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