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PubMed1998

A simple clinical model for the diagnosis of deep-vein thrombosis combined with impedance plethysmography: potential for an improvement in the diagnostic process.

OBJECTIVES: We recently demonstrated the utility of a clinical model combined with ultrasonography to assist the diagnostic approach in patients with suspected deep-vein thrombosis (DVT). In this study we also sought to demonstrate that the model is useful with impedance plethysmography, a less accurate and less utilized diagnostic test. The original clinical model is slightly cumbersome to use; thus at the completion of the study we attempted to develop a simpler scoring system with a goal of maintaining accuracy. DESIGN: An open, nonrandomized, multicentre trial. SETTING: Three centres, two in Canada, and one in Italy. SUBJECTS: Ambulatory patients with suspected deep-vein thrombosis. INTERVENTIONS: All patients were assessed clinically to determine the probability for deep-vein thrombosis prior to performing impedance plethysmography and venography. We compared the accuracy of impedance plethysmography between the three pretest probability categories of high, moderate and low. All of the above were performed and interpreted by independent observers. When the study was completed, we revised the clinical model by first performing a simple regression analysis then a multiple logistic regression analysis; a scoring system was devised using the latter. RESULTS: Impedance plethysmography is significantly more sensitive and less specific for all DVT in patients with high pretest probability for deep-vein thrombosis (P = 0.001). The post- test probability (positive predictive value) for deep-vein thrombosis with an abnormal impedance plethysmography result was significantly different (P = 0.0001) between the three pretest probability categories. Multiple regression analysis has provided a new model with only nine variables and a simple scoring system. The retrospective application of the revised clinical model, which is simpler to use, suggests it will provide similar results as the original clinical model when combined with impedance plethysmography. The combination of impedance plethysmography and the clinical model suggests patients are likely to have false positive results if they have a low or moderate pretest probability for deep-vein thrombosis and false negative results if the pretest probability is high. The combination of a low pretest probability and a normal impedance plethysmography result may exclude the need for serial testing, and represented more than 50% of our patient population. CONCLUSIONS: The use of the clinical model in conjunction with impedance plethysmography would decrease the number of false positive and negative diagnoses and could markedly decrease the need for serial impedance plethysmography. Combining the clinical model with impedance plethysmography could overcome the fact that impedance plethysmography is clearly less accurate than venous ultrasound imaging. The use of the revised clinical model may increase acceptability and utility, but prospective testing is required before widespread use.

Diagnosis, Differential↗

PubMed2003

Combined use of clinical assessment and d-dimer to improve the management of patients presenting to the emergency department with suspected deep vein thrombosis (the EDITED Study).

Suspected deep vein thrombosis (DVT) is a common problem facing emergency physicians. Timely diagnostic testing must be performed to accurately identify patients with DVT. The purpose of this study was to evaluate the safety and effectiveness of a management strategy that combined consideration of clinical pretest probability and a d-dimer test to evaluate patients presenting to the emergency department with suspected deep vein thrombosis (DVT). A prospective cohort study was performed in the emergency departments of four tertiary care institutions involving 1075 patients with suspected DVT. An emergency physician determined the pretest probability for DVT to be low, moderate, or high using an explicit clinical model. A blood sample was taken for d-dimer testing. Subsequent investigations (compression ultrasound, venography) were performed based upon the pretest probability and the d-dimer result. Patients considered at low pretest probability with negative d-dimer had no further diagnostic testing performed. All patients in whom the diagnosis of DVT was excluded by the algorithm did not receive anticoagulant therapy and were followed up for 90 days for the development of proximal DVT or pulmonary embolism. Overall, 195 (18.1%; 95% CI 15.9% to 20.6%) of 1075 patients were confirmed to have proximal DVT. Of the 882 patients who had proximal DVT excluded during the initial evaluation period using the algorithms, four (0.5%; 95% CI 0.1% to 1.2%) were subsequently diagnosed with proximal DVT in the follow-up period, including three patients in the low pretest probability group (1.0%; 95% CI 0.2% to 2.1%) who had normal d-dimer and no additional diagnostic testing performed. None of the 882 patients (0%: 95% CI 0% to 0.5%) developed pulmonary embolism in the follow-up period. A diagnostic strategy for the evaluation of patients with suspected DVT based on pretest probability and d-dimer is safe and feasible in the emergency department setting.

