Ch12: Trauma（创伤）

Preparatory Mindset

Trauma is a disease — predictable, preventable, and treatable — and the leading cause of death under age 45. The exam tests: mechanism & classification of trauma, the local & systemic pathophysiology, wound healing, clinical manifestations & complications, and resuscitation (ATLS principles). The lecture (Dr. Li, orthopaedics) covers epidemiology, mechanism, and the resuscitation approach; the trauma scores (ISS, RTS) and the trimodal death distribution are classic.

Exam mindset: the ATLS ABCDE approach is mandatory knowledge. Know the trauma death pattern (immediate, early, late), hypovolemic shock management (see Ch04), and the specific injury patterns (chest trauma in Y4S2 chapter, abdominal trauma in Y4S2 chapter).

Core Concepts

1. Epidemiology (MUST KNOW)

1. Immediate (minutes): severe brain/spinal/cardiac/大血管 injury — prevention is the only answer 2. Early (minutes-hours, "golden hour"): hemorrhage, hypoxia — where resuscitation saves lives 3. Late (days-weeks): sepsis, MODS — ICU care

• Trauma is the 4th leading cause of death in the US; #1 in people <45
• Worldwide: ~5.8 million deaths/year — 32% more than HIV, TB and malaria combined
• Causes: road traffic accidents, falls, violence, penetrating injury
• Trimodal death distribution:

2. Classification of trauma (MUST KNOW)

- GCS (Glasgow Coma Scale): eye 1-4 + verbal 1-5 + motor 1-6 (3-15); ≤8 = severe brain injury (intubate) - ISS (Injury Severity Score): based on AIS of 3 most injured regions; ISS >15 = severe (major trauma) - RTS (Revised Trauma Score): GCS + SBP + RR

• By mechanism: blunt (blunt force — RTA, falls, assault) vs penetrating (stab, gunshot)
• By severity: mild, moderate, severe (ISS-based)
• Closed vs open (open = skin broken)
• By injury pattern: isolated vs multiple injuries (多发伤), polytrauma
• Scoring:

3. Pathophysiology of trauma (MUST KNOW)

- Neuroendocrine: ↑ catecholamines, cortisol, glucagon, ADH, aldosterone → hyperglycemia, sodium/water retention - Cardiovascular: ↑ HR, vasoconstriction (preserve perfusion to brain/heart) - Metabolic: catabolism (protein breakdown, lipolysis), negative nitrogen balance - Immune/inflammatory: cytokine release → SIRS → (if excessive) MODS; immunosuppression → infection risk

- Early: hemorrhage & shock, hypoxia, head injury, cardiac arrest - Intermediate: ARDS, AKI, DIC, fat embolism, compartment syndrome, infection - Late: sepsis, MODS, venous thromboembolism, wound complications, psychological

• Local response: tissue damage → inflammation, hematoma, edema, pain; wound healing (see Ch07)
• Systemic (stress) response:
• Complications of trauma:

4. Initial assessment — ATLS ABCDE (MUST KNOW)

1. A — Airway with cervical spine protection: assess patency; clear obstruction; jaw thrust (not head tilt — C-spine injury risk); airway adjuncts (OPA/NPA); definitive airway (ETT) if GCS ≤8, severe facial injury, obstruction; C-collar + log roll
2. B — Breathing: expose chest, inspect/auscultate/percuss; treat tension pneumothorax (needle decompression 2nd ICS MCL), open pneumothorax (seal 3-sided), massive hemothorax (chest drain), flail chest; oxygen
3. C — Circulation with hemorrhage control: assess pulse/BP/skin/urine; direct pressure on bleeding; 2 large-bore IVs; warm crystalloid + blood (balanced 1:1:1); massive transfusion protocol; pelvic binder for pelvic fracture; tourniquet for exsanguinating extremity hemorrhage; treat shock (see Ch04)
4. D — Disability (neurological): GCS, pupils, lateralizing signs; glucose check; brief
5. E — Exposure/environment: fully undress (log roll), examine back, prevent hypothermia (warm fluids/blankets)

