Mechanisms of Trauma - Orthopedics

Snapshot

A 35-year-old male presents to the ED C-collared on a backboard after being hit in a motor vehicle accident. He breathes spontaneously without any frank bleeding, but bruises are noted throughout his hip and abdomen. His blood pressure is 90/60 mmHg, pulse is 110/min, respirations are 20/min, and SaO₂ is 95% on room air. After 1 L Lactated Ringer's and some pain medications are administered, the radiology technician takes images of his C-spine, chest, and pelvis. The pelvic radiograph is shown.

Introduction to Mechanisms of Trauma

Trauma is the leading cause of death in patients < 45 years old (accident, homicide, suicide)
- causes more deaths in children/adolescents than all diseases combined
Timeline of trauma mortality is important for prognosis
- minutes: death usually at scene
- early: death within 4-6 hours without intervention
- days-weeks: death from multiple organ dysfunction, sepsis, etc.
Broadly, trauma is either blunt or penetrating
- blunt is more common
Knowing mechanism is important to anticipate injuries for appropriate triage
Beyond managing trauma, underlying cause must always be sought (6 S's)

Presentation of Mechanisms

Motor vehicle collison
- head-on: head/facial, thoracic (aortic), lower extremitiy (LE) injury
  - aortic tear (aortic transection) presents with rapidly worsening blood pressure and a widened mediastinum
- lateral/T-bone: head, cervical, thoracic, abdominal, pelvic, LE injury
- rear-end: hyper-extension of cervical spine (whiplash injury)
- rollover accidents: most fatal
Pedestrian-automobile impact
- children: high risk of run-over injury (multisystem)
  - Waddell's triad: tibia-fibula or femur fracture, intrathoracic/abdominal injury, contralateral head injury
    - fibular fracture associated with fibular nerve injury
- adult: generally lower extremity injury, but also truncal and head injury from impact
Falls
- landing position important
  - vertical: LE, pelvic, spine, head injury (impact ascends through skeleton)
  - horizontal: facial, UE, rib fractures; intrathoracic and abdominal injuries
Gunshot wounds (GSW)
- injury depends on weapon used, location of GSW(s), and underlying structures
  - handgun: low/medium velocity, extent of damage may be limited to small area
  - hunting rifle: high velocity, widespread injury
  - shotgun: widespread tissue damage at close range, wadding deposition in wound
Stab wounds (SW)
- injury depends on weapon used (length in particular), location of SW(s), underlying structures
- type of penetration can vary (stab, slash, impalement)
Amputation
- transport amputated appendage wrapped in moist gauze, put in a plastic bag, placed on ice
Dental trauma
- avulsed tooth should be immediately gently cleaned (rinse, do not scrub) and replaced in the socket as soon as possible
- transport medium for avulsed tooth
  - milk or special tooth solution

Evaluation and Management

Primary and secondary surveys with resuscitation as needed
- intubation - secure the airway first
  - indications
    - failure to oxygenate
    - failure to ventilate
    - inability to protect airway (GCS < 8)
    - impending airway loss
  - complications
    - esophageal intubation
    - intubation of the right mainstem bronchus
    - inability to intubate
      - perform an emergency cricothyrotomy
    - inability to extubate
      - tracheal stenosis
        
        from chronic intubation resulting in a narrowed airway and inspiratory stridor
- type and cross for potential transfusions as soon as possible
  - establish IV access or IO access if not possible
- for penetrating injuries, do NOT remove object if present in body
  - may be tamponading vessel
  - remove in operating room
Imaging
- Doppler ultrasound
  - perform to assess vascular injury or compromise
  - the presence of distal pulses does not rule out vascular injury
- radiography (XR/CT)
  - based on mechanism of injury
  - never send unstable patient to CT scanner - obtain focused assessment with sonography in trauma (FAST) exam or diagnostic peritoneal lavage if FAST equivocal
Amputated body part
- wrap amputated body part in saline-moistened sterile gauze and sealed in sterile plastic bag

Summary

Trauma does not cause isolated injuries
- as suggested in Waddell's triad above, think about other possible injuries to anticipate necessary interventions (and possible test question answer choices!)
Principles
- chief concern: vascular compromise
  - consider nearby vasculature
  - if no nearby vasculature next best step: cleaning + tetanus ppx
  - if nearby vasculature and stable vitals next best step: doppler studies or CT angiogram
  - if clear vascular injury (absent pulses, worsening hematoma) next best step: surgical exploration
- injury to bone, artery and nerve
  - next best step: repair the bone first - this is rough work
  - second step: vascular repair
  - third step: nerve repair
  - ppx: fasciotomy to protect from compartment syndrome
- shotgun, military contraband injuries
  - tend to be high velocity and cause a large area ("cone") of tissue destruction
  - next best step: surgical debridement, amputation if severe, antibiotics, tetanus
- crushing injuries
  - worry about hyperkalemia, myoglobinemia/uria, renal failure and compartment syndrome
  - next best step: IV fluids, mannitol, alkalinization of the urine and management of severe electrolyte abnormalities as presented
The next best step is never management of the pathology if the patient's vitals are unstable or could lose an airway - never forget ABCs of resuscitation!

