Frédéric Thys

Diagnosis of pulmonary embolism by multidetector CT alone or combined with venous ultrasonography of the leg: a randomised non-inferiority trial

BACKGROUND Multislice CT (MSCT) combined with D-dimer measurement can safely exclude pulmonary embolism in patients with a low or intermediate clinical probability of this disease. We compared this combination with a strategy in which both a negative venous ultrasonography of the leg and MSCT were needed to exclude pulmonary embolism. METHODS We included 1819 consecutive outpatients with clinically suspected pulmonary embolism in a multicentre non-inferiority randomised controlled trial comparing two strategies: clinical probability assessment and either D-dimer measurement and MSCT (DD-CT strategy [n=903]) or D-dimer measurement, venous compression ultrasonography of the leg, and MSCT (DD-US-CT strategy [n=916]). Randomisation was by computer-generated blocks with stratification according to centre. Patients with a high clinical probability according to the revised Geneva score and a negative work-up for pulmonary embolism were further investigated in both groups. The primary outcome was the 3-month thromboembolic risk in patients who were left untreated on the basis of the exclusion of pulmonary embolism by diagnostic strategy. Clinicians assessing outcome were blinded to group assignment. Analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00117169. FINDINGS The prevalence of pulmonary embolism was 20.6% in both groups (189 cases in DD-US-CT group and 186 in DD-CT group). We analysed 855 patients in the DD-US-CT group and 838 in the DD-CT group per protocol. The 3-month thromboembolic risk was 0.3% (95% CI 0.1-1.1) in the DD-US-CT group and 0.3% (0.1-1.2) in the DD-CT group (difference 0.0% [-0.9 to 0.8]). In the DD-US-CT group, ultrasonography showed a deep-venous thrombosis in 53 (9% [7-12]) of 574 patients, and thus MSCT was not undertaken. INTERPRETATION The strategy combining D-dimer and MSCT is as safe as the strategy using D-dimer followed by venous compression ultrasonography of the leg and MSCT for exclusion of pulmonary embolism. An ultrasound could be of use in patients with a contraindication to CT.

Noninvasive ventilation for acute respiratory failure: a prospective randomised placebo-controlled trial

The aim of the present study was to clarify whether the known effects of noninvasive positive-pressure ventilation (NPPV) in patients with respiratory failure are real or due to placebo effects and whether early application of NPPV in the emergency department leads to rapid improvement of the patients condition and outcome. A prospective randomised placebo-controlled study was conducted in 20 patients with severe acute respiratory failure (ARF) secondary to an acute exacerbation of chronic obstructive pulmonary disease (COPD) or acute pulmonary oedema, not improving under conventional medical therapy and on the edge of intubation. Patients received either conventional medical therapy plus two-level NPPV (bi-level NPPV) or conventional medical therapy plus “placebo” NPPV. The main outcome measures involved the need for endotracheal intubation in the bi-level NPPV arm and in the placebo arm after crossing over to active NPPV. Morbidity, length of stay, mortality and the effect of the ventilatory mode on clinical, arterial-blood gas parameters, and the sternocleidomastoid muscles electromyogram (EMG) activity were also measured. The 10 patients in the active NPPV group rapidly improved and none needed intubation. Placebo NPPV resulted in no change in the clinical condition of patients that continued to worsen and the 10 patients were crossed over to active NPPV. Three patients were intubated. No differences in terms of morbidity, length of stay or mortality between the two groups were observed. Active NPPV (but not placebo NPPV) led to a rapid and significant improvement in the clinical parameters, pH and the carbon dioxide tension in arterial blood and to a decrease in respiratory frequency and sternocleidomastoid EMG activity. Early application of bi-level noninvasive positive-pressure ventilation in patients with severe acute respiratory failure, due to chronic obstructive pulmonary disease and acute pulmonary oedema, leads to a rapid improvement in clinical status and blood gases. Noninvasive positive-pressure ventilation had no placebo effect.

Comparison of the Unstructured Clinician Gestalt, the Wells Score, and the Revised Geneva Score to Estimate Pretest Probability for Suspected Pulmonary Embolism

