Impact of clinical decision rules on clinical care of traumatic injuries to the foot and ankle, knee, cervical spine, and head
Introduction
Clinicians are faced with a multitude of clinical decisions for traumatic injury for patients seen in emergency departments (ED). These decisions are weighted by several factors including: the desire to provide excellent clinical care, fear of malpractice litigation, and pressures to provide care with less cost to the insurers (government or private). Many decisions to perform investigations are based on personal experience and not evidence-based medicine. There are now several clinical decision rules to assist emergency physicians to determine using evidence based medicine which patients require investigations for some of the most frequent traumatic injuries seen in the ED.
Clinical decision (or prediction) rules attempt to reduce the uncertainty of medical decision making by standardising the collection and interpretation of clinical data. A decision rule is derived from original research and may be defined as a decision making tool that incorporates three or more variables from the history, physical examination, or simple tests.12, 26 These decision rules help clinicians with diagnostic or therapeutic decisions at the bedside. The methodological standards for their development and validation and can be summarized (Fig. 1).
Unfortunately, many clinical decision rules to our knowledge have not been prospectively assessed to determine their accuracy, reliability, clinical sensibility, or potential impact on clinical practice. The validation process is very important because many statistically derived rules or guidelines fail to perform well when tested in a new population.9, 23, 4 The reason for this poor performance may be statistical, i.e., overfitting or instability of the original derived model,5 or may be due to differences in prevalence of disease or differences in how the decision rule is applied.20, 44 Likewise, the process of implementation is important to demonstrate the true effect on patient care and is the ultimate test of a decision rule; transportability can be tested at this stage.13
Clinical decision rules must undergo field trials to test their effectiveness, as the rationale for such rules lies in their ability to alter actual patient care.13, 43 Our research group has previously conducted derivation, validation and implementation studies for the following widely used clinical decision rules: Ottawa ankle rules,28, 29, 30 Ottawa knee rules,31, 32, 33 Canadian C-spine rule34, 35, 37 and the Canadian CT head rule36 (for minor head injuries).
The impact of clinical decision rules may be assessed by multiple approaches. Implementation studies likely provide the most concrete evidence that the rules are reliable and work in the real world. Other methods include surveys of physician practices and opinions. Finally, we outline the current assessment of the impact of four well-known clinical decision rules, which were developed using the accepted methodology for conducting clinical decision rules, relating to traumatic injuries. We review the clinical impact of the Ottawa ankle rule, Ottawa knee rule, Canadian C-spine rule and the Canadian CT head rule for minor head injuries.
Section snippets
Ottawa ankle rule
Ankle injuries are one of the most common problems seen in the emergency department. Most patients routinely underwent radiography prior to the development of the Ottawa ankle rule despite a relatively low fracture rate of less than 15%. Although ankle radiography is a relatively low cost investigation, the annual cost of ankle radiography is well over 500 million dollars for the US and Canadian health care systems.29
The Ottawa ankle rules were prospectively derived (N = 750 patients), refined,
Ottawa knee rule
Traumatic knee injuries account for about 1 million ED visits annually in the USA.16 Approximately 80% of patients underwent radiography prior to the development of knee rules, with over 94% being negative for acute fracture.14
The Ottawa knee rules were also prospectively derived (N = 1054 patients)31 and prospectively validated (N = 1096).32 They incorporate simple historical and physical findings which are well defined to determine if patients require radiography of their knee following a
Canadian C-spine rule
Potential traumatic cervical spine injury is a very frequent problem in emergency departments around the world. In the USA, there are approximately 1 million blunt trauma patients a year with potential cervical spine injury.14 For patients who are alert and oriented and neurologically intact, the risk of spinal injury or acute fracture is less than 1%.21 Despite this low risk most patients undergo cervical spine imaging studies resulting in 98% of the studies being negative for acute injury.8,
Canadian CT head rule
Head injuries are among the most common types of trauma seen in North American emergency departments. An estimated 800,000 cases of head injury are seen annually in US emergency departments.14 Although some of these patients die or suffer serious morbidity requiring months of hospitalisation and rehabilitation, many others are classified as having a “minimal” or “minor” head injury. “Minimal” head injury patients have not suffered loss of consciousness or amnesia and rarely require admission to
Conclusions
Emergency physicians should use the Ottawa ankle rule, Ottawa knee rules, Canadian CT head rule, and Canadian C-spine rules to provide more standardised care, to decrease the chances of misdiagnosis and reduce health care costs. International surveys and implementation studies have confirmed that the rules are effective and can be successfully implemented in a wide spectrum of emergency department settings around the world.
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