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Arnaud Perrier

Publications and source records attributed to Arnaud Perrier.

At least 37 records · Page 2Linked to original sources
PubMed2006

A positive compression ultrasonography of the lower limb veins is highly predictive of pulmonary embolism on computed tomography in suspected patients.

The presence of a clot-- even asymptomatic-- in the proximal lower limb veins of a patient with clinically suspected pulmonary embolism (PE) provides evidence for venous thromboembolism and indicates anticoagulant therapy in such patients. We aimed at assessing the diagnostic performance of compression ultrasonography as compared to multi-slice computed tomography (MSCT) for the diagnosis of PE. We analyzed data from a large outcome management study that included consecutive outpatients referred to the emergency ward with clinically suspected PE. All high clinical probability patients, and all non-high clinical probability patients with a positive D-dimer test underwent both MSCT and CUS. Of the 756 included patients, 232 had PE ruled out on the basis of a negative D-dimer test, and 524 patients underwent both MSCT and CUS. PE was found in 187 out of the 511 patients with a conclusive MSCT. The sensitivity of CUS for the presence of PE on MSCT was 39% (95% confidence interval: 32 to 46%), and its specificity was 99% (95% CI:97 to 100%). Positive and negative likelihood ratios were 42.2 (95% CI: 13.5 to 131.9) and 0.6 (95% CI: 0.5 to 0.7), respectively. We conclude from that large study of unselected patients that CUS has high specificity but low sensitivity, for the diagnosis of PE at MSCT in suspected patients. It allows ruling in the diagnosis of PE without further invasive and/or expensive testing in suspected patients.

Adolescent↗
PubMed2006

Clinical relevance of distal deep vein thrombosis. Review of literature data.

The standard diagnostic approach of suspected deep vein thrombosis (DVT) is serial lower limb compression ultrasound (CUS) of proximal veins. Although it only assesses the proximal veins, withholding anticoagulant treatment in patients with a negative CUS on day one and after one week has been proven to be safe. However, in many centres, distal DVT is systematically screened for and treated by anticoagulants. The objectives of the review were 1) to evaluate the rate of extension of distal DVTs to proximal veins 2) to compare the safety of proximal limited CUS versus single complete CUS. We performed a MEDLINE search covering the period from January 1983 to January 2005 by using the key-words "calf vein thrombosis", "distal thrombosis" and "compression ultrasonography". English, German and French language original studies were retrieved. Moreover, references of retrieved articles were screened in order to detect missed pertinent articles. We pooled data of management studies where proximal or complete (i.e. proximal and distal) CUS were used, respectively. Studies evaluating CUS limited to the proximal veins showed a good safety profile with a pooled estimate of the 3-month thromboembolic rate of 0.6% (95% CI: 0.4-0.9%) in patients in whom anticoagulation was withheld. Studies using proximal and distal CUS showed a similar pooled estimate of the 3-month thromboembolic rate (0.4%, 95% CI: 0.1-0.6%) but distal DVT accounted for as many as 50% of all diagnosed DVTs in those series. Therefore, searching for distal DVT potentially doubles the number of patients given anticoagulant therapy and entails a risk of over-treatment. Data suggesting that anticoagulation is indicated for distal DVT are limited, and realizing distal CUS entails a risk of over-treatment. There is an urgent need for randomised trials assessing the usefulness of anticoagulant treatment in distal DVT.

Anticoagulants↗
PubMed2006

Clinical usefulness of D-dimer testing in cancer patients with suspected pulmonary embolism.