Adult↗

PubMed2004

[Comparison of the cost-effectiveness of the most common diagnostic methods for coronary artery disease].

BACKGROUND AND OBJECTIVE: The cost-effectiveness of medical procedures is becoming a crucial factor besides their efficacy in clinical decision-making. We performed a cost-effectiveness analysis of the most common diagnostic modalities used in assessing coronary artery disease (CAD). METHODS: A decision tree model for determining the cost-effectiveness in CAD diagnosis was applied to the situation in Germany to calculate the cost-effectiveness of exercise ECG (ExECG), stress echocardiography (ECHO), myocardial scintigraphy (SPECT), and coronary angiography (ANGIO). The cost-effectiveness was defined as direct and induced costs per correctly identified patient. A sensitivity analysis was performed varying the predictive accuracies, the complication-related costs, and costs and complication rates of ANGIO. RESULTS: The costs per correctly identified patient decreased in a hyperbolic fashion as the pretest likelihood of CAD increased due to the higher incidence of positive findings. For a pretest likelihood between 10 and 40%, ExECG and ECHO were most cost effective with costs per CAD patient of 5,880 - 2,500 EUR and 6,410 - 2,280 EUR, respectively. The combination of ExECG und ECHO (application of the second modality in case the first one was nondiagnostic) further improved the cost-effectiveness up to a pretest likelihood of 35%. For a pretest likelihood of 50% or greater, ANGIO costing 1,880 - 940 EUR per correct diagnosis was most cost-effective. Sensitivity analysis revealed no significant changes demonstrating the robustness of the model. CONCLUSION: ANGIO is the most cost-effective procedure for a pretest likelihood of 50% or greater. At lower pretest likelihoods, ExECG, ECHO and the combined ExECG/ECHO strategy based on economic considerations are the preferred modalities for diagnosis of CAD.

Cohort Studies↗

PubMed2006

Involvement of NMDA receptors in morphine state-dependent learning in mice.

In the present study, the effects of intracerebroventricular (i.c.v.) injection of NMDA receptor agonist and antagonist on impairment of memory formation and the state-dependent learning by morphine have been investigated in mice. Pretraining administration of morphine (5 mg/kg; s.c.) decreased the learning of one-trial passive avoidance task. Pretest administration of morphine (5 mg/kg) induced state-dependent learning acquired under pretraining morphine influence. Pretest administration of NMDA receptor agonist, L-glutamate (0.00001 and 0.0001 and 0.001 microg/mouse, i.c.v.) following pretraining saline treatment did not affect retention. Amnesia induced by pretraining morphine was significantly reversed by pretest administration of L-glutamate (0.0001 and 0.001 microg/mouse, i.c.v.). Pretest administration of noncompetitive NMDA receptor antagonist, MK-801 (0.5, 1, and 2 microg/mouse, i.c.v.) significantly impaired memory formation. Amnesia induced by pretraining morphine was increased by pretest administration of MK-801 (2 microg/mouse, i.c.v.). Pretest coadministration of L-glutamate (0.0001 and 0.001 microg/mouse, i.c.v.) or MK-801 (0.5, 1, and 2 microg/mouse, i.c.v.) with morphine (5 mg/kg, s.c.) increased and decreased morphine state-dependent learning, respectively. The results suggest that NMDA receptors are involved in morphine state-dependent learning in mice.

Animals↗

PubMed2005

Immediate and delayed bilateral transfer of throwing accuracy in male and female children.

In the present study, an attempt was made to examine the nature and persistence of bilateral transfer of a throwing skill for a large sample of male and female children. One hundred sixty children ages 6, 8, 10, and 12 years were randomly assigned to either an experimental or control group with an equal number of boys and girls in each group. The experiment lasted 2 days and consisted of a pretest, a practice phase, an immediate transfer test, and a delayed transfer test. On the pretest, each participant performed 10 trials of a novel one-hand throwing task. Following the pretest, participants in the experimental group practiced the skill with the hand opposite the one used during the pretest until they had successfully reached a designated criterion for their age. Participants in the control group performed a balancing activity. Following the practice phase, all participants performed immediate (10 min later) and delayed (24 hr later) transfer tests under the same conditions as the pretest. The results revealed no group differences on the pretest but significantly higher throwing accuracy for the experimental group than the control group on both transfer tests. In addition, boys' throwing accuracy was significantly superior to the girls. It was concluded that bilateral transfer of throwing accuracy can be both a temporary and relatively persistent phenomenon for children and the superior throwing accuracy for boys is consistent with similar gender differences in throwing distance and throwing velocity (Thomas & French, 1985).

