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Biomedical subjects

Alan B Storrow

Publications and source records attributed to Alan B Storrow.

At least 19 recordsLinked to original sources

Brain dynamics reflecting an intra-network brain state is associated with increased posttraumatic stress symptoms in the early aftermath of trauma.

Post-traumatic stress (PTS) encompasses a range of psychological responses following trauma, which may lead to more severe outcomes such as post-traumatic stress disorder (PTSD). Identifying early neuroimaging biomarkers that link brain function to PTS outcomes is critical for understanding PTSD risk. This longitudinal study examines the association between brain dynamic functional network connectivity (dFNC) and current/future PTS symptom severity, and the impact of sex on this relationship. By analyzing 275 participants' dFNC data obtained ~2 weeks after trauma exposure, we noted that brain dynamics of an inter-network brain state link negatively with current (r=-0.197, p corrected = 0.0079) and future (r=-0.176, p corrected = 0.0176) PTS symptom severity. Also, dynamics of an intra-network brain state correlated with future symptom intensity (r = 0.205, p corrected = 0.0079). We additionally observed that the association between the network dynamics of the inter-network and intra-network brain state with symptom severity is more pronounced in female group. Our findings highlight a potential link between brain network dynamics in the aftermath of trauma with current and future PTSD outcomes, with a stronger effect in female group, underscoring the importance of sex differences.

Journal Article↗

The role of cardiac risk factor burden in diagnosing acute coronary syndromes in the emergency department setting.

STUDY OBJECTIVE: We seek to determine whether cardiac risk factor burden (defined as the number of conventional cardiac risk factors present) is useful for the diagnosis of acute coronary syndromes in the emergency department (ED) setting. METHODS: This was a post hoc analysis of the Internet Tracking Registry of Acute Coronary Syndromes (i*trACS) registry, which had 17,713 ED visits for suspected acute coronary syndromes. First visit for US patients who were not cocaine or amphetamine users, who did not leave against medical advice, and for whom ECG and demographic data were complete were included. Acute coronary syndrome was defined by 30-day revascularization, diagnostic-related group codes, or death within 30 days, with positive cardiac biomarkers at index hospitalization. Cardiac risk factors were diabetes, hypertension, smoking, hypercholesterolemia, and family history of coronary artery disease. Cardiac risk factor burden was defined as the number of risk factors present. Because multiple logistic regression analysis revealed that age modified the relationship between cardiac risk factor burden and acute coronary syndromes, a stratified analysis was performed for 3 age categories: younger than 40, 40 to 65, and older than 65 years. Positive likelihood ratios and negative likelihood ratios with their 95% confidence intervals (CIs) were calculated for each total risk factor cutoff. RESULTS: Of 10,806 eligible patients, 871 (8.1%) had acute coronary syndromes. In patients younger than 40 years, having no risk factors had a negative likelihood ratio of 0.17 (95% CI 0.04 to 0.66), and having 4 or more risk factors had a positive likelihood ratio of 7.39 (95% CI 3.09 to 17.67). In patients between 40 and 65 years of age, having no risk factors had a negative likelihood ratio of 0.53 (95% CI 0.40 to 0.71), and having 4 or more risk factors had a positive likelihood ratio of 2.13 (95% CI 1.66 to 2.73). In patients older than 65 years, having no risk factors had a negative likelihood ratio of 0.96 (95% CI 0.74 to 1.23), and having 4 or more risk factors had a positive likelihood ratio of 1.09 (95% CI 0.64 to 1.62). CONCLUSION: Cardiac risk factor burden has limited clinical value in diagnosing acute coronary syndromes in the ED setting, especially in patients older than 40 years.

Adult↗

Clinical characteristics of emergency department heart failure patients initially diagnosed as non-heart failure.