Limited data are available about the diagnostic value of D-dimer testing in cancer patients with clinically suspected pulmonary embolism (PE). Therefore, we evaluated i) the safety and clinical usefulness of an ELISA D-dimer test to rule out PE in cancer patients compared with non-cancer patients and ii) whether adopting a higher D-dimer cut-off value might increase the usefulness of D-dimer in cancer patients. We analysed data from two outcome studies which enrolled 1,721 consecutive patients presenting in the emergency department with clinically suspected PE. Presence of an active malignancy was abstracted from the database. All patients underwent a sequential diagnostic work-up including an ELISA D-dimer test and a 3-month followup. Sensitivity and predictive value (NPV) were 100% in both cancer and non-cancer patients. PE was ruled out by a negative D-dimer test in 494/1,554 (32%) patients without cancer, and in 18/164 (11%) patients with a malignancy. At cut-off values varying from 500 to 900 microg/l, the sensitivity was unchanged (100%, 95% CI: 93% to 100%) and the specificity increased from 16% (95% CI: 11% to 24%) to 30% (95% CI: 22% to 39%). The 3-month thromboembolic risk was 0% (95% CI: 0% to 18%) in cancer patients with a negative D-dimer test. ELISA D-dimer appears safe to rule out pulmonary embolism in cancer patients but it is negative in only one of ten patients at the usual cut-off value. Increasing the cut-off value of D-dimer in cancer patients might increase the test's clinical usefulness.

Aged↗
PubMed2006

Prognostic value of D-dimer in patients with pulmonary embolism.

D-dimer levels appear to be associated with the extent of the thromboembolic burden in patients with pulmonary embolism (PE). We therefore hypothesized that D-dimer levels at admission would be associated with prospective risk of mortality in patients with PE. We used data from 366 patients diagnosed with PE at four hospital emergency departments. A highly sensitive D-dimer test was prospectively performed at admission. The outcome was overall mortality within three months. We divided patients into quartiles on the basis of their D-dimer levels and compared mortality rates by quartile. We estimated sensitivity, specificity, and predictive values for mortality in the first and fourth quartile. Overall mortality was 5.2%. Patients who died had higher median D-dimer levels than patients who survived (4578 versus 2946 microg/l; p = 0.005). Mortality increased with increasing D-dimer levels, rising from 1.1% in the first quartile (<1500 microg/l) to 9.1% in the fourth quartile (>5500 microg/l) (P = 0.049). Sensitivity, specificity, and positive and negative predictive values of D-dimer levels <1500 microg/l to predict mortality were 95%, 26%, 7%, and 99%, respectively. Patients with PE who have D-dimer levels below 1500 microg/l have a very low mortality. Further studies must assess whether D-dimer, alone or combined with other prognostic instruments for PE, can be used to identify low-risk patients with PE who are potential candidates for outpatient treatment or an abbreviated hospital stay.

Aged↗
PubMed2005

[Nurse-physician collaboration: a determinant of the quality of care?].

In hospital practice, the most elementary form of interdisciplinary care is the collaboration between nurses and physicians. Physicians rate the quality of collaboration with nurses higher than nurses themselves. Studies on the impact of interdisciplinary interventions on quality of care evaluate complex interventions and it is impossible to distinguish the effects of interdisciplinary care from other facets of the intervention. Two recent studies suggest that a better collaboration between physicians and nurses may improve patient outcomes, and reduce length of stay and hospital costs. What is meant by collaboration should be better defined to allow developing strategies for training health care professionals to collaborate efficiently and for evaluating their impact on health care quality.

Cost Control↗
PubMed2005

Derivation and validation of a prognostic model for pulmonary embolism.

RATIONALE: An objective and simple prognostic model for patients with pulmonary embolism could be helpful in guiding initial intensity of treatment. OBJECTIVES: To develop a clinical prediction rule that accurately classifies patients with pulmonary embolism into categories of increasing risk of mortality and other adverse medical outcomes. METHODS: We randomly allocated 15,531 inpatient discharges with pulmonary embolism from 186 Pennsylvania hospitals to derivation (67%) and internal validation (33%) samples. We derived our prediction rule using logistic regression with 30-day mortality as the primary outcome, and patient demographic and clinical data routinely available at presentation as potential predictor variables. We externally validated the rule in 221 inpatients with pulmonary embolism from Switzerland and France. MEASUREMENTS: We compared mortality and nonfatal adverse medical outcomes across the derivation and two validation samples. MAIN RESULTS: The prediction rule is based on 11 simple patient characteristics that were independently associated with mortality and stratifies patients with pulmonary embolism into five severity classes, with 30-day mortality rates of 0-1.6% in class I, 1.7-3.5% in class II, 3.2-7.1% in class III, 4.0-11.4% in class IV, and 10.0-24.5% in class V across the derivation and validation samples. Inpatient death and nonfatal complications were <or= 1.1% among patients in class I and <or= 1.9% among patients in class II. CONCLUSIONS: Our rule accurately classifies patients with pulmonary embolism into classes of increasing risk of mortality and other adverse medical outcomes. Further validation of the rule is important before its implementation as a decision aid to guide the initial management of patients with pulmonary embolism.

