CHEST TRAUMA
MI Zucker, MD
A dr Z Lecture
• On Major Chest Trauma
• In Three Parts
Chest trauma
• Blunt
• Penetrating
• Explosion Related
Chemical Agent Related
Biological Agent Related
Oh, yeah:
There’s a separate lecture on Traumatic Aortic Injury
But first:
A few comments on Trauma Imaging
Trauma Chest Radiograph
• Usually AP, often supine, frequently in poor inspiration.
• So, a challenge to interpret.
CT ChestMore sensitive and specific
CT Chest: Reformat
• The new MDCT scanners do awesome reformats without additional scanning.
Part the First:
BLUNT TRAUMA
Fractures and Dislocations
• Spine
• Ribs
• Clavicles
• Sternum
• Shoulders
Spine Injuries
• Look for loss of alignment, fractures and paraspinal hematoma.
• The findings may be very subtle.
Rib Fractures
• In themselves, not too much of a problem, but may be an indicator of underlying pleura, lung, liver, spleen, kidney injuries.
Flail Chest
• Multiple rib fractures, especially if individual ribs fractured more than once, may cause paradoxical motion.
• The major problem actually is associated pulmonary contusion.
Clavicle Injuries
• Fractures not usually much of a problem
Sterno-Clavicular Dislocations
• Anterior: Not much of a problem
• Posterior: Less common; can injure great vessels or trachea
Sterno-clavicle joint dislocation
Sterno-clavicle dislocation: CT
Shoulder Injuries
• Look particularly for dislocations and scapula fractures
CT Needed if Scapula Fracture Seen
Sternum Fractures
• Not usually a problem.
• Controversial association with myocardial injury.
AIR where it shouldn’t be
• Pneumothorax
• Pneumomediastinum
• Subcutaneous emphysema
• Systemic venous air embolism
• Pneumopericardium
• Pneumoperitoneum/retroperitoneum
PNEUMOTHORAX
• Simple• Tension• Open
PNEUMOTHORAX: CT
• Much more sensitive than plain films.
• Even a small traumatic pneumothorax is important, especially if patient mechanically ventilated or going to OR: A simple pneumothorax can be converted into a
life- threatening tension pneumothorax.
PNEUMOTHORAX: CT
Pneumothorax: Simple
• Erect AP/PA view best
• Visceral pleural line
• No vessels or markings
• Variable degree of lung collapse
• No shift
PNEUMOTHORAX: Simple
PNEUMOTHORAX: Tension
• Erect AP/PA view best
• Shift of mediastinum/heart/trachea away from PTX side
• Depressed hemidiaphragm
• Degree of lung collapse is variable
PNEUMOTHORAX: Tension
PNEUMOTHORAX: Tension
PNEUMOTHORAX: Supine
• Supine AP view has limited sensitivity: 50%• Deep sulcus sign• Too sharp heart border/hemidiaphragm sign• Increased lucency over lower chest• Subpulmonic air sign• Can see vessels
PNEUMOTHORAX on Supine View: Visceral pleural line
PNEUMOTHORAX on Supine View: Deep sulcus sign
PNEUMOTHORAX on Supine View: Why vessels are visible
PNEUMOTHORAX on Supine View: Subpulmonic sign
CT: subpulmonic sign explained
PNEUMOTHORAX: Open
• A large hole in the chest caused by a large low velocity missile.
• Air enters the hole rather than the trachea causing hypoxia.
PNEUMOMEDIASTIUM
• Usually from ruptured alveoli.
• Can also be from trachea, bronchi, esophagus, bowel and neck injuries.
