Penetrating Trauma

See Also

Definitions

Puncture Wound
1. Sharp object pierces the skin and creates a small hole without entering a body cavity (e.g. Cat Bite)
Penetrating Wound
1. Sharp object pierces the skin, creating a single open wound, AND enters a tissue or body cavity (e.g. knife stab)
Perforating Wound
1. Object passes completely through the body, having both an entry and exit wound (e.g. Gunshot Wound)

Pathophysiology

Stab Wounds (or other hand initiated projectiles)
1. Lacerate local tissues along the weapon path
2. Stab Wounds enter skin perpendicularly and are deeper than long
  1. By contrast, Lacerations are typically from blunt forces that strike parallel or tangential to the skin
  2. Lacerations result in incomplete tearing of tissue with some residual bridging tissue remaining
Medium velocity Gunshot Wound (e.g. handguns)
1. Can create a cavity 5-6 times the bullet diameter
2. Yaw (rotation of the bullet on its long axis) results in greater cavitation and secondary injury
High-velocity Gunshot Wound (esp. >600 m/sec, hunting or military rifles, magnum rounds with increased gunpowder)
1. Transmits energy more broadly to more distant tissue via shock waves
2. Results in cavity up to 30x the diameter of the bullet (depending on bullet velocity, contact area, underlying tissue)
3. Bullets may ricochet off bony structures and fragment into multiple projectiles with individual destructive paths
4. Injuries from semijacketed or hollow-point bullets
  1. Increases the degree of injury due to flattening on impact and increasing contact surface area
Shotgun wound (360 m/sec at muzzle, but individual pellet velocity rapidly declines)
1. Shotguns can cause fatal injury at close range
2. Typically causes low energy impacts of "shot" at distance with each projectile embedding superficially in skin
3. May result in Retained Foreign Body if "shot" carries with it material from shell casing or clothing

Approach
General

Start with stabilization
1. See ABC Management (Cardiopulmonary Resuscitation)
2. See Primary Trauma Evaluation
3. See Secondary Trauma Evaluation
4. See FAST Exam
5. Avoid aggressive crystalloid (risk of Coagulopathy)
  1. Replace blood losses with Blood Products (order early)
  2. Blood Pressure need not be Restored to fully normal levels (mild permissive Hypotension is preferred)
6. Hemorrhage control
  1. External pressure to sites of bleeding
  2. Consider Tranexamic Acid (start within first hour)
Evaluate for extent of injury
1. Path and velocity of penetrating object (match bullet entry wounds to bullets)
2. Sterile cotton swab or gloved finger may be used to gently probe wound for depth (Exercise caution)
3. Injury to vessels, organs, bone, nerve, soft tissue (Muscle, tendon, fascia)
4. Consider Diaphragmatic Injury (often occult) in chest or Abdominal Trauma
Evaluate for vascular injury
1. Hard signs (emergent surgery indications)
  1. Pulsatile bleeding
  2. Expanding Hematoma
  3. Pulseless extremity
  4. Arterial Bruit or thrill
  5. Hypovolemic Shock
2. Soft signs (imaging with CT angiogram)
  1. Blood oozing from wound site
  2. Small Hematoma
  3. Perfusion discrepancy (e.g. reduced Ankle-Brachial Index)
    1. Compare limbs (e.g. ankle-ankle index or brachial-brachial index)
Evaluate for neurologic injury
1. Identify distribution of nerve injury (Motor Exam, Sensory Exam)
2. Distinguish Neuropraxia versus complete transection
3. Consult appropriate specialty (neurosurgery, orthopedics)
Evaluate for Compartment Syndrome
1. Rare in the acute setting without vascular injury
2. Most commonly affects the distal leg below the knee
3. Be alert for significant swelling and pain out out of proportion to injury (cold and immobile is a late finding)
4. Compartment Pressure >30 mmHg is concerning for Compartment Syndrome
  1. Pdelta (DBP - Pcompartment) <30 mmHg is also concerning
Retained penetrating objects (e.g. knives, impaled objects)
1. Emergent surgical evaluation
2. Leave all penetrating objects in place until surgically evaluated
  1. Risk of vascular injury or uncontrollable bleeding with removal under uncontrolled circumstances
Stab Wound Repair
1. Simple, superficial clean-edged new wounds
  1. Irrigate, debride and repair
2. Dirty, macerated or old wounds
  1. Irrigation and repair (or packing) in operating room
Gunshot Wound precautions
1. Do not close Gunshot Wounds
Shotgun wound precautions
1. Shotgun injuries should be imaged unless unstable (consult with Trauma service)
2. CT Angiography is frequently needed, but often nondiagnostic due to pellet artifact
3. Higher risk of Compartment Syndrome
Other measures
1. Tetanus Prophylaxis (e.g. DTap)

