Effectiveness of a bivalent mRNA vaccine dose against symptomatic SARS-CoV-2 infection among U.S. Healthcare personnel, September 2022-May 2023

BACKGROUND

Bivalent mRNA vaccines were recommended since September 2022. However, coverage with a recent vaccine dose has been limited, and there are few robust estimates of bivalent VE against symptomatic SARS-CoV-2 infection (COVID-19). We estimated VE of a bivalent mRNA vaccine dose against COVID-19 among eligible U.S. healthcare personnel who had previously received monovalent mRNA vaccine doses.

METHODS

We conducted a case-control study in 22 U.S. states, and enrolled healthcare personnel with COVID-19 (case-participants) or without COVID-19 (control-participants) during September 2022-May 2023. Participants were considered eligible for a bivalent mRNA dose if they had received 2-4 monovalent (ancestral-strain) mRNA vaccine doses, and were ≥67 days after the most recent vaccine dose. We estimated VE of a bivalent mRNA dose using conditional logistic regression, accounting for matching by region and four-week calendar period. We adjusted estimates for age group, sex, race and ethnicity, educational level, underlying health conditions, community COVID-19 exposure, prior SARS-CoV-2 infection, and days since the last monovalent mRNA dose.

RESULTS

Among 3,647 healthcare personnel, 1,528 were included as case-participants and 2,119 as control-participants. Participants received their last monovalent mRNA dose a median of 404 days previously; 1,234 (33.8%) also received a bivalent mRNA dose a median of 93 days previously. Overall, VE of a bivalent dose was 34.1% (95% CI, 22.6%-43.9%) against COVID-19 and was similar by product, days since last monovalent dose, number of prior doses, age group, and presence of underlying health conditions. However, VE declined from 54.8% (95% CI, 40.7%-65.6%) after 7-59 days to 21.6% (95% CI 5.6%-34.9%) after ≥60 days.

CONCLUSIONS

Bivalent mRNA COVID-19 vaccines initially conferred approximately 55% protection against COVID-19 among U.S. healthcare personnel. However, protection waned after two months. These findings indicate moderate initial protection against symptomatic SARS-CoV-2 infection by remaining up-to-date with COVID-19 vaccines.

Factors associated with the decision to receive bivalent COVID-19 booster vaccination among health care personnel

COVID-19 vaccination is effective at reducing SARS-CoV-2 complications, but uptake has been low. Our objective in this study was to compare the importance of factors reported to influence the decision to receive a bivalent COVID-19 booster vaccine among health care personnel (HCP) tested for SARS-CoV-2 between October 2022 and April 2023 in a 20-hospital vaccine effectiveness study in the United States (n = 1656). Compared with those who had not received the booster, the factors most likely to be reported to be important were concerns about contracting COVID-19 (84.0% of those who had received the bivalent booster vs. 47.5% of those who had not, difference 36.6% points (PP), 95% confidence interval [CI] 32.1 to 41.1%), spreading infection to family members (89.2% vs. 62.8%, difference 26.3 PP, 95% CI 22.3 to 30.4%), and spreading infection to colleagues at work (85.5% vs. 59.4%, difference 26.1 PP, 95% CI 21.7 to 30.5%). HCP who had received the booster more frequently cited the primary literature (61.7% vs. 31.8%, difference 29.9 PP, 95% CI 24.6 to 35.2%) and employer recommendations (48.3% vs. 29.8%, difference 18.5 PP, 95% CI 13.2 to 23.9%) as influencing their decision. This analysis provides insight into factors for targeting future vaccine messaging.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022

Background

Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant.

Methods

We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates.

Results

Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants.

Conclusions

A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

Effectiveness of mRNA Covid-19 Vaccine among U.S. Health Care Personnel

BACKGROUND

The prioritization of U.S. health care personnel for early receipt of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), allowed for the evaluation of the effectiveness of these new vaccines in a real-world setting.

METHODS

We conducted a test-negative case-control study involving health care personnel across 25 U.S. states. Cases were defined on the basis of a positive polymerase-chain-reaction (PCR) or antigen-based test for SARS-CoV-2 and at least one Covid-19-like symptom. Controls were defined on the basis of a negative PCR test for SARS-CoV-2, regardless of symptoms, and were matched to cases according to the week of the test date and site. Using conditional logistic regression with adjustment for age, race and ethnic group, underlying conditions, and exposures to persons with Covid-19, we estimated vaccine effectiveness for partial vaccination (assessed 14 days after receipt of the first dose through 6 days after receipt of the second dose) and complete vaccination (assessed ≥7 days after receipt of the second dose).

RESULTS

The study included 1482 case participants and 3449 control participants. Vaccine effectiveness for partial vaccination was 77.6% (95% confidence interval [CI], 70.9 to 82.7) with the BNT162b2 vaccine (Pfizer-BioNTech) and 88.9% (95% CI, 78.7 to 94.2) with the mRNA-1273 vaccine (Moderna); for complete vaccination, vaccine effectiveness was 88.8% (95% CI, 84.6 to 91.8) and 96.3% (95% CI, 91.3 to 98.4), respectively. Vaccine effectiveness was similar in subgroups defined according to age (<50 years or ≥50 years), race and ethnic group, presence of underlying conditions, and level of patient contact. Estimates of vaccine effectiveness were lower during weeks 9 through 14 than during weeks 3 through 8 after receipt of the second dose, but confidence intervals overlapped widely.

CONCLUSIONS

The BNT162b2 and mRNA-1273 vaccines were highly effective under real-world conditions in preventing symptomatic Covid-19 in health care personnel, including those at risk for severe Covid-19 and those in racial and ethnic groups that have been disproportionately affected by the pandemic. (Funded by the Centers for Disease Control and Prevention.).

Symptom Duration and Risk Factors for Delayed Return to Usual Health Among Outpatients with COVID-19 in a Multistate Health Care Systems Network - United States, March-June 2020

Prolonged symptom duration and disability are common in adults hospitalized with severe coronavirus disease 2019 (COVID-19). Characterizing return to baseline health among outpatients with milder COVID-19 illness is important for understanding the full spectrum of COVID-19-associated illness and tailoring public health messaging, interventions, and policy. During April 15-June 25, 2020, telephone interviews were conducted with a random sample of adults aged ≥18 years who had a first positive reverse transcription-polymerase chain reaction (RT-PCR) test for SARS-CoV-2, the virus that causes COVID-19, at an outpatient visit at one of 14 U.S. academic health care systems in 13 states. Interviews were conducted 14-21 days after the test date. Respondents were asked about demographic characteristics, baseline chronic medical conditions, symptoms present at the time of testing, whether those symptoms had resolved by the interview date, and whether they had returned to their usual state of health at the time of interview. Among 292 respondents, 94% (274) reported experiencing one or more symptoms at the time of testing; 35% of these symptomatic respondents reported not having returned to their usual state of health by the date of the interview (median = 16 days from testing date), including 26% among those aged 18-34 years, 32% among those aged 35-49 years, and 47% among those aged ≥50 years. Among respondents reporting cough, fatigue, or shortness of breath at the time of testing, 43%, 35%, and 29%, respectively, continued to experience these symptoms at the time of the interview. These findings indicate that COVID-19 can result in prolonged illness even among persons with milder outpatient illness, including young adults. Effective public health messaging targeting these groups is warranted. Preventative measures, including social distancing, frequent handwashing, and the consistent and correct use of face coverings in public, should be strongly encouraged to slow the spread of SARS-CoV-2.