PNEUMOMEDIASTINUM: Signs
• Linear paratracheal lucencies
• Air along heart border• “V” sign at aortic-
diaphragm junction• Continuous diaphragm
sign
PNEUMOMEDIASTINUM:Paratracheal lucencies
PNEUMOMEDIASTINUM: Continuous diaphragm sign
PNEUMOMEDIASTINUM: CT
Trachea/bronchi injuries
• Tears occur within 2cm of carina
• Persistant pneumothorax
• Large pneumomediastinum
• “Fallen lung”
Subcutaneous Emphysema
• Causes: Same as pneumomediastinum
Pneumopericardium
• Causes: penetrating trauma
• Rare
Pneumoperitoneum
• Pneumoperitoneum and sometimes pneumo-
retroperitoneum are seen on upright chest film, but occasionally are visible on supine chest radiograph.
Pneumoperitoneum
Systemic Venous Air Embolism
• Tears in airspaces with resulting communication with veins; or outside access to systemic veins
• Often lethal: Air block in heart or coronary, cerebral, mesenteric, peripheral arteries.
Systemic Venous Air Embolism
HEMOTHORAX
• Venous or arterial bleeding
• 60% controlled by chest tube, 40% need operative management
• Can miss hundreds of cc’s on supine film
• Can be tension
HEMOTHORAX
CT: HEMOTHORAX
PULMONARY CONTUSION and LACERATION
• Contusion: Blood in intact lung parenchyma
• Laceration: Blood in torn lung parenchyma
• Can’t tell difference on chest film. Contusions peak in 2-3 days, begin to resolve in a week; lacerations take much longer to resolve and may leave scars
Pulmonary Contusion and Laceration
Subtle contusions
Marked contusions
CT: Pulmonary Contusion
CT: Pulmonary laceration
The tear in the lung can fill with blood or air.
DIAPHRAGM Injuries
• 5% of major blunt trauma, also thoraco-abdominal penetrating trauma
• Left clinically injured more than right 60/40
• Sensitivity of Chest film 40%. CT better, but still misses some
• Hard signs: NGT through g.e. junction then up into chest, and hollow viscus above diaphragm
• Soft signs: Indistinct diaphragm, effusion, atelectasis
Diaphragm Injury
Diaphragm Injury: Position of NG Tube
Diaphragm Injury: Gut in Chest
Part the Second:
PENETRATING TRAUMA
Gunshot Wounds
Stab Wounds
Gunshot Wounds
• Match all entrance and exit wounds
• Find the bullet(s) and keep looking until all are accounted for
• Estimate path of bullet, which may not be straight
• Estimate organs injured
INJURIES depend upon:
• Caliber, weight, construction of bullet
• Velocity
• Tissue impacted
Gunshot Wounds: some terms
• Rounds: the bullet and its casing, propellant and primer
• Bullet: the part of the round that is propelled from the weapon
• Firearms: pistol, rifle, shotgun• “Blast” : a property of high explosives, not
firearms. Don’t use with GSW.
Rounds: Pistol and Rifle
BULLET
• Size: diameter in millimeters or caliber (fractions of an inch)
• Weight: in grains
• Construction: round nose, hollow point, full metal jacket, semi-jacket, no jacket
Injuries: Bullet
The larger the diameter of the bullet and the more it weighs, the bigger the wound.
Hollow point and semi-jacket bullets mushroom or fragment on impact and cause bigger wounds than FMJ.
Injuries: Velocity
• Hand guns are low velocity (1000 fps) and cause a permanent wound channel (crush) only.
• High-powered and assault rifles are high velocity (3000 fps) and cause a permanent wound channel and also temporary cavitation (blunt or stretch trauma) and so a bigger wound.
Injuries: Tissue
• Lung is elastic and more resistant to injury than solid organs. Bone is least resistant.
• Obviously, the more vital the organ the more serious the injury.
Gunshot Wounds
• GSWs of the CHEST cause: pulmonary lacerations/contusions, hemothorax, pneumothorax, mediastinum/heart injuries,
pneumomediastinum, fractures.