BACKGROUND: Since previous studies suggest the emergency department (ED) misdiagnosis rate of heart failure is 10-20% we sought to describe the characteristics of ED patients misdiagnosed as non-decompensated heart failure in the ED. METHODS: We analyzed a prospective convenience sample of 439 patients at 4 emergency departments who presented with signs or symptoms of decompensated heart failure. Patients with a cardiology criterion standard diagnosis of decompensated heart failure and an ED diagnosis of decompensated heart failure were compared to patients with a criterion standard of decompensated heart failure but no ED diagnosis of decompensated heart failure. Two senior cardiology fellows retrospectively determined the patient's heart failure status during their acute ED presentation. The Mann-Whitney u-test for two groups, the Kruskall-Wallis test for multiple groups, or Chi-square tests, were used as appropriate. RESULTS: There were 173 (39.4%) patients with a criterion standard diagnosis of decompensated heart failure. Among those with this criterion standard diagnosis of decompensated heart failure, discordant patients without an ED diagnosis of decompensated heart failure (n = 58) were more likely to have a history of COPD (p = 0.017), less likely to have a previous history of heart failure (p = 0.014), and less likely to have an elevated b-type natriuretic peptide (BNP) level (median 518 vs 764 pg/ml; p = 0.038) than those who were given a concordant ED diagnosis of decompensated heart failure. BNP levels were higher in those with a criterion standard diagnosis of decompensated heart failure than in those without a criterion standard diagnosis (median 657 vs 62.7 pg/ml). However, 34.6% of patients with decompensated heart failure had BNP levels in the normal (<100 pg/ml; 6.1%) or indeterminate range (100-500 pg/ml; 28.5%). CONCLUSION: We found the ED diagnoses of decompensated heart failure to be discordant with the criterion standard in 14.3% of patients, the vast majority of which were due to a failure to diagnose heart failure when it was present. Patients with a previous history of COPD, without a previous history of heart failure and with lower BNP levels were more likely to have an ED misdiagnosis of non-decompensated heart failure. Readily available, accurate, objective ED tests are needed to improve the early diagnosis of decompensated heart failure in ED patients.

Journal Article↗

Discordant cardiac biomarkers: frequency and outcomes in emergency department patients with chest pain.

STUDY OBJECTIVE: We evaluate associations between pairs of discordant cardiac biomarkers (positive MB band of creatine kinase [CKMB] with negative creatine kinase, positive CKMB with negative cardiac troponin, and positive troponin with negative CKMB) and the presence of acute coronary syndromes in emergency department (ED) chest pain patients. METHODS: This was a secondary analysis of a prospective registry. Data were obtained from the multicenter Internet Tracking Registry of Acute Coronary Syndromes, which included 17,713 ED visits for possible acute coronary syndrome between June 1999 and August 2001. First visits and first ED cardiac biomarker results from the 9 sites, 8 in the United States and 1 in Singapore, were included. Subjects were excluded for incomplete information or an initial ECG consistent with ST-segment elevation myocardial infarction. Acute coronary syndrome was defined by diagnosis-related group code indicating myocardial infarction, positive invasive or noninvasive diagnostic testing, revascularization, or death during hospitalization or within 30 days. RESULTS: Of 8,769 eligible patients, 1,614 (18.4%) had acute coronary syndrome. The CKMB and cardiac troponin results were discordant in 7% of patients (CKMB+/cardiac troponin-, 4.9%, CKMB-/cardiac troponin+ 2.1%), whereas increased CKMB with normal creatine kinase levels occurred in 239 (3.1%) patients. The unadjusted odds ratios with 95% confidence intervals for acute coronary syndrome in patients with and without discordant markers were: CKMB+/CK- 5.7 (4.4-7.4), CKMB+/CK+ 4.4 (3.6-5.2), CKMB-/cTn+ 4.8 (3.4-6.8), CKMB+/cTn- 2.2 (1.7-2.8), CKMB+/cTn+ 26.6 (18.0-39.3). For the group with cardiac troponin, the reference category was negative troponin and negative CKMB; for the group with creatine kinase, the reference category was negative CKMB but either a positive or negative creatine kinase. CONCLUSION: Among the spectrum of ED patients with chest pain, an increased CKMB level with a normal creatine kinase level identifies patients at increased risk for acute coronary syndrome. Similarly, an increased troponin level regardless of CKMB level and an increased CKMB level regardless of troponin level identify patients at higher risk for acute coronary syndrome than those with uniformly normal cardiac biomarker levels. Our data suggest that discordant cardiac biomarkers may identify patients at increased risk for acute coronary syndrome.