Characteristics of Adult Outpatients and Inpatients with COVID-19 - 11 Academic Medical Centers, United States, March-May 2020

Descriptions of coronavirus disease 2019 (COVID-19) in the United States have focused primarily on hospitalized patients. Reports documenting exposures to SARS-CoV-2, the virus that causes COVID-19, have generally been described within congregate settings, such as meat and poultry processing plants (1) and long-term care facilities (2). Understanding individual behaviors and demographic characteristics of patients with COVID-19 and risks for severe illness requiring hospitalization can inform efforts to reduce transmission. During April 15-May 24, 2020, telephone interviews were conducted with a random sample of adults aged ≥18 years who had positive reverse transcription-polymerase chain reaction (RT-PCR) test results for SARS-CoV-2 in outpatient and inpatient settings at 11 U.S. academic medical centers in nine states. Respondents were contacted 14-21 days after SARS-CoV-2 testing and asked about their demographic characteristics, underlying chronic conditions, symptoms experienced on the date of testing, and potential exposures to SARS-CoV-2 during the 2 weeks before illness onset (or the date of testing among those who did not report symptoms at the time of testing). Among 350 interviewed patients (271 [77%] outpatients and 79 [23%] inpatients), inpatients were older, more likely to be Hispanic and to report dyspnea than outpatients. Fewer inpatients (39%, 20 of 51) reported a return to baseline level of health at 14-21 days than did outpatients (64%, 150 of 233) (p = 0.001). Overall, approximately one half (46%) of patients reported known close contact with someone with COVID-19 during the preceding 2 weeks. This was most commonly a family member (45%) or a work colleague (34%). Approximately two thirds (64%, 212 of 333) of participants were employed; only 35 of 209 (17%) were able to telework. These findings highlight the need for screening, case investigation, contact tracing, and isolation of infected persons to control transmission of SARS-CoV-2 infection during periods of community transmission. The need for enhanced measures to ensure workplace safety, including ensuring social distancing and more widespread use of cloth face coverings, are warranted (3).

Supplemental thiamine for the treatment of acute heart failure syndrome: a randomized controlled trial

Background

The purpose of this pilot study was to determine if a definitive clinical trial of thiamine supplementation was warranted in patients with acute heart failure. We hypothesized that thiamine, when added to standard of care, would improve dyspnea (primary outcome) in hospitalized patients with acute heart failure. Peak expiratory flow rate, type B natriuretic peptide, free fatty acids, glucose, hospital length of stay, as well as 30-day rehospitalization and mortality were pre-planned secondary outcome measures.

Methods

This was a blinded experimental study at two urban academic hospitals. Consecutive patients admitted from the Emergency Department with a primary diagnosis of acute heart failure were recruited over 2 years. Patients on a daily dietary supplement were excluded. Randomization was stratified by type B natriuretic peptide and diabetes medication categories. Subjects received study drug (100 mg thiamine or placebo) in the evening of their first and second day. Outcome measures were obtained 8 h after study drug infusion. Dyspnea was measured on a 100-mm visual analog scale sitting up on oxygen, sitting up off oxygen, and lying supine off oxygen with 0 indicating no dyspnea. Data were analyzed using mixed-models as well as linear, negative binomial and logistic regression models to assess the impact of group on outcome measures.

Results

Of 130 subjects randomized, 118 had evaluable data (55 in the control and 63 in the treatment groups), 89% in both groups were adjudicated to have primarily AHF. Thiamine values increased significantly in the treatment group and were unchanged in the control group. One patient had thiamine deficiency. Only dyspnea measured sitting upright on oxygen differed significantly by group over time. No change was found for the other measures of dyspnea and all of the secondary measures.

Conclusions

In mild-moderate acute heart failure patients without thiamine deficiency, a standard dosing regimen of thiamine did not improve dyspnea, biomarkers, or other clinical parameters.

Trial registration

ClinicalTrials.gov: NCT00680706, May 20, 2008 (retrospectively registered).

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2506-8) contains supplementary material, which is available to authorized users.

Independent evaluation of a simple clinical prediction rule to identify right ventricular dysfunction in patients with shortness of breath

BACKGROUND

Many patients have unexplained persistent dyspnea after negative computed tomographic pulmonary angiography (CTPA). We hypothesized that many of these patients have isolated right ventricular (RV) dysfunction from treatable causes. We previously derived a clinical decision rule (CDR) for predicting RV dysfunction consisting of persistent dyspnea and normal CTPA, finding that 53% of CDR-positive patients had isolated RV dysfunction. Our goal is to validate this previously derived CDR by measuring the prevalence of RV dysfunction and outcomes in dyspneic emergency department patients.

METHODS

A secondary analysis of a prospective observational multicenter study that enrolled patients presenting with suspected PE was performed. We included patients with persistent dyspnea, a nonsignificant CTPA, and formal echo performed. Right ventricular dysfunction was defined as RV hypokinesis and/or dilation with or without moderate to severe tricuspid regurgitation.

RESULTS

A total of 7940 patients were enrolled. Two thousand six hundred sixteen patients were analyzed after excluding patients without persistent dyspnea and those with a significant finding on CTPA. One hundred ninety eight patients had echocardiography performed as standard care. Of those, 19% (95% confidence interval [CI], 14%-25%) and 33% (95% CI, 25%-42%) exhibited RV dysfunction and isolated RV dysfunction, respectively. Patients with isolated RV dysfunction or overload were more likely than those without RV dysfunction to have a return visit to the emergency department within 45 days for the same complaint (39% vs 18%; 95% CI of the difference, 4%-38%).

CONCLUSION

This simple clinical prediction rule predicted a 33% prevalence of isolated RV dysfunction or overload. Patients with isolated RV dysfunction had higher recidivism rates and a trend toward worse outcomes.

Emergency medicine residents' knowledge of mechanical ventilation

BACKGROUND

Although Emergency physicians frequently intubate patients, management of mechanical ventilation has not been emphasized in emergency medicine (EM) residency curricula.

OBJECTIVES

The objective of this study was to quantify EM residents' education, experience, and knowledge regarding mechanical ventilation.

METHODS

We developed a survey of residents' educational experiences with ventilators and an assessment tool with nine clinical questions. Correlation and regression analyses were performed to evaluate the relationship between residents' scores on the assessment instrument and their training, education, and comfort with ventilation.

RESULTS

Of 312 EM residents, 218 responded (69.9%). The overall correct response rate for the assessment tool was 73.3%, standard deviation (SD) ± 22.3. Seventy-seven percent (n = 167) of respondents reported ≤ 3 h of mechanical ventilation education in their residency curricula over the past year. Residents reported frequently caring for ventilated patients in the ED, as 64% (n = 139) recalled caring for ≥ 4 ventilated patients per month. Fifty-three percent (n = 116) of residents endorsed feeling comfortable caring for mechanically ventilated ED patients. In multiregression analysis, the only significant predictor of total test score was residents' comfort with caring for mechanically ventilated patients (F = 10.963, p = 0.001).

CONCLUSIONS

EM residents report caring for mechanically ventilated patients frequently, but receive little education on mechanical ventilation. Furthermore, as residents' performance on the assessment tool is only correlated with their self-reported comfort with caring for ventilated patients, these results demonstrate an opportunity for increased educational focus on mechanical ventilation management in EM residency training.

Evaluation of pulmonary embolism in the emergency department and consistency with a national quality measure: quantifying the opportunity for improvement

BACKGROUND

The National Quality Forum (NQF) has endorsed a performance measure designed to increase imaging efficiency for the evaluation of pulmonary embolism (PE) in the emergency department (ED). To our knowledge, no published data have examined the effect of patient-level predictors on performance.

METHODS

To quantify the prevalence of avoidable imaging in ED patients with suspected PE, we performed a prospective, multicenter observational study of ED patients evaluated for PE from 2004 through 2007 at 11 US EDs. Adult patients tested for PE were enrolled, with data collected in a standardized instrument. The primary outcome was the proportion of imaging that was potentially avoidable according to the NQF measure. Avoidable imaging was defined as imaging in a patient with low pretest probability for PE, who either did not have a D-dimer test ordered or who had a negative D-dimer test result. We performed subanalyses testing alternative pretest probability cutoffs and imaging definitions on measure performance as well as a secondary analysis to identify factors associated with inappropriate imaging. χ(2) Test was used for bivariate analysis of categorical variables and multivariable logistic regression for the secondary analysis.

