Abstract: BACKGROUND: Mechanical ventilation is delivered to sedated patients during anesthesia, but also to nonsedated patients (ventilator weaning, noninvasive ventilation). In these circumstances, patient-ventilator asynchrony may occur, provoking discomfort and unduly increasing work of breathing. In certain cases, it is associated with an increased inspiratory load. Inspiratory loading in awake humans activates the premotor cortical regions, as illustrated by the occurrence of electroencephalographic premotor potentials. In normal humans during noninvasive ventilation, the authors used an experimental model of patient-ventilator asynchrony to determine whether premotor cortical activation occurs in this setting. METHODS: Noninvasive pressure support ventilation was administered to seven healthy volunteers aged 22-27 yr with continuous electroencephalographic recordings in Cz. The ventilator settings were first adjusted to make the subjects feel comfortable ("comfort"), and then modified to induce respiratory "discomfort" (evaluated on a 10-cm visual analog scale). This was achieved by setting the ventilator to a higher trigger level, reducing the slope of the pressure support rise, and reducing the level of pressure support. The settings were finally brought back to their initial values. To identify a respiratory-related premotor activity, a minimum of 80 preinspiratory electroencephalographic epochs were averaged. RESULTS: Altering ventilator settings induced respiratory discomfort (average visual scale 4 [1.5-6.0] vs. 0 [0-1.0] cm during "comfort"; P < 0.0001). This was associated with premotor potentials in all cases, which disappeared upon return to "comfort." CONCLUSIONS: This study indicates that "ventilator fighting" in healthy humans is associated with an activation of higher cerebral areas. Premotor potentials could thus be markers of patient-ventilator asynchrony at the brain level. Both corroboration in patients and the elucidation of the causative or reactive nature of the association are needed before determining clinical implications.

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Abstract: OBJECTIVE: We compared the usefulness of plasma N-terminal-pro B-type natriuretic peptide and troponin I levels for risk stratification of patients with pulmonary embolism. METHODS: This was a prospective study performed in an emergency department. N-terminal-B-type natriuretic peptide assay and troponin I were performed blindly at admission in patients with pulmonary embolism confirmed by imaging tests. A complicated pulmonary embolism was defined as any of the following: death, cardiopulmonary resuscitation, requirement for mechanical ventilation, use of pressors, thrombolysis, surgical embolectomy or admission in an intensive care unit. RESULTS: Sixty patients (mean age+/-standard deviation of 72+/-15 years) were included. Seventeen (28%) patients had adverse events: all were admitted in intensive care unit, one was treated with surgical embolectomy and one with thrombolysis, and three died. The median N-terminal-pro B-type natriuretic peptide level (95% confidence interval) was higher in the group of patients with complicated pulmonary embolism, 4086 pg/ml (505-8998) versus 352 pg/ml (179-662), respectively (P<0.05). The mean value of troponin I was similar in the complicated pulmonary embolism group, 0.09+/-0.17 microg/l versus 0.08+/-0.41 microg/l, respectively (P=0.93). The best threshold value of N-terminal-pro B-type natriuretic peptide was 1000 pg/ml, and the receiver operating characteristic curve demonstrated that N-terminal-pro B-type natriuretic peptide significantly predicted the complicated pulmonary embolism with an area under the receiver operative curve of 0.72 (0.58-0.83) (P<0.05), whereas troponin I did not [area under the receiver operative curve of 0.58 (0.42-0.71)]. CONCLUSION: Unlike troponin I, N-terminal-pro B-type natriuretic peptide may be an accurate marker of in-hospital complication after pulmonary embolism.