Biomarkers↗

The use of noninvasive ventilation in emergency department patients with acute cardiogenic pulmonary edema: a systematic review.

STUDY OBJECTIVE: Acute cardiogenic pulmonary edema is a common cause of respiratory distress in emergency department (ED) patients. Noninvasive ventilation by noninvasive positive pressure ventilation or continuous positive airway pressure has been studied as a treatment strategy. We critically evaluate the evidence for the use of noninvasive ventilation on rates of hospital mortality and endotracheal intubation. METHODS: We searched the databases of MEDLINE, EMBASE, and the Cochrane Library from 1980 to 2005. Additional sources included key journals, bibliographies of selected articles, and expert contact. We included studies that incorporated a randomized design; patients older than 18 years and with acute cardiogenic pulmonary edema; diagnosis and treatment initiated in the ED; noninvasive ventilation in addition to standard medical therapy compared to standard medical therapy alone, or noninvasive positive pressure ventilation compared to continuous positive airway pressure (both in addition to standard medical therapy); and data on hospital mortality or intubation. A random-effects model was used to obtain the summary risk ratios (RRs) and 95% confidence intervals (CIs) for hospital mortality and intubation. RESULTS: A pooled analysis of 494 patients suggested that noninvasive ventilation in addition to standard medical therapy significantly reduced hospital mortality compared to standard medical therapy alone (RR 0.61; [95% CI 0.41, 0.91]). Similarly, a meta-analysis of 436 patients suggested that noninvasive ventilation was associated with a significant decrease in intubation rates (RR 0.43; [95% CI 0.21, 0.87]). CONCLUSION: Our results suggest that noninvasive ventilation with standard medical therapy is advantageous over standard medical therapy alone in ED patients with acute cardiogenic pulmonary edema. Future studies, powered appropriately for mortality and intubation rates, are necessary to confirm these findings.

Acute Disease↗

How obesity affects the cut-points for B-type natriuretic peptide in the diagnosis of acute heart failure. Results from the Breathing Not Properly Multinational Study.

BACKGROUND: B-type natriuretic peptide (BNP) is valuable in diagnosing heart failure (HF), but its utility in obese patients is unknown. Studies have suggested a cut-point of BNP > or = 100 pg/mL for the diagnosis of HF; however, there is an inverse relation between BNP levels and body mass index. We evaluated differential cut-points for BNP in diagnosing acute HF across body mass index levels to determine whether alternative cut-points can improve diagnosis. METHODS: The Breathing Not Properly Multinational Study was a 7-center, prospective study of 1586 patients who presented to the Emergency Department with acute dyspnea. B-type natriuretic peptide was measured on arrival. Height and weight data were available for 1368 participants. The clinical diagnosis of HF was adjudicated by 2 independent cardiologists who were blinded to BNP results. RESULTS: Heart failure was the final diagnosis in 46.1%. Mean BNP levels (pg/mL) in lean, overweight/obese, and severely/morbidly obese patients were 643, 462, and 247 for patients with acute HF, and 52, 35, and 25 in those without HF, respectively (P < .05 for all comparisons except 35 vs 25). B-type natriuretic peptide cut-points to maintain 90% sensitivity for a HF diagnosis were 170 pg/mL for lean subjects, 110 pg/mL for overweight/obese subjects, and 54 pg/mL in severely/morbidly obese patients. CONCLUSIONS: Body mass index influences the selection of cut-points for BNP in diagnosing acute HF. A lower cut-point (BNP > or = 54 pg/mL) should be used in severely obese patients to preserve sensitivity. A higher cut-point in lean patients (BNP > or = 170 pg/mL) could be used to increase specificity.

