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Objectives: We examined the analytical correlation N-terminal pro-brain natriuretic peptide (NT-proBNP) and brain natriuretic peptide (BNP)., Design and Methods: Electrochemiluminescence and fluorescence immunoassays were used to measure NT-proBNP and BNP levels, respectively., Results: The analytical correlation was satisfactory using the equation: NT-proBNP = 8.56 x BNP + 91.7 and a correlation r = 0.85. The correlation was not influenced by age, gender and BMI of patients., Conclusions: We conclude that NT-proBNP correlates with BNP.

Aim: To assess medical emergency radiology referral practice compared with a set of French guidelines and to measure the efficiency of computer-based guidelines on unnecessary medical imaging., Materials and Methods: All radiological requests were computerized in the medical emergency departments of two French teaching hospitals. During control periods, radiological requests were recorded but no action was taken. During intervention periods, reminder displays on screen indicated the appropriate recommendations. Three control and three intervention periods of 1 month each were conducted. The percentage of requests that did not conform to the guidelines and variation related to periods of control and intervention were measured., Results: The proportion of requests that did not conform to the guidelines was 33.2% when the guidelines were inactive and decreased to 26.9% when the recommendations were active (P < 0.0001). The three imaging examinations (chest radiographs, abdominal plain radiographs and CT of the brain) accounted for more than 80% of all requests; more than 50% of abdominal plain radiographs requests did not conform with recommendations while this percentage was respectively 24.9% and 15.8% for chest radiographs and computed tomography (CT) of the brain. Seven situations accounted for 70% of non-conforming radiological referrals; in these situations, junior practitioners' knowledge was inadequate., Conclusion: While the computer provided advice that was tailored to the needs of individual patients, concurrent with care, the effect of our intervention was weak. However, our study identified the few situations that were responsible for the majority of unnecessary radiological requests; we expect that this result could help clinicians and radiologists to develop more specific actions for these situations., (Copyright 2002 The Royal College of Radiologists.)

Benzodiazepines are mostly used for their antianxiety and sedative effects. In recent years, new compounds have been developed with a hypnotic action. Although marked toxicity is uncommon with the use of these compounds, the clinician requires a rapid laboratory report in emergency and intensive care units in case of self-poisoning. To reduce the incidence of false-negative results routinely observed with our enzyme immunoassay kit (Emit tox benzodiazepine), the performance of a new kit (Emit dau benzodiazepine) was evaluated in 57 patients who had taken an overdose of benzodiazepines. Results were compared with those obtained by high performance liquid chromatography (HPLC) using a diode array detector and giving a semi-quantitative result. Seventy-four percent of the patients studied gave readings above the cut-off value, which was consistent with benzodiazepine intoxication, according to the results of the specific HPLC analysis (bromazepam, triazolam, alprazolam and flunitrazepam were clearly identified). No false negatives were obtained in this study with the Emit dau benzodiazepine. Finally, HPLC is unsuitable in the emergency setting; the enzyme multiplied immunoassay technique is the most appropriate method used in cases of self-poisoning with benzodiazepines having a low therapeutic index.

In ten patients requiring respiratory support for an episode of acute respiratory failure (ARF), the best therapeutic level of PEEP was determined by measurement of changes in lung and chest wall compliance (CT) during a PEEP challenge from 0 to 20 cm H2O. During this challenge, hemodynamic monitoring combined with thermodilution measurement of right ventricular (RV) ejection fraction (EF) and two-dimensional echocardiographic measurement of RV size permitted assessment of the effects of increasing levels of PEEP on RV function. RV preload, as reflected by RV end-diastolic volume (EDV) and two-dimensional RV end-diastolic area (EDA), remained unchanged and RV diastolic compliance progressively decreased. On the other hand, RV systolic function, as assessed by RVEF and two-dimensional RV fractional area contraction (FAC), was progressively depressed. Substantial deleterious effects of PEEP were noted at high levels of PEEP including reduced CT and augmented pulmonary vascular resistance. Inadequate increase in RV preload to compensate for increased RV afterload resulted in depressed RV systolic function and contributed to the reduction in cardiac output. Finally, two-dimensional echocardiography proved to be more sensitive than fast-response thermodilution to evaluate change in RV function.