Analysis of Variance↗

PubMedDate not supplied

Assessing recalibration as a response-shift phenomenon.

BACKGROUND: Traditionally, the difference between pretest and posttest scores is used as an estimate of change. This can be problematic when repeated self-report measures are used to assess change resulting from interventions intended to change beliefs, behaviors, attitudes, or values about health or safety. If the intervention is effective, participants may apply more stringent criteria in response to a posttest questionnaire than they did at the pretest. This kind of change has been termed a recalibration response shift. OBJECTIVES: To present scale recalibration as a measurable response shift, and to illustrate a method that can be used to estimate its magnitude and direction: the retrospective pretest. METHODS: In a quasi-experimental study investigating the effectiveness in small construction companies of narrative simulation exercises targeting back and fall injuries, a retrospective pretest was administered concurrently with a delayed posttest 4 months after the simulation exercises. RESULTS: : In the first intervention year, the results from a brief (two-item) retrospective pretest pertaining to safety climate were consistent with a recalibration response shift in the intervention group, but not in the control group. In the second intervention year, when all 10 items of the safety climate questionnaire were used for the retrospective pretest, no evidence of recalibration was found. CONCLUSIONS: Although the evidence of recalibration was equivocal, the findings illustrate circumstances in which recalibration response shifts may occur and characteristic patterns of findings may suggest that recalibration has or has not occurred.

Back Injuries↗

PubMed1985

High school students' long-term retention of sex education information.

Ninth grade students in a rural South Carolina school were pretested about sexuality information, completed a 12-unit reproductive health course in eight months, and were posttested. A control group received the same pretest and posttest. Both groups were retested after the 10th and 11th grades and mean scores were calculated and compared. The difference between the experimental group's pretest and posttest mean scores was 8.49 (p less than .001); the difference between the control group's pretest and posttest mean scores was 1.0 (p = .003). The experimental group's mean score remained at least 5.2 points higher (p less than .001) than the control group's score on the same test one and two years after the course. Comparison of the mean gain between the pretest and posttest scores, and between the pretest and fourth test scores, confirmed the results obtained by mean test scores. The test scores indicated that the knowledge of the experimental students increased significantly and was sustained for two years. Their scores remained significantly higher than those of the control group on the posttest, and on tests one and two years later.

Adolescent↗

PubMed2003

Evaluating change in attitude towards mathematics using the 'then-now' procedure in a cooperative learning programme.

BACKGROUND: Tertiary students' attitudes to mathematics are frequently negative and resistant to change, reflecting low self-efficacy. Some educators believe that greater use should be made of small group, collaborative teaching. However, the results of such interventions should be subject to assessments of bias caused by a shift in the frame of reference used by students in reporting their attitudes. AIMS: This study was designed to assess whether traditional pretest-post-test procedures would indicate positive changes in mathematics attitude during a programme of cooperative learning, and whether an examination of any attitudinal change using the 'then-now' procedure would indicate bias in the results due to a shift in the internal standards for expressing attitude. SAMPLE: Participants were 141 undergraduate students enrolled in a 12-week statistics and research design component of a course in educational psychology. METHOD: Using multivariate procedures, pretest, post-test, and then-test measures of mathematics self-concept and anxiety were examined in conjunction with a cooperative learning approach to teaching. RESULTS: Significant positive changes between pretest and post-test were found for both mathematics self-concept and mathematics anxiety. There were no significant differences between the actual pretest and retrospective pretest measures of attitude. The results were not moderated by prior level of mathematics study. CONCLUSION: Conclusions about the apparent effectiveness of a cooperative learning programme were strengthened by the use of the retrospective pretest procedure.

