Deep-vein thrombosis can be ruled out in a patient who is judged clinically unlikely to have deep-vein thrombosis and who has a negative D-dimer test. Ultrasound testing can be safely omitted in such patients.

Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.

We have derived the Canadian C-Spine Rule, a highly sensitive decision rule for use of C-spine radiography in alert and stable trauma patients. If prospectively validated in other cohorts, this rule has the potential to significantly reduce practice variation and inefficiency in ED use of C-spine radiography.

ACH YEAR, PHYSICIANS IN CANAdian and US emergency departments (EDs) treat more than 8 million patients with head injury, representing approximately 6.7% of the 120 million total ED visits. 1 Although some of these patients have sustained moderate or severe head injury leading to death or serious morbidity, the vast majority of patients are classified as having minimal or minor head injury. 2,3 Patients with minimal head injury have not experienced loss of consciousness or other neurological alteration. Minor head injury or concussion is defined by a history of loss of consciousness, amnesia, or disorientation See also pp 1519 and 1551 and Patient Page.

For alert patients with trauma who are in stable condition, the CCR is superior to the NLC with respect to sensitivity and specificity for cervical-spine injury, and its use would result in reduced rates of radiography.