Acute Disease↗

The effect of treatment on the presence of abnormal heart sounds in emergency department patients with heart failure.

OBJECTIVE: We sought to assess the proportion of ED patients with an electronically detected S(3) or S(4), determine the relation of these heart sounds to heart failure (HF), and analyze how the proportion changes with ED treatment. METHODS: Heart sounds were assessed in ED patients with suspected HF. The presence or absence of HF and whether treatment with diuretics or vasodilators had occurred were recorded. RESULTS: Three hundred seventy-six patients had complete data. The proportion of patients with an S(3) and an S(4) was significantly higher for those with HF compared with those without (P < .001). Of 59 patients with HF evaluated before treatment, 57.6% had an S(3) and 35.6% had an S(4). For the 35 patients with HF evaluated after treatment, the proportions of both S(3) and S(4) were lower (28.6% and 8.6%, respectively; P < or = .0064). CONCLUSIONS: This study suggests the proportion of patients with an electronically detected S(3) in HF is more than 50%, and that its presence is affected by prior treatment with diuretics or vasodilators.

Aged↗

An evaluation of emergency physician selection of observation unit patients.

OBJECTIVE: Appropriate patient selection is critical for maximal observation unit (OU) effectiveness. We hypothesized emergency physicians underuse the OU for admitted patients and overuse the OU for patients who would otherwise be discharged. METHODS: Treating emergency physicians were asked about patient suitability for admission to an OU at a busy, urban, academic emergency department (ED) as part of a prospective cohort study of ED patients who were admitted or had an ED length of stay exceeding 4 hours. The OU was closed for renovation during the 2-month study, so physician opinion could be compared with patient course in the absence of observation services. Two blinded emergency physicians reviewed charts using structured forms and explicit definitions to determine actual patient course. Hospitalized patients were considered potential OU candidates according to a priori criteria: (1) hospital length of stay less than 48 hours, (2) no procedure or diagnosis requiring hospitalization, and (3) no death. RESULTS: Of 1747 enrolled patients, 131 were excluded with incomplete data. Median age was 45 years. Patients were 40% white and 48% men. Emergency physicians identified 363 (23%) patients as observation candidates. Of these, 182 (50%) were actually discharged directly. The remaining 181 (50%) were hospitalized; 101 (56%) were observation candidates based on chart review. Of 799 admitted patients not selected for observation, 232 (29%) were suitable for observation by chart review. CONCLUSIONS: Selection of patients for observation was suboptimal; emergency physicians routinely identified patients as OU candidates who were not ultimately admitted, and they missed many admitted patients who might have been appropriate OU candidates. Both over- and underuse should be addressed to maximize the effectiveness of OUs.

Adolescent↗

Impact of the history of congestive heart failure on the utility of B-type natriuretic peptide in the emergency diagnosis of heart failure: results from the Breathing Not Properly Multinational Study.

PURPOSE: B-type natriuretic peptide is known to correlate with hemodynamic state, presence and severity of congestive heart failure, and prognosis. Although low-range B-type natriuretic peptide less than 100 pg/mL has a high negative predictive value (90%), and high-range B-type natriuretic peptide greater than 500 pg/mL has a high positive predictive value (87%), there remains some ambiguity in the interpretation of results in the medium range (100-500 pg/mL). We hypothesized that taking into account the history of congestive heart failure along with other clinical variables would be helpful in this range of B-type natriuretic peptide levels. METHOD: The Breathing Not Properly Multicenter Study was an international, 7-center, prospective study including 1475 patients with a mean age of 63 years (57% were male, and 54% were female); 35% of patients with a history of congestive heart failure were enrolled, and a final diagnosis of congestive heart failure was made in 46%. The index criteria was defined as positive if any 2 index findings (ie, history of coronary artery disease, lower extremity edema, pulmonary edema, cephalization of the pulmonary arteries, and cardiomegaly) were present. RESULTS: The interval likelihood ratios (LR) for low, medium, and high B-type natriuretic peptide ranges are 0.13, 1.85, and 8.1, respectively. For medium B-type natriuretic peptide levels a positive history of congestive heart failure makes the diagnosis of congestive heart failure more probable with a cumulative LR of 4.3. Also in this range a positive index criterion was strongly indicative of congestive heart failure even in the absence of a history of congestive heart failure (LR 3.3). Where there are both a positive history of congestive heart failure and a positive index criteria for the medium B-type natriuretic peptide group, the cumulative LR (10.2) is similar to that of a high B-type natriuretic peptide level (8.1). CONCLUSION: Even in the medium range (100-500 pg/mL), when using the history of congestive heart failure and index criteria, B-type natriuretic peptide can be a powerful diagnostic tool in the hands of clinicians in the emergency department.

