Introduction

Significant chest injury is rare in paediatric trauma.  Most cases occur secondary to blunt chest trauma, with penetrating injuries accounting for less than 10% or the total reported incidence worldwide.

Over a 5 year period to 2007 there were 204 cases of severe paediatric thoracic trauma in Victoria¹.  The most common injuries identified were lung contusion (65%) and haemo/pneumothorax (37%).  Blunt trauma accounted for 96% of injuries and 75% were secondary to motor vehicle accidents (including pedestrian vs motor vehicle).  Due to this frequent association with motor vehicle accidents (MVAs) patients with chest trauma usually have concomitant injuries to other major systems, most commonly the head and abdomen.  In the above study 99% of patients had an injury to one of more other body regions.  This underscores the high level of force involved in most paediatric chest trauma.

Mortality

Mortality in children with chest trauma has been quoted to be as high as 30% although death is not always related directly to the chest injury.  Death usually occurs soon after the injury in a child, whereas an adult with comparable injuries tends to survive longer.

How children are different

• A major difference between adults and children is the compliance of the chest wall, due to the greater elasticity of the ribs. This allows greater deformation of the chest wall before the ribs fracture. Thus major internal injuries may occur without any external chest wall injury.
• Children have a greater cardiopulmonary reserve, and so compensatory mechanisms may mask hypovolaemia and respiratory distress.
• A drop in blood pressure in the paediatric population is a very late sign, signifying imminent death.
• The mobility of the mediastinum decreases the risk of major airway and vessel injury. However, ventilatory and cardiovascular compromise may occur rapidly, due to the mediastinal shift.
• A common response to injury in children is aerophagia, which is often associated with a reflex ileus. This can lead to acute gastric dilatation, which may further compromise respiratory function.
• There should be a high index in paediatric trauma for orogastric / nasogastric placement, with orogastric only indicated where head injury is a concern.

In all aspects of trauma management, the primary survey is first priority

Primary survey

The purpose of the primary survey is to identify and manage life threats.  The particular thoracic injuries that are necessary to identify during the primary survey include:

• Tension pneumothorax
• Open pneumothorax
• Massive haemothorax
• Flail chest
• Cardiac tamponade

In these injuries frequent reassessment of ABC is a necessary part of their assessment & management

Types of injuries

Tension Pneumothorax

• Accumulation of air in the pleural space under pressure resulting in compression of the ipsilateral lung
• Progressive air accumulation causes mediastinal shift and development of compression to the contralateral lung
• Impaired venous return
• Compromised cardiac output

Diagnosis

• Hypoxia
• Severe respiratory distress
• Altered level of consciousness
• Shift in mediastinum or trachea to the contralateral side
• Distended neck veins
• Absent or decreased breath sounds bilaterally
• Hyper-resonance to percussion
• Impaired venous return to the heart
• Patient will be tachycardic with peripheral vasoconstriction and in hypotensive shock

Treatment 

(see also Management of Traumatic Pneumothorax and Haemothorax)

• High flow oxygen
• Analgesia
  
• Immediate finger thoracostomy is the preferred management in the in-hospital environement. This is done in the 4th or 5th intercostal space, between the anterior and mid-axillary line, on the side of the pneumothorax, followed immediately by an intercostal catheter in the same location (Figure 1).
• If unable to do an immediate finger thoracostomy, an immediate needle thoracocentesis – midclavicular line, 2^nd intercostal space, on the side of the pneumothorax (Figure 2 & 3).  This should be followed as soon as possible by a finger thoracostomy and intercostal catheter insertion – 4^th or 5^th intercostal space anterior axillary line  

Figure 1 - surface marking for left sided finger thoracostomy and intercostal catheter insertion

Figure 2 – surface marking for needle thoracocentesis

Figure 3 – needle thoracocentesis insertion

There is a 10-20% chance of causing a pneumothorax if thoracocentesis is attempted in the absence of a pre-existing pneumothorax.  This procedure must be followed up by a chest x-ray and insertion of an intercostal catheter.

Open Pneumothorax

• This injury occurs secondary to penetrating wounds of the chest.  It occurs where the wound is greater than two thirds the diameter of the trachea.  At this size and above, the negative pressure generated through excursion of the chest in inspiration, will lead to the preferential influx of air via the wound into the pleural space, rather than via the upper airway.   If air fails to escape with expiration, a tension pneumothorax will develop.  

