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Mechanisms of injury
- blunt injuries
- crush injuries
- penetrating injuries
- inhalation burns
- aspiration of foreign bodies
2 major forces within chest which lead to injury: compression and
distraction. Compression results in destruction of vascular components,
haemorrhage, oedema and impairment of function. Distraction injuries usually
result in shearing forces which destroy integrity of intrathoracic viscera
Blunt trauma
- mode of injury important
- where there has been massive deformity of a car or a history of a fall of 5
metres or more major intrathoracic injuries should always be suspected. The
physical nature of chest wall allows for considerable elastic recoil, especially
in young patients and therefore degree of injury within chest may need to be
judged initially by deformity to car rather than appearance of patient
- blunt injuries occur in 3 major directions: AP, lateral and transdiaphragmatic
- AP deformity results in relative backward motion of heart. This may result in
disruption of aorta at level of ligamentum arteriosum just below left subclavian.
As heart swings back and up it may cause so-called wishbone # of a proximal
bronchus
- injuries to heart occur in up to 1/2 of patients after deceleration injuries
- deceleration with impact to back causes relatively few intrathoracic injuries
- lateral compression of chest during deceleration causes fractures typically of
lower ribs with risk of injury to liver, spleen and kidneys
- when lateral compression results in flail segments damage to thoracic cavity
is usually relatively small and most frequently limited to contusion and
laceration of lung parenchyma
- lap belt of seat belts leads to rise in intrabdominal pressure in massive
deceleration and this, combined with shearing and twisting of upper trunk may
result in diaphragmatic rupture
Penetrating injuries
- result in parenchymal damage related to track of missile or stabbing
implement and velocity
- more solid structures (eg heart and major vessels) suffer greater injury where
high-velocity missiles are penetrating weapon
- most lethal complication is haemorrhage
- often associated with abdominal trauma
Crush injury
- occurs where elastic limits of chest and its contents have been exceeded
- patients usually have AP deformity
- majority have flail chests with multiple fractures, pneumothorax or
haemothorax
- most have pulmonary contusion
- injuries of heart, aorta, diaphragm, liver , kidney and spleen are common
- another group of patients with crush injuries are those with "traumatic
asphyxia" syndrome, where constrictive forces are applied over a wide area
for as little as 2-5 mins. Profound venous hypertension associated with relative
stasis is mechanism of injury. There is widespread capillary dilatation and
rupture, subconjunctival haemorrhage and retinal haemorrhage. Simultaneous
injuries (eg intracranial haemorrhage) must be suspected
- severe crush injuries have a high mortality
Chest trauma haemodynamics
- hypovolaemia most important mechanism
- cardiac tamponade
- myocardial contusion
- valve injury
- intracardiac shunt
Chest trauma hypoxia
Due to:
- reduced blood volume
- ventilatory failure
- contusion
- displacement of mediastinum
- pneumothorax
Clinical features:
Initial history and examination are often abbreviated
Examination
- air hunger; use of accessory muscles; tracheal deviation; cyanosis or
distended neck veins; (evidence of tension pneumothorax, or tamponade);
- tracheal deviation (evidence of tension pneumothorax)
- major defects in the chest (sucking chest wounds);
- unilaterally diminished breath sounds or hyperresonance to percussion
(evidence of closed pneumothorax or tension pneumothorax);
- decreased heart sounds (pericardial tamponade);
- location of foreign bodies;
- location of entry and exit wounds.
Investigations
CXR
- CXR most useful screening investigation
- Look for subcutaneous air, foreign bodies, bony fractures, widening of
mediastinum, pneumothorax, pneumomediastinum, pleural fluid, pulmonary
parenchymal abnormalities(infiltrates, atelectasis etc)
- Check ETT, and other hardware.
- Inspiratory/expiratory films for checking for pneumothorax.