Anxiety↗

PubMed2000

Are the American College of Cardiology/American Heart Association guidelines for exercise testing for suspected coronary artery disease correct?

BACKGROUND: Recently published American College of Cardiology (ACC)/American Heart Association (AHA) guidelines state that patients with suspected coronary disease and an intermediate pretest probability are appropriate candidates for exercise ECG, while those with low or high pretest probability are not. METHODS: From 5,103 consecutive patients with symptoms of suspected coronary disease, we evaluated 872 patients who underwent coronary angiography following exercise ECG. Differences in test performance were determined using receiver operating characteristic curve area analysis. A score using age, gender, symptoms, and risk factors was used to classify patients into low, intermediate, and high pretest probability groups. RESULTS: When patients with inadequate exercise tests were excluded, overall sensitivity and specificity were 70% and 66%, respectively. Only the intermediate pretest probability group demonstrated significant incremental value: pretest vs posttest intermediate, 70 +/- 3 vs 79 +/- 3 (p < 0.0001); low, 71 +/- 6 vs 76 +/- 7 (p = 0.39); and high, 69 +/- 8 vs 75 +/- 7 (p = 0.12). From the low- to the high-probability groups, there was a progressive increase in positive predictive value (21%, 62%, and 92%) and decrease in negative predictive value (94%, 72%, and 28%), respectively. The frequencies of abnormal exercise ECGs were lower in the unselected groups compared with the angiography groups (low, 13% vs 36%; intermediate, 22% vs 53%; high, 36% vs 63%). CONCLUSIONS: Based on the information added by exercise testing to clinical data, these results confirm the ACC/AHA guideline assignments for test selection. However, despite these guidelines, patients with a low pretest probability can be selected for exercise testing with the knowledge that a positive result is infrequent and a negative result carries a very high negative predictive value. Intermediate-probability patients on average carry a significant false-negative rate, suggesting that exercise ECG alone may not be a sufficient screening test in all intermediate-probability patients. Because of poor negative predictive value and a large percentage of negative tests, high-probability patients should undergo coronary angiography as the initial strategy, unless the goal of exercise testing is to assess prognosis.

American Heart Association↗

PubMed2004

Pathology informatics questions and answers from the University of Pittsburgh pathology residency informatics rotation.

CONTEXT: Effective pathology practice increasingly requires familiarity with concepts in medical informatics that may cover a broad range of topics, for example, traditional clinical information systems, desktop and Internet computer applications, and effective protocols for computer security. To address this need, the University of Pittsburgh (Pittsburgh, Pa) includes a full-time, 3-week rotation in pathology informatics as a required component of pathology residency training. OBJECTIVE: To teach pathology residents general informatics concepts important in pathology practice. DESIGN: We assess the efficacy of the rotation in communicating these concepts using a short-answer examination administered at the end of the rotation. Because the increasing use of computers and the Internet in education and general communications prior to residency training has the potential to communicate key concepts that might not need additional coverage in the rotation, we have also evaluated incoming residents' informatics knowledge using a similar pretest. DATA SOURCES: This article lists 128 questions that cover a range of topics in pathology informatics at a level appropriate for residency training. These questions were used for pretests and posttests in the pathology informatics rotation in the Pathology Residency Program at the University of Pittsburgh for the years 2000 through 2002. With slight modification, the questions are organized here into 15 topic categories within pathology informatics. The answers provided are brief and are meant to orient the reader to the question and suggest the level of detail appropriate in an answer from a pathology resident. RESULTS: A previously published evaluation of the test results revealed that pretest scores did not increase during the 3-year evaluation period, and self-assessed computer skill level correlated with pretest scores, but all pretest scores were low. Posttest scores increased substantially, and posttest scores did not correlate with the self-assessed computer skill level recorded at pretest time. CONCLUSIONS: Even residents who rated themselves high in computer skills lacked many concepts important in pathology informatics, and posttest scores showed that residents with both high and low self-assessed skill levels learned pathology informatics concepts effectively.

Internship and Residency↗

PubMed1998

Use of a clinical model for safe management of patients with suspected pulmonary embolism.