Approach
Penetrating Head Injury (intracranial)

See Penetrating Neck Trauma
Imaging
1. CT Head
2. CT Angiogram indications
  1. Bullet trajectory approaches vessels near skull base or dural venous sinus
  2. Wound involving face or orbit
  3. Wound involves temporal region (middle meningeal artery region)
  4. Subarachnoid Hemorrhage
  5. Delayed Subdural Hematoma formation
Monitoring
1. Intracranial Pressure
Management
1. Prophylactic broad spectrum antibiotics
2. Seizure Prophylaxis (continued for at least the first week after injury)
3. Defer penetrating object removal to neurosurgery (risk of vascular injury or increased bleeding)
4. Open penetrating wounds require careful Debridement, and watertight dura closure (CSF-tight)
  1. Scalp Wounds may be temporarily closed to control Hemorrhage
  2. Definitive closure is by surgery

Approach
Trunk or Chest Penetrating Trauma

Evaluation
1. FAST Exam is highest yield (Pericardial Effusion, Pneumothorax, Hemothorax, intraabdominal bleeding)
  1. However, negative FAST Exam does not completely exclude cardiac injury
  2. Suspected cardiac Trauma, despite negative FAST Exam, should warrant Thoracostomy
2. Chest imaging (Chest XRay or CT Chest) for negative FAST Exam in a stable patient
  1. Repeat in Chest XRay in 1 hour if initially non-diagnostic (previously 3-6 hours was recommended)
  2. Berg (2013) World J Surg 37(6):1286-90 +PMID:23536101 [PubMed]
  3. Seamon (2008) J Trauma 65(3): 549-53 +PMID:18784567 [PubMed]
Immediate management
1. Decompress Hemothorax or Pneumothorax (Ultrasound is sufficient to make diagnosis)
  1. See Needle Decompression of Thorax
  2. See Chest Tube
Unstable
1. Emergent sternotomy in operating room indications (required in 10-15% of thoracic Trauma)
  1. Traumatic Pericardial Effusion
  2. Pericardial Tamponade (Tachycardia, pulsus parodoxus, Kussmaul sign, Beck triad)
  3. Chest Tube output >1000 ml initially or 250 ml/hour for 3 consecutive hours
  4. Patient deterioration
  5. Large Hemothorax by Chest XRay
    1. Especially if associated shock (end-organ damage, unresponsive to fluid Resuscitation)
  6. Large Chest Tube air leak
  7. Diaphragmatic Injury
2. Immediate Emergency Thoracotomy indications
  1. Pericardial Effusion and loss of pulses
Stable (no cardiac or large vessel injury)
1. Observe on surgical ward with repeat exam at least every 4 hours
2. Obtain serial Complete Blood Count (CBC) every 8 hours
3. Consider Diaphragmatic Injury
4. Encourage activity (eg. walking)
5. Chest Tube removal indications
  1. No air leak for >24 hours AND
  2. No Positive Pressure Ventilation AND
  3. Chest Tube drainage <200 ml serous fluid per day

