Chest Trauma
Rib fractures & Flail Chest

Chest wall injury is a extremely common following blunt trauma. It varies in severity from minor bruising or an isolated rib fracture to servere crush injuries of both hemithoraces leading to respiratory compromise.

While many chest injuries will require no specific therapy, they may be indicators of more significant underlying trauma. Multiple rib fractures will often be associated with an underlying pulmonary contusion, which may not be immediately apparent on an initial chest X-ray. Fractures of the lower ribs may be associated with diaphragmatic tears and spleen or liver injuries. Injuries to upper ribs are less commonly associated with injuries to adjacent great vessels. This is especially true of a first rib fracture, which requires a significant amount of force to break and indicates a major energy transfer. A fracture of the first rib should prompt a careful search for other injuries. Note also that the rib cage and sternum provide a significant amount of stability to the thoracic spine. Severe disruption of this 'fourth column' may convert what would otherwise be a stable thoracic spine fracture into an unstable one.

Flail Chest

A flail chest occurs when a segment of the thoracic cage is separated from the rest of the chest wall. This is usually defined as at least two fractures per rib (producing a free segment), in at least two ribs. A segment of the chest wall that is flail is unable to contribute to lung expansion. Large flail segments will involve a much greater proportion of the chest wall and may extend bilaterally or involve the sternum. In these cases the disruption of normal pulmonary mechanics may be large enough to require mechanical ventilation.

R flail chest	Video

The main significance of a flail chest however is that it indicates the presence of an underlying pulmonary contusion. In most cases it is the severity and extent of the lung injury that determines the clinical course and requirement for mechanical ventilation. Thus the management of flail chest consists of standard management of the rib fractures and of the pulmonay contusions underneath.

Diagnosis

Most significant chest wall injuries will be identified by physical examination. Bruising, grazes or seat-belt signs are visible on inspection, and palpation may reveal the crepitus associated with broken ribs. Awake patients will complain of pain on palpation of the chest wall or on inspiration.

A flail chest is identified as paradoxical movement of a segment of the chest wall - ie indrawing on inspiration and moving outwards on expiration. This is often better appreciated by palpation than by inspection.

Chest X-ray

The antero-posterior chest radiograph will identify most significant chest wall injuries, but will not identify all rib fractures. Lateral or anterior rib fractures will often be missed on the initial plain film. However, since the management of rib fractures is determined by their clinical significance rather than by their number or position, dedicated rib views are never indicated.

For adult blunt trauma patients, a haemothorax, pneumothorax or pulmonary contusion seen on chest X-ray will almost always be associated with a rib fractures, whether or not identified clinically or by X-ray. In paediatric patients the ribs are more pliable and less likely to fracture, although there will still be significant contusion of chest wall structures.

R flail segment L rib fractures	R flail segment close-up

Computed Tomography

Computed tomography provides very little further clinical information and is not indicated for the initial evaluation of chest wall injuries.
 

CHEST TRAUMA INITIAL EVALUATION PNEUMOTHORAX TENSION PNEUMO OPEN PNEUMO HAEMOTHORAX CONTUSION RIB FRACTURE / FLAIL AORTIC INJURY CHEST DRAINS

CHEST WALL INJURY PRIMARY SURVEY AIRWAY BREATHING CIRCULATION DISABILITY EXPOSURE ADJUNCTS CXR SECONDARY SURVEY

R chest injury
clinical deformity

R chest injury
R rib fractures

Management

Management of chest wall injury is directed towards protecting the underlying lung and allowing adequate oxygenation, ventilation and pulmonary toilet. This strategy is aimed at preventing the development of pneumonia, which is the most common complication of chest wall injury. Note that while a young fit patient will easily manage one or two rib fractures with simple analgesia, the same injury in an elderly patient is regarded as major and will frequently lead to pneumonia and respiratory failure if not appropriately managed (and even then).

All patients should initially be placed on 100% oxygen via a non-rebreathing facemask.

Analgesia

Analgesia is the mainstay of therapy for rib fractures. While strapping the chest to splint rib fractures may seem like a good idea, it impedes chest wall movement and prevents adequate inspiration and clearance of secretions. Opioid analgesics are useful, but when used as the sole analgesic agent may require such high doses that they produce respiratory depression - especially in the elderly. Patient controlled administration of an opioid infusion (PCA) is the best method for cooperative patients. The addition of a non-steroidal anti-inflammatory agent may provide adequate relief, but these should be withheld until other injuries have been excluded (eg. traumatic brain injury) and used with caution in the elderly.

Undoubtedly the best analgesia for a severe chest wall injury is a continuous epidural infusion of a local anaesthetic agent (+/- an opioid). This provides complete analgesia allowing normal inspiration and coughing without the risks of respiratory depression. Epidurals may be placed in the thoracic or high-lumbar positions.