Acute Disease↗
PubMed2005

Multidetector-row computed tomography in suspected pulmonary embolism.

BACKGROUND: Single-detector-row computed tomography (CT) has a low sensitivity for pulmonary embolism and must be combined with venous-compression ultrasonography of the lower limbs. We evaluated whether the use of D-dimer measurement and multidetector-row CT, without lower-limb ultrasonography, might safely rule out pulmonary embolism. METHODS: We included 756 consecutive patients with clinically suspected pulmonary embolism from the emergency departments of three teaching hospitals and managed their cases according to a standardized sequential diagnostic strategy. All patients were followed for three months. RESULTS: Pulmonary embolism was detected in 194 of the 756 patients (26 percent). Among the 82 patients with a high clinical probability of pulmonary embolism, multidetector-row CT showed pulmonary embolism in 78, and 1 patient had proximal deep venous thrombosis and a CT scan that was negative for pulmonary embolism. Of the 674 patients without a high probability of pulmonary embolism, 232 (34 percent) had a negative D-dimer assay and an uneventful follow-up; CT showed pulmonary embolism in 109 patients. CT and ultrasonography were negative in 318 patients, of whom 3 had a definite thromboembolic event and 2 died of possible pulmonary embolism during follow-up (three-month risk of thromboembolism, 1.7 percent; 95 percent confidence interval, 0.7 to 3.9). Two patients had proximal deep venous thrombosis and a negative CT scan (risk, 0.6 percent; 95 percent confidence interval, 0.2 to 2.2). The overall three-month risk of thromboembolism in patients without pulmonary embolism would have been 1.5 percent (95 percent confidence interval, 0.8 to 3.0) if the D-dimer assay and multidetector-row CT had been the only tests used to rule out pulmonary embolism and ultrasonography had not been performed. CONCLUSIONS: Our data indicate the potential clinical use of a diagnostic strategy for ruling out pulmonary embolism on the basis of D-dimer testing and multidetector-row CT without lower-limb ultrasonography. A larger outcome study is needed before this approach can be adopted.

Aged↗
PubMed2005

Common strategies in clinical data collection displayed by experienced clinician-teachers in internal medicine.

The role model displayed by clinician-teachers influences learning experiences but learners may face various reasoning styles. Our goal was to describe common strategies in clinical data collection displayed by experienced clinician-teachers in internal medicine. We studied six internists heavily involved in teaching while they were working up the same seven cases portrayed by a standardized patient. Each encounter was audio-recorded and replayed to allow the subjects commenting on the purpose and diagnostic hypotheses considered for each piece of information collected. Information and hypotheses elicited by all physicians were considered key items. Although the subjects reached the same final diagnoses, they differed on several characteristics of their data collection process. They also displayed common behaviours, such as: early acquisition of key data (half of them acquired within the first 19 questions asked) through clarification of the patients' complaints and focused data collection; early generation of the final diagnosis (within the first 10 questions asked) and use of diagnostic hypotheses to frame data collection; and summarization of the information at hand during the encounter (at least twice). Whether making teachers explicitly conscious about their own reasoning processes may help them better model and explain their diagnostic approach to specific cases should be assessed in follow-up studies.

Adolescent↗
PubMed2005

The challenge of diagnosing pulmonary embolism in elderly patients: influence of age on commonly used diagnostic tests and strategies.