RESULTS

We enrolled 5940 patients, of whom 4113 (69%) had low pretest probability of PE. Imaging was performed in 2238 low-risk patients (38%), of whom 811 had no D-dimer testing, and 394 had negative D-dimer test results. Imaging was avoidable, according to the NQF measure, in 1205 patients (32%; 95% CI, 31%-34%). Avoidable imaging owing to not ordering a D-dimer test was associated with age (odds ratio [OR], 1.15 per decade; 95% CI, 1.10-1.21). Avoidable imaging owing to imaging after a negative D-dimer test result was associated with inactive malignant disease (OR, 1.66; 95% CI, 1.11-2.49).

CONCLUSIONS

One-third of imaging performed for suspected PE may be categorized as avoidable. Improving adherence to established diagnostic protocols is likely to result in significantly fewer patients receiving unnecessary irradiation and substantial savings.

D-dimer threshold increase with pretest probability unlikely for pulmonary embolism to decrease unnecessary computerized tomographic pulmonary angiography

BACKGROUND

Increasing the threshold to define a positive D-dimer could reduce unnecessary computed tomographic pulmonary angiography (CTPA) for a suspected pulmonary embolism (PE) but might increase rates of a missed PE and missed pneumonia, the most common non-thromboembolic diagnosis seen on CTPA.

OBJECTIVE

Measure the effect of doubling the standard D-dimer threshold for 'PE unlikely' Revised Geneva (RGS) or Wells' scores on the exclusion rate, frequency and size of a missed PE and missed pneumonia.

METHODS

Patients evaluated for a suspected PE with 64-channel CTPA were prospectively enrolled from emergency departments (EDs) and inpatient units of four hospitals. Pretest probability data were collected in real time and the D-dimer was measured in a central laboratory. Criterion standard was CPTA interpretation by two independent radiologists combined with clinical outcome at 30 days.

RESULTS

Of 678 patients enrolled, 126 (19%) were PE+ and 93 (14%) had pneumonia. Use of either Wells' ≤ 4 or RGS ≤ 6 produced similar results. For example, with RGS ≤ 6 and standard threshold (< 500 ng mL(-1)), D-dimer was negative in 110/678 (16%), and 4/110 were PE+ (posterior probability 3.8%) and 9/110 (8.2%) had pneumonia. With RGS ≤ 6 and a threshold < 1000 ng mL(-1) , D-dimer was negative in 208/678 (31%) and 11/208 (5.3%) were PE+, but 10/11 missed PEs were subsegmental and none had concomitant DVT. Pneumonia was found in 12/208 (5.4%) with RGS ≤ 6 and D-dimer < 1000 ng mL(-1).

CONCLUSIONS

Doubling the threshold for a positive D-dimer with a PE unlikely pretest probability could reduce CTPA scanning with a slightly increased risk of missed isolated subsegmental PE, and no increase in rate of missed pneumonia.

Pharmacokinetics of high-dose oral thiamine hydrochloride in healthy subjects

BACKGROUND

High dose oral thiamine may have a role in treating diabetes, heart failure, and hypermetabolic states. The purpose of this study was to determine the pharmacokinetic profile of oral thiamine hydrochloride at 100 mg, 500 mg and 1500 mg doses in healthy subjects.

METHODS

This was a randomized, double-blind, single-dose, 4-way crossover study. Pharmacokinetic measures were calculated.

RESULTS

The AUC₀₋₁₀ hr and C(max) values increased nonlinearly between 100 mg and 1500 mg. The slope of the AUC₀₋₁₀ hr vs dose, as well as the C(max) vs dose, plots are steepest at the lowest thiamine doses.

CONCLUSION

Our study demonstrates that high blood levels of thiamine can be achieved rapidly with oral thiamine hydrochloride. Thiamine is absorbed by both an active and nonsaturable passive process.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00981877.

The feasibility of measuring phosphocreatine recovery kinetics in muscle using a single-shot (31)P RARE MRI sequence

RATIONALE AND OBJECTIVES

Heterogeneity of skeletal muscle structure, composition, and perfusion results in spatial differences in oxidative function between muscles and muscle regions. The simultaneous measurement of the postexercise phosphocreatine (PCr) recovery rate across all muscles of a human limb cross-section may provide new insights into normal physiology and disease states. The objective of this work was to assess the feasibility of acquiring PCr rapid acquisition with relaxation enhancement (RARE) images with sufficient temporal and spatial resolution to accurately measure PCr recovery kinetics in a cross-section of a human limb.

MATERIALS AND METHODS

One normal subject performed a finger exercise until fatigued. At cessation of exercise surface coil localized pulse-and-acquire phosphorus-31 MR spectra ((31)P- magnetic resonance spectroscopy [MRS]) of the forearm were acquired at 6 S intervals for 4 minutes. The exercise protocol was repeated 7 days later and axial PCr RARE images of the forearm were acquired following exercise with 5.6 cm(3) voxels at 6-second intervals for 4 minutes.

RESULTS

The PCr recovery time constants for the PCr RARE and (31)P-MRS measurements were 91.0 and 91.1 seconds, respectively, based on a monoexponential fit. A Pearson correlation test showed that the PCr recovery data that resulted from the RARE PCr imaging were highly correlated with the data resulting from the (31)P-MRS (r = 0.91, P < .0001).

DISCUSSION

Data from selected regions of RARE PCr images acquired at 6-second intervals compare well to those acquired using surface coil (31)P MR spectroscopy and can provide an accurate assessment of PCr recovery kinetics.

Simultaneous acquisition of phosphocreatine and inorganic phosphate images for Pi:PCr ratio mapping using a RARE sequence with chemically selective interleaving

The ratio of inorganic phosphate to phosphocreatine (Pi:PCr) is a validated marker of mitochondrial function in human muscle. The magnetic resonance imaging rapid acquisition with relaxation enhancement (RARE) pulse sequence can acquire phosphorus-31 ((31)P) images with higher spatial and temporal resolution than traditional spectroscopic methods, which can then be used to create Pi:PCr ratio maps of muscle regions. While the (31)P RARE method produces images that reflect the content of the (31)P metabolites, it has been limited to producing an image of only one chemical shift in a scan. This increases the scan time required to acquire images of multiple chemical shifts as well as the likelihood of generating inaccurate Pi:PCr maps due to gross motion. This work is a preliminary study to demonstrate the feasibility of acquiring Pi and PCr images in a single scan by interleaving Pi and PCr chemical shift acquisitions using a chemically selective radiofrequency excitation pulse. The chemical selectivity of the excitation pulse evaluated and the Pi:PCr maps generated using the interleaved Pi and PCr acquisition method with the subject at rest and during exercise are compared to those generated using separate Pi and PCr acquisition scans. A paired t test indicated that the resulting Pi:PCr ratios for the exercised forearm muscle regions were not significantly different between the separate Pi and PCr acquisition method (3.18±1.53) (mean±standard deviation) and the interleaved acquisition method (3.41±1.66). This work demonstrates the feasibility of creating Pi:PCr ratio maps in human muscle with Pi and PCr images acquired simultaneously by interleaving between the Pi and PCr resonances in a single scan.

Assessing validity by comparing transition and static measures of dyspnea in patients with acute decompensated heart failure

This study assessed the convergent validity of 2 dyspnea measures, the transition measure and the change measure, by comparing them with each other in patients admitted to the hospital with acute decompensated heart failure. Static measures of dyspnea were obtained at baseline (pre-static measure) and at time 1 hour and 4 hour (post-static measures). The change measure was calculated as the difference between the pre-static and post-static measures. Transition measures were obtained at time 1 hour and 4 hour. Visual analog scales and Likert scales were used. Both physicians and patients measured the dyspnea independently. A total of 112 patients had complete data sets at time 0 and 1 hour and 86 patients had complete data sets at all 3 time points. Correlations were calculated between the transition measures and static measures (pre-static, post-static, and change measure). Bland-Altman plots were generated and the mean difference and limits of agreement between the transition measures and the change measures were calculated. In general, short-term dyspnea assessment using transition measures and serial static measures can not be used to validate each other in this population of patients being admitted with acute decompensated heart failure.