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Abstract: OBJECTIVE: The aim of this study was to evaluate the usefulness of various laboratory results for differential diagnosis of bacterial (BM) and nonbacterial meningitis (NBM) with negative initial Gram stain. DESIGN AND SETTING: A prospective multicenter study was conducted in the emergency departments of 3 teaching hospitals. PARTICIPANTS AND METHODS: Consecutive adult patients with a diagnosis of meningitis based on compatible clinical features and cerebrospinal fluid (CSF) culture findings with a CSF leukocyte count greater than 5/mm(3) were included in the study. Symptoms, examination findings, data from laboratory results, including CSF results and serum C-reactive protein (CRP) levels, and clinical outcome were assessed. RESULTS: One hundred fifty-one patients (age, 35 +/- 15 years) with confirmed meningitis were admitted: 133 with NBM and 18 with BM. CRP and procalcitonin (PCT) levels, CSF white cell and absolute neutrophil counts, and CSF glucose/blood glucose and CSF protein levels were significantly higher in the BM group. However, as diagnostic indicators of BM, none of these variables except PCT was more efficient than that of the emergency physician. Values of the area under the receiver operating characteristic curve were 0.59 (95% confidence interval [CI], 0.21-0.82), 0.79 (95% CI, 0.47-0.92), 0.18 (95% CI, 0.0-0.43), 0.70 (95%CI, 0.30-0.89), 0.81 (95% CI, 0.58-0.92), and 0.98 (95% CI, 0.83-1.0) for CSF leukocyte count, percentage of CSF leukocyte, CSF/blood glucose ratio, CSF protein level, serum CRP, and serum PCT (P < .05 vs CRP), respectively. CONCLUSION: CSF results have a modest role in distinguishing BM from NBM in a negative Gram stain for bacteria. PCT serum levels seem to be an excellent predictor of BM.

Abstract: PURPOSE: Noninvasive methods that could predict preload responsiveness are lacking. Our objective was to evaluate variations in pulse oximetry plethysmographic (POP) waveform amplitude (deltaPOP) induced by passive leg raising (PLR). METHODS: We attached a pulse oximeter to the middle finger of 25 spontaneously breathing volunteers at several time points: baseline (ie, semirecumbent position), during PLR at 60 degrees while each subject's trunk was lowered in a supine position at 1 minute, and after putting the patient back in the semirecumbent position (5-minute rest). Heart rate, noninvasive arterial pressures (mean arterial pressure and pulse pressure), maximal POP (POPmax), minimal POP (POPmin), and deltaPOP defined as [POPmax - POPmin]/[(POPmax + POPmin)/2] were recorded using a monitor. RESULTS: Heart rate, mean arterial pressure, pulse pressure, POPmax, and POPmin values were not different at baseline, during PLR at 1 minute, and after the 5-minute rest (repeated-measures analysis of variance). The median deltaPOP significantly decreased from 16% (95% confidence interval = 11%-23%) to 11% (95% confidence interval = 8%-14%) (P < .05) and then increased to 13% (95% confidence interval = 10%-21%) after the 5-minute rest (P = nonsignificant). CONCLUSION: Passive leg raising induces a significant decrease in deltaPOP among spontaneously breathing volunteers.

Abstract: BACKGROUND: Cardiac asthma is common, but has been poorly investigated. The objective was to compare the characteristics and outcome of cardiac asthma with that of classical congestive heart failure (CHF) in elderly patients. METHODS: Prospective study in an 1,800-bed teaching hospital. RESULTS: Two hundred and twelve consecutive patients aged > or = 65 years presenting with dyspnea due to CHF (mean age of 82 +/- 8 years) were included. Findings of cardiac echocardiography and natriuretic peptides levels were used to confirm CHF. Cardiac asthma patients were defined as a patient with CHF and wheezing reported by attending physician upon admission to the emergency department. The CHF group (n = 137) and the cardiac asthma group (n = 75), differed for tobacco use (34% vs. 59%, p < 0.05), history of chronic obstructive pulmonary disease (16% vs. 47%, p < 0.05), peripheral arterial disease (10% vs. 24%, p < 0.05). Patients with cardiac asthma had a significantly lower pH (7.38 +/- 0.08 vs. 7.43 +/- 0.06, p < 0.05), and a higher PaCO2 (47 +/- 15 vs. 41 +/- 11 mmHg, p < 0.05) at admission. In the cardiac asthma group, patients had greater distal airway obstruction: forced expiratory volume in 1 second of 1.09 vs. 1.33 Liter (p < 0.05), and a forced expiratory flow at 25% to 75% of vital capacity of 0.76 vs. 0.99 Liter (p < 0.05). The in-hospital (23% vs. 19%) and one year mortality (48% vs. 43%) rates were similar. CONCLUSION: Patients with cardiac asthma represented one third of CHF in elderly patients. They were more hypercapnic and experienced more distal airway obstruction. However, outcomes were similar.