Diagnosis

• Respiratory distress
• Hypoxia
• Decreased chest movement
• Decreased air entry
• Hyper-resonant to percussion
• Chest wound through which air may be heard passing with inspiration & expiration

Treatment

• High flow oxygen
• Analgesia
• In hospital, cover with  occlusive dressing (small wounds) or suture/staple the wound closed (larger wounds) 
• Immediate insertion of intercostal catheter
• The use of a 3 sided occlusive dressing - to act as a one way valve - is no longer recommended as treatment for an open pneumothorax once the patient has arrived in hospital.  If may be applied when the patient is being managed in the pre-hsopital environment and there will be a delay to insertion of an intercostal catheter.  However, they can be hard to apply to a bleeding wound, and they have variable efficacy.

Figure 4 - A 3 sided occlusive dressing

Massive Haemothorax

• This is a rare injury in the paediatric population
• Rapid, large volume accumulation of blood in the pleural space
• May result secondary to a blunt or penetrating injury – cardiac or great vessel injury
• Potential to lose up to 40% of blood volume in each hemithorax

Diagnosis

• Respiratory distress
• Decreased chest movement
• Decreased air entry
• Dullness to percussion

Treatment

• High flow oxygen
• Analgesia
• Ventilatory support
• Rapid fluid resuscitation
• Insertion of intercostal catheter – 4^th or 5^th intercostal space, anterior axillary line (Figure 1)
• Urgent surgical review for possible thoracotomy if ongoing haemorrhage with inability to stabilise circulation despite aggressive fluid resuscitation

Flail Chest

• This occurs secondary to blunt injury - it is less common in children than in adults due to the greater elastic properties of the paediatric ribcage - which permits far greater plastic deformation on impact without resultant broken ribs.  However, the underlying lung parenchyma is susceptible to contusion
• A flail chest is the result of 2 or more fractures in two or more adjacent ribs interrupting the bony continuity of the thoracic wall (Figure 5)    

Figure 5 – Flail chest with pulmonary contusions

Diagnosis

• “Paradoxical movement” – the flail segment is seen to collapse with inspiration and bulge with expiration while the rest of the chest wall moves in the opposite way
• Respiratory distress
• Possible decreased air entry due to associated pulmonary contusion and splinting
• Possible subcutaneous emphysema

Treatment

• Aggressive analgesia
• High flow oxygen with ventilatory support as necessary
• Stabilisation of flail segment.  Patient may be placed injured side down
• Positive pressure ventilation improve ventilation, and intubation may be necessary to help with analgesic demands.
• Referral to cardiothoracic surgeons for consideration of rib fixation

Cardiac Tamponade

• Bleeding into the pericardium secondary to blunt or penetrating injury
• Blood may originate from cardiac chamber, a great vessel or from the myocardium in the presence of a myocardial contusion
• Results in decreased filling of the heart and thus reduced stroke volume and shock

Diagnosis

• Respiratory distress
• Hypotension
• Narrow pulse pressure
• Distended neck veins
• Soft heart sounds
• Refractory shock

 Investigations

• Bedside USS for confirmation if time permits

Treatment

• ECG monitoring
• High flow oxygen
• Fluid resuscitation (to increase preload and minimise right ventricular collapse)
• The optimum treatment for a pericardial tamponade secondary to blunt or penetrating trauma is open surgical drainage in theatre.  
• In the situation where there is severe shock and no surgical facilities available, needle pericardiocentesis can be performed as a temporising measure.
• A long needle is inserted at a left sub-xiphoid position, and directed posteriorly at a 45° angle and towards the left shoulder - this is better performed under ultrasound guidance where skills and equipment permit.

There is limited evidence for the role of an ED thoracotomy in the paediatric population who have sustained a blunt injury, it should be considered in the event of penetrating trauma

Pulmonary Contusion

• The most common thoracic injury in children
• Often associated with other injuries such as fractures and haemothorax
• May occur in absence of obvious chest wall injury
• Haemorrhage and oedema within affected lung segment

Diagnosis

• Hypoxia – degree of compromise will depend on size of contusion
• Respiratory distress – may very in severity
• Decreased air entry on ipsilateral side

Investigations

• Chest x-ray – patchy consolidation, may be bilateral (Figure 5)  - may initially be unremarkable with changes evolving over 24-72 hours

Treatment

• High flow oxygen
• Analgesia
• Pulmonary toilet including regular suction and chest physiotherapy
• Ventilatory support
• Contusions may evolve clinically & radiologically over first 24-72 hours

Rib Fractures

• The paediatric chest wall can sustain more deformation before rib fractures occur compared with the adult chest wall
• Despite this rib fractures are still common in paediatric chest trauma
• Indicative of significant injury and greater likelihood of comcommitant multisystem injuries
• Almost always associated with pulmonary contusions