Physician vs patient assessment of dyspnea during acute decompensated heart failure

This study assessed agreement between physician and patient self-reported measures of dyspnea severity during acute decompensated heart failure (ADHF). Both the physician and patient measured the change in dyspnea severity over 1 hour using 2 methods: (1) the difference of two static dyspnea measures (STATIC) and (2) a single transitional measure (TRANS). Likert scales and visual analog scales (VASs) were used. Data on 112 patients were analyzed. The mean difference between physician and patient VAS scores was 1 mm (limits of agreement: -54 to 56 mm) using the STATIC data. For TRANS data, the mean difference was 5 mm (limits of agreement: -75 to 86 mm). For the Likert scales, the weighted kappa was 0.13 and 0.23 for STATIC and TRANS data, respectively. The wide limits of agreement restrict our ability to substitute physician assessment for patient self-assessment of dyspnea in patients with ADHF.

Emergency department patients who stay more than 6 hours contribute to crowding

BACKGROUND

Admitted and discharged patients with prolonged emergency department (ED) stays may contribute to crowding by utilizing beds and staff time that would otherwise be used for new patients.

OBJECTIVES

To describe patients who stay > 6 h in the ED and determine their association with measures of crowding.

METHODS

This was a retrospective, observational study carried out over 1 year at a single, urban, academic ED.

RESULTS

Of the 96,562 patients seen, 16,017 (17%) stayed > 6 h (51% admitted). When there was at least one patient staying > 6 h, 60% of the time there was at least one additional patient in the waiting room who could not be placed in an ED bed because none was open. The walk-out rate was 0.34 patients/hour when there were no patients staying in the ED > 6 h, vs. 0.77 patients/hour walking out when there were patients staying > 6 h in the ED (p < 0.001). When the ED contained more than 3 patients staying > 6 h, a trend was noted between increasing numbers of patients staying in the ED > 6 h and the percentage of time the ED was on ambulance diversion (p = 0.011).

CONCLUSION

In our ED, having both admitted and discharged patients staying > 6 h is associated with crowding.

Factors associated with positive D-dimer results in patients evaluated for pulmonary embolism

OBJECTIVES

Available D-dimer assays have low specificity and may increase radiographic testing for pulmonary embolism (PE). To help clinicians better target testing, this study sought to quantify the effect of risk factors for a positive quantitative D-dimer in patients evaluated for PE.

METHODS

This was a prospective, multicenter, observational study. Emergency department (ED) patients evaluated for PE with a quantitative D-dimer were eligible for inclusion. The main outcome of interest was a positive D-dimer. Odds ratio (ORs) and 95% confidence intervals (CIs) were determined by multivariable logistic regression. Adjusted estimates of relative risk were also calculated.

RESULTS

A total of 4,346 patients had D-dimer testing, of whom 2,930 (67%) were women. A total of 2,500 (57%) were white, 1,474 (34%) were black or African American, 238 (6%) were Hispanic, and 144 (3%) were of other race or ethnicity. The mean (+/-SD) age was 48 (+/-17) years. Overall, 1,903 (44%) D-dimers were positive. Model fit was adequate (c-statistic = 0.739, Hosmer and Lemeshow p-value = 0.13). Significant positive predictors of D-dimer positive included female sex; increasing age; black (vs. white) race; cocaine use; general, limb, or neurologic immobility; hemoptysis; hemodialysis; active malignancy; rheumatoid arthritis; lupus; sickle cell disease; prior venous thromboembolism (VTE; not under treatment); pregnancy and postpartum state; and abdominal, chest, orthopedic, or other surgery. Warfarin use was protective. In contrast, several variables known to be associated with PE were not associated with positive D-dimer results: body mass index (BMI), estrogen use, family history of PE, (inactive) malignancy, thrombophilia, trauma within 4 weeks, travel, and prior VTE (under treatment).

CONCLUSIONS

Many factors are associated with a positive D-dimer test. The effect of these factors on the usefulness of the test should be considered prior to ordering a D-dimer.

D-dimer and exhaled CO2/O2 to detect segmental pulmonary embolism in moderate-risk patients

RATIONALE

Pulmonary embolism (PE) decreases the exhaled end-tidal ratio of carbon dioxide to oxygen (etCO(2)/O(2)).

OBJECTIVES

To test if the etCO(2)/O(2) can produce clinically important changes in the probability of segmental or larger PE on computerized tomography multidetector-row pulmonary angiography (MDCTPA) in a moderate-risk population with a positive D-dimer.

METHODS

Emergency department and hospitalized patients with one or more predefined symptoms or signs, one or more risk factors for PE, and 64-slice MDCTPA enrolled from four hospitals. D-dimer greater than 499 ng/ml was test(+), and D-dimer less than 500 ng/ml was test(-). The median etCO(2)/O(2) less than 0.28 from seven or more breaths was test(+) and etCO(2)/O(2) greater than 0.45 was test(-). MDCTPA images were read by two independent radiologists and the criterion standard was the interpretation of acute PE by either reader. PE size was then graded.

MEASUREMENTS AND MAIN RESULTS

We enrolled 495 patients, including 60 (12%) with segmental or larger, and 29 (6%) with subsegmental PE. A total of 367 (74%) patients were D-dimer(+), including all 60 with segmental or larger PE (posterior probability 16%). The combination of D-dimer(+) and etCO(2)/O(2)(+) increased the posterior probability of segmental or larger PE to 28% (95% confidence interval [CI] for difference of 12%, 3.0-22%). The combination of D-dimer(+) and etCO(2)/O(2)(-) was observed in 40 patients (8%; 95% CI, 6-11%), and none (0/40; 95% CI, 0-9%) had segmental or larger PE on MDCTPA. No strategy changed the prevalence of subsegmental PE.

CONCLUSIONS

In moderate-risk patients with a positive D-dimer, the et etCO(2)/O(2) less than 0.28 significantly increases the probability of segmental or larger PE and the etCO(2)/O(2) greater than 0.45 predicts the absence of segmental or larger PE on MDCTPA.

A randomized placebo-controlled study of intravenous montelukast for the treatment of acute asthma

BACKGROUND

Current treatments for acute asthma provide inadequate benefit for some patients. Intravenous montelukast may complement existent therapies.

OBJECTIVE

To evaluate efficacy of intravenous montelukast as adjunctive therapy for acute asthma.

METHODS

A total of 583 adults with acute asthma were treated with standard care during a < or = 60-minute screening period. Patients with FEV(1) < or =50% predicted were randomly allocated to intravenous montelukast 7 mg (n = 291) or placebo (n = 292) in addition to standard care. This double-blind treatment period lasted until a decision for discharge, hospital admission, or discontinuation from the study. The primary efficacy endpoint was the time-weighted average change in FEV(1) during 60 minutes after drug administration. Secondary endpoints included the time-weighted average change in FEV(1) at various intervals (10-120 minutes) and percentage of patients with treatment failure (defined as hospitalization or lack of decision to discharge by 3 hours postadministration).

RESULTS

Montelukast significantly increased FEV(1) at 60 minutes postdose; the difference between change from baseline for placebo (least-squares mean of 0.22 L; 95% CI, 0.17, 0.27) and montelukast (0.32 L; 95% CI, 0.27, 0.37) was 0.10 L (95% CI, 0.04, 0.16). Similar improvements in FEV(1)-related variables were seen at all time points (all P <.05). Although treatment failure did not differ between groups (OR 0.92; 95% CI, 0.63, 1.34), a prespecified subgroup analysis suggests likely benefit for intravenous montelukast at US sites.

CONCLUSION

Intravenous montelukast added to standard care in adults with acute asthma produced significant relief of airway obstruction throughout the 2 hours after administration, with an onset of action as early as 10 minutes.

