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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- ATLS primary survey = ABCDE: Airway with cervical spine protection, Breathing, Circulation/hemorrhage control, Disability, Exposure/environment.
- Treat life threats immediately as they are found; do not wait to complete the full survey.
- Hemorrhagic shock is the most common cause of preventable trauma death.
- Unstable trauma patient with positive FAST generally needs operative or interventional hemorrhage control.
- Secondary survey is head-to-toe evaluation only after primary survey and resuscitation are underway.
Overview
The ATLS approach provides a standardized sequence for evaluating and resuscitating injured patients. The primary survey identifies and treats immediate threats to life. Adjuncts such as ECG, pulse oximetry, blood pressure monitoring, pelvic X-ray, chest X-ray, and FAST support clinical resuscitation but must not delay life-saving intervention.
Epidemiology
Trauma is a leading cause of death in children and adults under age 45 in the United States. Major mechanisms include motor vehicle collisions, falls, firearm injuries, assaults, and occupational injuries. Early deaths often result from airway obstruction, tension pneumothorax, massive hemorrhage, traumatic brain injury, or cardiac tamponade.
Clinical Features
Symptoms
History of blunt or penetrating injury, fall, blast, crush, burn, or high-energy mechanism
Dyspnea, chest pain, abdominal pain, pelvic pain, limb pain, headache, or neurologic symptoms
Anticoagulant use, pregnancy, older age, or intoxication increases risk of occult severe injury
Loss of consciousness, vomiting, seizure, amnesia, or severe headache suggests traumatic brain injury
AMPLE history: Allergies, Medications, Past history/pregnancy, Last meal, Events/environment
Signs
Airway obstruction, facial trauma, expanding neck hematoma, or blood/vomit in airway
Tension pneumothorax signs: severe respiratory distress, hypotension, unilateral absent breath sounds
External hemorrhage, unstable pelvis, distended abdomen, or long-bone deformity suggesting major blood loss
GCS <8, lateralizing signs, unequal pupils, or spinal deficit
Hypothermia, acidosis, and coagulopathy indicate high-risk trauma physiology
Investigations
First-line
Primary survey monitoringContinuous pulse oximetry, ECG, noninvasive BP or arterial line, temperature, and frequent reassessment.
FAST / eFASTBedside ultrasound for intraperitoneal, pericardial, and pleural fluid plus pneumothorax; most useful in unstable patients.
Trauma labsCBC, CMP, PT/INR, fibrinogen, lactate/base deficit, type and crossmatch, pregnancy test when relevant.
Portable chest and pelvic X-raysIdentify pneumothorax, hemothorax, widened mediastinum, pelvic ring disruption, and tube/line position in unstable trauma.
Second-line
CT imagingCT head/c-spine/chest/abdomen/pelvis with contrast as indicated for stable patients with concerning mechanism or exam findings.
CT angiographyEvaluate vascular injury, active extravasation, blunt cerebrovascular injury, aortic injury, or extremity ischemia.
Serial examinationsEssential when intoxication, distracting injury, early abdominal injury, or evolving compartment syndrome is possible.
Specialist
Operative/interventional evaluationTrauma surgery, neurosurgery, orthopedics, vascular surgery, interventional radiology, or burn center depending on injury pattern.
1
A — Airway with cervical spine protection
- Open airway using jaw thrust if cervical spine injury possible.
- Remove blood, vomitus, teeth, or foreign material; suction aggressively.
- Definitive airway for inability to protect airway, severe facial/neck injury, GCS <=8, hypoxemia, shock, or expected deterioration.
- Maintain cervical spine precautions until clinically or radiographically cleared.
2
B — Breathing
- Expose chest, inspect, palpate, percuss, auscultate, and provide high-flow oxygen.
- Treat tension pneumothorax immediately with needle/finger decompression followed by chest tube.
- Chest tube for traumatic hemothorax, pneumothorax requiring intervention, or positive-pressure ventilation with pneumothorax.
- Open pneumothorax: occlusive dressing then chest tube away from wound.
3
C — Circulation and hemorrhage control
- Control external bleeding with direct pressure, tourniquet, hemostatic dressing, or pelvic binder.
- Two large-bore IVs or IO; activate massive transfusion protocol for suspected major hemorrhage.
- Balanced transfusion with packed RBCs, plasma, and platelets; give calcium during massive transfusion.
- Tranexamic acid within 3 hours for significant traumatic hemorrhage when indicated.
- Definitive hemorrhage control: OR, interventional radiology, pelvic stabilization, endoscopy, or thoracotomy in selected cases.
4
D/E, secondary survey, and disposition
- Disability: GCS, pupils, glucose, lateralizing signs, spinal motor/sensory exam.
- Exposure: fully undress patient, logroll, inspect posterior surfaces, then prevent hypothermia with active warming.
- Secondary survey: complete head-to-toe exam and AMPLE history after stabilization.
- Tetanus prophylaxis, antibiotics for open fractures/contaminated wounds, analgesia, and early transfer to appropriate trauma center.
Complications
- Missed injury: Distracting pain, intoxication, altered mental status, and incomplete exposure increase risk
- Hemorrhagic shock: Pelvis, chest, abdomen, long bones, and external bleeding are major sources
- Lethal triad: Hypothermia, acidosis, and coagulopathy worsen bleeding and mortality
- Compartment syndrome: Limb-threatening after fractures, crush injury, reperfusion, or tight dressings/casts
- Secondary brain injury: Hypotension and hypoxemia after TBI worsen neurologic outcome
USMLE Step 2 CK Exam Tips
- 1ATLS is sequential but therapeutic: treat life threats as soon as you find them.
- 2GCS <=8 or inability to protect airway = definitive airway.
- 3Tension pneumothorax in unstable trauma = needle decompression before chest X-ray.
- 4Unstable blunt trauma + positive FAST = exploratory laparotomy.
- 5Pelvic fracture + shock = pelvic binder and massive transfusion; consider preperitoneal packing or IR embolization.
- 6Do not send an unstable trauma patient to CT unless a life-saving diagnosis cannot be made otherwise.
- 7Prevent hypothermia early — cold trauma patients bleed more.
- 8Secondary survey occurs after primary survey/resuscitation.
practicetest your knowledge on trauma primary & secondary survey (atls)Apply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — emergency medicine and beyond.
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