Tamsulosin does not increase 1-week passage rate of ureteral stones in ED patients.

OBJECTIVE: The objective of the study is to determine if tamsulosin initiated in the emergency department (ED) decreases the time to ureteral stone passage at 1 week or time to pain resolution, compared to placebo. METHODS: We performed a prospective, randomized, double-blinded, placebo-controlled trial of tamsulosin vs placebo in ED patients with ureterolithiasis on computed tomography. Patients were identified and enrolled between April 2007 and February 2009 and were randomized to either 0.4 mg of tamsulosin or placebo for 1 week. We contacted participants using a telephone survey on post-ED visit days 1, 2, 3, and 7. The primary outcome was time to stone passage, with secondary outcomes being maximum pain score and amount of pain medication required. RESULTS: Of the 127 patients enrolled during this study, 15 were lost to follow-up, and 12 required surgical interventions before the 7-day mark, leaving 100 patients for analysis. Of the 100 patients, 53 received tamsulosin and 47 received placebo. There was no difference between groups in percentage of male, mean age, initial serum creatinine, average stone size, stone location, and history of prior stone. The probability that the patient did not pass a stone at 7 days was not different between tamsulosin and placebo, 62.1% (95% confidence interval, 49.1%-75.1%) vs 54.4% (95% confidence interval, 40.3%-68.6%; P = .58). There was no significant difference in the high pain score (P = .12) or hydrocodone/acetaminophen intake (P = .76) between treatment groups at any of the time points. CONCLUSION: This study reveals no difference in the proportion of stone passage or high pain score and pain medication utilization at 7 days between tamsulosin and placebo.

Assessing the impact of prehospital intubation on survival in out-of-hospital cardiac arrest.

UNLABELLED: There is a developing body of literature documenting adverse survival outcome of out-of-hospital endotracheal intubation for critical multiple trauma and head injury patients. OBJECTIVE: To compare the rates of survival to hospital admission and discharge of nontraumatic out-of-hospital cardiac arrest (OHCA) patients who received successful out-of-hospital endotracheal intubation and those who were not intubated. METHODS: We conducted a retrospective analysis from an ongoing database of OHCA patients brought to a large suburban tertiary care emergency department by paramedic services between 1995 and 2006. We dichotomized patients by whether they were successfully endotracheally intubated or not prior to hospital arrival. Utstein style cardiac arrest variables were abstracted for all cases. All survivors to hospital admission were reviewed to exclude those patients in whom intubation was not attempted or unnecessary, such as those who had successful first-shock recovery of spontaneous circulation. We used chi square and logistic regression techniques for analysis, using survival to discharge as the primary outcome and survival to admission as a secondary outcome. RESULTS: There were 1,515 total cases with 33 early survivors excluded. Overall, 1,220 (86.2%) were intubated; of those intubated, 270 (20.2%) survived to admission and 93 (7.0%) survived to discharge. Upon univariate analysis, there was no difference in survival between intubated and non intubated groups (6.5% vs 10.0%, OR = 0.63, 95% CI 0.37,1.08). For patients initially in ventricular fibrillation/ventricular tachycardia (VT/VF), in a multivariate Logit model, intubation significantly decreased survival to discharge, adjusted odds ratio (OR) = 0.52 (95% confidence interval 0.27, 0.998). Intubated non-VF patients were more likely to survive to admission, adjusted OR 2.96 (1.04, 8.43), but not to discharge (1.8% vs. 1.0%, p = 1.0). CONCLUSION: This observational study in an unselected population shows that patients in VF/VT arrest who underwent out-of-hospital intubation were less likely to survive to discharge than those not intubated. Out-of-hospital intubation of patients with non-VF arrest was associated with an increased rate of survival to admission, but not survival to discharge. Future prospective studies are needed to define the role of out-of-hospital endotracheal intubation in cardiac arrest patients.

Emergency Department Urosepsis and Abdominal Imaging.

