Heart-type fatty acid binding protein and the diagnosis of acute coronary syndrome in the ED.

BACKGROUND: In combination with cardiac troponin, heart-type fatty acid binding protein (h-FABP)-a biomarker of myocardial necrosis-offers the possibility of rapidly eliminating the diagnosis of acute myocardial infarction (AMI). OBJECTIVE: The main objective of this study was to assess the incremental value of h-FABP to cardiac troponin for a rapid elimination of AMI, according to the pretest probability (PTP) of AMI. METHODS: In consecutive patients presenting to emergency departments (ED) with chest pain less than 6 hours suggestive of AMI, h-FABP levels were measured, blinded to the ED physicians, who were asked to quote the PTP of AMI. The discharge diagnosis was adjudicated by 2 independent experts, blind to the h-FABP level. RESULTS: Three hundred seventeen patients (mean age of 57 years) were included in whom 149 had (47%) low, 117 (37%) moderate, and 51 (16%) high PTP. The final diagnosis was AMI in 45 patients (14%), including 16 STEMIs (5%). The negative predictive value for diagnostic elimination of AMI of an h-FABP less than 3 µg/L, combined with a negative cTnI was not higher than that of cardiac troponin I (cTnI) alone (96% [95% confidence interval, 93%-98%] vs 95% [93%-98%]), regardless of the PTP). Even in the low-PTP group, we did not demonstrate a significant improvement in negative predictive value with the addition of h-FABP, compare with that of cTnI alone (100% [97%-100%] vs 99% [96%-100%]). CONCLUSION: In triage of patients with chest pain, use of h-FABP does not provide useful additional information to cTnI for excluding the diagnosis of ST-elevation myocardial infarction and non-ST-elevation myocardial infarction diagnosis, whatever the PTP.

High-sensitivity versus conventional troponin in the emergency department for the diagnosis of acute myocardial infarction.

INTRODUCTION: Recently, newer assays for cardiac troponin (cTn) have been developed which are able to detect changes in concentration of the biomarker at or below the 99th percentile for a normal population. The objective of this study was to compare the diagnostic performance of a new high-sensitivity troponin T (HsTnT) assay to that of conventional cTnI for the diagnosis of acute myocardial infarction (AMI) according to pretest probability (PTP). METHODS: In consecutive patients who presented to our emergency departments with chest pain suggestive of AMI, levels of HsTnT were measured at presentation, blinded to the emergency physicians, who were asked to estimate the empirical PTP of AMI. The discharge diagnosis was adjudicated by two independent experts on the basis of all available data. RESULTS: A total of 317 patients were included, comprising 149 (47%) who were considered to have low PTP, 109 (34%) who were considered to have moderate PTP and 59 (19%) who were considered to have high PTP. AMI was confirmed in 45 patients (14%), 22 (9%) of whom were considered to have low to moderate PTP and 23 (39%) of whom were considered to have high PTP (P < 0.001). In the low to moderate PTP group, HsTnT levels ≥ 0.014 µg/L identified AMI with a higher sensitivity than cTnI (91%, 95% confidence interval (95% CI) 79 to 100, vs. 77% (95% CI 60 to 95); P = 0.001), but the negative predictive value was not different (99% (95% CI 98 to 100) vs. 98% (95% CI 96 to 100)). There was no difference in area under the receiver operating characteristic (ROC) curve between HsTnT and cTnI (0.93 (95% CI 0.90 to 0.98) vs. 0.94 (95% CI 0.88 to 0.97), respectively). CONCLUSIONS: In patients with low to moderate PTP of AMI, HsTnT is slightly more useful than cTnI. Our results confirm that the use of HsTnT has a higher sensitivity than conventional cTnI.

Offline exhaled nitric oxide in emergency department and subsequent acute asthma control.

BACKGROUND: Few studies have evaluated exhaled NO measurement during acute asthma. OBJECTIVES: To evaluate exhaled NO fraction (FE(NO)) and peak expiratory flow (PEF) time-courses during acute asthma treatment (beta 2-agonist plus systemic steroid) and to assess whether FE(NO) time-course predicts subsequent asthma control. METHODS: Sixty-five asthmatic patients (mean +/- SD, 34 +/- 10 years) were prospectively enrolled in three Emergency Departments. RESULTS: Sixteen patients were excluded (failure of offline FE(NO) measurement at 100 mL/s [FE(NO 0.1)], n = 4, and early discharge). The 49 remaining patients performed FE(NO 0.1) and PEF on admission, at the 2nd (H2) and 6th hour (H6). Follow-up using an Asthma Control Diary was obtained in 27 of 49 patients, whether they were hospitalized (n = 9) or discharged (n = 18). All but 2 patients had elevated FE(NO) on admission (median [interquartile], 49 [26-78] ppb). Unlike PEF, mean FE(NO 0.1) of our sample was not significantly modified by treatment. No significant relationship was evidenced between exhaled NO and PEF variations. The variation of FE(NO 0.1) [H0 minus H6] was different in patients who were hospitalized (decrease of 8 +/- 20 ppb) versus discharged (increase of 5 +/- 20 ppb, p = 0.04). This variation of FE(NO 0.1) was correlated with the Diary score (control of subsequent week), an initial increase in FE(NO 0.1) being associated with better asthma control. Nevertheless, neither exhaled NO nor PEFR were good predictors of asthma control. CONCLUSIONS: An increase in FE(NO) is observed in almost all patients with acute asthma, and its subsequent increase within 6 hours is associated with a better degree of asthma control in the subsequent week.