BACKGROUND: The low specificity of ventilation-perfusion lung scanning complicates the management of patients with suspected pulmonary embolism. OBJECTIVE: To determine the safety of a clinical model for patients with suspected pulmonary embolism. DESIGN: Prospective cohort study. SETTING: Five tertiary care hospitals. PATIENTS: 1239 inpatients and outpatients with suspected pulmonary embolism. INTERVENTIONS: A clinical model categorized pretest probability of pulmonary embolism as low, moderate, or high, and ventilation-perfusion scanning and bilateral deep venous ultrasonography were done. Testing by serial ultrasonography, venography, or angiography depended on pretest probability and lung scans. MEASUREMENTS: Patients were considered positive for pulmonary embolism if they had an abnormal pulmonary angiogram, abnormal ultrasonogram or venogram, high-probability ventilation-perfusion scan plus moderate or high pretest probability, or venous thromboembolic event during the 3-month follow-up. All other patients were considered negative for pulmonary embolism. Rates of pulmonary embolism during follow-up in patients who had a normal lung scan and those with a non-high-probability scan and normal serial ultrasonogram were compared. RESULTS: Pretest probability was low in 734 patients (3.4% with pulmonary embolism), moderate in 403 (27.8% with pulmonary embolism), and high in 102 (78.4% with pulmonary embolism). Three of the 665 patients (0.5% [95% CI, 0.1% to 1.3%]) with low or moderate pretest probability and a non-high-probability scan who were considered negative for pulmonary embolism had pulmonary embolism or deep venous thrombosis during 90-day follow-up; this rate did not differ from that in patients with a normal scan (0.6% [CI, 0.1% to 1.8%]; P > 0.2). CONCLUSION: Management of patients with suspected pulmonary embolism on the basis of pretest probability and results of ventilation-perfusion scanning is safe.

Algorithms↗

PubMed2001

Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer.

BACKGROUND: The limitations of the current diagnostic standard, ventilation-perfusion lung scanning, complicate the management of patients with suspected pulmonary embolism. We previously demonstrated that determining the pretest probability can assist with management and that the high negative predictive value of certain D -dimer assays may simplify the diagnostic process. OBJECTIVE: To determine the safety of using a simple clinical model combined with D -dimer assay to manage patients presenting to the emergency department with suspected pulmonary embolism. DESIGN: Prospective cohort study. SETTING: Emergency departments at four tertiary care hospitals in Canada. PATIENTS: 930 consecutive patients with suspected pulmonary embolism. INTERVENTIONS: Physicians first used a clinical model to determine patients' pretest probability of pulmonary embolism and then performed a D -dimer test. Patients with low pretest probability and a negative D -dimer result had no further tests and were considered to have a diagnosis of pulmonary embolism excluded. All other patients underwent ventilation-perfusion lung scanning. If the scan was nondiagnostic, bilateral deep venous ultrasonography was done. Whether further testing (by serial ultrasonography or angiography) was done depended on the patients' pretest probability and the lung scanning results. MEASUREMENTS: Patients received a diagnosis of pulmonary embolism if they had a high-probability ventilation-perfusion scan, an abnormal result on ultrasonography or pulmonary angiography, or a venous thromboembolic event during follow-up. Patients for whom the diagnosis was considered excluded were followed up for 3 months for the development of thromboembolic events. RESULTS: The pretest probability of pulmonary embolism was low, moderate, and high in 527, 339, and 64 patients (1.3%, 16.2%, and 37.5% had pulmonary embolism), respectively. Of 849 patients in whom a diagnosis of pulmonary-embolism had initially been excluded, 5 (0.6% [95% CI, 0.2% to 1.4%]) developed pulmonary embolism or deep venous thrombosis during follow-up. However, 4 of these patients had not undergone the proper diagnostic testing protocol. In 7 of the patients who received a diagnosis of pulmonary embolism, the physician had performed more diagnostic tests than were called for by the algorithm. In 759 of the 849 patients in whom pulmonary embolism was not found on initial evaluation, the diagnostic protocol was followed correctly. Only 1 (0.1% [CI, 0.0% to 0.7%]) of these 759 patients developed thromboembolic events during follow-up. Of the 437 patients with a negative D -dimer result and low clinical probability, only 1 developed pulmonary embolism during follow-up; thus, the negative predictive value for the combined strategy of using the clinical model with D -dimer testing in these patients was 99.5% (CI, 99.1% to 100%). CONCLUSION: Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.

