Clinical assessment and presentation should guide which diagnostic tests to order
Lab testing can provide a baseline assessment of metabolic derangements to guide resuscitation (e.g., base deficit and lactate)
Radiographic evaluation of the multiple<unk> patient is crucial in identifying acute injuries that may not be elucidated on physical exam
Chest X-rays and pelvic X-rays are standard exams for multiple<unk> patients
eFAST should be performed as part of the primary survey
eFAST is not appropriate (sensitivity is low) to assess for retroperitoneal fluid
Ultrasound can help to examine the inferior vena cava during the secondary survey to assess volume status
Although operator dependent, ultrasound is superior to chest X-ray to screen for hemothorax, pneumothorax and tamponade
Perform CT scans based on clinical judgment after completion of the primary and secondary survey
If c-spine injury is suspected, apply decision rules such as National Emergency X-Radiography Utilization Study (NEXUS) criteria or Canadian cervical spine rule (CCR) to help determine if a CT C-spine is indicated
eFAST is not appropriate (sensitivity is low) to assess for retroperitoneal fluid
^Base excess is the quantity of base (HCO3-, in mEq/L) that is above or below the normal range in the body. A negative number is called a base deficit and indicates metabolic acidosis.
Trauma 
Traumatic brain injury
Cold injuries
Intracranial hemorrhage
Drugs of abuse
Moderate-to-severe traumatic brain injury
Head trauma 
Elevated intracranial pressure