GSW: Hemothorax, PTX
GSW: Tension Hemopneumothorax
GSW: Lacerations, abnormal Mediastinum, PTX
GSW: Transmediastinum
• Bilateral chest tubes• Angiography• Pericardial window• Triple endoscopy• Esophagram• Thoracic spine films
Gunshot Wounds: CT
• Experimental• May be able to
establish bullet tract and avoid surgery, especially thoraco-abdominal wounds
Knife wounds
• All low energy, small diameter wounds. Frequently, superficial stab or slash.
• Look for lung laceration, pneumothorax, hemothorax, pneumomediastinum, abnormal contour of mediastinum or heart.
• Path of wound is straight.
Knife Wound: PTX
Part the Third:
Explosions
Chemical events
Biological events
Since, so far, Los Angeles has experienced few of these events,
most of the images are simulations
Radiological Events
• We aren’t going to discuss these today.• An isotope combined with an explosive
makes a Radiological Dispersion Device.• In an RDD event, all of the immediate
casualties would be from the explosion.• Radiation injuries would be delayed to
negligible, depending upon the type and amount of the isotope.
EXPLOSION Related Chest Injuries
Accidental/Terrorist Event
Conventional explosive device
Improvised explosive device
EXPLOSIVES
• High Explosives:
TNT, dynamite, C-4, ANFO, RDX, PETN
• Low Explosives:
Gun powder, smokeless propellant, fireworks
Explosions
• Blast wave: sudden increase in atmospheric pressure. High explosives only.
• Blast wind: sudden expansion of hot gases. High and low explosives.
EXPLOSION Related Injuries
• Blast Wave: Lung laceration, contusion, edema, barotrauma
• Penetrating Trauma• Blast Wind:
Displacement• Crush, burns,
inhalation injuries
• Primary
• Secondary
• Tertiary
• Quartanary
EXPLOSION: Blast Wave causes blast lung
EXPLOSION: Blast Wave causes barotrauma/laceration
EXPLOSION: Blast wave causes abdominal injuries
• Pressure wave injures bowel wall, causing hematoma and perforation, and so pneumoperitoneum
EXPLOSION: Blast wave causes SVAE
• Lacerated lung with bronchovascular fistulae cause systemic venous air embolism
EXPLOSION: Blast Wind
• Displaces victim causing blunt trauma
EXPLOSION: Blast Wind causes structural collapse
EXPLOSION: Penetrating trauma
• Metal fragments from conventional bomb housing
• Scraps of metal, nails attached to Improvised Explosive Device
EXPLOSION: Penetrating injury
EXPLOSION: Penetrating injury
EXPLOSION: Flying glass
CHEMICAL AGENTS
Accidental/Terrorist
CHEMICAL AGENTS
• Nerve agents: Sarin, soman, tabun, XV
• Blister agents: Lewisite, mustards
• Choking agents: Chlorine, phosgene
• Blood agents: Cyanides
CHEMICAL AGENTS
• Nerve agents inactivate acetylcholinesterase
• Blister and Choking agents cause acute airway and lung injury
• Blood agents inactivate cytochrome oxidase causing cell hypoxia
NERVE AGENTS: Aspiration
CHOKING/BLISTER AGENTS: Acute Lung Injury
BIOLOGICAL AGENTS
Accidental/terrorist
BIOLOGICAL AGENTS
• Inhalational Anthrax
• Plague
• Tularemia
• Viral hemorrhagic fevers
• Ricin
To be effective, agents must be aerosolized.
INHALATIONAL ANTHRAX
• Necrotizing hemorrhagic mediastinitis
PLAGUE: Bilateral pneumonia
TULAREMIA
• Pneumonia with lymphadenopathy
VHFs
• Bleeding into lung parenchyma
RICIN
• Biological toxin from castor bean
• Inhibits protein synthesis
• Causes pulmonary edema/ARDS
People who liked this lecture also liked: “TRAUMATIC AORTIC
INJURY”Available from your local Emergency
Radiology lecturer now!
But for now, GOODBYE
• Copyright 2004
MI Zucker