Adolescent↗

PubMed1987

A comparison of computer-assisted instruction and printed information as methods of pharmacy continuing education.

A continuing education (CE) program was developed to teach hospital pharmacists parameters for monitoring adult total parenteral nutrition (TPN) patients. The effectiveness of a computer-assisted instruction (CAI) module as a method of CE was compared with that of printed information (PI). The computer program was developed using an Apple IIe personal computer and Apple Pilot. Forty-nine hospital pharmacists were given a pretest, the CAI or PI program, a posttest immediately after the instruction, and a retention test 2 weeks later. The CAI group (n = 23) had mean test scores of 53.3% for the pretest, 87.7% for the posttest, and 81.9% for the retention test. The PI group (n = 26) had mean test scores of 54.2% for the pretest, 84.7% for the posttest, and 78.2% for the retention test. Both methods were effective CE programs based on increases in mean test scores from pretest to posttest. Retention-test scores showed a statistically significant drop from posttest scores for each group. A comparison of mean retention-test scores with mean pretest scores for each group demonstrated that participants in each group had retained a statistically significant amount of material from baseline knowledge. When differences in mean pretest, posttest, and retention-test scores were compared between the two groups, no statistically significant differences were found. CAI and PI were equally effective methods of continuing education.

Computer-Assisted Instruction↗

PubMed1999

D-dimer testing in the diagnosis of acute venous thromboembolism.

Patients with acute VTE require clinical assessment and objective testing to be accurately diagnosed. Almost all patients with acute VTE have an elevated D-dimer level. An elevated D-dimer is associated with many illnesses, and therefore, is not specific for VTE. D-dimer tests can have a high sensitivity, however, which is useful because a normal test excludes the diagnosis of VTE. D-dimer testing is most appropriate in the assessment of outpatients because the prevalence of disease and the likelihood of comorbid conditions are lower than in inpatient populations, making a test of exclusion particularly valuable. Accuracy studies using conventional ELISA assays have confirmed that a test with a high sensitivity can be used to exclude a diagnosis of VTE, but conventional ELISA testing is not practical. Studies of more practical D-dimer testing indicate that, for patients with suspected DVT or PE, the need for serial testing or further investigation can be reduced if normal results are obtained using assays with a high sensitivity. There are, however, many sources of variation in the test characteristics of D-dimer assays. Therefore there is no reassurance that results from one manufacturer's test are applicable to other tests and different investigators may obtain varied results when using the same manufacturer's product. In addition, the results of D-dimer accuracy studies lack generalizability. This lack of generalizability has led to the recommendation that clinicians await the results of management studies before adopting the routine use of D-dimer assays in the diagnosis of VTE. Further, it may be reasonable to perform an accuracy study when planning to adopt a specific D-dimer assay from a published management trial, to be confident of its characteristics can be reproduced. In the management of patients with suspected DVT, rapid ELISA tests show promise as a practical D-dimer test, in that they have a sensitivity similar to that of the conventional ELISA assay. Two management studies have recently confirmed that a normal D-dimer result (using the SimpliRED whole-blood assay or the Instant IA rapid ELISA) in combination with a noninvasive test or a clinical model can reliably exclude DVT in outpatients. Use of a clinical model can reduce the need for VU, and the combination of a clinical model and D-dimer testing could further reduce the number of VU procedures required. As noted by Wells et al, who recently published a clinical model, however, a normal D-dimer result was most accurate in the patients with a low pretest likelihood (NPV = 99.5%) and least accurate in patients with a high pretest likelihood (NPV = 85.7%) Patients with a low pretest likelihood and a normal D-dimer are the largest proportion of outpatients referred for testing, and considerable resources may be saved if additional management studies confirm the usefulness of D-dimer testing in such patients. In patients with suspected PE, there is a lack of published management trials despite a number of accuracy studies indicating that D-dimer testing may be useful as a method of PE diagnosis exclusion. Recent results, however, from an accuracy study of patients with suspected PE who had D-dimer testing complement the findings of Wells et al in patients with suspected DVT. Using a standardized clinical model of PE in combination with a SimpliRED D-dimer assay, Ginsberg and colleagues found that the combination of a low pretest likelihood and a normal D-dimer had a negative predictive value of 99%, whereas the negative predictive value was only 78% in patients with a high pretest likelihood and a normal D-dimer. Similar to the findings in DVT, these results indicate that D-dimer testing is most useful in patients with a low pretest likelihood for PE and raise the possibility that such patients may not require lung scans. This finding is currently being evaluated in a prospective management trial.