• Primary survey → resuscitation → secondary survey (head-to-toe) → definitive care
• Adjuncts: focused assessment with sonography in trauma (FAST — free fluid: RUQ, LUQ, pelvis, pericardium), CXR, pelvic X-ray, bloods (cross-match, lactate, ABG), urinary catheter (after excluding urethral injury), NG tube (after excluding cribriform plate fracture)
• "Don't let the diagnosis interfere with treatment" — treat life threats immediately

5. Specific injuries (overview — details in organ chapters)

• Head: epidural (lens, lucid interval), subdural (crescent), SAH, diffuse axonal injury; raised ICP management (head up, hyperventilation briefly, mannitol, decompressive craniectomy)
• Chest: rib fractures, flail chest, pneumothorax/hemothorax, cardiac tamponade (Beck's triad), aortic rupture, diaphragmatic rupture (see Y4S2 chest chapter)
• Abdomen: solid organ injury (liver, spleen — bleeding), hollow viscus injury (perforation — peritonitis); hemodynamically unstable + positive FAST → laparotomy; stable → CT (see Y4S2)
• Pelvis: pelvic fracture → major retroperitoneal hemorrhage → pelvic binder, angioembolization
• Spine: C-spine clearance (clinical + CT); spinal cord injury (neurogenic shock — bradycardia, warm; vs hypovolemic — tachycardia)
• Extremities: fractures, dislocations, compartment syndrome (pain out of proportion, tense, pain on passive stretch → fasciotomy), vascular injury, nerve injury
• Burns: see Ch14

6. Emergency principles (MUST KNOW)

• Damage control surgery (DCS): for severe trauma — control hemorrhage & contamination quickly (abbreviated surgery), pack, temporary closure, ICU resuscitation, then definitive surgery ("blood, not time") — avoids the "lethal triad" of hypothermia, acidosis, coagulopathy
• Lethal triad: hypothermia + acidosis + coagulopathy → vicious cycle of bleeding & death
• Permissive hypotension: in uncontrolled hemorrhage without head injury, keep SBP ~80-90 mmHg until bleeding is controlled (less clot disruption)
• Tourniquet: for exsanguinating extremity bleeding; note time; remove in OR
• Golden hour: rapid transport + resuscitation improves survival

High-Yield Points

• Trauma = #1 cause of death <45; trimodal distribution (immediate/early golden hour/late MODS)
• ATLS: ABCDE (Airway w/ C-spine, Breathing, Circulation w/ hemorrhage control, Disability/GCS, Exposure/hypothermia prevention)
• GCS ≤8 → intubate; GCS: E4 V5 M6
• Tension PTX: needle decompression 2nd ICS midclavicular; Open PTX: 3-sided seal; Massive hemothorax: chest drain
• FAST: RUQ, LUQ, pelvis, pericardium — unstable + positive → laparotomy
• Damage control: abbreviated surgery + ICU + definitive; lethal triad = hypothermia + acidosis + coagulopathy
• Permissive hypotension in uncontrolled hemorrhage (no head injury)
• Compartment syndrome: fasciotomy (pain out of proportion, pain on passive stretch)
• Tourniquet for exsanguinating extremity bleeding; pelvic binder for pelvic fracture
• Golden hour; ABC first

Topic Summary

Trauma is a disease and the leading cause of death under 45; deaths follow a trimodal pattern (immediate brain/vascular, early hemorrhage/hypoxia in the "golden hour," late sepsis/MODS). Pathophysiology: local tissue damage + systemic neuroendocrine stress (catecholamines/cortisol → hyperglycemia, catabolism) + inflammation (SIRS→MODS). Assessment is ATLS ABCDE: airway with C-spine protection (intubate if GCS ≤8), breathing (tension PTX decompression, open PTX seal, hemothorax drain, flail chest), circulation with hemorrhage control (direct pressure, IVs, blood 1:1:1, pelvic binder, tourniquet), disability (GCS), exposure/hypothermia prevention; then secondary survey + FAST + CT. Principles: damage control surgery for severe trauma (avoid the lethal triad of hypothermia/acidosis/coagulopathy), permissive hypotension, golden hour. Complications: ARDS, AKI, DIC, compartment syndrome (fasciotomy), sepsis, MODS.