Diagnosis

• Chest wall bruising/abrasions
• Respiratory distress
• Hypoventilation secondary to splinting
• Decreased chest expansion
• Hyper-resonance or dullness to percussion (depending on associated pneumothorax or contusion)
• Normal or decreased air entry

Investigations

• Chest x-ray – fractures & consolidation may be evident - may be unremarkable initially

Treatment

• High flow oxygen
• Aggressive analgesia
• Ventilator support as necessary
• Inpatient monitoring as deterioration may occur due to associated pulmonary contusions

Simple Pneumothorax

• Accumulation of air in the pleural space
• Degree of compromise related to the size of the pneumothorax and other associated injuries

Diagnosis

• Respiratory distress
• Pleuritic chest pain
• Decreased chest wall movement ipsilateral side
• Decreased air entry
• Ipsilateral hyper-resonance to percussion
• May be asymptomatic

Investigations

• Chest x-ray – collapse of lung parenchyma on ipsilateral side with slightly increased expansion of chest wall 
• Ultrasound – absence of lung sliding and B-lines, presence of A-lines; presence of a lung point.  This should be performed by experienced clinician

Treatment:

• Supplemental oxygen
• Analgesia
• Ventilatory support as necessary
• If patient has respiratory compromise or the pneumothorax is >20% on chest x-ray insertion of intercostal chest catheter is required
• If the patient does not meet above criteria and thus doesn’t require immediate chest drain insertion, admission and intensive monitoring is required as a simple pneumothorax may enlarge and become symptomatic or even convert to a tension pneumothorax

Haemo-Pneumothorax

• A combination of the accumulation of both blood and air in the pleural space

Diagnosis

• Respiratory distress
• Decreased chest wall movement
• Decreased air entry
• Dullness to percussion

Investigations

• Chest x-ray – collapse of ipsilateral lung, pleural effusion with air/fluid level in pleural space

Treatment

• High flow oxygen
• Analgesia
• Ventilatory support as necessary
• Fluid resuscitation
• Insertion of intercostal chest drain

Pulmonary Laceration

• Most commonly secondary to penetrating injury but may occur with blunt trauma
• Typically associated with pulmonary contusions and haemopneumothorax on the ipsilateral side

Diagnosis

• Signs of trauma to chest wall ie. Bruising/abrasions
• Respiratory distress
• Hypoxia
• Decreased chest expansion
• Dullness to percussion
• Decreased breath sounds

Investigations

• Chest x-ray - collapse of ipsilateral lung, pleural effusion with air/fluid level in pleural space

Treatment

• High flow oxygen
• Analgesia
• Ventilatory support as required
• May require surgical intervention if persisiting air leak or bleeding
  

Traumatic Rupture of the Aorta

• Very rare injury in the paediatric population
• Typically occurs in rapid deceleration injuries such as that sustained in high-speed motor vehicle accidents
• Commonly occurs at, or very close to, the ligamentum arteriosum which attaches to the proximal descending aorta just beyond the left subclavian artery.  The ascending aorta and aortic arch are much more mobile compared with the descending aorta and it is probable that at the time of impact a major torsional inury occurs at this junction
• In many cases this injury will result in immediate massive blood loss into the left pleural cavity and death occurs at the scene of the accident.

Diagnosis

• Respiratory distress
• Decreased air entry and dullness to percussion on the left
• Tachycardia
• Hypotension

If suspected on plain radiography further investigation is required – CT chest, aortogram or trans-oesophageal echocardiogram.

Investigations

• Chest x-ray – suspect with any of the following features
  • Widened mediastinum on erect film
  • Pleural cap over the apex of the left lung (due to haemoatoma tracking upwards)
  • Loss of the aortic knuckle
  • Deviation of trachea or oesophagus to the right
  • Depression of left main stem bronchus
• If diagnosis suspected on plain radiography further investigation required
  • CT chest
  • Aortogram (Gold Standard)
  • Trans-oesophageal echocardiogram

Treatment

• Analgesia
• Fluid resuscitation
• Supplemental oxygen
• Ventilatory support as needed
• If diagnosis confirmed will require aortic surgery to resect the site of injury with either aortic repair of replacement

Tracheo-Bronchial Injury

• Rare injury
• Potentially life threatening
• Almost exclusively occurs due to penetrating injury
• Results from trauma to region between larynx and segmental bronchus

Diagnosis

• Respiratory distress
• Hypoxia
• Partial airway obstruction
• Subcutaneous emphysema
• Decreased air entry
• Continuous air leak after insertion of intercostal catheter

Investigations

• Chest x-ray – pneumothorax (may be bilateral), pneumomediastinum, subcutaneous emphysema