Aged↗

The combined utility of an S3 heart sound and B-type natriuretic peptide levels in emergency department patients with dyspnea.

BACKGROUND: Emergency department (ED) patients with undifferentiated dyspnea are a diagnostic dilemma. We hypothesized that electronic detection of an S3 would be more accurate in determining decompensated heart failure than physician auscultation, and that combining electronic heart sounds with B-type natriuretic peptide (BNP) would provide additional decision making information to the emergency physician, especially in the BNP indeterminate range (100-500 pg/mL). METHODS AND RESULTS: We collected demographic, clinical, and laboratory data in a convenience sample of ED patients presenting with signs or symptoms of acute decompensated heart failure between September 2003 and June 2004. The electronic presence of an S3 or S4 was determined using the Audicor system, a validated device that algorithmically detects S3 and S4 heart sounds. Two independent reviewers determined the presence or absence of acute decompensated heart failure (primary HF) based on chart review, while blinded to BNP and Audicor results. Test characteristics were determined with 95% confidence intervals. Of 422 enrolled patients, 343 had complete data and were included in the final analysis. Median age was 61 years, 54% were female, and 48% were white. The sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy of an electronic S3 for primary HF were 34% (26% to 43%), 93% (89% to 96%), 66% (57% to 74%), 7% (4% to 11%), and 70% (65% to 75%) and for physician auscultation were 16% (11% to 24%), 97% (93% to 99%), 84% (76% to 89%), 3% (2% to 7%), and 66% (61% to 71%). The addition of an Audicor S3 to intermediate BNP levels improved the positive LR from 1.3 to 2.9; the positive predictive value from 53% to 80%. CONCLUSION: An S3 is highly specific for primary HF and it is ideally suited for use in combination with BNP to improve diagnostic accuracy in ED patients with dyspnea of unclear etiology.

Adult↗

B-type natriuretic peptide levels in patients in the emergency department with possible heart failure and previous stable angina pectoris and/or healed myocardial infarction.

We examined the relation between B-type natriuretic peptide (BNP) levels and a history of stable angina pectoris and/or healed myocardial infarction in 1,240 patients who were evaluated in the emergency department for possible heart failure. In patients who had heart failure, there was no relation between BNP levels and previous stable angina pectoris and/or healed myocardial infarction. However, in patients who did not have heart failure, there was a relation between BNP levels and previous stable angina pectoris and/or healed myocardial infarction but no significant independent relation in multiple regression analysis.

Adult↗

Impact of atrial fibrillation on the diagnostic performance of B-type natriuretic peptide concentration in dyspneic patients: an analysis from the breathing not properly multinational study.