Acute Disease↗

PubMed1983

Hospital diabetes education: classroom and self-instruction.

This study was conducted to assess the effectiveness of two approaches to instructing hospitalized patients with diabetes mellitus on the food exchange system. Both groups were given the same pretest and post-test, but one group received self-instruction and the other group received classroom instruction. The pretest scores of the two groups indicated differences in their initial understanding of the food exchange system. The mean score on the pretest for the classroom instruction group was 1.95 points higher than for the self-instruction group on the 18-point test. The self-instruction group gained 3.45 more points than the classroom instruction group on their post-test scores. An analysis of gain between pretest and post-test for both groups indicated that both treatments could be considered effective. However, when the pretest was analyzed as an independent variable, it was shown to have an influence on the post-test results. In controlling for the pretest in the analysis of covariance, the LAP treatment was found to be more effective than the classroom instruction for teaching patients with diabetes mellitus about the food exchange system. As diabetes affects persons from all demographic groups, a variety of programs are needed to meet individual needs (15). Demands for education programs in institutions are being met as patients' needs change. The two instructional approaches assessed in this research are recommended as viable options to use in educating the increasing number of persons with diabetes mellitus.

Adolescent↗

PubMed1999

Thrombosis in the emergency department: use of a clinical diagnosis model to safely avoid the need for urgent radiological investigation.

CONTEXT: The management of patients presenting to hospital emergency departments with suspected deep vein thrombosis (DVT) is problematic because urgent diagnostic imaging capability is sometimes unavailable. Experienced physicians using clinical skills alone can classify patients with suspected DVT into low-, moderate-, and high-probability categories. OBJECTIVES: To determine the accuracy of an explicit clinical model for the diagnosis of DVT when applied by emergency department physicians and to assess the safety and feasibility of a management strategy based on the clinical pretest probability for patients presenting to the emergency department with suspected DVT outside of regular hospital staff work hours. METHODS: A prospective cohort study was performed in the emergency departments of 2 tertiary care institutions involving 344 patients with suspected DVT. Patient conditions were evaluated by an emergency department physician who determined the pretest probability for DVT to be low, moderate, or high using an explicit clinical model. Patients for whom DVT was considered a low pretest probability were discharged from the emergency department and returned the following day for venous compression ultrasound imaging of the affected leg. Patients for whom DVT was considered a moderate pre-test probability received a single, weight-adjusted dose of subcutaneous unfractionated heparin sodium (between 12 500 and 20 000 U), were discharged from the emergency department, and returned the next morning to undergo ultrasonography. Patients for whom DVT was considered a high pretest probability were admitted to the hospital, administered intravenous unfractionated heparin, and ultrasonography was arranged within 24 hours. Patients with positive ultrasonographic findings were diagnosed with DVT, except for those with low pretest probability for whom confirmatory venography was performed. Patients with DVT excluded in the initial evaluation period did not receive anticoagulant therapy. All patients were followed up for 90 days to monitor development of thromboembolic or bleeding complications. RESULTS: Twenty-four (49.0% [95% confidence interval (CI), 34.5%-63.6%]) of 49 patients in the high-probability category, 15 (14.3% [95% CI, 8.3%-22.4%]) of 105 in the moderate-, and 6 (3.2% [95% CI, 1.2%-6.7%]) of 190 in the low-probability category were confirmed to have DVT. Overall, 45 (13.1%) of 344 patients were confirmed to have DVT. No patient developed pulmonary embolism or major bleeding complications within 48 hours of initial evaluation in the emergency department. Of the 301 patients who had DVT excluded during the initial evaluation period, only 2 (0.7% [95% CI, 0.1%-2.3%]) developed venous thromboembolic complications (calf vein thromboses in both) in the 3-month follow-up period. CONCLUSIONS: Using an explicit clinical model, emergency department physicians can accurately classify patients with suspected DVT into high-, moderate-, and low-probability groups. A management plan based on probability for DVT that avoids the need for urgent diagnostic imaging is safe and feasible in the emergency department setting.

