The potential impact of adherence to a guideline on the utilization of head CT scans in traumatic head injury patients. Frederick K. Korley M.D.

Background (1)  2001 Institute of Medicine report “Crossing the quality chasm” reported “uneven” adherence to well established evidence by clinicians (IOM report 2001)  Barriers to adherence: lack of awareness, inadequate familiarity, variable agreement, questioning of self-efficacy and outcome, and inertia (Cabana et al, JAMA 1999).  Example of potential gap between evidence and practice: Utilization of head CT scans in traumatic head injury.

Background (2)  Over 1 million patients present to EDs annually for traumatic head injury (Guerrero et al, Brain Inj 2000).  > 70% get head CT scans (Stiell et al, Lancet 2001).  Important findings < 20% (Atzema, Ann E Med 2004).  Unnecessary CT scans are at an enormous cost (health care expenditure, exposure to ionizing radiation, ED length of stay). Unnecessary CT scans  2008: American College of Emergency Physicians (ACEP) developed a clinical policy on CT utilization in head injury cases using best available evidence.

National trends for CT scan utilization in all injury-related illness 1 1.Korley FK, Pham JC, Kirsch TK. The use of advanced imaging in Emergency Department patients with injury-related complaints Submitted for publication.

Knowledge gap 1. Baseline level of adherence of routine ED practice to ACEP guidelines unknown. 2. Potential impact of the ACEP policy on safe reduction of head CT scans in traumatic head injury unknown.

Hypothesis  If adhered to, the ACEP clinical policy would result in a 10% or more decrease in the proportion of patients receiving head CT scans.  Further, this would not result in missing patients with acute traumatic findings.

Study Population  Patients presenting to the Adult Johns Hopkins Hospital ED with traumatic head injury.  Inclusion: Age > 18 years; time of injury < 24 hours from ED presentation.  Exclusion: Unstable vital signs; victims of stabbing or gunshot wound; obvious depressed skull fracture; initial ED GCS < 15; seizure event after traumatic episode; pregnant; return reassessment for the same head injury.

Methods  Subject enrollment: Assess all ED patients for eligibility. Prospectively, continuously enroll patients meeting eligibility criteria.  Primary outcome: Difference between actual and ACEP recommended head CT scans.  Secondary outcomes:  % encounters where physician followed ACEP policy  Among patients in whom CT would have not been recommended:  % with acute findings on CT (defined by Haydel et al, NEJM 2000)  % needing neurosurgical intervention by 14 days

Data collection  Interview in the ED: patient history, baseline characteristics. Chart review for exam findings. Categorize patients based on ACEP policy.  Chart reviewed at 14 days: determine if a head CT scan was obtained, and whether patient needed a neurosurgical intervention.  A physician masked to patient characteristics and exam findings will review CT scan reports and classify them on the presence of acute traumatic finding.

Sample size and feasibility  190 patients needed to have 90% power to detect a 10% or greater change in the proportion of patients with no acute traumatic CT scan finding (alpha=0.05, two tailed).  90 eligible patients per month  3 month enrollment period

Data analysis  Chi-square test to determine difference between % of actual and ACEP recommended head CT scans.  Descriptive statistics to determine  % encounters where physician followed ACEP policy  % with acute findings on CT  % needing neurosurgical intervention by 14 days

Limitations Methods to address Single center studyPilot study, plan larger study later Chart review may not yield complete information We will account for missing data in analysis Collecting data may lead to behavior change Mask physicians to study aims Study will not provide information on actual impact of ACEP policy implementation This will be investigated in another study. Data from this study will serve as baseline for evaluating that study.

Significance  Results will help establish the current level of adherence to the ACEP policy and the potential impact of adherence.  Use as baseline data to assess effectiveness of a future intervention to implement this policy.