- supine AP film Þ some conditions have different
radiological features. Look in particular for the following:
- pneumothorax: (NB up to 30% of pneumothoraces missed on supine CXR) air collects in anterior-inferior pleural space producing:
- "deep" costophrenic sulcus (image)
- "double-diaphragm" contour +/- depression of hemidiaphragm
- hyperlucency in lower thorax and upper abdomen
- sharp demarcation of cardiac apex
- visceral pleura at base of lung may be outlined
- pneumomediastinum:
- parietal pleura visible along left mediastinal border. NB pleura descends
below mid-hemidiaphragm
- sharply defined edge to descending aorta which can often be followed into
upper abdomen
- "continuous diaphragm" sign under cardiac shadow
- subcutaneous, retroperitoneal or intraperitoneal emphysema
- pneumopericardium
- air around heart that does not rise above level of pericardial reflection
at root of great vessels
- air shifts with position of patient (unlike pneumomediastinum)
- pleural effusion:
- uniform increase in density over hemithorax
- pleural cap
- pulmonary contusion:
- homogenous infiltrates that tend to be peripheral and non-segmental
- may be associated with adjacent rib fractures
- air bronchograms are rare due to blood in small airways
- ruptured hemidiaphragm:- more commonly left sided
- non-specific signs include: apparent elevation of hemidiaphragm,
obliteration or distortion of contour of hemidiaphragm, contralateral
displacement of mediastinum, pleural effusion
- presence of gas containing viscera in thorax, particularly with a focal
constriction across gas-containing bowel is pathognomonic
- haemopneumothorax may be misdiagnosed when dilated stomach gives
horizontal air-fluid interface on erect CXR
- in absence of right rib #s a small right haemothorax with a "high R
diaphragm" suggestive of ruptured diaphragm
- findings may be absent in 25-50% initially
- chest wall injuries:
- may give clues to associated injuries
- fractures of first 3 ribs in particular indicates significant trauma
- thoracic outlet fractures associated with brachial plexus or vascular
injuries
- subclavian vascular injury should be suspected in patients with fractures
of first 3 ribs, clavicle and scapula, particularly when associated with
significant fracture displacement, extrapleural haematoma, brachial plexus
neuropathy or radiological evidence of mediastinal haemorrhage (image)
- fractures of sternum are rare and require both lateral and oblique views
of thorax for diagnosis. The presence of a fractured sternum and an abnormal
mediastinal contour should prompt a search for injury to great vessels
- haemopericardium:
- NB rapid accumulation of blood in pericardial space often causes cardiac
tamponade wthout altering appearance of cardiac silhouette
CT Scan
- Valuable tool
- Aids in diagnosis and precise location of numerous lesions.
- Contrast is useful particularly when looking for mediastinal haemorrhage
and periaortic haematomas.
Echocardiography
Cardiac wall motion abnormalities and valve function and presence of
pericardial fluid or blood.
ECG
Most common abnormality in thoracic trauma are S-T and T wave changes and
findings indicative of bundle branch block
Angiography
Remains the gold standard for defining thoracic vascular injuries
Bronchoscopy
Indications include evaluation of airway injury, haemoptysis, segmental or
lobar collapse, and removal of aspirated foreign bodies.
Management
Immediate management
- assure patent airway, oxygenation and ventilation
- exclude or treat:
- pneumothorax
- haemothorax
- cardiac tamponade
- assess for extrathoracic injuries
- decompress stomach
- provide pain relief
- reconsider endotracheal intubation, ventilation. In particular take into
account gross obesity, significant pre-existing lung disease, severe pulmonary
contusion or aspiration, need for surgery for thoracic or extrathoracic injuries
General management
Treatment of specific injuries
Monitoring
Should include follow-up CXRs. Common for patients with pulmonary contusion
to deteriorate in first 24-48 hrs following injury. Not necessarily due to
progression of contusion but is more often due to development of pneumothorax,
haemothorax, atelectasis or pulmonary oedema. For this reason serial CXRs are
necessary in first 24 hrs
Following are danger signs requiring full reassessment:
- resp rate > 20/min
- heart rate > 100/min
- systolic BP < 100 mmHg
- reduced breath sounds on affected side
- Pao2 < 9 kPa on room air
- Paco2 > 8 kPa
- increased size of pneumothorax, haemothorax or increased width of
mediastinum on CXR
Deterioration in any of these signs must be followed by a search for evidence
of blood loss, tension pneumothorax, head injury, sepsis or fat embolism. Chest
