Trauma
Primary survey
Follow a structured approach with catastrophic haemorrhage control first: direct pressure, tourniquet, and a pelvic binder placed at the level of the greater trochanters (a binder at the iliac crests does nothing). Then airway with in-line stabilisation, breathing with bilateral chest assessment, circulation with two large-bore lines and blood products, disability with GCS and pupils, and exposure with a log roll and active warming.
Permissive hypotension (systolic around 90 mmHg) applies to active haemorrhage until control, but not to traumatic brain injury, where systolic pressure of 110 mmHg or more is the target. Activate massive transfusion early with a balanced 1:1:1 ratio, give tranexamic acid 1 g within 3 hours of injury, and minimise crystalloid.
Tension pneumothorax is a clinical diagnosis: needle decompression in the 5th intercostal space at the anterior axillary line, before any imaging. A transient response to fluid followed by deterioration means ongoing bleeding.
C-spine: apply NEXUS or the Canadian rule, but do not clear immobilisation in an intoxicated, distracting or unexamined patient.
Imaging traps: taking an unstable patient to the CT scanner. The lethal triad is hypothermia, acidosis and coagulopathy - the resuscitation room is the right place for the unstable patient.
Rule of thumb: sudden hypotension in a previously stable trauma patient means new bleeding (pelvis, femur, abdomen), tension pneumothorax or tamponade - reassess rather than simply transfusing.