STUDY OBJECTIVE The assessment of clinical probability (as low, moderate, or high) with clinical decision rules has become a cornerstone of diagnostic strategy for patients with suspected pulmonary embolism, but little is known about the use of physician gestalt assessment of clinical probability. We evaluate the performance of gestalt assessment for diagnosing pulmonary embolism. METHODS We conducted a retrospective analysis of a prospective observational cohort of consecutive suspected pulmonary embolism patients in emergency departments. Accuracy of gestalt assessment was compared with the Wells score and the revised Geneva score by the area under the curve (AUC) of receiver operating characteristic curves. Agreement between the 3 methods was determined by κ test. RESULTS The study population was 1,038 patients, with a pulmonary embolism prevalence of 31.3%. AUC differed significantly between the 3 methods and was 0.81 (95% confidence interval [CI] 0.78 to 0.84) for gestalt assessment, 0.71 (95% CI 0.68 to 0.75) for Wells, and 0.66 (95% CI 0.63 to 0.70) for the revised Geneva score. The proportion of patients categorized as having low clinical probability was statistically higher with gestalt than with revised Geneva score (43% versus 26%; 95% CI for the difference of 17%=13% to 21%). Proportion of patients categorized as having high clinical probability was higher with gestalt than with Wells (24% versus 7%; 95% CI for the difference of 17%=14% to 20%) or revised Geneva score (24% versus 10%; 95% CI for the difference of 15%=13% to 21%). Pulmonary embolism prevalence was significantly lower with gestalt versus clinical decision rules in low clinical probability (7.6% for gestalt versus 13.0% for revised Geneva score and 12.6% for Wells score) and non-high clinical probability groups (18.3% for gestalt versus 29.3% for Wells and 27.4% for revised Geneva score) and was significantly higher with gestalt versus Wells score in high clinical probability groups (72.1% versus 58.1%). Agreement between the 3 methods was poor, with all κ values below 0.3. CONCLUSION In our retrospective study, gestalt assessment seems to perform better than clinical decision rules because of better selection of patients with low and high clinical probability.

Epiploic appendagitis: color Doppler sonographic findings.

Abstract The aim of this study was to analyze the color Doppler sonographic findings in primary epiploic appendagitis. Color Doppler sonographic findings of ten patients with primary epiploic appendagitis were reviewed. The following sonographic features were analyzed: identification of a mass adjacent to the colonic wall; identification of spotty color areas with arterial flow in this mass and detection of abnormalities of the colonic wall adjacent to the infiltrated fatty tissue. A well-delineated hyperechoic mass adjacent to the colonic wall was detected in each patient with sonography. No colonic wall abnormalities were observed nor color Doppler signal in and around the hyperechoic area. Absence of flow at color Doppler sonography is an additional feature of epiploic appendagitis.

Performance of age-adjusted D-dimer cut-off to rule out pulmonary embolism

Summary:  Background:  Age‐adjusted D‐dimer cut‐off has recently been proposed to increase D‐dimer usefulness in older patients suspected of pulmonary embolism (PE).

Determinants of Fi,O2 with oxygen supplementation during noninvasive two-level positive pressure ventilation.

To maintain arterial oxygen saturation (Sa,O2) above 90% in patients with acute respiratory failure, oxygen (O2) is often added to the circuit of two-level noninvasive positive pressure ventilation (NPPV). However, the final inspiratory oxygen fraction (Fi,O2) is not known. To clarify this issue, the effect of different inspiratory positive airway pressures (IPAP) of the oxygen tubing connection site and the flow rate of O2, on Fi,O2 was assessed. The effects of the tidal volume (VT) and the respiratory rate on the Fi,O2 were then clarified in a model study. The Fi,O2 varied depending on the point where O2 was added to the circuit. When all other variables were constant, the connection closest to the exhaust port (ventilator side) gave the highest Fi,O2. Increases in IPAP led to decreases in Fi,O2. Finally, Fi,O2 increased with O2 flow, although it was difficult to obtain an Fi,O2 >0.30 unless very high O2 flows were used. Paradoxically, NPPV with low IPAP values and without O2 supplementation led to a Fi,O2 <0.21 at the circuit-patient interface. VT and respiratory rate did not appear to influence Fi,O2. To conclude, when using noninvasive positive pressure ventilation with two-level respirators, oxygen should be added close to the exhaust port (ventilator side) of the circuit. If inspiratory airway pressure levels are >12 cmH2O, oxygen flows should be at least 4 L·min−1.

Performance of the Pulmonary Embolism Rule-out Criteria (the PERC rule) combined with low clinical probability in high prevalence population.