drains should be checked for patency
Chest drains
Indications for insertion of chest drains in stable patients:
- pneumothorax > 10% in non-ventilated patient (ie >1 intercostal
space)
- haemothorax > 500 ml (ie above neck of 7th rib)
- surgical emphysema
- confluent opacity of lung field in a supine CXR suggesting haemothorax
There are arguments both for and against the insertion of prophylactic chest
drains in patients with rib fractures who are to be ventilated for a GA. However
without air or fluid draining the drain is likely to become blocked at an early
stage. In a series of patients with blunt chest trauma one pneumothorax occurred
per 79 days of ventilation when prophylactic drains were used as opposed to one
per 62 days when they were not. Complication rate associated with insertion 6-9%
Theoretically, all that is required to drain pneumothorax is a small-bore
tube but this is more likely to become blocked. When blood or pus is to be
drained in an adult a 32 FG tube is recommended
Antibiotics
- use of prophylactic antibiotics controversial. Some recommend them for
patients treated conservatively in whom a chest drain is inserted
- cefuroxime and metronidazole for patients with perforated viscus (in
addition to exploration and drainage)
Clearance of secretions and prevention of atelectasis
General measures:
- pain relief (eg pleural block)
- physio
- humidification
- bronchodilators (especially smokers or those exposed to smoke, irritant
chemicals or those with tracheobronchial burns)
- consider cricothyroidotomy or "minitracheostomy" for those in
whom general measures insufficient
Bronchoscopy
Indications for flexible bronchoscopy:
- massive air leak
- failure of lung to re-expand
- lobar collapse
- diagnosis and assessment of tracheal burns
- bronchial toilet
Rigid bronchoscopy has less of a role in the trauma patient but may be used
in cases of persistent lobar collapse to aspirate a blood clot or plug of sputum
Mechanical ventilation
- most centres use PCV or PSV to reduce incidence of barotrauma
- PCV and PSV also provide some compensation for air leaks
Analgesia
Of extreme importance in determining whether deep breathing and coughing
possible. Options:
- IV opioids in frequent small doses or by continuous infusion
- Entonox inhalation during physiotherapy
- intercostal nerve block:
- multiple individual nerve blocks (rptd as necessary)
- single large volume (eg 20 ml 0.5% bupivicaine) into 1 intercostal space.
Spreads to block nerves above and below
- intrapleural bupivicaine via intercostal catheters using intermittent
injections or continuous infusions
- epidural LA/opioids
- NSAIDs: fully resuscitated patients with normal renal function
Post-operative intensive care
- following tracheobronchial, lung or diaphragmatic repair high inflation
pressures should be avoided
- tracheal suction must be minimal where there is a tracheobronchial suture
line
- avoid fluid overload
- prevent gastric distension
Specific injuries
Classification
- Require immediate intervention
- Injuries with potential for threatening survival
Tension pneumothorax
- respiratory distress, tachycardia, hypotension, tracheal deviation,
unilateral absence of breath sounds, distended neck veins. Cyanosis is a late
manifestation
- may be confused with cardiac tamponade but tension pneumothorax is more
common. Differentiation may be made by unilateral hyper-resonance
- treat by immediate decompression: insert needle into 2nd
intercostal space in MCL. Ability to easily aspirate air confirms diagnosis. In
event of failure to aspirate air, withdraw needle but remember possibility of
iatrogenic pneumothorax now exists
Open pneumothorax
- "sucking chest wound"
- if opening in chest wall is approximately 2/3 the diameter of trachea air
passes preferentially through chest defect
- promptly close defect with sterile occlusive dressing, large enough to overlap
the wound’s edges and taped securely on 3 sides to provide a flutter-type
valve effect. As patient breathes in the dressing is sucked over wound while the
open end of the wound allows air to escape during expiration
- place a chest drain in an area remote from the open wound
Disruption of major airway
- clinical features vary with level of rupture but usual picture is one of
respiratory distress, subcutaneous emphysema, haemoptysis
- pneumothorax invariable with ruptured bronchus. Suspect bronchial rupture if
pneumothorax associated with a persistent large air leak after placement of
chest drain. Rupture usually occurs within 2.5 cm of carina
- mediastinal emphysema common
- treatment of tracheal injuries: immediate intubation with cuff positioned
distal to tear. Drain pneumothorax.