Accuracy of very low pretest probability estimates for pulmonary embolism using the method of attribute matching compared with the Wells score

OBJECTIVES

Attribute matching matches an explicit clinical profile of a patient to a reference database to estimate the numeric value for the pretest probability of an acute disease. The authors tested the accuracy of this method for forecasting a very low probability of venous thromboembolism (VTE) in symptomatic emergency department (ED) patients.

METHODS

The authors performed a secondary analysis of five data sets from 15 hospitals in three countries. All patients had data collected at the time of clinical evaluation for suspected pulmonary embolism (PE). The criterion standard to exclude VTE required no evidence of PE or deep venous thrombosis (DVT) within 45 days of enrollment. To estimate pretest probabilities, a computer program selected, from a large reference database of patients previously evaluated for PE, patients who matched 10 predictor variables recorded for each current test patient. The authors compared the outcome frequency of having VTE [VTE(+)] in patients with a pretest probability estimate of <2.5% by attribute matching, compared with a value of 0 from the Wells score.

RESULTS

The five data sets included 10,734 patients, and 747 (7.0%, 95% confidence interval [CI] = 6.5% to 7.5%) were VTE(+) within 45 days. The pretest probability estimate for PE was <2.5% in 2,975 of 10,734 (27.7%) patients, and within this subset, the observed frequency of VTE(+) was 48 of 2,975 (1.6%, 95% CI = 1.2% to 2.1%). The lowest possible Wells score (0) was observed in 3,412 (31.7%) patients, and within this subset, the observed frequency of VTE(+) was 79 of 3,412 (2.3%, 95% CI = 1.8% to 2.9%) patients.

CONCLUSIONS

Attribute matching categorizes over one-quarter of patients tested for PE as having a pretest probability of <2.5%, and the observed rate of VTE within 45 days in this subset was <2.5%.

Clinical features from the history and physical examination that predict the presence or absence of pulmonary embolism in symptomatic emergency department patients: results of a prospective, multicenter study

STUDY OBJECTIVE

Prediction rules for pulmonary embolism use variables explicitly shown to estimate the probability of pulmonary embolism. However, clinicians often use variables that have not been similarly validated, yet are implicitly believed to modify probability of pulmonary embolism. The objective of this study is to measure the predictive value of 13 implicit variables.

METHODS

Patients were enrolled in a prospective cohort study from 12 centers in the United States; all had an objective test for pulmonary embolism (D-dimer, computed tomographic angiography, or ventilation-perfusion scan). Clinical features including 12 predefined previously validated (explicit) variables and 13 variables not part of existing prediction rules (implicit) were prospectively recorded at presentation. The primary outcome was venous thromboembolism (pulmonary embolism or deep venous thrombosis), diagnosed by imaging up to 45 days after enrollment. Variables with adjusted odds ratios from logistic regression with 95% confidence intervals not crossing unity were considered significant.

RESULTS

Seven thousand nine hundred forty patients (7.2% venous thromboembolism positive) were enrolled. Mean age was 49 years (standard deviation 17 years) and 67% were female patients. Eight of 13 implicit variables were significantly associated with venous thromboembolism; those with an adjusted odds ratio (OR) greater than 1.5 included non-cancer-related thrombophilia (OR 1.99), pleuritic chest pain (OR 1.53), and family history of venous thromboembolism (OR 1.51). Implicit variables that predicted no venous thromboembolism outcome included substernal chest pain, female sex, and smoking. Nine of 12 explicit variables predicted a positive outcome of venous thromboembolism, including patient history of pulmonary embolism or deep venous thrombosis in the past, unilateral leg swelling, recent surgery, estrogen, hypoxemia, and active malignancy.

CONCLUSION

In symptomatic outpatients being considered for possible pulmonary embolism, non-cancer-related thrombophilia, pleuritic chest pain, and family history of venous thromboembolism increase probability of pulmonary embolism or deep venous thrombosis. Other variables that are part of existing pretest probability systems were validated as important predictors in this diverse sample of US emergency department patients.

Geography and travel distance impact emergency department visits

BACKGROUND

Little has been written about the geographic basis of emergency department (ED) visits.

OBJECTIVE

The objective of this study is to describe the impact of geography on ED visits.

METHODS

A retrospective analysis was conducted of ED visits during a 1-year period at a single institution using spatial interaction analysis that models the pattern of flow between a series of origins (census block groups) and a destination (ED). Patients were assigned to census block groups based upon their verified home address. The study hospital is the only Level I trauma, pediatric, and tertiary referral center in the area. There are 11 other hospitals with EDs within a 40-mile radius. Each patient visit within this radius, including repeat visits, was included. Patients with an invalid home address, a post office box address, or those who lived outside a 40-mile radius were excluded. ED visits per 100 population were calculated for each census block group.

RESULTS

There were 98,584 (95%) visits by 63,524 patients that met study inclusion criteria. Visit rates decreased with increasing distance from the ED (p < 0.0001). Nineteen percent of patients lived within 2 miles, 48% within 4 miles, and 92% within 12 miles of the ED. The Connecticut border, 7 miles south of the ED (p < 0.0001), the Connecticut River, 1 mile west of the ED (p < 0.0001), and the presence of a competing ED within 1 mile (p < 0.0001) negatively impacted block group ED visit rates. Travel distance was related to the percentage of visits that were high acuity (p < 0.0001), daytime (p < 0.01), or resulted in admission (p < 0.0001).

CONCLUSIONS

Geography and travel distance significantly impact ED visits.

Potential impact of adjusting the threshold of the quantitative D-dimer based on pretest probability of acute pulmonary embolism

OBJECTIVES

The utility of D-dimer testing for suspected pulmonary embolism (PE) can be limited by test specificity. The authors tested if the threshold of the quantitative D-dimer can be varied according to pretest probability (PTP) of PE to increase specificity while maintaining a negative predictive value (NPV) of >99%.

METHODS

This was a prospective, observational multicenter study of emergency department (ED) patients in the United States. Eligible patients had a diagnostic study ordered to evaluate possible PE. PTP was determined by the clinician's unstructured estimate and the Wells score. Five different D-dimer assays were used. D-dimer test performance was measured using 1) standard thresholds and 2) variable threshold values: twice (for low PTP patients), equal (intermediate PTP patients), or half (high PTP patients) of standard threshold. Venous thromboembolism (VTE) within 45 days required positive imaging plus decision to treat.

RESULTS

The authors enrolled 7,940 patients tested for PE, and clinicians ordered a quantitative D-dimer for 4,357 (55%) patients who had PTPs distributed as follows: low (74%), moderate (21%), or high (4%). At standard cutoffs, across all PTP strata, quantitative D-dimer testing had a test sensitivity of 94% (95% confidence interval [CI] = 91% to 97%), specificity of 58% (95% CI = 56% to 60%), and NPV of 99.5% (95% CI = 99.1% to 99.7%). If variable cutoffs had been used the overall sensitivity would have been 88% (95% CI = 83% to 92%), specificity 75% (95% CI = 74% to 76%), and NPV 99.1% (95% CI = 98.7% to 99.4%).

CONCLUSIONS

This large multicenter observational sample demonstrates that emergency medicine clinicians currently order a D-dimer in the majority of patients tested for PE, including a large proportion with intermediate PTP and high PTP. Varying the D-dimer's cutoff according to PTP can increase specificity with no measurable decrease in NPV.

Emergency department patients who stay more than 6 hours contribute to crowding

BACKGROUND

Admitted and discharged patients with prolonged emergency department (ED) stays may contribute to crowding by utilizing beds and staff time that would otherwise be used for new patients.

OBJECTIVES

To describe patients who stay > 6 h in the ED and determine their association with measures of crowding.

METHODS

This was a retrospective, observational study carried out over 1 year at a single, urban, academic ED.

RESULTS

Of the 96,562 patients seen, 16,017 (17%) stayed > 6 h (51% admitted). When there was at least one patient staying > 6 h, 60% of the time there was at least one additional patient in the waiting room who could not be placed in an ED bed because none was open. The walk-out rate was 0.34 patients/hour when there were no patients staying in the ED > 6 h, vs. 0.77 patients/hour walking out when there were patients staying > 6 h in the ED (p < 0.001). When the ED contained more than 3 patients staying > 6 h, a trend was noted between increasing numbers of patients staying in the ED > 6 h and the percentage of time the ED was on ambulance diversion (p = 0.011).