N-Terminal pro B-type natriuretic peptide testing for short-term prognosis in breathless older adults.

BACKGROUND: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful for the triage of patients with dyspnea. Our aim was to determine whether NT-proBNP levels could predict in-hospital outcome in breathless elderly patients. METHODS: At admission, NT-proBNP plasma concentrations were determined in 324 dyspneic patients aged 75 years and older. The association between NT-proBNP values and in-hospital mortality was assessed. RESULTS: Median NT-proBNP concentrations were not different in deceased patients (n = 43, 13%) compared to that of survivors (n = 281, 87%) (4354 vs 2499 pg/mL, respectively; P = .06). To predict in-hospital mortality, the optimum threshold of NT-proBNP was 3855 pg/mL, as defined by the receiver operating characteristic (ROC) curve, with a nonsignificant area under the ROC curve of 0.59. Mortality was significantly higher in patients (n = 139) with NT-proBNP levels 3855 pg/mL or higher (17.9% vs 9.7%, P = .045). After multivariate analysis, NT-proBNP level 3855 pg/mL or higher at admission was predictive of mortality (odds ratio, 2.41; 95% confidence interval, 1.02-5.68; P = .04). CONCLUSION: NT-proBNP higher than 3855 pg/mL is associated with in-hospital mortality in patients aged 75 years and older admitted for dyspnea.

Copeptin for rapid rule out of acute myocardial infarction in emergency department.

BACKGROUND: Copeptin, in combination with conventional troponin (cTn), has been suggested as a means of rapid rule out of the diagnosis of acute myocardial infarction (AMI). This study aims to assess the value of copeptin for rule out of AMI, according to the pre-test probability (PTP). METHODS: In a prospective multicentric study, we enrolled patients presenting into emergency departments with chest pain <6h, copeptin was measured, and PTP was quoted. The discharge diagnosis was adjudicated by 2 independent experts using all available data, including cTnI. RESULTS: 317 patients were included: 148 (46%) had low, 110 (35%) moderate and 59 (19%) high PTP. Final diagnosis was AMI in 45 patients (14%). Median copeptin level was higher in AMI patients compared with that in patients having other diagnoses (23.2 vs. 9.9 pmol/L, p=0.01). A copeptin level ≥10.7 pmol/L in combination with cTnI detected AMI with higher sensitivity than for cTnI alone (98 [87-100] vs. 71 [55-83] %, p=0.001), whatever the PTP. The negative predictive value of the combination copeptin+cTnI was increased, compared to that of cTnI alone (99 [97-100] vs. 95 [92-97] %, p<0.05). CONCLUSIONS: In triage of chest pain patients, the additional use of copeptin with conventional cTnI might allow a rapid and reliable rule out of the diagnosis of AMI regardless of the PTP.

Appropriateness of diagnosis and orientation of 996 consecutive patients admitted in an emergency department with flow-based organization.

BACKGROUND: Recent data, focused on the inability to transfer emergency patients to inpatient beds, has shown this to be the single most important factor contributing to overcrowding. Our Emergency Department (ED) was reorganized in the year 2000 based on the optimization of patients' flow. In this model, the emergency team had to refer patients to units fitting best to their condition with minimal delays. OBJECTIVES: To evaluate adequacy of both diagnosis between emergency room and hospitalization wards and patients' orientation in the context of an early discharge from the ED. METHODS: We collected data from 996 consecutive nontrauma patients for whom an admission was decided. Duration of stay in the ED and all related parameters were studied. Patients were categorized according to the adequacy of the diagnosis proposed at ED discharge as compared with the final diagnosis at hospital discharge. The patients' orientation appropriateness was also assessed. RESULTS: Despite a median duration of time of 6 h (21 min-54 h) diagnostics made by the emergency physicians and the patients' orientation were considered as adequate in most of the cases (66 and 96%, respectively). Fast track developed with medical intensive care and cardiology intensive care allowed referral of patients requiring these specific units within 2.2 h (27 min-17 h) and 2 h (41 min-8 h), respectively. The ED length of stay was highly influenced by the admission location and by the patient's age. CONCLUSION: A short time of stay in the ED is compatible with both a good diagnosis and a good orientation of ED patients requiring admission for specialized care.