Decision Trees↗

PubMed2002

Simplification of the diagnostic management of suspected deep vein thrombosis.

BACKGROUND: The standard diagnostic approach in patients with suspected deep vein thrombosis is to repeat the compression ultrasonography after 1 week in all patients with an initial normal result. We hypothesized that a normal finding of a D-dimer assay safely obviates the need for repeated ultrasonography. In addition, we evaluated the potential value of a pretest probability assessment for this purpose. METHODS: At presentation, consecutive outpatients with suspected thrombosis underwent independent assessment by means of ultrasonography of the proximal veins, a whole-blood D-dimer assay, and a pretest clinical model. Patients with normal ultrasonographic findings and an abnormal D-dimer assay result were scheduled for repeated ultrasonography. We evaluated the incidence of symptomatic venous thromboembolic complications during a 3-month follow-up, and the value of clinical pretest probability with ultrasonography or D-dimer assay in scenario analyses. RESULTS: We studied 1756 patients with prevalence of thrombosis of 22%. At entry, results of the D-dimer assay and ultrasonography were normal in 828 patients (47%). Of these, 6 returned with confirmed symptomatic venous thromboembolism (complication rate, 0.7%; 95% confidence interval [CI], 0.3%-1.6%). Repeated ultrasonography was avoided in 61% of the patients with an initial normal test result. Scenario analyses disclosed that the complication rate was 1.6% (95% CI, 0.8%-2.6%) in those with a low clinical pretest probability and a normal result of ultrasonography at referral, whereas this figure was 1.8% (95% CI, 0.9%-3.3%) in patients with a low clinical probability result and a normal result of the D-dimer assay at referral. CONCLUSIONS: It is safe to withhold repeated ultrasonography in patients with suspected deep vein thrombosis who have normal results of ultrasonograpy and the SimpliRED D-dimer assay at presentation. The combination of a low clinical pretest probability with a normal result of compression ultrasonography or the D-dimer assay appears to be equally safe in refuting the diagnosis of deep vein thrombosis.

Adolescent↗

PubMed2006

Impact of reliance on CT pulmonary angiography on diagnosis of pulmonary embolism: a Bayesian analysis.

BACKGROUND: Spiral computed tomographic pulmonary angiography (CTPA) has become the primary test used to investigate suspected pulmonary embolism (PE) at many institutions, despite uncertainty regarding its sensitivity and specificity. Although CTPA-based diagnostic algorithms focus on minimizing the false-negative rate, we hypothesized that increasing use of CTPA also might lead to false-positive diagnoses. OBJECTIVE: Determine the frequency of possible false-positive diagnoses of PE when CTPA is the primary diagnostic test. DESIGN: Retrospective cohort study. SETTING: Two academic teaching hospitals. PARTICIPANTS: 322 patients with suspected PE evaluated with CTPA. MEASUREMENTS: We used a validated prediction rule to determine the pretest probability of PE in each patient. We combined these pretest probabilities with published estimates of CTPA test characteristics to generate expected posttest probabilities of PE. We compared these posttest probabilities to actual treatment decisions to determine the rate of false-positive diagnoses of PE. RESULTS: Among 322 patients investigated for PE, 37 (12%) had high pretest probability, 101 (32%) moderate, and 184 (57%) low. CT scans were interpreted as positive for PE in 57 patients (17.8%). Regardless of the pretest probability of PE, 96.5% of patients with a positive CTPA were treated with anticoagulants. Even under an optimistic assumption of CTPA test characteristics, as many as 25.4% of these patients may have been treated unnecessarily as a result of a false-positive diagnosis. Most of these patients had a low pretest probability of PE. CONCLUSIONS: Failure to utilize Bayesian reasoning when interpreting CTPA may lead to false-positive diagnoses of pulmonary embolism in a substantial proportion of patients.

Bayes Theorem↗