Pulmonary embolism (PE) is a potentially fatal disease if left untreated. The prevalence of PE increases markedly with age, and its diagnosis in elderly people is difficult because many cardiopulmonary conditions may mimic clinical presentation of PE, and age may unfavorably influence the characteristics of diagnostic tests for PE. The modern approach to PE is based on sequential diagnostic strategies based on clinical probability, D-dimer measurement, lower limb compression ultrasonography, ventilation-perfusion lung scan, and helical computed tomography (hCT). Pulmonary angiogram is rarely necessary because the noninvasive diagnostic evaluation is usually conclusive. Age reduces the clinical usefulness of D-dimer and ventilation-perfusion lung scan. D-dimer allows excluding PE in only 5% of patients aged 80 and older, compared with 60% younger than 40. Similarly, the rate of inconclusive ventilation-perfusion lung scans is almost twice as high (58%) in patients older than 70 and in patients younger than 40 (32%). In contrast, aging does not change the diagnostic accuracy of clinical probability assessment, whether empirical or as determined by prediction rules, nor appear to influence the diagnostic characteristics of lower limb compression ultrasonography and hCT. Therefore, a rational diagnostic approach to PE in older people should rest mainly on the sequential use of those tests that have demonstrated strong diagnostic yield, accuracy, and safety in this population.

Aged↗
PubMed2004

Exploring the major difficulties perceived by residents in training: a pilot study.

OBJECTIVES: To assess residents' difficulties during the first year of residency. In contrast to previous studies that mainly used structured questionnaires, a qualitative procedure was applied. METHODS: Twenty-four consecutive first-year residents in internal medicine were asked to "Please identify two to three major difficulties or concerns related to your practice of medicine within this hospital". The answers were submitted to content analysis performed by three independent researchers. Inter-rater agreement was high (kappa coefficient = 0.92). Disagreements were solved by consensus. RESULTS: Physicians' characteristics: female 37%, mean age 28 +/- 2.2 years, mean duration of postgraduate training 2.5 +/- 1.3 years. Total number of answers: 122, average answers/resident 5.1 +/- 1.3. Nine categories were extracted from content analysis: communication problems at the workplace, feelings of not being respected, constraints of collaborative work, experiencing the gap between medical school and clinical care, work overload, responsibility towards and emotional investment in patients, worries about career plans, and lack of theoretical knowledge. Residents expressed major difficulties in communicating with and being respected by seniors and peers in particular, and hospital staff in general. They also voiced problems in coping with emotions, either their own or those of their patients. CONCLUSIONS: The residents' responses stressed the complexity of blending the requirements of the physician's role when instrumental/cognitive knowledge is not sufficient to deal with problems requiring personal and relational dimensions. Learning to combine medical knowledge and practice necessitates helping students/residents identify and deal with the constraints of these requirements.

Adult↗
PubMed2004

Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.

PURPOSE: To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT). METHODS: A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months. RESULTS: A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%). CONCLUSION: A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Emergency Service, Hospital↗
PubMed2004

Spectrum bias: a quantitative and graphical analysis of the variability of medical diagnostic test performance.

The performance of a medical diagnostic test may vary in a subgroup of patients according to the severity and clinical presentation of the disease. This phenomenon is often referred to as the spectrum effect. There is currently no technique to determine in which situations this spectrum effect may lead to a spectrum bias, that is, a distortion of the posterior probability which can potentially affect the clinical decision. We show that spectrum bias, on either a positive or a negative test result, can be expressed as the subgroup-specific likelihood ratio (LR) divided by the LR in the overall population of patients. This assessment of spectrum bias is independent of the pretest probability. We present here the test statistic and its variance and also propose a mode of graphically visualizing the presence of spectrum bias. We applied it to 15 examples from the literature, of which three are discussed in detail. In two examples, there was spectrum bias: (1) diagnosis of urinary tract infection in subgroups of low or high risk patients when using the dipstick test, and (2) diagnosis of left ventricular hypertrophy using electrocardiography in subjects with different body mass index. In a third example, there was no spectrum bias for the diagnosis of coronary heart disease in subgroups of patients defined by age, sex or comorbidities when using exercise electrocardiography. As sensitivity and specificity usually vary in opposite directions from one subgroup to the other, the ratio of LRs tends to remain constant, resulting in no or little spectrum bias. We conclude that spectrum effect is more common than spectrum bias and that clinical decisions are affected only under certain conditions.

Adult↗
PubMed2004

Medical researchers evaluate their methodological skills.