Introduction Insufficient attention has been directed towards urosepsis. Notably, no protocols or clinical decision rules currently exist outlining the appropriate use of imaging in uroseptic patients. The primary objective of our study was to retrospectively evaluate uroseptic emergency department (ED) patients who underwent abdominal imaging, to report the proportion of patients with imaging findings necessitating emergent surgical consultation. Methods We retrospectively identified 1142 patients ≥ 18 years of age that presented to the ED from January 2009 to December 2012 with ICD9 code indicative of urosepsis. All included patients underwent ED-ordered abdominal computerized tomography (CT) or retroperitoneal ultrasound (US). Imaging and urinalysis (UA) results were categorized. We report proportions with odds ratios and 95% confidence intervals. Results Of 1142 patients, we excluded 80 for neg UA, 167 for < 2 SIRS (systemic inflammatory response syndrome), 320 for positive blood cultures, and 37 for incomplete data. This yielded 538 patients which the authors reviewed the results of the CT or US to determine the proportion who required emergent surgical consultation and who underwent surgical or interventional procedure. There were 243 (45%) that had CT or US results that necessitated emergency surgical consultation, of those 180 (33%) underwent surgical or interventional procedure. Similar rates of emergency surgical consultation occurred when sub-divided by positive versus equivocal UA, with 43% and 47%, respectively. Conclusions Forty-five percent of our abdominally imaged urosepsis cohort had imaging findings that necessitated emergent surgical consultation, with a similar proportion in the subset with positive versus equivocal UA. The utility of abdominal imaging in this population should be studied prospectively.

Modification of transcriptional factor ACE3 enhances protein production in Trichoderma reesei in the absence of cellulase gene inducer.

BACKGROUND: Trichoderma reesei is one of the best-known cellulolytic organisms, producing large quantities of a complete set of extracellular cellulases and hemicellulases for the degradation of lignocellulosic substances. Hence, T. reesei is a biotechnically important host and it is used commercially in enzyme production, of both native and foreign origin. Many strategies for producing enzymes in T. reesei rely on the cbh1 and other cellulase gene promoters for high-level expression and these promoters require induction by sophorose, lactose or other inducers for high productivity during manufacturing. RESULTS: We described an approach for producing high levels of secreted proteins by overexpression of a transcription factor ACE3 in T. reesei. We refined the ace3 gene structure and identified specific ACE3 variants that enable production of secreted cellulases and hemicellulases on glucose as a sole carbon source (i.e., in the absence of an inducer). These specific ACE3 variants contain a full-length Zn2Cys6 binuclear cluster domain at the N-terminus and a defined length of truncations at the C-terminus. When expressed at a moderate level in the fungal cells, the ACE3 variants can induce high-level expression of cellulases and hemicellulases on glucose (i.e., in the absence of an inducer), and further improve expression on lactose or glucose/sophorose (i.e., in the presence of an inducer). Finally, we demonstrated that this method is applicable to industrial strains and fermentation conditions, improving protein production both in the absence and in the presence of an inducer. CONCLUSIONS: This study demonstrates that overexpression of ACE3 variants enables a high level of protein production in the absence of an inducer, and boosts protein production in the presence of an inducer. It is an efficient approach to increase protein productivity and to reduce manufacturing costs.

Protein engineering of nitrilase for chemoenzymatic production of glycolic acid.

A key step in a chemoenzymatic process for the production of high-purity glycolic acid (GLA) is the enzymatic conversion of glycolonitrile (GLN) to ammonium glycolate using a nitrilase derived from Acidovorax facilis 72W. Protein engineering and over-expression of this nitrilase, combined with optimized fermentation of an E. coli transformant were used to increase the enzyme-specific activity up to 15-fold and the biocatalyst-specific activity up to 125-fold. These improvements enabled achievement of the desired volumetric productivity and biocatalyst productivity for the conversion of GLN to ammonium glycolate.

Do outcome measures for trauma triage agree?