CONCLUSION

In our ED, having both admitted and discharged patients staying > 6 h is associated with crowding.

Emergency department admissions are more profitable than non-emergency department admissions

STUDY OBJECTIVE

We compare the contribution margin per case per hospital day of emergency department (ED) admissions with non-ED admissions in a single hospital, a 600-bed, academic, tertiary referral, Level I trauma center with an annual ED census of 100,000.

METHODS

This was a retrospective comparison of the contribution margin per case per day for ED and non-ED inpatient admissions for fiscal years 2003, 2004, and 2005 (October 1 through September 30). Contribution margin is defined as net revenue minus total direct costs; it is then expressed per case per hospital day. Service lines are a set of linked patient care services. Observation admissions and outpatient services are not included. Resident expenses (eg, salary and benefits) and revenue (ie, Medicare payment of indirect medical expenses and direct medical expenses) are not included. Overhead expenses are not included (eg, building maintenance, utilities, information services support, administrative services).

RESULTS

For fiscal year 2003 through fiscal year 2005, there were 51,213 ED and 57,004 non-ED inpatient admissions. Median contribution margin per day for ED admissions was higher than for non-ED admissions: ED admissions $769 (interquartile range $265 to $1,493) and non-ED admissions $595 (interquartile range $178 to $1,274). Median contribution margin per day varied by site of admissions, by diagnosis-related group, by service line, and by insurance type.

CONCLUSION

In summary, ED admissions in our institution generate a higher contribution margin per day than non-ED admissions.

Prospective multicenter evaluation of the pulmonary embolism rule-out criteria

BACKGROUND

Over-investigation of low-risk patients with suspected pulmonary embolism (PE) represents a growing problem. The combination of gestalt estimate of low suspicion for PE, together with the PE rule-out criteria [PERC(-): age < 50 years, pulse < 100 beats min(-1), SaO(2) >or= 95%, no hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within 4 weeks, no prior venous thromboembolism (VTE), and no unilateral leg swelling], may reduce speculative testing for PE. We hypothesized that low suspicion and PERC(-) would predict a post-test probability of VTE(+) or death below 2.0%.

METHODS

We enrolled outpatients with suspected PE in 13 emergency departments. Clinicians completed a 72-field, web-based data form at the time of test order. Low suspicion required a gestalt pretest probability estimate of <15%. The main outcome was the composite of image-proven VTE(+) or death from any cause within 45 days.

RESULTS

We enrolled 8138 patients, 85% of whom had a chief complaint of either dyspnea or chest pain. Clinicians reported a low suspicion for PE, together with PERC(-), in 1666 patients (20%). At initial testing and within 45 days, 561 patients (6.9%, 95% confidence interval 6.5-7.6) were VTE(+), and 56 others died. Among the low suspicion and PERC(-) patients, 15 were VTE(+) and one other patient died, yielding a false-negative rate of 16/1666 (1.0%, 0.6-1.6%). As a diagnostic test, low suspicion and PERC(-) had a sensitivity of 97.4% (95.8-98.5%) and a specificity of 21.9% (21.0-22.9%).

CONCLUSIONS

The combination of gestalt estimate of low suspicion for PE and PERC(-) reduces the probability of VTE to below 2% in about 20% of outpatients with suspected PE.

Feasibility of Using Near-Infrared Spectroscopy to Diagnose Testicular Torsion: An Experimental Study in Sheep

STUDY OBJECTIVE

To assess whether near-infrared spectroscopy can detect testicular hypoxia in a sheep model of testicular torsion within 6 hours of experimental torsion.

METHODS

This was a randomized, controlled, nonblinded study. Trans-scrotal, near-infrared, spectroscopy-derived testicular tissue saturation of oxygen values were obtained from the posterior hemiscrota of 6 anesthetized sheep at baseline and every 15 minutes for 6 hours after either experimental-side, 720-degree, unilateral, medial testicular torsion and orchidopexy or control-side sham procedure with orchidopexy and then for 75 minutes after reduction of torsion and pexy. Color Doppler ultrasonography was performed every 30 minutes to confirm loss of vascular flow on the experimental side, return of flow after torsion reduction, and preserved flow on the control side.

RESULTS

Near infrared spectroscopy detected a prompt, sustained reduction in testicular tissue saturation of oxygen after experimental torsion. Further, it documented a rapid return of these values to pretorsion levels after reduction of torsion. Experimental-side testicular tissue saturation of oxygen fell from a median value of 59% (interquartile range [IQR] 57% to 69%) at baseline to 14% (IQR 11% to 29%) at 2.5 hours of torsion, and postreduction values were approximately 70%. Control-side testicular tissue saturation of oxygen values increased from a median value of 67% (IQR 59% to 68%) at baseline to 77% (IQR 77% to 94%) at 2.5 hours and remained at approximately 80% for the entire protocol. The difference in median testicular tissue saturation of oxygen between experimental and control sides, using the Friedman test, was found to be significant (P=.017).

CONCLUSION

This study demonstrates the feasibility, in a sheep model, of using near-infrared spectroscopy for the noninvasive diagnosis of testicular torsion and for quantification of reperfusion after torsion reduction. The applicability of these findings, from an animal model using complete torsion, to the clinical setting remains to be established.

Prospective comparison of helical CT of the abdomen and pelvis without and with oral contrast in assessing acute abdominal pain in adult Emergency Department patients

PURPOSE

This prospective study compares the agreement of nonenhanced helical computed tomography (NECT) with oral contrast-enhanced computed tomography (CECT) in Emergency Department (ED) patients presenting with acute abdominal pain.

MATERIALS AND METHODS

One hundred eighteen patients presenting to the ED with acute abdominal pain undergoing CT were enrolled over a 13-month period using convenience sampling. Exclusion criteria included acute trauma, pregnancy, unstable patients, and patients suspected of having urinary calculi. Patients were scanned helically using 5-mm collimation before and approximately 90 min after oral contrast administration. Both exams were prospectively interpreted by different attending radiologists in a blinded fashion using an explicit data sheet specifying the presence or absence of 28 parameters relating to various common diagnoses.

RESULTS

The 118 patients had a mean age of 49 years, a male: female ratio of 7:13, and a median height, weight, and BMI of 166 cm, 80 kg, and 29, respectively. The most common indications for the study included appendicitis (32%) and diverticular disease (12%). Pain maximally localized to the right lower quadrant in 37% and the left lower quadrant in 21%. There were 21 patients that had significant disagreement of interpretations between NECT and CECT resulting in a simple agreement of 79% (95% CI: 70-87%). For specific radiologic parameters, agreement ranged from 77 to 100%. A post hoc agreement analysis was subsequently performed by two radiologists and only five paired scans were identified as discordant between the NECT and CECT. For only one of these patients did both radiologists agree that there was a definite discordant result between the two studies. A final unblinded consensus review demonstrated that much of the disagreement between the interpretations was related to interobserver variation.

CONCLUSION

There is 79% simple agreement between NECT and CECT in diagnosing various causes of acute abdominal pain in adult ED patients. Post hoc analysis indicates that a significant portion of the discordance was attributable to interobserver variability. This data suggests that NECT should be considered in adult ED patients presenting with acute abdominal pain.

Research opportunities in the management of acute exacerbations of chronic obstructive pulmonary disease

Acute exacerbations of chronic obstructive pulmonary disease are a common problem in the emergency department. Despite considerable research involving the management of this disease over the past decade, much remains unclear from an emergency medicine perspective. Increased research would better guide the management of these complex patients from the perspectives of the patient, the caregiver, and society. The major areas of research can be divided into diagnosis, therapy, and education. The reliability and validity of different definitions of acute exacerbations of chronic obstructive pulmonary disease need to be assessed. The utility and performance characteristics of diagnostic testing need to be determined for this difficult patient population. Specific diagnostic tests include measures of dyspnea, spirometry and exercise tolerance, measures of gas exchange, airway inflammation, and chest imaging. It remains unclear which patient-specific therapies (oxygen, bronchodilators, corticosteroids, antibiotics, noninvasive positive pressure ventilation, and methylxanthines) should be used and monitored. Finally, the utility of education of both health care providers and patients and how it may be applied to the acute setting need to be addressed.