Cardiac tamponade
- most commonly results from penetrating injuries but may follow blunt trauma
- relatively small amounts of blood (approx. 100 ml) required to restrict
cardiac activity and interfere with cardiac filling. Removal of small amounts of
blood or fluid (often as little as 15-20 ml) by pericardiocentesis may have
enormous beneficial effects
- diagnosis is often difficult:
- volume of heart sounds difficult to assess in
noisy environment
- distended neck veins may be absent because of hypovolaemia
- pulsus paradoxus may be absent and tension pneumothorax may mimic tamponade
- consider possibility in patients who do not respond to usual
resuscitation and have a mechanism of injury compatible with tamponade
- pericardiocentesis
- blind pericardiocentesis
- only if ultrasound/echo not available
- use sub-xiphoid route and preferably a plastic sheathed needle for
pericardiocentesis. ECG monitoring is necessary to detect needle induced
arrhythmias
- pericardial aspiration may not be diagnostic or therapeutic if blood has
clotted, which may be the case after rapid bleeding. Open pericardiotomy may be
life-saving but is indicated only when an experienced surgeon is available
- even if pericardial tamponade is strongly suspected volume resuscitation
should continue while preparations are made for pericardiocentesis
- aspiration of blood alone may temporarily relieve symptoms because of the self
sealing qualities of the myocardium but all patients with positive
pericardiocentesis following trauma require open thoracotomy and inspection of
the heart
Massive haemothorax
- incidence of haemothorax and haemopneumothorax ~50-60% in penetrating
trauma and 60-70% in blunt trauma. Majority are not massive
- massive haemothorax defined as >1500 ml of blood in chest cavity
- clinical signs:
- unilateral dullness to percussion
- shock
- unilateral absence of breath sounds
- deviation of trachea
- neck veins may be flat due to severe hypovolaemia or distended because of the
mechanical effects of intrathoracic blood
- blood loss complicated by hypoxia
Management
- manage initially by simultaneous restoration of volume deficits and
decompression of chest cavity. If auto-transfusion device is available it should
be used
- emergency thoracotomy for massive haemothorax or haemothorax with ongoing loss
of >200 ml of blood per hour for 3-4 h
Systemic air embolism
- more common in penetrating injuries
- immediately life-threatening
- usually due to broncho-pulmonary vein fistula
- suspect if:
- focal neurological signs exist in the absence of head injury
- circulatory collapse occurs on initiation of IPPV in absence of tension
pneumothorax
- froth is obtained in arterial blood gas sample from a collapsed patient
Management
If suspected:
- 100% O2
- minimise ventilation volumes and pressures
- emergency thoracotomy to clamp ascending aorta, remove air source (by clamping
pulmonary hilum) and aspirate air from LV and ascending aorta
Flail segment
- major physiological insult is contusion of underlying lung and decreased
vital capacity
- occurs when 3 or more consecutive ribs or costal cartilages are fractured
bifocally.
- these circumscribed segments, having lost continuity with the rigid thorax,
move inwards with inspiration and push outward with exhalation, thus moving
paradoxically.
- presenting symptoms of pain, tachypnoea, dyspnoea, and thoracic splinting,
along with chest wall contusions, tenderness, crepitance, and palpable rib
fractures are suggestive, but paradoxical chest wall motion is the diagnostic sine
qua non.
- may be difficult to diagnose if patient is already mechanically ventilated,
in pain, obese, or has large breasts or subcutaneous emphysema.
- CXR is helpful in identifying multiple fractured ribs, but will not reveal
cartilaginous disruptions. Major value of the CXR is in detecting associated
injures (more than 90% will have associated injuries-and 3 out of 4 require tube
thoracostomy for haemopneumothorax; extrathoracic injuries are common: head
injury in ~40%; major fractures in 40%, and intraabdominal injuries in 30%.
Distribution of flail
Anterior: typically secondary to blows to the sternum, eg motor
vehicle accident, CPR
Lateral: due to T-bone impacts or AP crush mechanisms
Posterior: result from direct blow to the back and are characterized
by simultaneous fractures along the midaxillary line and the rib neck.
