image by: The Skeptics' Guide to EM

HWN Suggests

We should stop using the Canadian CT head rule

In order for a clinical decision rule to be valuable it must change clinical practice, and that change must improve patient care... The Canadian CT head rule doesn’t decrease imaging and doesn’t improve our rate of diagnosis, even in idealized research settings. In the real world, this rule has almost certainly caused tremendous harm by driving increased CT rates over the last decade. No one should be using this rule in clinical practice. This has been true for over a decade, but nobody should be using the Canadian CT head rule. It is one of the few decision rules that we have implementation research for, and this cluster RCT demonstrates no benefit, and I believe suggests harm, despite being…

read full article

Featured

  Canadian CT Head Injury/Trauma Rule

Rules out need for head CT in minor head trauma.

 Should US physicians use the Canadian head CT rule?

Are the standards of care in Canada and the U.S. different with regard to ordering CT scans for minor head trauma? Does practicing defensive medicine ignore evidence-based best practice or is it just our American reality. The issues I have with the Canadian CT Head rule are a lack of external validity, the exclusion of “clinically unimportant” lesions and the use of a utilization reduction tool that may result in missed intracranial injuries.

Articles of Interest

SGEM#106: O Canada- Canadian CT Head Rule for Patients with Minor Head Injury

The Canadian CT rule has a considerably higher specificity and you only miss CT findings that don’t need neurosurgical intervention. These findings don’t really matter . . . except, possibly to a plaintiff’s lawyer.

SGEM#266: Old Man Take a Look at the Canadian CT Rule I'm a Lot Like You Wetre

The original Canadian Head CT Rule that was published back in 2001 has successfully reduced the number of head CT imaging obtained in the emergency department for mTBI. One major limitation to the decision instrument is using 65 years of age or older as a high-risk criterion. While this new study attempting to increase the age cutoff to 75 years is interesting and hypothesis generating it is not yet ready for clinical application at this time.

A prospective cluster-randomized trial to implement the Canadian CT Head Rule in emergency departments

Our knowledge–translation-based trial of the Canadian CT Head Rule did not reduce rates of CT imaging in Canadian emergency departments.

Canadian CT Head Rule

The Canadian Head CT Rule allows for minor or clinically unimportant brain injury to go unimaged and without hospital admission, which in some countries, like the United States, is considered important and to many clinicians usually necessitates both imaging and admission.

Canadian CT Head Rule by Dr. Ian Stiell

This video features Dr. Ian Stiell, Professor in the Department of Emergency Medicine at the University of Ottawa, discussing the assessment of a patient using the Canadian CT Head Rule.

Canadian CT Head Rule Is Superior to New Orleans Criteria in Minor Head Injury

In patients with Glasgow Coma Scale scores of 15, both decision rules had 100% sensitivity for identifying significant intracranial injuries, but the Canadian CT Head Rule had higher specificity.

Canadian Head CT Decision Tool

The final decision instrument had excellent sensitivity for detecting clinically relevant intracranial injuries (defined here as requiring neurosurgical intervention) but even the expanded rule will miss a small portion of patients with identifiable intracranial injuries (although not clinically significant ones).

Clinical Decision Instruments in Minor Head Trauma – New Orleans + Canadian Decision Instruments

Bottom Line: The New Orleans head CT criteria allow clinicians to identify all patients who will have intracranial injuries whether they are clinically significant or not but is unlikely to produce anything more than very small reductions in CT utilization. The Canadian Head CT decision instrument is a highly sensitive tool for determining which patients with minor head injury do not need emergent advanced imaging performed.

EM Quick Hits

The CT Head rule has been prospectively validated, undergone an implementation trial and meta-analysis, and when adhered to, may decrease the utilization of CT head and perhaps improve patient flow in the ED Exclusion criteria include age ≤16 years, patient on anticoagulant or antiplatelet agent and seizure after injury which raises the question: Do all patients on anticoagulants or antiplatelet agents who sustain a head injury require CT head imaging? According to Dr. Stiell while there is some evidence to suggest that patients taking oral anticoagulants may have a higher risk of intracranial bleeding, there is no good evidence that patients taking antiplatelet agents are at higher risk of bleeding; therefore, patients who fulfill the CT head rules taking antiplatelet agents do not require CT head imaging necessarily.

The Canadian CT Head Rule for patients with minor head injury

We have developed the Canadian CT Head Rule, a highly sensitive decision rule for use of CT. This rule has the potential to significantly standardise and improve the emergency management of patients with minor head injury.

Tiny Tips: Canadian CT Head Rule

The Canadian CT Head Rule (CCHR) was developed to help clinicians determine when to order a CT image for patients with minor head injury.1 In 2010, a multi-centre prospective trial implemented the CCHR and found that the rate of CT imaging increased despite the use of the clinical decision rule.2 Of the many factors influencing this, the greatest seems to be that clinicians inappropriately apply the CCHR and may be unfamiliar with the inclusion and exclusion criteria.

Use of the Canadian CT head rule for patients on anticoagulant/anti-platelet therapy presenting with mild traumatic brain injury: prospective observational study

The CCHR might be used for mTBI patients on either therapy. Anticoagulants and anti-platelet drugs should not be considered a risk factor for patients with mTBI and a GCS of 15. Multicentric studies are needed to confirm this result.

Resources

Canadian Head CT Rule

Failing the rule means the medical provider should use his/her judgement to determine the need for imaging. It is not mandatory. The rule was created and validated in Canada. It has also been validated once in the US.

EB Medicine

The original validation trial and multiple subsequent studies (Stiell 2001, Stiell 2005, Stiell 2010) each found the high-risk criteria of the Canadian CT (computed tomography) Head Rule (CCHR) to be 100% sensitive for injuries requiring neurosurgical intervention. The CCHR has an 87% to 100% sensitivity for detecting “clinically important” brain injuries that do not require neurosurgery.

Radiopaedia

The Canadian CT head rule (CCTHR) is a validated clinical decision rule to determine the need for CT head in adult emergency department patients with minor head injuries.