A descriptive study of heavy emergency department users at an academic emergency department reveals heavy ED users have better access to care than average users

INTRODUCTION

Emergency department (ED) overcrowding has been a significant problem for the last 10 years. Several studies have shown that a relatively small number of ED patients are responsible for a disproportionate amount of ED visits. This study aims to describe the frequent users of our emergency department.

METHODS

This was an institutional review board-approved descriptive study performed by a retrospective review of electronic records. This pilot describes and compares patients who had 12 or more ED visits during the study year with those who visited less.

RESULTS

The 234 patients who met criteria for high-frequency use (HFU) of the emergency department were responsible for a total of 4633 visits. Sex, race, and age distribution of HFU patients were similar to those of general ED patients. Eighty-four percent of HF users have insurance and 93% have primary care providers. A relatively small percentage of HFU visits, 4%, were mental health-related visits and 3% were alcohol- and drug-related visits. The HFU visits are socially connected: 93% have their own homes; 94% have relatives or friends; 73% have a religious affiliation. Pain or pain-related conditions are the most common diagnoses. These patients are also frequent users of ambulatory care services.

CONCLUSION

The similarities between our HFU and the general ED population are more numerous than their differences. The HFU patients of our emergency department are different in terms of age, employment status, and type of insurance. IMPLICATIONS FOR NURSES: A detailed description of local HFU may help to inform planning and better meet ED patients' needs. As one of many results of this study, the ED chairman met with the Hematology-Oncology team and reviewed the protocol for ED management of sickle cell crisis. The meeting resulted in a revised protocol, including an immediate change in their pain medication from meperidine to either morphine or hydromorphone.

A report of dangerously high carbon monoxide levels within the passenger compartment of a snow-obstructed vehicle

Background

We sought to determine how quickly carbon monoxide would accumulate in the passenger compartment of a snow-obstructed vehicle.

Methods

A 1992 sedan was buried in snow to the level of the undercarriage, the ignition was then engaged and carbon monoxide levels recorded at 2.5-minute intervals. The primary outcome was the time at which a lethal carbon monoxide level was detected. Six trials were conducted: windows closed; windows open one inch; windows open 6 inches; windows closed and tailpipe swept clear of snow; windows closed and one cubic foot of snow removed around tailpipe; windows closed and tailpipe completely cleared of snow to ground level in a path 12 inches wide.

Results

Lethal levels of carbon monoxide occurred within 2.5 minutes in the vehicle when the windows were closed, within 5 minutes when the widows were opened one inch, and within 7.5 minutes when the widows were opened six inches. Dangerously high levels of carbon monoxide were detected within the vehicle when the tailpipe had been swept clear of snow and when a one cubic foot area had been cleared around the tailpipe. When the tailpipe was completely unobstructed the carbon monoxide level was zero.

Conclusions

Lethal levels of carbon monoxide occurred within minutes in this snow-obstructed vehicle.

Beckman Access versus the Bayer ACS:180 and the Abbott AxSYM cardiac Troponin-I real-time immunoassays: an observational prospective study

Background

Reliability of cardiac troponin-I assays under real-time conditions has not been previously well studied. Most large published cTnI trials have utilized protocols which required the freezing of serum (or plasma) for delayed batch cTnI analysis. We sought to correlate the presence of the acute ischemic coronary syndrome (AICS) to troponin-I values obtained in real-time by three random-mode analyzer immunoassay systems: the Beckman ACCESS (BA), the Bayer ACS:180 (CC) and the Abbott AxSYM (AX).

Methods

This was an observational prospective study at a university tertiary referral center. Serum from a convenience sampling of telemetry patients was analyzed in real-time for troponin-I by either the BA-CC (Arm-1) or BA-AX (Arm-2) assay pairs. Presence of the AICS was determined retrospectively and then correlated with troponin-I results.

Results

100 patients were enrolled in Arm-1 (38 with AICS) and 94 in Arm-2 (48 with AICS). The BA system produced 51% false positives in Arm-1, 44% in Arm-2, with negative predictive values of 92% and 100% respectively. In Arm-1, the BA and the CC assays had sensitivities of 97% and 63% and specificities of 18% and 87%. In Arm-2, the BA and the AX assays had sensitivities of 100% and 83% and specificities of 11% and 78%.

Conclusions

In real-time analysis, the performance of the AxSYM and ACS:180 assay systems produced more accurate troponin-I results than the ACCESS system.

Does morphine change the physical examination in patients with acute appendicitis?

The objective of this study was to determine if judicious dosing of morphine sulfate can provide pain relief without changing important physical examination findings in patients with acute appendicitis. We conducted a prospective, randomized, double-blind crossover design. Patients scheduled for appendectomy were randomized to two groups. Group A received 0.075 mg/kg intravenous morphine sulfate and 30 minutes later received placebo. The sequence of medication was reversed in group B. Patients were examined by a surgical resident and an EM attending before and after receiving medication. Six explicit physical examination findings were documented as absent, indeterminate, or present. Physicians were also asked if they felt overall examination findings had changed after medication. Patient's visual analog scale (VAS) was recorded before each medication and at study completion. Thirty-four patients were enrolled and full data were available for 22 patients. Neither morphine nor placebo caused a significant change in individual examination findings. Three patients in both groups were judged to have a change in their examination after medication. The median change in VAS was 20 mm after morphine and 0 mm after placebo (P =.01). In this pilot study, patients with clinical signs of appendicitis were treated with morphine and had significant improvement of their pain without changes in their physical examination.

Patient encounter time intervals in the evaluation of emergency department patients requiring abdominopelvic CT: oral contrast versus no contrast

The aim of the study was to assess various time intervals during patient encounters involving unenhanced (NECT) versus oral-contrast-enhanced (CECT) abdominopelvic (A/P) CT performed in the emergency department (ED) on adult patients presenting with acute abdominal pain. Computerized patient order entry and administrative data as well as scans themselves were retrospectively evaluated at a high-volume (107,000 visits per annum) regional medical center urban ED for a period of 30 consecutive days. All adult patients who had CT of abdomen and pelvis for abdominal pain during the 30 days of the study period were included. Data collected included demographic information, time of registration, time of first encounter in the ED, time of CT order, clinical indication for scan, time of scan, time of disposition (i.e., discharge or admit), and final disposition. Patients were excluded if they were less than 16 years old, pregnant, or met criteria for major trauma and evaluation in the trauma suite. Patients were also excluded from analysis if they received more than one scan on the same day (3 patients). Of 183 patients, 102 underwent NECT and 81 CECT. Some of the patients who underwent NECT had urinary colic. Among patients who did not have urinary colic there is a statistically significant difference in the median time intervals between: (1) patient arrival in the ED and evaluation by a physician (NECT 57 min, CECT 84 min, P<0.001); (2) patient exam by the physician and the time the A/P CT was ordered (NECT 35 min, CECT 63 min, P<0.01); (3) receipt of the CT order and the time of the scan (NECT 104 min, CECT 172 min, P<0.001); and (4) time of arrival in ED and disposition (NECT 358 min, CECT 599 min, P<0.001). There are significant time interval differences between CECT and NECT during patient encounters involving adults presenting with abdominal pain to the ED. The differences are greater than the amount of time allotted for opacification of small bowel (90 min). Baseline data such as these may prove useful in assessing the efficacy of scan techniques and improving resource utilization.

