Background: Physicians in Canadian emergency departments (EDs) annually treat 185,000 alert and stable trauma victims who are at risk for cervical spine (c-spine) injury. Only 0.9% of these patients have, however, suffered a cervical spine fracture. Current use of radiography is not efficient. More than 98% of c-spine radiographs are negative and there is considerable variation among hospitals and physicians in radiography use. C-spine radiographs are little ticket items, low cost procedures that significantly add to health care costs due to high volume. In addition, alert and stable trauma patients are often immobilized on a backboard with a rigid collar and sandbags for many hours. This leads to considerable patient discomfort and unnecessary use of valuable time and space in our crowded EDs. This renewal application builds on previous MRC/CIHR grants to determine feasibility (phase 0, MRC GR-13304D, 1995-96), develop a decision rule for c-spine radiography (phase I, MRC MT-13700, 1996-99, N=8,924), and prospectively validate this Canadian C-Spine Rule (phase II, CIHR MT13700, 1999-2002, N=8,000), all part of the University of Ottawa Group Grant in Decision Support Techniques (CIHR 2000-143). The Canadian C-Spine Rule is comprised of simple clinical variables (Figure 1) and allows physicians to be much more selective in ordering radiography (JAMA 2001). In the recently completed prospective validation (phase II), we confirmed the accuracy and reliability of the rule.

Objectives: The goal of phase III is to evaluate the effectiveness and safety of an active strategy to implement the Canadian C-Spine Rule into physician practice. Specific objectives are to: 1) Determine clinical impact by comparing the intervention and control sites for: a) C-spine radiography rates, b) Missed fractures, c) Serious adverse outcomes, d) Length of stay in ED, and e) Patient satisfaction; 2) Determine sustainability of the impact; 3) Evaluate performance of the Canadian C-Spine Rule, with regards to: a) Accuracy, b) Physician accuracy in interpretation, and c) Physician comfort and compliance with use; 4) Conduct an economic evaluation to determine the potential for cost savings with widespread implementation.

Methods: We propose a matched-pair cluster design study which compares outcomes during 3 consecutive 12-month before, after, and decay periods at 6 pairs of intervention and control sites (Figure 3). These 12 hospital ED sites will be stratified as teaching or community hospitals, matched according to baseline c-spine radiography ordering rates, and then allocated within each pair to either intervention or control groups. During the after period at the intervention sites, simple and inexpensive strategies will be employed to actively implement the Canadian C-Spine Rule: a) physician group discussion and consensus, b) educational initiatives (lecture, posters, pocket cards), and c) a process-of-care modification with a mandatory reminder of the Rule at the point of requisition for radiography. These outcomes will be assessed: 1) Measures of clinical impact will compare the changes from before to after between the intervention and control sites: a) C-spine radiography ordering proportions (the primary analysis); b) Number of missed fractures; c) Number of serious adverse outcomes; d) Length of stay in ED; e) Patient satisfaction. 2) Performance of the Canadian C-Spine Rule: a) Accuracy of the rule; b) Physician accuracy of interpretation; c) Physician comfort and compliance. 3) Economic evaluation measures: a) Radiography rate after discharge; b) Length of stay in ED and hospital; c) Hospital admission; d) Operative repair. During the 12-month decay period, implementation strategies will continue, allowing us to evaluate the sustainability of the effect. We estimate a sample size of 4,800 patients in each period in order to have adequate power to evaluate the main outcomes.

Importance: This implementation study (phase III) is an essential step in the process of developing a new clinical decision rule guideline for health care practitioners. Phase I successfully derived the Canadian C-Spine Rule and phase II confirmed the accuracy and safety of the rule and, hence, the potential for physicians to improve care. What remains unknown is the actual change in clinical behaviour that can be effected by implementation of the Canadian C-Spine Rule and whether implementation can be achieved with simple and inexpensive measures. We believe that the Canadian C-Spine Rule has the potential to significantly reduce health care costs and improve the efficiency of patient flow in busy Canadian EDs.