Splinting, plus a supine position effectively limit paradoxical motion.
Management
- ~50% of cases can be managed without ventilation
- others require ventilation for 1-3 weeks
- chest wall usually stabilises in 1-2 weeks
- operative fixation is suggested by some authors. Main benefit is to prevent
deformity.
- weaning should not wait till paradoxical movement improves, rather should
be initiated when gas exchange is adequate.
- in absence of systemic hypotension control administration of IV fluids to
prevent overhydration
Lung contusion
- essentially a bruise of the lung. Aetiology controversial: probably a
combination of shear stress (tearing tissue) and bursting forces (popping the
balloons)
- direct injury causes pulmonary vascular damage with secondary alveolar
haemorrhage
- initially not much shunt as these alveoli are poorly perfused
- subsequently tissue inflammation develops. Resultant surrounding pulmonary
oedema produces regional alterations in compliance and airways resistance,
leading to localised V/Q mismatch
- atelectasis
- diagnosis is radiological.
- classically see nonsegmental pulmonary infiltrates-progress in first 12-24
hours of injury. Note that CXR undestimates degree of contusion. CT more
sensitive and better method of assessing severity
- may be irregular nodular densities that are discrete or confluent
- homogeneous consolidation
- diffuse patchy pattern
- early CXR changes suggest more severe contusion. Early pulmonary contusion
infiltrates are due to alveolar haemorrhage
- radiological differential diagnosis includes:
- Aspiration
- Re-expansion of collapsed RUL following right endobronchial intubation
- in most cases infiltrates associated with pulmonary contusion are not
visible till after fluid resuscitation.
- contusions tend to worsen over 24-48 hours and then slowly resolve unless
complicated by infection, ARDS or cavitation
Management
- supplemental oxygen
- only about 25% of patients require invasive ventilation
- good analgesia
- physiotherapy
Other pulmonary parenchymal injuries
Pulmonary Laceration
- Commonly associated with haemopneumothorax and haemoptysis
- Usually managed with simple tube drainage
Pulmonary Haematoma
Uncomplicated cases usually resolve in 3-4 weeks
Posttraumatic Pulmonary Cavitary Lesions
- Posttraumatic cysts, pseudocysts, or pneumatoceles are cavitary lesions
within the lung parenchyma filled with fluid, blood, of air.
- CT is useful in diagnosis
- Most resolve spontaneously
- Some can become infected requiring antibiotics, CT guided aspiration, and
in some cases surgical resection
AV fistulas
- diagnosis by pulmonary angiography
Torsion of the lung
XR signs:
- Opacification of affected hemithorax
- Mediastinal shift toward the contralateral side
- Reversal of bronchoalveolar markings of the affected side, with the major
pulmonary vessels coursing cephalad instead of caudad.
ARDS
Myocardial contusion
Definition and epidemiology
- direct traumatic myocardial damage without traumatic involvement of
coronary arteries
- common in blunt trauma but difficult to diagnose
- tends to occur in acceleration/deceleration and crush/compression injuries
Clinical features
- consider possibility in any patient with a mechanism of injury that
suggests likelihood of cardiac contusion
- patients who are conscious may complain of dyspnoea or chest pain
- may lead to significant physiological dysfunction and even death but massive
contusion leading to cardiogenic shock is rare. In patients with chest trauma
cardiogenic shock is usually due to cardiac tamponade or ventricular akinesia
- with compression in diastole valvular dysfunction may occur; usually aortic
valve in older patients and mitral in younger
- pericardial rub, S3 gallop, cardiac failure
- serious damage to virtually every cardiac structure has been reported
- most common presentation is with asymptomatic ECG abnormalities although
severe contusion will produce cardiac failure.
- LAD damage may occur with
resulting anteroapical infarction
Investigations
- enzyme elevations, specifically CKMB correlate poorly with contusion
- ECG changes: range from non-specific T wave changes to pathological Qs.
Multiple VPBs, unexplained sinus tachycardia, AF, BBB (usually R) and ST segment
changes are most common ECG findings. Normal ECG at admission makes cardiac
contusion unlikely.
