2 seperate ribs
• Radiological definition = three or more contiguous ribs are fractured in two or more places

Features

• Flail segment of chest wall does not contribute to lung expansion and ventilation
• Severe cases may require mechanical ventilation
• Typically associated with other thoracic injuries
• Indicator of significant mechanism
• Almost universally associated with underlying pulmonary contusion
• May be main indicator for need for ventilatory assistance
• Considered a clinical diagnosis
• Flail sternum = bilateral ribs or costal cartilage fractures with independantly mobile sternum

Causes

• Blunt thoracic trauma
• Occurs in 5-13% of patients with chest wall injuries
• High impact with severe anteropsterior compression forces
• Motor Vehicle Accident (MVA) 75%
• Blast injuries
• Crush injuries
• Falls in elderly 15%

Associated Signs & Symptoms

• Overlying bruising or grazes
• Bony crepitus
• Pain on palpation and/or inspiration
• Usually severe requiring opiates
• Inspiratory splinting
• Asymetrical chest rise and fall
• Evident flail segment with paradoxical wall movement
• May be better appreciated with palpation rather than inspection
• May be occult particularly if posterior flail
• Stove-in-chest = collapse of medial segment
• Associated with higher mobidity and mortality
• Subcutaneous emphysema
• Seat belt sign

Risk Factors

• Osteoporosis, osteopaenia

Complications

• Pulmonary contusion
• Pneumothorax
• Haemothorax
• Pneumonia
• Contributed to by inadequate analgesia
• Atelectasis
• Respiratory failure
• Particularly in context of other chest/pulmonary injuries
• Pulmonary contusion, hypoventilation, ineffective ventilation, atelectasis
• Contributed to by inadequate analgesia
• Scapula fracture
• Clavicle fracture
• Intercostal neuralgia

Investigations

• Vitals
• Pulse oximetry: hypoxia
• Blood gas (ABG, VBG)
• pH: <7.45: respiratory acidosis
• PCO2: >45cmH2O: respiratory acidosis
• CXR
• AP may not identify rib fractures
• Pulmonary contusion
• Pneumothorax
• Haemothorax
• Scapula and/or clavicle fracture




Left sided flail chest



• CT Chest
• Not indicated specifically
• More sensitive than CXR

Management

• ALS
• Primary and secondary survey
• High index of suspicion of other injuries
• Oxygen
• 15L via Non-rebreather face mask
• Or High Flow Nasal Prongs (HFNP)
• Intubation and ventilation
• Rarely required for chest injury alone
• Severe cases with significant chest wall instability may require positive pressure
• Typically only required until underlying pulmonary contusion resolves
• If intubated on positive pressure ventilation consider prophylactic intercostal catheter (ICC) due to significant risk of developing pneumothorax + tension
• Analgesia
• Elderly patients or those with limited reserve likely to splint respiration without adequate analgesia
• Patient Controlled Analgesia (PCA)
• Morphine
• Or Oxycodone
• Ketamine infusion
• Thoracic epidural
• Allows full respiration and cough
• Or Paravertebral block
• Or Intercostal nerve blocks (for 1-2 rib fractures)
• Chest physiotherapy
• Assist volume expansion
• Secretion management
• Surgical management
• Not usually required
• Open Reduction Internal Fixation (ORIF)
• Consider if
• Intractable pain
• Failure to ween from mechanical ventialtion
• Estimated 6-12 months for full recovery

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References

1. Sarani B. Inpatient management of traumatic rib fractures. UpToDate. 19/11/2018
2. Perera T, Daley B. Flail Chest. StatPearls [Internet]. 24/12/2018
3. Skandhan A, Stanislavsky A. Flail Chest. Radiopaedia - accessed online 20/09/2019
4. Trauma.org: Chest Trauma - Rib fractures and Flail Chest - accessed online 20/09/2019
5. Taylor B. Flail Chest. Orthobullets. 10/05/2016