Abstract: INTRODUCTION: Our objectives were to determine the causes of acute respiratory failure (ARF) in elderly patients and to assess the accuracy of the initial diagnosis by the emergency physician, and that of the prognosis. METHOD: In this prospective observational study, patients were included if they were admitted to our emergency department, aged 65 years or more with dyspnea, and fulfilled at least one of the following criteria of ARF: respiratory rate at least 25 minute-1; arterial partial pressure of oxygen (PaO2) 70 mmHg or less, or peripheral oxygen saturation 92% or less in breathing room air; arterial partial pressure of CO2 (PaCO2) > or = 45 mmHg, with pH < or = 7.35. The final diagnoses were determined by an expert panel from the completed medical chart. RESULTS: A total of 514 patients (aged (mean +/- standard deviation) 80 +/- 9 years) were included. The main causes of ARF were cardiogenic pulmonary edema (43%), community-acquired pneumonia (35%), acute exacerbation of chronic respiratory disease (32%), pulmonary embolism (18%), and acute asthma (3%); 47% had more than two diagnoses. In-hospital mortality was 16%. A missed diagnosis in the emergency department was noted in 101 (20%) patients. The accuracy of the diagnosis of the emergency physician ranged from 0.76 for cardiogenic pulmonary edema to 0.96 for asthma. An inappropriate treatment occurred in 162 (32%) patients, and lead to a higher mortality (25% versus 11%; p < 0.001). In a multivariate analysis, inappropriate initial treatment (odds ratio 2.83, p < 0.002), hypercapnia > 45 mmHg (odds ratio 2.79, p < 0.004), clearance of creatinine < 50 ml minute-1 (odds ratio 2.37, p < 0.013), elevated NT-pro-B-type natriuretic peptide or B-type natriuretic peptide (odds ratio 2.06, p < 0.046), and clinical signs of acute ventilatory failure (odds ratio 1.98, p < 0.047) were predictive of death. CONCLUSION: Inappropriate initial treatment in the emergency room was associated with increased mortality in elderly patients with ARF.

Abstract: PURPOSES: We evaluated the use of plasma B-type natriuretic peptide (BNP) levels for risk stratification in elderly patients with acute pulmonary embolism (PE). BASIC PROCEDURES: Bedside BNP assay was performed blindly at admission in consecutive patients older than 65 years with acute PE. A complicated PE was defined as any of the following: death, cardiopulmonary resuscitation, mechanical ventilation, use of vasopressors, thrombolysis, surgical embolectomy, or admission in intensive care unit. MAIN FINDINGS: Fifty-one patients (age, 79 +/- 9 years) were included. Thirteen patients had adverse events: 11 were admitted in the intensive care unit and 3 died. The median BNP level (95% confidence interval [CI]) was higher in the group of patients with complicated PE, 274 pg/mL (95% CI, 142-581 pg/mL) vs 78 pg/mL (95% CI, 33-230 pg/mL) (P < .05), respectively. The receiver operating characteristic curve showed that BNP significantly predicted a complicated PE with an area under the receiver operating characteristic curve of 0.72 (95% CI, 0.58-0.83) (P < .05). The best threshold value was 200 pg/mL with a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 0.69 (0.43-0.87), 0.63 (0.47-0.77), 0.39 (0.22-0.59), 0.86 (0.69-0.94), and 0.65 (0.51-0.77), respectively. CONCLUSION: Our study suggests that BNP is not a reliable marker of complicated PE in elderly patients.

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Abstract: OBJECTIVE: The aim of this study was to assess in clinical practice the accuracy of a referent d-dimer enzyme-linked immunosorbent assay for the exclusion of venous thromboembolic disease (VTED). PATIENTS AND METHODS: An observational prospective study took place in an emergency department; 205 consecutive outpatients suspected of having VTED were included. Blood samples were collected at admission for VIDAS DD measurement. Venous thromboembolic disease was confirmed by standard clinical imaging. All patients were followed up at 3 months. RESULTS: Venous thromboembolic disease was confirmed in 57 patients (28%). The sensitivity and negative predictive value of a DD assay lower than 500 ng/mL were 78% (95% confidence interval = 67%-87%) and 84% (95% confidence interval = 73%-90%), respectively. Twelve patients had a false-negative DD with one or more of the following: (a) symptoms reported for more than 15 days (n = 2), (b) prior anticoagulation (n = 3), (c) distal VTED (n = 5), or (d) high clinical probability (n = 3). CONCLUSION: In our cohort of patients, DD was less accurate than previously reported, with an upper estimate of the sensitivity of only 87%.