To further define cardiovascular abnormalities in patients with septic shock, serial conventional hemodynamic measurements combined with two-dimensional echocardiographic studies were performed at the bedside in 21 patients admitted for an acute episode of sepsis-related circulatory failure. Measurements obtained during the first hours of hospitalization revealed a group of six patients (group 1) with markedly depressed left ventricular function, as evidenced by a low cardiac index (CI) (2.2 +/- 0.8 L/min.m2), reduced left ventricular ejection fraction (LVEF) (21 +/- 8%), and an increased arterial-venous oxygen content difference. Right ventricular systolic function was also severely depressed. These patients were characterized as having sepsis-related cardiogenic shock secondary to profound myocardial depression, which was reversible within 24 to 48 h with inotropic support. The 15 remaining patients (group 2) exhibited an initially increased CI (4.9 +/- 1.8 L/min.m2), with a low systemic vascular resistance. In group 2, LVEF remained within the normal range despite abnormally low peripheral vascular resistance. This finding would suggest the presence of slight to moderate depression of left ventricular systolic function. All patients in this series had a normal left ventricular end-diastolic volume, whether profound myocardial depression was present or not.

Simultaneous recordings of airway pressure, pleural pressure, and right ventricular (RV) pressure were obtained during mechanically controlled ventilation in a group of patients requiring respiratory support. Changes in transpulmonary pressure (calculated as airway pressure minus pleural pressure) were measured at end-expiration and end-inspiration during intermittent positive pressure ventilation with or without the application of a positive end-expiratory pressure, and were related to RV isovolumetric pressure changes at the onset of systole. It was found that any increase in transpulmonary pressure by intermittent positive pressure ventilation, or positive end-expiratory pressure (PEEP), or both, was associated with a proportional increase in RV isovolumetric pressure change. Moreover, when lung volume was progressively increased by incremental increases in tidal volume or PEEP level, transpulmonary pressure and RV isovolumetric pressure changes were strongly and linearly correlated. These results suggest that: 1) RV isovolumetric pressure change might be used as an index of RV output impedance during respiratory support by mechanically controlled ventilation; and 2) lung inflation resulting from the use of a positive airway pressure during respiratory support can increase RV output impedance and thereby contribute to the decrease in RV stroke output.

Nineteen patients with acute respiratory failure were divided into three groups according to their total compliance (CT). Transmission of airway pressure to the pleural space was then evaluated by measurement of esophageal pressure at both end-expiration and end-inspiration, and at three levels of PEEP. Chest wall (CW) and lung complicance (CL) were also calculated from simultaneous measurements of lung volume changes induced by tidal delivery. In group 1 (CT greater than 45 ml/cmH2O), 37 percent of airway pressure was transmitted to pleural space. In group 2 (CT between 45 and 30 ml/cmH2O), 32 percent of airway pressure was transmitted to the pleural space. In group 3 (CT less than 30 ml/cmH2O), only 24 percent of airway pressure was transmitted to the pleural space. These differences are statistically significant (p less than 0.001) and illustrate the influence of a progressive increase in lung stiffness (CL = 100.3 +/- 17.2 ml/cmH2O in group 1, CL = 45.0 +/- 6.3 ml/cmH2O in group 2, and CL = 28.6 +/- 8.9 ml/cmH2O in group 3) on transmission of airway pressure to the pleural space. Despite lesser transmission of airway pressure to the pleural space in the most damaged lungs, no significant difference was found between groups with regard to transmural venous pressure changes throughout the study.

Intravenous dobutamine was used in ten patients requiring aggressive therapy for massive pulmonary embolism with circulatory failure. Except in one patient who rapidly died, a 30-min dobutamine infusion (8.3 +/- 2.7 micrograms/kg . min) increased both cardiac index (from 1.7 +/- 0.4 to 2.3 +/- 0.6 L/min . m2, p less than .001) and stroke index (from 16.6 +/- 6.7 to 21 +/- 5 ml/m2, p less than .01), and also reduced pulmonary vascular resistance. Additional hemodynamic improvement was observed until weaning from dobutamine, which was successfully completed 3.3 +/- 0.9 days after the start of infusion.