Approach
Abdomen and pelvis Penetrating Trauma

Stab Wounds most commonly injure liver, Small Bowel, diaphragm and colon
1. Anterior abdominal Stab Wounds enter peritoneal cavity in 50-75% of cases
2. However, only a 50-75% subset of peritoneal penetrating wounds are hemodynamically unstable
  1. Remainder may be observed closely for other laparotomy indications
Evaluation
1. FAST Exam
  1. Positive intraabdominal blood in Penetrating Trauma is sufficient surgery indication
2. CT Abdomen and Pelvis with IV contrast
  1. Best for ruling-in surgical abdominal conditions of solid organs in the upper quadrants
  2. Test Sensitivity is not high enough for 100% ruling-out of penetrating GI Tract injury
    1. Penetrating abdominal injuries evident on CT are typically also symptomatic
    2. Contrast with gun shot wounds which are well evaluated with CT imaging
3. Diagnostic Peritoneal Lavage
  1. Used historically, but most U.S. Trauma Centers do not perform now
4. Local wound exploration
  1. Typically requires Local Anesthetic and may require sedation
  2. Evaluate for penetration of anterior fascia and observe if breached
Pregnancy
1. Gravid, muscular Uterus absorbs considerable energy from Penetrating Trauma
2. Pregnant women tend to sustain less intrabdominal bowel injury than nonpregnant patients
3. Fetal injury and death from penetrating Abdominal Trauma is common
Management
1. Unstable: Emergent laparoscopy (often preferred as start) or laparotomy indications
  1. Peritonitis
  2. Hemorrhage
  3. Hemodynamic instability
  4. Unreliable examination
  5. Evisceration
  6. Retained Foreign Body
    1. Do not remove pentrating foreign body outside the operating room
    2. Removal requires direct visualization of involved structures
    3. Removal may require fluoroscopy
2. Stable: Observation protocol for those not requiring emergent surgery
  1. Local wound exploration in emergency department (as above)
  2. Consider Diaphragmatic Injury
  3. Obtain serial Complete Blood Count (CBC) every 8 hours
  4. Observe for 24 hours
    1. May initiate dietary intake at 17 hours
    2. Patients that deteriorate typically do so within first 24 hours
  5. Serial abdominal exams (at least every 4 hours)
    1. Exams should be performed by same medical provider if possible
    2. At patient sign-out, strongly consider performing the exam together
  6. Surgery (laparotomy or laparoscopy) indications for those being observed
    1. Sinus Tachycardia
    2. Increasing Leukocytosis
    3. Increasing pain
References
1. Rezende-Neto (2014) Rev Col Bras Cir 41(1): 75-9 [PubMed]

Approach
Extremity Penetrating Trauma

Exam
1. Remove all clothing and thoroughly examine injured extremity
2. Complete extremity neurovascular exam
Diagnostics
1. Extremity XRay
2. Arterial Pressure Index (API)

Approach
Forensics

Precautions
1. Document only objective findings
  1. Do not speculate on cause or mechanism of the injury in the medical record
  2. Do not speculate on manner of death (e.g. Suicide or homicide) in the medical record
2. Document wound characteristics
  1. Take photos for the medical record if possible
  2. Describe wound location in anatomic position (arms at side with palms facing forward)
3. Preserve evidence
  1. Avoid cutting or ripping clothing immediately around the injury site
Findings consistent with self-inflicted wound
1. Suicide attempts are typically during daytime, at home, in a private location (often with psychiatric history)
2. Injury is typically over bare skin, with signs of hesitation marks (superficial wounds in the same area)
3. Most typical site for self-injury is right Abdomen, with liver, diaphragm and heart most commonly injured
  1. Neck, chest and arms are also sites for self inflicted wound
  2. Head and legs are rare sites of self-inflicted wound
Findings consistent with assault
1. Assaults are typically at night, in public places and often involve Alcohol
2. Left Abdomen and defensive wounds of the left hand and Forearm are most common (right-handed attacker)

References

(2008) ATLS, American College Surgeons, Chicago, p. 113-4, 148-9, 287-8
Cowling and Mullins (2017) Crit Dec Emerg Med 31(10): 3-10
Hicks and Orman in Herbert (2016) EM:Rap 16(4): 9-11
Spangler and Inaba in Herbert (2017) EM:Rap 17(5): 7-8
Spangler and Inaba in Herbert (2016) EM:Rap 16(7):14-5