Antipyretic effectiveness of intravenous ketorolac tromethamine

We assessed the antipyretic effectiveness of intravenously administered ketorolac tromethamine in the febrile adult. A double-blind placebo controlled trial enrolling a convenience sample of febrile (T > 38.0 degrees C, oral) patients (18-65 years old) randomized to receive either 0.5 mg/kg (max 30 mg) intravenous ketorolac or placebo. Oral temperatures were recorded every 15 min during the 1-h study period. There were 20 patients in each group. At 60 min, the temperature decrease was 0.4 degrees C (95% CI: 0.0 degrees, 0.7 degrees ) for the control group and 0.8 degrees C (95% CI: 0.5 degrees, 1.1 degrees ) for the ketorolac group. Logistic regression modeling of afebrile at 60 min, controlling for baseline temperature, yielded an odds ratio for ketorolac of 7.1 (95% CI: 1.3, 39.5). In conclusion, our data support that intravenously administered ketorolac has antipyretic properties.

Errors in a busy emergency department

STUDY OBJECTIVE

We describe errors occurring in a busy ED.

METHODS

This is a prospective, observational study of reported errors at an academic emergency department (ED) with 100000 annual visits. Trained personnel interviewed all ED staff with direct patient contact, during and at the end of every shift, by using standardized data sheets.

RESULTS

One thousand nine hundred thirty-five ED patients registered during the 7-day study period in the summer of 2001. Four hundred error reports were generated, identifying 346 nonduplicative errors (18 per 100 registered patients; 95% confidence interval [CI] 15.9 to 20.0). Forty percent of errors were reported by nurses, 25% by providers, 19% by clerical staff, 13% by technicians and orderlies, and 3% multiple reporters. Errors reported for every 100 hours worked were similar for all groups (5.5; 95% CI 5.2 to 5.9). Errors were categorized as 22% diagnostic studies, 16% administrative procedures, 16% pharmacotherapy, 13% documentation, 12% communication, 11% environmental, and 9% other. Patients involved in errors were more likely to be older (P <.0001) and more likely to have higher visit level intensity (P <.0001) than registered ED patients. Ninety-eight percent of errors did not have a significant adverse outcome. Seven errors (0.36 per 100 registered patients; 95% CI 0.14 to 0.72) were associated with an adverse outcome.

CONCLUSION

Reported errors occurred in almost every aspect of emergency care. Ninety-eight percent of errors in the ED do not result in adverse outcomes. System changes need to be implemented to reduce ED errors.

How reliable are pain scores? A pilot study of 20 healthy volunteers

INTRODUCTION

Pain scales such as the 100-MM Visual Analog Scale and the 10-point Numeric Rating Scale are used to describe pain intensity. The Visual Analog Scale and the Numeric Rating Scale provide accurate descriptors for a patient's perceived level of pain. But how accurate or reliable is a patient's perception of pain?

METHODS

To test the relationship between the intensity of the pain stimulus and pain perception, we devised an experiment using a convenience sample of 20 healthy adult volunteers. A cutaneous nerve stimulator delivered a series of shocks of increasing intensity to the individual via a pediatric EKG electrode. The participants indicated their threshold for "intolerable pain." With use of this same level of stimulus in subsequent shocks, the participants, blinded to the amount of stimulus, were then asked to rate each shock as either "the same," "a little less," or "a little more" than the baseline stimulus. They then recorded their VAS score for each stimulus.

RESULTS

"Intolerable pain" varied widely between 8 mm to 73 mm; likewise, the level of stimulus that produced this pain ranged from 4 to 9. Once a person's threshold of "intolerable pain" had been reached, 49% of the subsequent shocks were perceived as different, even though the stimulus was exactly the same.

DISCUSSION

This experiment showed that (1) given the same intensity of pain stimulus, different persons have different perceptions of pain; and (2) the same intensity of pain stimulus, given to the same person repeatedly, does not result in the same self-report of pain intensity.

Can CK-MB and cTn-I be detected in the peripheral circulation within the first 10 min of acute coronary ischemia?

There are approximately 4 million patients hospitalized with suspected acute coronary syndromes (ACS) annually. However, the current standard tools for assessing ACS in the Emergency Department are felt to have insufficient sensitivity and specificity. Animal studies have demonstrated that CK-MB and troponin-I are released in a biphasic pattern with an initial transient release which peaks and falls within the first 10 min of ischemia. We hypothesize that transient elevations of CK-MB and troponin-I can be detected in the peripheral circulation within the first 10 min of ischemia in a human model of brief coronary ischemia. We also present results from our pilot study that failed to confirm this hypothesis; however, this pilot studied was insufficiently powered to detect potentially clinically important results.

A randomized controlled trial of intravenous aminophylline for atropine-resistant out-of-hospital asystolic cardiac arrest

OBJECTIVES

Myocardial ischemia, during cardiopulmonary arrest, can lead to atropine-resistant bradyasystole from interstitial accumulation of endogenous adenosine. Aminophylline is a nonspecific adenosine receptor antagonist capable of reversing ischemia-induced bradyasystole in a variety of settings. The hypothesis of this study was that aminophylline improves the rate of return of spontaneous circulation (ROSC) in atropine-resistant asystolic out-of-hospital cardiac arrest when used early in the resuscitation effort.

METHODS

This was a prospective, randomized, double-blinded, placebo-controlled trial set in an urban emergency medical services system serving a population of 250,000. All non-pregnant, normothermic adults suffering nontraumatic out-of-hospital cardiac arrest (February 1999 to August 2000) with asystole were eligible. Patients remaining in asystole after initial doses of epinephrine and atropine received either aminophylline 250 mg or matching placebo as a bolus injection through a peripheral intravenous line. All other aspects of the attempted resuscitation proceeded in accordance with standard Advanced Cardiac Life Support (ACLS) guidelines. A sample size of 102 patients was calculated to yield a power of 80% to show an absolute improvement of 25% in ROSC. The aminophylline and control groups were compared by calculating 95% confidence intervals (95% CIs) and the data were modeled using logistic regression.

RESULTS

The investigators enrolled 112 consecutive patients. One subject was dropped prior to analysis because of missing data. Data for 111 patients were analyzed on an intention-to-treat basis. Baseline characteristics were similar for the two groups. Comparing the control and aminophylline groups, ROSC was achieved in 15.6% (95% CI = 6% to 29%) and 22.7% (95% CI = 13% to 35%), while reversal of asystole occurred in 26.7% (95% CI = 15% to 42%) and 40.9% (95% CI = 29% to 54%), respectively. Group allocation had an odds ratio of 1.8 (95% CI = 0.6 to 5.3) for ROSC. Witnessed arrest was an independent predictor of outcome with an odds ratio of 3.8 (95% CI = 1.3 to 11.2).

CONCLUSIONS

Addition of aminophylline appears to be a promising new intervention in the ACLS treatment of atropine-resistant asystolic out-of-hospital cardiac arrest.

A randomized controlled trial of intravenous montelukast in acute asthma

Many patients with acute asthma do not respond adequately to currently accepted therapy, including oxygen, beta-agonists, and corticosteroids. Leukotriene receptor antagonists such as montelukast have demonstrated efficacy in chronic asthma, but their efficacy in acute asthma is unknown. In this randomized, double-blind, parallel-group pilot study, adults with moderate to severe acute asthma received standard therapy plus either intravenous montelukast (7 or 14 mg) or matching placebo. A total of 201 patients were randomized, and 194 had complete data available for analysis. There was no difference in FEV1 response between the 7- and 14-mg montelukast groups. Montelukast improved FEV1 over the first 20 minutes after intravenous administration (mean percentage change from prerandomization baseline, 14.8% versus 3.6% for the pooled montelukast and placebo treatment groups, respectively; p = 0.007). This benefit was observed at 10 minutes and over 2 hours after intravenous therapy. Patients treated with montelukast tended to receive less beta-agonists and have fewer treatment failures than patients receiving placebo. The tolerability profile for montelukast was similar to that observed for placebo, and no unexpected adverse experiences were observed. We conclude that intravenous montelukast in addition to standard therapy causes rapid benefit and is well tolerated in adults with acute asthma.