Treatment

• High flow oxygen – adequate oxygenation may be difficult to achieve
• Analgesia
• ETT placement beyond level of injury
• Ventilatory support
• Referral to thoracic surgeon for definitive management

Oesophageal Injury

• Rare
• Most commonly due to penetrating injury but may occur following blunt injury to the upper abdomen causing forceful ejection of stomach contents into the oesophagus resulting in a linear tear in the lower oesophagus

Diagnosis

• Respiratory distress
• Fever may be present
• Subcutaneous emphysema
• Peritonism - guarding, rigdity
• Decreased air entry
• Intercostal catheter may drain gastric contents

Investigations

• Chest x-ray – pneumomediastinum, pneumothorax, pleural effusion, subcutaneous emphysema

Treatment

• Supplemental oxygen
• Analgesia
• Insertion of nasogastric tube
• Broad spectrum antibiotic cover
• May be managed conservatively or require insertion of intercostal chest drain
• Surgical intervention may be required

Myocardial contusion

• Typically occurs following direct blunt trauma to the sternum
• Most often involves the anterior wall of the heart
• Should be suspected in any patient with injury over the sternum, in particular if there is a sternal fracture

Diagnosis

• Anterior chest wall bruising/tenderness
• Tachycardia
• Tachypnoea
• Prolonged capillary refill time
• Hypotension
• May have arrhythmia
• May be asymptomatic
• May be complicated by cardiac tamponade

Investigations

• ECG – monitor for changes similar to those of myocardial infarction or arrhythmias
• Cardiac enzymes
• Echocardiogram to detect impaired myocardial function (dyskinesis or akinesis)

Treatment

• Supplemental oxygen
• Analgesia
• ECG monitoring
• Serial cardiac enzymes
• Follow up echocardiogram

Diaphragmatic Rupture

• Rare injury but well recognised
• Occurs due to forceful blunt abdominal injury causing a sudden, major increase in intra-abdominal pressure
• Usually left sided
• May result in abdominal viscera being displaced into thoracic cavity

Diagnosis

• Tachypnoea
• Possible hypoxia
• Evidence of abdominal trauma – contusion/abrasion
• Decreased chest wall movement
• May have decreased air entry on left with potential for bowel sounds in chest
• Mediastinal shift may occur

Investigations

• CXR – difficult to identify diaphragm, abdominal contents in hemithorax, tip of NGT in chest (Figure 6 & 7)
• Contrast study gives definitive diagnosis (Figure 8)

Figure 6 - diagphragmatic rupture, unable to visualise left diaphragm

Figure 7 - diagphragmatic injury, nasogastric tip visible in left hemithorax

Figure 8 - diaphragmatic injury, contrast within stomach visible in left hemithorax

Contrast study or CT will give definitive diagnosis.

Treatment

• High flow oxygen
• Analgesia
• NGT placement
• Surgical referral

Traumatic Asphyxiation (“run over” injury)

• Very rare
• Caused by severe, prolonged compression of the chest
• Results in obstruction of venous return leading to extravasation of blood into tissues

Diagnosis

• Petechiae of upper chest, neck, arms and face
• Bulging eyes
• Subconjunctival haemorrhages
• Massive subcutaneous oedema
• Respiratory distress
• Tachypnoea
• Hypoxia
• Decreased chest movement
• Decreased air entry
• Underlying vascular injury – assess for pulses, bruits, haematomas, intracranial haemorrhage
• Underlying nerve injury – assess for motor and sensory deficits

Treatment

• High flow oxygen
• Intubation and ventilator support
• Analgesia
• Management must be directed to underlying injuries
• Referral to thoracic surgeon

IMAGING

Chest X-ray

• Good screening tool
• Limited in trauma assessment as images are taken with patient supine and therefore more difficult to appreciate certain injuries ie. Pneumothorax, Hamothorax
• Consider cross-table film to better assess for these injuries
• Useful guide for selective CT imaging
• Normal chest x-ray essentially excludes significant thoracic injury requiring intervention^2,3,4

CT Chest

• Not routine in paediatric trauma
• Selective use in cases with abnormal chest x-ray or high clinical suspicion
• Radiation exposure is approximately 6x that of plain radiography and increases lifetime risk of malignancy to 1/500 and risk of fatal malignancy up to 1/1200^2,3
• Injuries picked up on chest CT with normal x-ray most commonly rib fractures or pneumothorax, usually not of clinical significance and not requiring intervention^2,3,4.
• Therefore radiation risk versus clinical benefit too high^2,4