Other methods of local anaesthetic administration are available, but are poor in comparison to an epidural. For one or two isolated rib fractures, posterior rib blocks may be appropriate. Local anaesthetic is infiltrated around the intercostal nerve posteriorly. These blocks will last 4-24 hours and will then have to be repeated. Where a chest tube is present, some practitioners advocate instilling a local anaesthetic solution into the pleural splace. However the volume needed is large, the results very variable, and local anaesthetic toxicity due to rapid pleural absorbtion a possibility.
  

Intubation & Ventilation

Intubation and mechanical ventilation is rarely indicated for chest wall injury alone. Where ventilation is necessary it is usually for hypoxia due to underlying pulmonary contusions. Positive pressure ventilation may be required for severe chest wall instability resulting in inadequate spontaneous ventilation. Intubation and ventilation may be required when anaesthesia is necessary to provide immediate and adequate analgesia and allow further assessment and management.

Ventilation is usually necessary only until the resolution of the pulmonary contusion. Healing and stabilisation of rib fractures is rarely the limiting step in weaning from mechanical ventilation, except in the most severe chest injuries.

Chest tube insertion

Patients with rib fractures who receive positive pressure ventilation are at an increased risk of developing a pneumothorax or tension pneumothorax due to laceration of the lung by the sharp fracture end. Many authors recommend placement of a prophylactic chest tube for all patients with rib fractures who receive mechanical ventilation. This practice varies depending on the presence of other injuries, monitoring environent and available resources. For example, the patient with isolated chest injuries with continuous cardiorepiratory monitoring in an intensive care unit can probably be observed without a chest tube. In contrast, in a patient anaesthetised for prolonged surgery, placement of a prophylactic chst tube may be more appropriate. Especially where the signs of a tension pneumothorax may be mistaken for signs of haemorrhagic shock.

Rib fracture fixation

The popularity of rib fracture fixation has waxed and waned over the past 5 decades. External fixation and stabilisation was common for large chest wall injuries prior to the development of tracheal intubation and mechanical ventilation.

External stabilisation c1960	External stabilisation c1960

Positive pressure ventilation essentially provides an 'internal stabilisation' to the thoracic cage as well as improving oxygenation and ventilation for the management of pulmonary contusion. Hence it has essentially replaced fracture fixation over the past twenty years. In the last few years however a few studies have suggested that some groups of patients (as yet unidentified) may benefit from early fracture fixation, allowing earlier weaning from mechanical ventilation and reducing acute complications and chronic chest wall pain.

Complications

R chest injury

positive pressure
ventilation

operative stabilisation

post-op X-ray

References

Rib fractures

Ziegler DW, Agarwal NN. 'The morbidity & mortality of rib fractures.' J Trauma 1994;37:975

Dubinsky I, Low A. 'Non-life-threatening blunt chest trauma: appropriate investigation and treatment.' Am J Emerg Med 1997;15:240

Lee RB, Bass SM, Morris JA jr et al. 'Three or more rib fractures as an indicator for transfer to a level 1 trauma center: a population-based study.' J Trauma 1990;30:689

Flail Chest

Clark GC, Schecter WP, Trunkey DD. 'Variables affecting outcome in blunt chest trauma: Flail chest vs. pulmonary contusion.' J trauma 1990;30:93

Freedland M, Wilson RF, Bender JS. 'The management of flail chest injury: Factors affecting outcome.' J Trauma 1990;30:1460

Pelosi P, Cereda M, Foti G. 'Alterations of lung and chest wall mechanics in patients with acute lung injury: effects of positive end-expiratory pressure.' Am J Resp Crit Care Med 1995;152:531

Craven KD, Oppenheimer L, Wood LD. 'Effects of contusion and flail chest on pulmonary perfusion and oxygen exchange.' J Appl Physiol 1979;47:729

Landercasper J, Cogbill T, Lindesmith L. 'Long-term disability after flail chest injury.' J Trauma 1984;24:410

Analgesia

Hedderich R, Ness T. 'Analgesia for trauma and burns.' Crit Care Clin 1999;15:167

Desai P. 'Pain management & pulmonary dysfunction.'. Cri Care Clin 1999;15:151

Mackersie RC, Shackford SR, Hoyt DB et al. 'Continouous fentanyl analgesia: ventilatory function improvement with routine use in treatment of blunt chest injury.' J Trauma 1987;27:1207

Rib fracture fixation

Tanaka H, Yukioka T, Yamaguti Y et al. 'Surgical stabilization of internal pneumatic stabilization? A prospective randomized study of management of severe flail chest patients.' J Trauma 2002;52:727

Ahmed Z, Mohyuddin Z. 'Management of flail chest injury: internal fixation versus endotracheal intubation and ventilation.' J Thorac Cardiovasc Surg 1995;110:1676

Voggenreiter G, Neudeck F, Aufm'Kolk M et al. 'Operative chest wall stabilization in flail chest - outcomes of patients with and without pulmonary contusion.' J Am Coll Surg 1998;130:187