- TOE: +/- cardiac wall motion abnormalities. Exclude lesions that will
benefit from revascularization or other cardiac surgery
- sternal # associated with low incidence of cardiac contusion & arrhythmias
Management
- all patients with myocardial contusion should be admitted to ICU for
observation and cardiac monitoring (This view is being challenged). Admit
patients with arrhythmias or heart failure to level 3 ICU
- non-urgent surgery should be postponed where possible because of life
threatening operative complications. Consider invasive haemodynamic monitoring
for patients who have to undergo urgent surgery
- treat arrhythmias if life-threatening or associated with cardiac failure;
treat specific valve abnormalities surgically.
- treat cardiogenic shock along usual lines with optimization of preload,
inotropes ± IABP. Exclude tamponade.
Prognosis
- resolution of wall motion abnormalities in ~25% only (NB based on only 14
patients)
Ruptured aorta
- traumatic aortic injuries are the second most frequent causes of death in
patients with chest injuries
Mechanism and types of injury
Deceleration and traction-are the classic wounding mechanisms of the thoracic
arteries
- Horizontal deceleration creates shearing forces at the aortic isthmus, the
junction between the relatively mobile aortic arch and the fixed descending
aorta. 90-98% of traumatic injuries of the thoracic aorta occur at the
isthmus
- Vertical deceleration displaces the heart caudally and into the left
pleural cavity and acutely strains the ascending aorta or the innominate
artery.
- Sudden extension of the neck or traction on the shoulder can overstrech
the arch vessels and produce tears of the intima, or complete rupture of the
arterial wall® dissection, thrombosis,
pseudoaneurysm or haemorrhage.
Diagnosis
- circumstances may be only clue: head-on collision at high speed, ejection
from a vehicle, fall from great height
- one characteristic shared by all survivors is that blood that leaks from
aorta is in a contained haematoma. Other than initial pressure drop associated
with loss of 500-1000 ml of blood, hypotension responds to intravascular
infusion. Persistent or recurrent hypotension is usually due to another source
of bleeding. Free rupture does occur but it is usually fatal unless patient is
operated on within minutes
- CXR essential - always suspect ruptured aorta if mediastinum wide especially
if associated with any of following:
- L haemothorax
- depressed L main bronchus
- blurred outline of arch or descending aorta
- (?) # 1st rib or L apical haematoma
- displacement of mid-oesophagus to R
- other suspicious CXR features: loss of aorticopulmonary window, ant or lat
deviation of trachea, loss of paraspinal "stripe", calcium
"layering" in aortic arch
- signs such as apical pleural cap, mediastinal width > 8 cm, 1st &
2nd rib #s no value in indicating major arterial injury
- further investigations depend on CXR findings:
- further investigation not indicated if CXR normal
- if CXR technically unsatisfactory or mediastinal contour equivocally
abnormal then perform thoracic CT first to look for mediastinal
haemorrhage. This often also demonstrates aortic pseudoaneurysm if
present. If mediastinal haemorrhage is present and aortic pseudoaneurysm
is not demonstrated then proceed to aortogram
- if mediastinal contour on CXR clearly abnormal proceed directly to
aortography
- aortography is gold standard investigation although TOE may supercede it.
TOE may miss lesions of distal ascending aorta or of arch vessels
- typical aortographic finding in patients with an aortic tear is an irregular
outpouching of aorta just distal to left subclavian artery. Outpouching may be
circumferential with appearance of a "sleeve" around aorta or may be
localized, with abnormal area present only along medial or lateral aspect of
aorta
NB there is frequently a convexity or a bulge in region of embryonic ductus
arteriosus. This is usually smooth and symmetrical
Treatment
- prompt surgery. Often requires cardiopulmonary bypass
Injuries to aortic arch vessels
- Bleeding from an arch vessel is usually contained, but in rare instances,
the avulsion of the origin of an arch artery causes massive bleeding into
pericardial or pleural cavity.