OBJECTIVES: This study was designed to assess the diagnostic performance of B-type natriuretic peptide (BNP) in the diagnosis of acute congestive heart failure (CHF) in patients with permanent/paroxysmal atrial fibrillation (AF) presenting with acute dyspnea. BACKGROUND: It is unknown to what extent AF affects the diagnostic performance of BNP in patients presenting with acute dyspnea. METHODS: We studied 1,431 patients drawn from a cohort of patients (n = 1,586) with acute dyspnea who had BNP levels measured on arrival. Patients were prospectively classified according to the presence or absence of permanent/paroxysmal AF. RESULTS: In total, 292 patients had permanent/paroxysmal AF. In patients without HF, permanent/paroxysmal AF was associated with significantly higher BNP levels (p = 0.001). Conversely, in patients with HF, BNP levels did not differ significantly between patients with and without AF (p = 0.533). A BNP cutoff value of 100 pg/ml had a specificity of 40% and 79% for the diagnosis of acute HF in patients with and without AF, respectively. The areas under the receiver-operating characteristic curves were 0.84 (95% confidence interval 0.78 to 0.89) and 0.91 (95% confidence interval 0.89 to 0.93) for patients with and without AF, respectively. CONCLUSIONS: In patients without, but not in those with HF, the presence of AF is associated with higher circulating BNP levels, suggesting that a higher diagnostic threshold should be used in patients with AF.

Acute Disease↗

Prevalence of negative chest radiography results in the emergency department patient with decompensated heart failure.

STUDY OBJECTIVE: Although chest radiography is quick and inexpensive, previous research suggests that it is often misleading in emergency department (ED) patients with decompensated heart failure, resulting in misdiagnosis and inappropriate treatment. This study determines the rate of negative chest radiography results in patients found to have disease and the potential contribution of negative findings to a diagnosis discordant with heart failure by an emergency physician. METHODS: We used data from the Acute Decompensated Heart Failure National Registry (ADHERE), a registry of patients with a primary hospital discharge diagnosis of heart failure. We compared initial ED admitting diagnosis to the criterion standard of a hospital discharge diagnosis of heart failure and related these to radiographic findings of heart failure (interstitial edema, pulmonary edema, or vascular congestion, as determined by a staff radiologist) for patients first treated in the ED. The proportion of patients with a non-heart failure ED diagnosis and the diagnostic sensitivity of radiographic findings of heart failure are calculated. RESULTS: There were 85,376 patients with chest radiograph results and an ED admitting diagnosis. Overall, there were 15,937 patients with no signs of congestion on ED chest radiography, giving a negative rate of 18.7% (95% confidence interval [CI] 18.4% to 18.9%). The proportion of patients with an ED non-heart failure admitting diagnosis was higher in patients with a negative chest radiograph result (23.3%; 95% CI 22.6% to 23.9%) than in patients with a positive chest radiograph result (13.0%; 95% CI 12.7% to 13.2%). CONCLUSION: Approximately 1 of every 5 patients admitted from the ED with acute decompensated heart failure had no signs of congestion on chest radiography. Patients lacking signs of congestion on ED chest radiography were more likely to have an ED non-heart failure diagnosis than patients with signs of congestion. Clinicians should not rule out heart failure in patients with no radiographic signs of congestion.

Aged↗

Relationship of B-type natriuretic peptide and anemia in patients with and without heart failure: a substudy from the Breathing Not Properly (BNP) Multinational Study.

While anemia is a significant risk factor for poor outcomes in patients with heart failure (HF), it is not in defined guidelines for HF assessment. B-type natriuretic peptide (BNP) is a marker for diagnosis and management of patients with HF. We determined the incidence of anemia in patients with HF and the relationship between BNP and hemoglobin (Hgb) levels in patients with and without HF. Results from the Breathing Not Properly Multinational Trial consisted of 1,586 patients presenting to the emergency department (ED) with dyspnea. Because renal insufficiency is a confounding variable for BNP, patients with a creatinine of >or=2.0 mg/dL were excluded. The remaining data were evaluated from 620 non-HF patients (337 M, 283 F) and 547 HF patients (299 M, 248 F). The New York Heart Association (NYHA) HF classification and ejection fraction by echocardiography were assessed for HF patients. Blood was tested for Hgb, BNP, and creatinine. Using World Health Organization criteria for anemia, we observed that HF patients in NYHA class III or IV had lower mean Hgb levels (12.5 g/dL, P < 0.05) and a higher incidence of anemia (48.2%, P < 0.05) than did HF patients in class I or II (13.4 g/dL and 33.9%, respectively). There was no correlation between Hgb and log BNP for females without HF or the aggregate of all HF patients. In contrast, a significant inverse correlation was observed for males without HF (P < 0.001). Although there were differences in the BMI, age, and estimated glomerular filtration rate (eGFR) versus Hgb observed in this group, the log BNP correlation remained significant after multivariate analysis. A significant inverse correlation for log BNP and Hgb were also observed for diastolic (EF >or= 50) HF (P < 0.05) that was also not accounted for by the BMI, age, or eGFR. The presence of anemia is associated with worsening HF at ED presentation. For males without HF and diastolic HF patients of both genders, a low Hgb may be a confounding variable toward increasing BNP. Among systolic HF patients, the presence of a low hemoglobin concentration is not a factor in the interpretation of BNP results.

