Application of the Canadian Computed Tomography Head Rule to Patients With Minimal Head Injury.

STUDY OBJECTIVE: Two clinical decision rules, the Canadian CT Head Rule and the New Orleans Criteria, set the standard to guide clinicians in determining which patients with minor head trauma need computed tomography (CT) imaging. Both rules were derived with patients with minor head injury who had had a loss of consciousness or witnessed disorientation. No evidence exists for evaluating patients and need for CT imaging with minimal head injury; that is, patients who had a head injury but no loss of consciousness or disorientation and therefore would have been excluded from the Canadian CT Head Rule and New Orleans Criteria trials. We evaluate the Canadian CT Head Rule in patients with head injury without loss of consciousness or witnessed disorientation (minimal head injury). METHODS: We studied a prospective convenience sample of patients with minimal head injury who received head CTs as part of their evaluations in the emergency department (ED). Participants were enrolled after head CT was ordered, but before the physician received the imaging results. Physicians were surveyed on their clinical reasoning for ordering imaging in this low-risk cohort of patients. Physicians surveyed consisted of ED attending physicians and senior-level emergency medicine residents. Final patient disposition was recorded when it became available. Patients with positive CT findings had their medical records reviewed for specific disposition, admission length of stay, ICU stay, and any operative or procedural interventions. RESULTS: Two hundred forty patients with minimal head injury were enrolled. Five patients (2.1%) had head CTs that were positive for intracranial hemorrhage. All instances of intracranial hemorrhage occurred in patients who were at high or moderate risk by the Canadian CT Head Rule (2 high risk [age], 3 moderate risk [mechanism]). No patient with intracranial hemorrhage went to the ICU or underwent any intervention; the average hospital length of stay was 1.25 days. The Canadian CT Head Rule was 100% sensitive (95% confidence interval 40% to 100%) and 29% specific (95% confidence interval 23% to 35%) for the presence of intracranial hemorrhage. Physicians listed their own reassurance (24.6%), patient reassurance (24.2%), patient expectation (14.6%), and reduction of legal liability (11.7%) as the rationale for ordering head CT in patients with minimal head injury. Shared decisionmaking was used in 51% of cases. CONCLUSION: Risk of intracranial hemorrhage in patients with minimal head injury was very low, and even in patients found to have an intracranial hemorrhage, none had any serious adverse outcome (eg, death, intubation, prolonged hospitalization, surgical procedure). The Canadian CT Head Rule was 100% sensitive in this small cohort of patients with minimal head injury. Among our study cohort, which specifically included only patients who had CT scanning, applying the Canadian CT Head Rule may have reduced the need for CT, potentially saving costs and resources. However, because many patients with minimal head injury who present to the ED may not have CTs, it is unclear what effect the broad application of this rule would have on overall CT use. Providers' rationale for obtaining CT was multifactorial. These represent barriers that may need to be overcome before physicians are comfortable changing CT ordering patterns in this group of head injury patients.

Survey of patient and physician influences and decision-making regarding CT utilization for minor head injury.

OBJECTIVE: Assess factors that influence both the patient and the physician in the setting of minor head injury in adults and the decision-making process around CT utilization. METHODS: This is a convenience sample survey study of adult minor head injury patients (GCS 15) and their physicians regarding factors influencing the decision to use CT to evaluate for intra-cranial haemorrhage. Once a head CT was ordered and before the results were known, both the patient and physician were given a one-page survey asking questions about their concern for injury and rationale for CT use. CT results and surveys were then recorded in a centralized database and analyzed. RESULTS: 584 subjects were enrolled over the 27-month study period. The rate of any intra-cranial haemorrhage was 3.3%. Both the physicians (6% pre-test estimate) and the patients (22% pre-test estimate) over-estimated risk for haemorrhage. Clinical decision rules were not met in 46% of cases where CT was used. Physicians listed an average of 5 factors from a list of 9 that influenced their decision to order CT. Patients listed an average of 1.7 factors influencing their decision to present to the Emergency Department for evaluation. Many patients felt cost (45%) and low risk stratification (34%) should weigh heavily in the decision to use CT. If asked to limit CT utilization, physicians were able to identify a group with less than 2% risk of injury. CONCLUSIONS: Patients with low risk of intra-cranial injury continue to be evaluated by CT. Physician decision-making around the use of CT to evaluate minor head injury is multi-factorial. Shared decision-making between the patient and the physician in a low risk minor head injury encounter shows promise as a method to reduce CT utilization in this low risk cohort.