BACKGROUND AND OBJECTIVE: Clinical epidemiology and statistics skills of clinical researchers are often limited. We assessed methodological skills of medical researchers and identified factors associated with higher skill levels. METHODS: In a cross-sectional mail survey at two Swiss teaching hospitals, participants (N=409) rated their ability to perform 26 research-related activities, such as identifying the research question, selecting a study design, computing the required sample size, performing data analysis, and reporting results. RESULTS: The proportion of respondents who were able to perform a specific activity was 33.2% on average, ranging from 1.5% for "numerical statistics (bootstrap, simulation, cross-validation,...)" to 76.0% for "oral presentation of results." The overall skill level (expressed as a percentage of the 26 activities) was associated with principal investigator experience (+8.7%), greater percentage of time devoted to research (+12.4% for near full-time versus no time commitment), years of research experience (+17.6% for 15-40 years versus 0 years), past number of clinical research projects (+18.0% for 15-230 projects versus 0-1 projects), and hours of formal methodological training (+32.6% for 200-1200 hours versus 0-9 hours). CONCLUSION: Self-reported methodological skills were generally modest. The most important covariates of skill levels were current time commitment to research, past experience, and formal training.

Adult↗
PubMed2004

Nutritional assessment: lean body mass depletion at hospital admission is associated with an increased length of stay.

BACKGROUND: Low fat-free mass may be an independent risk factor for malnutrition that results in an increased length of hospital stay (LOS). OBJECTIVES: The objectives were to compare differences in fat-free mass and fat mass at hospital admission between patients and healthy control subjects and to determine the association between these differences and the LOS. DESIGN: Patients (525 men, 470 women) were prospectively recruited at hospital admission. Height-corrected fat-free mass and fat mass (fat-free-mass index or fat-mass index; in kg/m2) were determined in patients at admission by bioelectrical impedance analysis and were compared with values for sex-, age-, and height-matched control subjects. Patients were classified as well-nourished, moderately depleted, or severely depleted on the basis of a Subjective Global Assessment questionnaire and a body mass index (in kg/m2) < or > 20. RESULTS: Low fat-free mass was noted in 37% and 55.6% of patients hospitalized 1-2 d and > 12 d, respectively. The odds ratios were significant for fat-free-mass index and were higher in patients with a LOS of > 12 d [men (odds ratio: 5.6; 95% CI: 3.1, 10.4), women (4.4; 2.3, 8.7)] than in those with a LOS of 1-2 d [men (3.3; 2.2, 5.0), women (2.2; 1.6, 3.1)]. Severe nutritional depletion was significantly associated only with a LOS > 12 d. CONCLUSION: Fat-free mass and fat-free-mass index were significantly lower in patients than in control subjects. Because the fat-free-mass index is significantly associated with an increased LOS, provides nutritional assessment information that complements that from a Subjective Global Assessment questionnaire, and is a more sensitive determinant of the association of fat-free mass with LOS than is a weight loss > 10% or a body mass index < 20, it should be used to evaluate nutritional status.

Adipose Tissue↗
PubMed2004

Uptake of new treatment strategies for deep vein thrombosis: an international audit.

OBJECTIVE: Study of the uptake of new medical technologies provides useful information on the transfer of published evidence into usual practice. We conducted an audit of selected hospitals in three countries (Canada, France, and Switzerland) to identify clinical predictors of low-molecular-weight (LMW) heparin use and outpatient treatment, and to compare the pace of uptake of these new therapeutic approaches across hospitals. DESIGN: Historical review of medical records. SETTING AND PARTICIPANTS: We reviewed the medical records of 3043 patients diagnosed with deep vein thrombosis (DVT) in five Canadian, two French, and two Swiss teaching hospitals from 1994 to 1998. Measures. We explored independent clinical variables associated with LMW heparin use and outpatient treatment, and determined crude and adjusted rates of LMW heparin use and outpatient treatment across hospitals. RESULTS: For the years studied, the overall rates of LMW heparin use and outpatient treatment in the study sample were 34.1 and 15.8%, respectively, with higher rates of use in later years. Many comorbidities were negatively associated with outpatient treatment, and risk-adjusted rates of use of these new approaches varied significantly across hospitals. CONCLUSION: There has been a relatively rapid uptake of LMW heparins and outpatient treatment for DVT in their early years of availability, but the pace of uptake has varied considerably across hospitals and countries.

Aged↗