Abstract: OBJECTIVES: Differentiating cardiogenic pulmonary edema (CPE) from respiratory causes of dyspnea is difficult in elderly patients. The aim of this study was to compare the usefulness of B-type natriuretic peptide (BNP) and amino-terminal fragment BNP (proBNP), to diagnose CPE in patients aged 65 and older. DESIGN: Prospective study. SETTING: Medical emergency department of a 2,000-bed urban teaching hospital. PARTICIPANTS: Patients aged 65 and older presenting with acute dyspnea and a respiratory rate of 25 breaths/min or greater, a partial pressure of oxygen of 70 mmHg or less, or an oxygen saturation of 92% or less were included. MEASUREMENTS: Rapid BNP and proBNP assays, performed blind at admission, were compared with the final diagnosis (CPE or no CPE) as defined by an expert team. RESULTS: Two hundred two patients (mean age+/-standard deviation 80+/-9) were included; 88 (44%) had CPE. There was a strong correlation between proBNP and BNP values (correlation coefficient=0.91, P<.001). The median BNP and proBNP were higher in the group of patients with CPE (377 vs 74 pg/mL, P<.001, and 3,851 vs 495 pg/mL, P<.001, respectively). The best threshold values of BNP and proBNP were 250 pg/mL and 1,500 pg/mL, respectively. The area under the receiver operating characteristic curve was greater with BNP than with proBNP (0.85 vs 0.80, P<.05). BNP assay was more accurate in diagnosis than the emergency physician, whereas proBNP was not. Higher values of BNP and proBNP were associated with greater in-hospital mortality. CONCLUSION: BNP assay is a more useful diagnostic indicator for CPE than proBNP in patients aged 65 and older.

Abstract: There is a natural physiological decline in pulmonary function and the cardiovascular system with age. In emergency medicine, acute dyspnoea is a common problem among elderly patients. Some causes, such as pulmonary embolism and diastolic heart failure, are probably under-diagnosed. A good clinical history and examination are as important as arterial blood gas analysis, chest radiography and electrocardiography. Few studies have examined acute dyspnoea in elderly patients, except in the setting of pneumonia. Establishing the underlying diagnosis is often difficult because of atypical presentation and the interaction between cardiac and pulmonary underlying functions. This topic describes several respiratory and cardiac diseases presenting as acute dyspnoea, especially "cardiac asthma" and pulmonary embolism. The clinical usefulness of new investigations such as cardiac and lung echography, pulmonary function tests, serum Brain Natriuretic Peptide and thoracic CT scan are discussed. Further studies looking at acute dyspnoea in elderly patients are needed.

Abstract: In HIV-infected patients, acute respiratory failure is usually due to infectious pneumonia. In this report, we describe two cases of acute respiratory failure in HIV patients with clinical presentation suggesting infectious pneumonia. In both cases, the clinical condition deteriorated and death occurred after several days despite therapy. In both cases bronchial biopsies confirmed bronchogenic carcinoma responsible for carcinomatous lymphangitis.

Abstract: OBJECTIVE: Differentiating cardiogenic pulmonary edema (CPE) from respiratory causes of dyspnea is particularly difficult in elderly patients. The aim of our study was to evaluate B-type natriuretic peptide (BNP) in patients older than 65 years presenting with acute dyspnea. DESIGN: Prospective study. SETTING: Medical emergency department of a 2000-bed urban teaching hospital. PATIENTS: Patients aged over 65 years presenting with acute dyspnea and a respiratory rate more than 25/min or a PaO(2) below 70 mmHg, SpO(2 )less than 92%, PaCO(2) higher than 45 mmHg with pH less than 7.35, were included. BNP levels, measured blind at admission were compared with the final diagnosis (CPE or no CPE) as defined by experts. INTERVENTION: None. MEASUREMENTS AND RESULTS: Three hundred eight patients (mean age of 80 years) were enrolled in the study. The median BNP was 575 pg/ml [95% confidence interval (CI): 410-898] in the CPE group (n=141) versus 75 pg/ml (95% CI: 59-98) in the no CPE group (n=167) (p<0.001). The best threshold value of BNP was 250 pg/ml, with a sensitivity and specificity for CPE of 0.78 (95% CI: 0.71-0.84) and 0.90 (95% CI: 0.84-0.93), respectively. The area under the ROC curve was 0.874+/-0.081 (p<0.001). The accuracy of BNP-assisted diagnosis was higher than that of the emergency physician (0.84 versus 0.77, p<0.05). CONCLUSION: Analysis of BNP is useful in elderly patients with acute dyspnea, but the threshold value is higher than that previously determined.