- Acute occlusion of the innominate or subclavian may cause ischaemic symptoms
of hand or arm (acute ischaemia of the common carotid may lead to brain
ischaemia)
- Clinical features include cervical or supraclavicular haematomas, bruits,
diminished peripheral pulses
Oesophageal perforation
- usually due to penetrating injury but occasionally follows blunt trauma
- +/- retrosternal pain, difficulty in swallowing, haematemesis, cervical
emphysema
- CXR: +/- pneumomediastinum, widened mediastinum, pneumothorax, hydrothorax
- consider diagnosis in any patient:
- with L pneumothorax or haemothorax without a rib #
- who has received severe blow to lower sternum or epigastrium and is in
pain or shock out of proportion to the apparent injury
- who has particulate matter appearing in the chest tube drainage after the
blood begins to clear
- definitive investigation: gastrograffin swallow or endoscopy
- immediate surgical repair with gastrostomy or feeding jejunostomy
Ruptured diaphragm
- usually due to gross abdominal compression causing large radial tears.
Penetrating trauma tends to produce small perforations that take some time to
develop into diaphragmatic hernias
- rupture of L hemidiaphragm more common
- ± deterioration in respiratory status if MAST
trousers are inflated
- CXR features listed above
- if rupture of L hemidiaphragm is suspected a NG tube should be inserted. If
this appears in thoracic cavity no further investigations are required.
Occasionally it is necessary to inject contrast down NG tube to confirm
diagnosis
- if CT non-diagnostic consider MRI in stable patients
- significant risk of gut strangulation with L rupture
- 75% of patient with ruptured diaphragm have associated intra-abdominal injury
- surgery should follow basic resuscitation
Rib fractures
- Most common injury
- Extent of trauma and mortality correlates directly with the number of ribs
fractured
- First three ribs fractured means a large amount of force caused the injury
?recent study challenges this concept
- Ribs 10, 11, and 12 are associated with blunt injuries involving the
spleen, liver, kidneys and diaphragm.
- Fractures or three or more ribs are commonly associated with pulmonary
contusions
Simple haemopneumothorax
- usually diagnosed by a combination of physical examination and CXR
- generally insert a chest tube if it follows trauma regardless of size
- allows decompression of the pleural space, monitoring of drainage, and
safer in view of possibility of mechanical ventilation.
Traumatic Asphyxia
- Prolonged compression of the thorax results in increased SVC pressure and
obstruction of flow through the valveless veins of the innominate and jugular
system
- Clinical findings are craniocervical cyanosis and oedema, subconjunctival
haemorrhage or petechiae, and distension of the cervical neck veins.
- Commonly associated injuries include pulmonary contusion and haemothorax
- Treatment is directed at the associated injuries
Sternal, clavicular and scapular injuries
Sternal fractures
Think of ie myocardial contusion or rupture of the great vessels
Clavicular fractures and dislocations
- Fractured clavicle can injure subclavian vein or brachial plexus
- Rarer posterior displacement of the medial clavicle can cause serious
injury to the trachea or innominate vessels.
Scapular Fractures
- Isolated fractures are rare
- More than 50% are associated with rib fractures and pulmonary contusion
- 10-20% are associated with pneumothorax
- >10% are associated with brachial plexus or major arterial injuries
Clotted haemothorax
- result of blood clotting in pleural cavity
- liquidizes after few days and may be evacuated if drain suitably positioned
- large clot encased in fibrin will not drain and lung fails to re-expand
- if clot small it can be well tolerated but a larger haemothorax will leave
patient chronically unwell, SOB and easily fatigued. Ribs on that side will be
cramped together, muscles will atrophy and a scoliosis may develop. Treatment is
thoracotomy, evacuation of clot and decortication of lung allowing re-expansion.
This is a major procedure and depending on timing may be exceedingly dangerous
Empyema
- infection frequently introduced at time of penetrating trauma, by insertion
or manipulation of a chest drain or misplaced CVP line or by leakage of
gastrointestinal contents into pleura
- prophylactic broad-spectrum antibiotics should be given before insertion of
chest drain
Phrenic nerve palsy
- injury often only noticed as a difficulty in weaning off assisted
ventilation. In these circumstances thoracotomy and pliation of diaphragm may
provide a better platform against which opposite hemidiaphragm, intercostal
muscles and accessory muscles can act
Pericardial complications
- post-pericardiotomy syndrome
- infective pericarditis
- pericardial effusion (non-traumatic, non-infective and unrelated to post-pericardiotomy
syndrome)
- delayed haemopericardium; may be due to inflammatory or infected processes,
but may be due to secondary haemorrhage from an unsuspected cardiac wound.