Chest Ultrasound

• Can be useful in detection of pneumothorax and haemothorax that may not be evident on supine chest x-ray⁴ .
• More sensitive in diagnosing pneumothorax than plain chest x-ray in the hands of an experienced clinician
• FAST and EFAST not validated in the paediatric population

Resuscitative thoracotomy

• Resuscitative thoracotomy in the Emergency Department, in traumatic cardiac arrest, is controversial in paediatrics.  However it is an accepted procedure in adult trauma management.
• Given the rarity of severe chest trauma in children the literature of resuscitative thoracotomy, in the paediatric population, is scarce
• Studies investigating efficacy of emergency department thoracotomies in children have demonstrated some success in older children, primarily teenagers, with penetrating chest trauma who have detectable signs of life at the scene of trauma^5,6,7,8
• There have only been 2 patients documented in the literature who have survived ED thoracotomy following blunt chest trauma, these were in 1988 & 1989^6,7
• There has been no survival documented in the literature of children under 9 years of age who underwent emergency department thorocotomy^6,7
• However given that the alternative is death, most studies suggest that in selected cases ie. older children who fit the above criteria (penetrating chest trauma with signs of life at the scene) resuscitative thoracotomy be considered^5,8 (This is reliant on sufficient training and expertise existing, as well as the ongoing capability to provide thoracic surgical expertise to the patient).  
• A recent consensus based guideline developed by the PERUKI group has been developed⁹.  This looked at traumatic paediatric cardiac arrest that was not due to hypoxia (e.g. drowning, asphyxiation or imapact apnoea), and recommended the provision of specific lifesaving interventions over the use of chest compressions and defibrillation.  The lifesaving interventions recommended are:
  • external haemorrhage control,
  • adequate oxygenation and ventilation,
  • bilateral thoracostomies,
  • rapid volume replacement with warmed blood and blood products and,
  • application of a pelvic binder

Summary   

• A lack of external signs does not preclude major underlying thoracic injury
• Chest injuries rarely occur in isolation, usually being associated with injury to other systems, most commonly head or abdomen
• Physiological differences of the paediatric chest must be taken into consideration – especially during the primary and secondary survey
• Treatment in the absence of major cardiovascular or tracheobronchial injury will be guided by oxygenation.  In many cases, the use of adequate analgesia and supplemental oxygen may be all that is needed
• The insertion of intercostal catheters should be considered in the following cases¹⁰
  • Where there is an intrapleural collection causing compromise
  • Where there is a significant chest injury and the patient is to be placed on positive pressure ventilation
  • Where the patient is to be transported by air ambulance

References

1. Samarasekera SP, Mikocka-Walus A, Butt W, Cameron P.  Epidemiology of major paediatric chest trauma.  J of Paediatrics and Child Health.  2009; 45: 676-680
2. Holscher CM, Faulk LW, Moore EE et al.  Chest computed tomography imaging for blunt pediatric trauma: not worth the radiation risk.  J of Surgical Research.  2013; 184: 352-357
3. Yanchar NL, Woo K, Brennan M, et al.  Chest x-ray as a screening tool for blunt thoracic trauma in children.  J Trauma Acute Care Surg.  2013; 75: 613-619
4. Moore MA, Wallace EC, Westra SJ.  Chest Trauma in Children:  Current Imaging Guidelines and Techniques.  Radiol Clin N Am.  2011; 49: 949-968
5. Easter JS, Vinton DT, Haukoos JS.  Emergent pediatric thoracotomy following traumatic arrest.  Resuscitation.  2012; 83: 1521-1524
6. Allen CJ, Valle EJ, Thorson CM, et al.  Pediatric emergency department thoracotomy:  A large case series and systematic review.  J of Pediatric Surgery.  2015; 50: 177-181
7. Flynn-O’Brien KT, Stewart BT, Fallat ME, et al.  Mortality after emergency department thoracotomy for pediatric blunt trauma:  Analysis of the National Trauma Data Bank 2007-2012.  J of Pediatric Surgery.  2016; 51: 163-167
8. Moore HB, Moore EE, Bensard DD.  Pediatric Emergency Department Thoracotomy:  A 40-Year Review.  J of Pediatric Surgery.  2016;  51:  315-318
9. Vasallo, J., Nutbeam, T., Rickard, AC. et al.  Paediatric traumatic cardiac arrest: the development of an algorithm to guide recognition, management and decisions to terminate resuscitation. Emer Med J.  2018; 35:669-674 
10. Strutt J, Kharbanda A.  Pediatric Chest Tubes And Pigtails:  An Evidence-Based Approach To The Management Of Pleural Space Diseases.  Pediatric Emergency Medicine Practice.  2015; 12: 1-24