INTRODUCTION PERC rule was created to rule out pulmonary embolism (PE) without further exams, with residual PE risk<2%. Its safety is currently not confirmed in high PE prevalence populations even when combined with low clinical probability assessed by revised Geneva score (RGS). As PERC rule and RGS are 2 similar explicit rules with many redundant criteria, we hypothesized that the combination of PERC rule with gestalt clinical probability could resolve this limitation. METHODS We collected prospectively documented clinical gestalt assessments and retrospectively calculated PERC rules and RGS from a prospective study of PE suspected patients. We analyzed performance of combinations of negative PERC with low clinical probability assessed by both methods in high overall PE prevalence population. RESULTS Among the final study population (n = 959), the overall PE prevalence was 29.8%. Seventy-four patients (7.7%) were classified as PERC negative and among them, 4 patients (5.4%) had final diagnosis of PE. When negative PERC was combined with low pretest probability assessed by RGS or gestalt assessment, PE prevalence was respectively 6.2% and 0%. This last combination reaches threshold target of 2% and unnecessary exams could easily have been avoided in this subgroup (6%). However, it confidence interval was still wide (0%; CI 0-5). CONCLUSIONS PERC rule combined with low gestalt probability seems to identify a group of patients for whom PE could easily be ruled out without additional test. A larger study is needed to confirm this result and to ensure safety.

Volumetric capnography as a bedside monitoring of thrombolysis in major pulmonary embolism

ObjectiveTo describe the use of volumetric capnography, a plot of expired CO2 concentration against expired volume, in monitoring fibrinolytic treatment of major pulmonary embolism.Design and settingTwo case reports in the emergency department of a teaching hospital.PatientsTwo conscious and spontaneously breathing patients (69- and 31-year-old women) with major pulmonary embolism requiring thrombolysis. Decision for thrombolysis was based on the association of right ventricular afterload on echocardiography, with respiratory failure and hypotension in the first patient, and dyspnea and hemodynamically stable parameters in the second one.InterventionsSuccessive capnographic measurements were performed before, during, and after thrombolysis. Curves of volumetric capnography were obtained from a sidestream gas monitor with flow sensor and an arterial blood gas analysis for CO2 partial pressure.Measurements and resultsWe calculated late deadspace fraction, previously suggested as the most effective capnographic parameter in the diagnosis of pulmonary embolism. Late deadspace fraction decreased in the two patients, respectively, from 64.4% to 1.1% and from 25.6% to 5.7% after thrombolysis, with a concomitant disappearance of right heart dysfunction signs on echocardiography.ConclusionsVolumetric capnography can monitor thrombolysis in major pulmonary embolism. Differences between volumetric capnography technology and the more traditional arterial to end-tidal CO2 gradient are important to take into account for clinical application.

Versatile clinical information system design for emergency departments

Compared to other hospital units, the emergency department presents some distinguishing characteristics of its own. Emergency health-care delivery is a collaborative process involving the contribution of several individuals who accomplish their tasks while working autonomously under pressure and sometimes with limited resources. Effective computerization of the emergency department information system presents a real challenge due to the complexity of the scenario. Current computerized support suffers from several problems, including inadequate data models, clumsy user interfaces, and poor integration with other clinical information systems. To tackle such complexity, we propose an approach combining three points of view, namely the transactions (in and out of the department), the (mono and multi) user interfaces and data management. Unlike current systems, we pay particular attention to the user-friendliness and versatility of our system. This means that intuitive user interfaces have been conceived and specific software modeling methodologies have been applied to provide our system with the flexibility and adaptability necessary for the individual and group coordinated tasks. Our approach has been implemented by prototyping a web-based, multiplatform, multiuser, and versatile clinical information system built upon multitier software architecture, using the Java programming language.

European and American suspected and confirmed pulmonary embolism populations: comparison and analysis

Summary.  Background: If the prevalence of pulmonary embolism (PE) differs significantly between the US and Europe, this observation could reduce the generalizability of diagnostic protocols for PE derived in either location.Objective: To determine possible causes and potential clinical consequences of these PE prevalence differences.Methods: Secondary analysis of three prospectively collected multicenter samples (two French and one from the US) including 3174 European and 7940 American PE‐suspected patients in Emergency departments (ED) (117 for Europe and 12 for US). Comparison of clinical features, resource use and outcomes of European‐ and US‐suspected PE populations in ED.Results: European patients evaluated for PE were significantly older and had a higher clinical pretest probability (CPP) for PE. The final PE prevalence was significantly higher in Europe, in the overall sample (26.5% vs. 7.6%) and in each level of CPP. Suspected European patients categorized as low CPP had a higher posttest probability than US low CPP patients. Suspected US patients categorized as high CPP had a much lower posttest probability of PE than in Europe. The mean number of tests performed for one PE diagnosis was lower in Europe (7.4 vs. 21.6). Among patients diagnosed with PE, European patients had a higher mean severity of illness score and a higher PE‐mortality rate (3.4% vs. 0.7%).Conclusions: Among patients suspected of a PE and those ultimately diagnosed with a PE, European patients had higher acuity, a higher pretest probability and worse outcome than US patients. The present study underscores the importance of disease prevalence for pretest probability scoring approaches and for significance interpretation of imaging tests.