B-type natriuretic peptides for the diagnosis of congestive heart failure in dyspneic oldest-old patients.

OBJECTIVES: To evaluate the accuracy of B-type natriuretic peptide (BNP) and amino-terminal pro-brain natriuretic peptide (NT-proBNP) for the diagnosis of congestive heart failure (CHF) in dyspneic patients aged >or=85 years admitted to the Emergency Department (ED), and to define threshold values in this oldest-old population. DESIGN AND METHODS: This study involved 210 oldest-old patients, and 360 patients aged from 65 to 84 years (<85 years), admitted to the ED for dyspnea. RESULTS: Median BNP and NT-proBNP levels were significantly higher in CHF oldest-old patients (p<0.001). BNP and NT-proBNP threshold values were higher in oldest-old patients (290 and 2800 pg/mL, respectively) compared to that of patients <85 years (270 and 1700 pg/mL, respectively). In a multivariate analysis, both BNP and NT-proBNP were the strongest variables associated with CHF in oldest-old patients. Neither renal function nor gender had impact on the diagnostic utility of the two tests. CONCLUSION: Both BNP and NT-proBNP could potentially be reliable biomarkers for the diagnosis of CHF in oldest-old patients admitted with acute dyspnea to the ED.

Improved synchrony and respiratory unloading by neurally adjusted ventilatory assist (NAVA) in lung-injured rabbits.

With increasing pressure support ventilation (PSV), a form of pneumatically triggered ventilation, there can be an increase in wasted inspiratory efforts (neural inspiratory efforts that fail to trigger the ventilator). With neurally adjusted ventilatory assist (NAVA), a mode of ventilation controlled by the electrical activity of the diaphragm (EAdi), synchrony should be maintained at high levels of assist. The aim of this study was to evaluate the response to increasing levels of PSV and NAVA on synchrony and diaphragm unloading in lung-injured rabbits. Animals were ventilated on PSV or NAVA in random order, each at three levels. We measured neural and ventilator respiratory rates, EAdi, transdiaphragmatic pressure (Pdi), and tidal volume (VT). At low PSV, 95% of neural efforts were triggered, compared with high PSV, where only 66% of the neural efforts were triggered. During NAVA, all neural efforts were triggered, regardless of level. Increasing NAVA levels reduced EAdi and Pdi-time products by 48% (p < 0.05) and 66% (p < 0.05). In contrast, increasing PSV did not reduce the diaphragm electrical activity-time product and increased the transdiaphragmatic pressure-time product (p < 0.05) due to the increased wasted efforts. We conclude that synchrony with the ventilator is an important determinant for diaphragm unloading.

Influence of neurally adjusted ventilatory assist and positive end-expiratory pressure on breathing pattern in rabbits with acute lung injury.

OBJECTIVE: To evaluate the influence of neurally adjusted ventilatory assist (NAVA) and positive end-expiratory pressure (PEEP) on the control of breathing in rabbits with acute lung injury. DESIGN: Prospective animal study. SETTING: Experimental laboratory in a university hospital. SUBJECTS: Male White New Zealand rabbits (n = 18). INTERVENTION: Spontaneously breathing rabbits with hydrochloric acid-induced lung injury were ventilated with NAVA and underwent changes in NAVA gain and PEEP (six nonvagotomized and five vagotomized). Seven other nonvagotomized rabbits underwent 4 hrs of ventilation with hourly titration of PEEP, Fio2, and NAVA gain. MEASUREMENTS AND MAIN RESULTS: We studied diaphragm electrical activity, respiratory pressures, and breathing pattern. After lung injury, 0 cm H2O of PEEP resulted in high tonic and no discernible phasic diaphragm electrical activity in the nonvagotomized rabbits; stepwise increases in PEEP (up to 11.7 +/- 2.6 cm H2O) reduced tonic but increased phasic diaphragm electrical activity. Increasing the NAVA gain reduced phasic diaphragm electrical activity to almost half and abolished esophageal pressure swings. Tidal volume remained at 4-5 mL/kg, and respiratory rate did not change. In the vagotomized group, lung injury did not induce tonic activity, and phasic activity and tidal volume were several times higher than in the nonvagotomized rabbits. Four hours of breathing with NAVA restored breathing pattern and neural and mechanical breathing efforts to pre-lung injury levels. CONCLUSIONS: Acute lung injury can cause a vagally mediated atypical diaphragm activation pattern in spontaneously breathing rabbits. Modulation of PEEP facilitates development of phasic diaphragm electrical activity, whereupon implementation of NAVA can efficiently maintain unloading of the respiratory muscles without delivering excessive tidal volume in rabbits with intact vagal function.