Magnitude of D-dimer matters for diagnosing pulmonary embolus.

OBJECTIVE: The objective of this study is to determine whether the magnitude of the D-dimer correlates with a higher likelihood of pulmonary embolus (PE). METHODS: We performed an electronic chart review at our academic, tertiary care center, annual emergency department (ED) census greater than 100000. All patients with a chest computed tomographic (CT) scan with intravenous contrast and an elevated D-dimer level obtained in the ED between January 2001 and July 2008 were identified. Specific, predetermined, predefined data elements including sex, age, D-dimer level, and final ED diagnosis were recorded by a hypothesis-blinded extractor using a preformatted data form. D-dimer level less than 0.58 µg/mL constitutes the normal laboratory reference range for our turbidometric D-dimer assay. Data were analyzed using standard statistical methods, and a linear regression analysis was performed for correlation analysis of D-dimer and diagnosis of PE. RESULTS: We identified 544 subjects who had both a chest CT scan performed and an elevated D-dimer level obtained in the ED. Fifty-eight subjects (10.7%; mean D-dimer, 4.9 µg/mL) were diagnosed with PE, and 486 (89.3%; mean D-dimer, 2.0) did not have a PE. The percentages of PE diagnoses for D-dimers in the ranges 0.58 to 1.0, 1.0 to 2.0, 2.0 to 5.0, 5.0 to 20.0, and greater than 20.0 (n = 11) were 3.6%, 8.0%, 16.2%, 35.3%, and 45.5%, respectively. The positive predictive value of PE for D-dimer level cutoffs of greater than 0.58, greater than 1.0, greater than 2.0, greater than 5.0, and greater than 20.0 was 10.7%, 14.6%, 22.2%, 37.8%, and 45.5%, respectively. Increasing D-dimer values were strongly correlated with the presence of PE (odds ratio, 1.1685 per stratum; P < .001). CONCLUSION: Increasing magnitude of D-dimer correlates with increasing likelihood of PE diagnosed by CT angiography.

Utility of the digital rectal examination in the evaluation of undifferentiated abdominal pain.

OBJECTIVE: The digital rectal examination (DRE) is commonly recommended in the evaluation of individuals with undifferentiated abdominal pain (UAP) despite negligible evidence. We aimed to determine its clinical utility. METHODS: We prospectively enrolled 893 UAP subjects in an observational, convenience sample study at our urban, academic emergency department. Exclusion criteria were age younger than 18 years, vaginal or rectal bleeding, pregnancy, and primarily flank pain or vaginal complaint. Data forms were completed before laboratory testing, imaging, or other diagnostic maneuvers; and structured telephone and chart follow-up was performed. Physicians were asked to document DRE findings contemporaneously as well as their perception of the DRE's diagnostic impact. Final diagnosis in each case was compared with DRE result. RESULTS: Five hundred thirty-eight of 893 (60%) subjects had a DRE performed at the discretion of the examining physician. The DRE was classified as "not useful" in 494 of 538 (92%). In the remaining 44 subjects, physicians reported having their differential diagnosis influenced by the DRE. Seventeen of 538 (3%; 0.95 confidence interval, 1.9%-5.0%) were diagnostically helped, and 12 of 538 (2%; 0.95 confidence interval, 1.3%-3.9%) were diagnostically harmed. Eleven of 538 (2%) were lost to final follow-up. Sensitivity analysis indicates that unless all 11 had diagnostically helpful DREs, the DRE was statistically as likely to be harmful as helpful. CONCLUSION: Differential diagnosis was unaffected in most subjects undergoing DRE, and it appears as likely to be harmful as helpful in predicting final diagnosis. Given the discomfort and minimal predictive value of the DRE in this setting, highly selective use seems reasonable.