Trauma
Killers before complaints
Trauma is time-critical. The primary survey exists to find and fix lethal problems before moving on. Exsanguinating hemorrhage comes first: direct pressure, wound packing, and a tourniquet for life-threatening extremity bleeding (placed high and tight, time recorded). Then airway with spinal motion restriction as indicated, breathing (needle decompression for tension pneumothorax, occlusive dressing for an open chest wound), circulation (pelvic binder, splinting, tranexamic acid per protocol), disability (GCS, pupils, glucose), and exposure with immediate hypothermia prevention.
The big six: massive hemorrhage, tension pneumothorax, cardiac tamponade, flail chest, airway obstruction, and traumatic brain injury. Resuscitate with blood products and permissive hypotension rather than large crystalloid volumes, which worsen bleeding, dilution, and hypothermia. In TBI, hypoxia and hypotension each sharply increase mortality - keep SpO2 at 94% or above and systolic pressure adequate for age, and reserve hyperventilation as a brief bridge for herniation.
Burns: estimate total body surface area with the rule of nines, calculate fluids, and look for inhalational injury, circumferential burns, and associated trauma.
Traps
Assuming a normal blood pressure excludes hemorrhage - young patients compensate and then crash. Missing a second injury because the first was dramatic. Forgetting that elderly patients on anticoagulants decompensate with seemingly minor head trauma.
Rule of thumb
Hypotension in trauma with no visible external bleeding means chest, pelvis, or belly - and you treat the chest first.