Latter may nto be an acute event because inflammed pericardium from previous
insult is adherent to wound
Fistulae
- tend to occur where there has been injury to adjacent blood vessels or
viscera
- viscerovascular fistulae are often fatal although there may be warning bleeds
- treatment of large arteriovenous fistulae should be considered because of risk
of heart failure, cerebral abscess or paradoxical systemic emboli
Diaphragmatic hernia
- may track in any plane of chest wall. Beware of any pointing subcutaneous
"abscess" following an injury which could have caused an abdominal
wall or diaphragmatic breach
Chylothorax
- often diagnosed as a prolonged leak via a chest drain of clear, turbid or
milky fluid
- many cases respond to conservative treatment of low-fat diet combined with TPN
and chest drainage
- surgical treatment is ligation of lymphatic at thoracotomy
Prognosis
- mortality rates vary widely reflecting varied severity of chest and other
injuries
- one series of patients with chest and other injuries: overall mortality 5.3%.
Commonest causes of death: respiratory sepsis, severe head injury,
exsanguination. Mortality 37.5% for patients >60yrs with resp failure and
22.8% for patients requiring mechanical ventilation (22.8%)
- in another series: 16% mortality in patients with isolated pulmonary
contusion. When associated with flail chest: 42%
Indications for urgent surgery
Major thoracic surgical intervention can be broadly divided into 3
categories:
- emergency thoracotomy (to resuscitate patient)
- urgent thoracotomy (performed once patient has been stabilized by
resuscitation)
- thoracotomy for complications
Emergency thoracotomy
- indications:patients who have sustained truncal trauma and remains
unstable or moribund despite adequate resuscitation by way of infusion, chest
drainage and ventilation
- lack of pupillary response is not a contraindication to operation, though is
is an indication for thoracotomy in casaulty rather than transfer to theatre
- patients who have shown no respiratory effort and no cardiac output since
pick-up will not survive
- criteria for discontinuation of resuscitation:
- irretrievable anatomic injury (eg ruptured heart)
- failure of volume resuscitation within 15 mins of starting
- failure to sustain spontaneous cardiac rhythm and maintain mean systemic
blood pressure > 50 mmHg, with or without inotropic support,
within 30 mins
- in general those who survive with reasonable cerebral function are young,
previously fit and have only a short period of circulatory arrest
- patients with blunt trauma have a poor outcome and it may be deemed unwise
even to consider further measures if standard resuscitation fails
- overall only 5% of those undergoing emergency thoracotomy survive and many of
these have prolonged convalescence and cerebral damage
Urgent surgery
- purpose is to repair structures that will not heal optimally without
surgery and to prevent late complications
- indications for early (or emergency) surgery:
Absolute indications:
- cardiac arrest due to tamponade or exsanguination
- significant and continued haemorrhage: immediate blood loss from chest drain
> 1500 ml of total blood volume - immediate surgery. Loss > 500
ml in first hr. or 200 ml/hr thereafter is also an indication for thoracotomy.
Decision to operate should be made early before occurrence of a dilutional
coagulopathy
- dangerous predicted track/mediastinal traversing
- massive air leak
- certain specific injuries
Relative indications:
- thoracoabdominal injury
- bullet embolism
- high-velocity gunshot wound
- missile retrieval. In general missiles should only be removed if they pose a
risk of embolization from heart or pulmonary artery, erosion of adjacent
structures due to repetitive cardiorespiratory movements or infection due to
non-metallic pieces
- certain specific injuries
Relative contraindications:
- cardiac contusion
- pulmonary parenchymal contusion
- pneumomediastinum (without other injury). Exclude tracheobronchial tear,
pneumothorax, oesophageal perforation or gas forming organisms within
pericardium
© Charles Gomersall and Ross Calcroft September 1999, Charles Gomersall June
2003 |