References

Amputated body part wrap amputated body part in saline-moistened sterile gauze and sealed in sterile plastic bag

Blood, Plasma, Serum	Reference Range
ALT	8-20 U/L
Amylase, serum	25-125 U/L
AST	8-20 U/L
Bilirubin, serum (adult) Total // Direct	0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca²⁺)	8.4-10.2 mg/dL
Cholesterol, serum	Rec: < 200 mg/dL
Cortisol, serum	0800 h: 5-23 μg/dL //1600 h: 3-15 μg/dL 2000 h: ≤ 50% of 0800 h
Creatine kinase, serum	Male: 25-90 U/L Female: 10-70 U/L
Creatinine, serum	0.6-1.2 mg/dL
Electrolytes, serum
Sodium (Na⁺)	136-145 mEq/L
Chloride (Cl^-)	95-105 mEq/L
Potassium (K⁺)	3.5-5.0 mEq/L
Bicarbonate (HCO₃^-)	22-28 mEq/L
Magnesium (Mg²⁺)	1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)
24-28 wks // 32-36 wks	30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks	40-220 ng/mL // 80-350 ng/mL
Ferritin, serum	Male: 15-200 ng/mL Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma	Male: 4-25 mIU/mL Female: premenopause: 4-30 mIU/mL midcycle peak: 10-90 mIU/mL postmenopause: 40-250
pH	7.35-7.45
PCO₂	33-45 mmHg
PO₂	75-105 mmHg
Glucose, serum	Fasting: 70-110 mg/dL 2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation	Fasting: <5 ng/mL Provocative stimuli: > 7ng/mL
Immunoglobulins, serum
IgA	76-390 mg/dL
IgE	0-380 IU/mL
IgG	650-1500 mg/dL
IgM	40-345 mg/dL
Iron	50-170 μg/dL
Lactate dehydrogenase, serum	45-90 U/L
Luteinizing hormone, serum/plasma	Male: 6-23 mIU/mL Female: follicular phase: 5-30 mIU/mL midcycle: 75-150 mIU/mL postmenopause 30-200 mIU/mL
Osmolality, serum	275-295 mOsmol/kd H₂O
Parathyroid hormone, serume, N-terminal	230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C)	20-70 U/L
Phosphorus (inorganic), serum	3.0-4.5 mg/dL
Prolactin, serum (hPRL)	< 20 ng/mL
Proteins, serum

Hematologic	Reference Range
Bleeding time	2-7 minutes
Erythrocyte count	Male: 4.3-5.9 million/mm³ Female: 3.5-5.5 million mm³
Erythrocyte sedimentation rate (Westergren)	Male: 0-15 mm/h Female: 0-20 mm/h
Hematocrit	Male: 41%-53% Female: 36%-46%
Hemoglobin A1c	≤ 6 %
Hemoglobin, blood	Male: 13.5-17.5 g/dL Female: 12.0-16.0 g/dL
Hemoglobin, plasma	1-4 mg/dL
Leukocyte count and differential
Leukocyte count	4,500-11,000/mm³
Segmented neutrophils	54%-62%
Bands	3%-5%
Eosinophils	1%-3%
Basophils	0%-0.75%
Lymphocytes	25%-33%
Monocytes	3%-7%
Mean corpuscular hemoglobin	25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration	31%-36% Hb/cell
Mean corpuscular volume	80-100 μm³
Partial thromboplastin time (activated)	25-40 seconds
Platelet count	150,000-400,000/mm³
Prothrombin time	11-15 seconds
Reticulocyte count	0.5%-1.5% of red cells
Thrombin time	< 2 seconds deviation from control
Volume
Plasma	Male: 25-43 mL/kg Female: 28-45 mL/kg
Red cell	Male: 20-36 mL/kg Female: 19-31 mL/kg

Cerebrospinal Fluid	Reference Range
Cell count	0-5/mm³
Chloride	118-132 mEq/L
Gamma globulin	3%-12% total proteins
Glucose	40-70 mg/dL
Pressure	70-180 mm H₂O
Proteins, total	< 40 mg/dL

Sweat	Reference Range
Chloride	0-35 mmol/L
Urine
Calcium	100-300 mg/24 h
Chloride	Varies with intake
Creatinine clearance	Male: 97-137 mL/min Female: 88-128 mL/min
Estriol, total (in pregnancy)
30 wks	6-18 mg/24 h
35 wks	9-28 mg/24 h
40 wks	13-42 mg/24 h
17-Hydroxycorticosteroids	Male: 3.0-10.0 mg/24 h Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total	Male: 8-20 mg/24 h Female: 6-15 mg/24 h
Osmolality	50-1400 mOsmol/kg H₂O
Oxalate	8-40 μg/mL
Potassium	Varies with diet
Proteins, total	< 150 mg/24 h
Sodium	Varies with diet
Uric acid	Varies with diet
Body Mass Index (BMI)	Adult: 19-25 kg/m²