Anemia↗

Predictors of elevated B-type natriuretic peptide concentrations in dyspneic patients without heart failure: an analysis from the breathing not properly multinational study.

STUDY OBJECTIVE: B-type natriuretic peptide (BNP) is an established tool for the diagnosis of acute congestive heart failure in patients presenting with dyspnea. Some patients have moderately elevated BNP levels (ie, 100 to 500 pg/mL) in the absence of acute congestive heart failure. The objective of the current study was to identify independent predictors of elevated BNP concentrations in the absence of congestive heart failure. METHODS: We studied 781 patients without acute congestive heart failure and BNP levels 0 to 500 pg/mL drawn from a cohort of 1,586 patients with acute dyspnea who had BNP levels measured on emergency department arrival. Two cardiologists blinded to BNP results reviewed all clinical data and categorized patients according to whether they had acute congestive heart failure or not. RESULTS: Independent predictors of elevated BNP levels (ie, >100 pg/mL) were a medical history of atrial fibrillation, radiographic cardiomegaly, decreased blood hemoglobin concentration, decreased body mass index, and increased age. CONCLUSION: Knowledge of these commonly obtained variables should aid clinicians in the interpretation of moderately elevated BNP results in patients presenting with acute dyspnea in the emergency department.

Aged↗

Comparison of actual and stated concentrations of pharmaceuticals manufactured in Mexico.

BACKGROUND: During the past 5 years, there has been much concern about the safety of and ease of access to drugs that are unavailable without a prescription in the United States but are manufactured and can be purchased over the counter (OTC) in Mexico. However, based on a literature search, studies have not been performed to determine whether such drugs meet the US Pharmacopoeia (USP) standards for percent of labeled amount. OBJECTIVE: The aim of this study was to determine whether 5 drugs commonly prescribed in the United States and manufactured and purchased in Mexico met USP standards for stated concentration, were properly packaged and sealed, and had properly labeled expiration dates and lot numbers. METHODS: For the study, we purchased acetaminophen, carbamazepine, diazepam, digoxin, and phenytoin from 2 to 4 pharmacies in Ciudad Acuna, Mexico. Samples of each drug, each with a different lot number, were purchased OTC or with a prescription. None of the pharmacists had knowledge of the study. Brand-name or generic drugs manufactured and obtained in the United States were also analyzed for comparative purposes. Each drug was analyzed by high-performance liquid chromatography using USP guidelines established for the analysis of each drug. In addition, we visually examined the packaging, seals, color, and appearance of the drugs, and observed whether the packages contained lot numbers and whether the drugs were within the stated expiration dates. RESULTS: For all 5 drugs, the 95% CIs fell within the USP-defined acceptable ranges for percent of labeled amount. This was found to be true for drugs obtained at different pharmacies, for different drug manufacturers, and for drugs with different lot numbers. All of the drugs were found to be properly packaged and sealed, had lot numbers listed on the packages, and were sold before the stated expiration dates. CONCLUSION: Although health care practitioners should be aware that patients might be using drugs manufactured and purchased in Mexico, the results of this study of a small sample of such drugs suggest they meet the USP standards for percent of labeled amount.

Chromatography, High Pressure Liquid↗