OBJECTIVE: The goal of trauma triage is to match resources to the needs of seriously injured patients. The trauma triage literature has used a variety of outcome measures to assess appropriate trauma activation. The objective of this study was to determine the agreement between procedural and nonprocedural outcome measures in a population of seriously injured patients transported to a single trauma center. METHODS: Study authors reviewed all "level 2" trauma activations (January 2002-December 2003) at an American College of Surgeons (ACS) Level 1 trauma center. "Level 2" trauma activations were based on modified ACS Committee on Trauma (COT) triage criteria. Outcomes were classified as nonprocedural (Injury Severity Score [ISS] > 15 and intensive care unit [ICU] admission) and procedural (nonorthopedic emergent surgery, emergency chest tube placement, emergency department intubation, emergency department transfusion, or emergent interventional radiology care). RESULTS: Of 479 patients, five were transferred out of hospital. The remaining 474 were predominantly male (62%), with a mean age of 39.7 years. Their average ISS was 13.2. There were nine deaths. For all subjects, 144 (30%) were admitted to the ICU, 172 (36%) had an ISS > 15, 80 (17%) received an emergent procedure, and 46 (10%) went for emergent surgery. Kappas comparing agreement of ISS > 15 with emergent resuscitation and emergent surgery were 0.31 and 0.15, respectively. Kappas comparing ICU admission with emergent resuscitation and emergent surgery were 0.51 and 0.26, respectively. CONCLUSIONS: We identify moderate to poor agreement between nonprocedural and procedural outcomes of trauma triage in this population.

Sequencing and de novo draft assemblies of a fathead minnow (Pimephales promelas) reference genome.

The present study was undertaken to provide the foundation for development of genome-scale resources for the fathead minnow (Pimephales promelas), an important model organism widely used in both aquatic toxicology research and regulatory testing. The authors report on the first sequencing and 2 draft assemblies for the reference genome of this species. Approximately 120× sequence coverage was achieved via Illumina sequencing of a combination of paired-end, mate-pair, and fosmid libraries. Evaluation and comparison of these assemblies demonstrate that they are of sufficient quality to be useful for genome-enabled studies, with 418 of 458 (91%) conserved eukaryotic genes mapping to at least 1 of the assemblies. In addition to its immediate utility, the present work provides a strong foundation on which to build further refinements of a reference genome for the fathead minnow.

Isolation of chromosomal mutations that affect carotenoid production in Escherichia coli: mutations alter copy number of ColE1-type plasmids.

Chromosomal mutants were isolated in Escherichia coli that altered carotenoid production from transformed carotenoid biosynthesis genes on a pACYC-derived plasmid (pPCB15). The mutations were mapped by sequencing. One group of mutations appeared to affect the cell metabolism without changing the copy number of the carotenoid synthesis plasmid. The other group of mutations either increased or decreased the copy number of the pPCB15 plasmid as determined by real-time PCR. The copy number change in most mutants was likely specific for ColE1-type plasmids for which copy number is controlled by a small antisense RNA. This collection of host strains would be useful for fine tuning expression of proteins and adjusting production of desired molecules without recloning to different vectors.

Use of pulse oximetry to predict in-hospital complications in normotensive patients with pulmonary embolism.

PURPOSE: A simple method is needed to risk stratify normotensive patients with pulmonary embolism. We studied whether bedside clinical data can predict in-hospital complications from pulmonary embolism. METHODS: We performed a multicenter derivation phase, followed by validation in a single center. All patients were normotensive; the diagnosis of pulmonary embolism was established by objective imaging. Classification and regression analysis was performed to derive a decision tree from 27 parameters recorded from 207 patients. The validation study was conducted on a separate group of 96 patients to determine the derived criterion's diagnostic accuracy for in-hospital complications (cardiogenic shock, respiratory failure, or death). RESULTS: Mortality in the derivation phase was 4% (n = 8) at 24 hours and 10% (n = 21) at 30 days. A room-air pulse oximetry reading <95% was the most important predictor of death; mortality was 2% (95% confidence interval [CI]: 0% to 6%) in patients with pulse oximetry >or=95% versus 20% (95% CI: 12% to 29%) with pulse oximetry <95%. In the validation phase, the room-air pulse oximetry was <95% at the time of diagnosis in 9 of 10 patients who developed an in-hospital complication (sensitivity, 90%) and >or=95% in 55 of 86 patients without complications (specificity, 64%). CONCLUSION: Mortality from pulmonary embolism in normotensive patients is high. A room-air pulse oximetry reading >or=95% at diagnosis is associated with a significantly lower probability of in-hospital complications from pulmonary embolism.

A randomized controlled trial of chest compression only CPR for older adults-a pilot study.

UNLABELLED: Older people are trained infrequently in cardiopulmonary resuscitation (CPR), yet are more likely to witness a cardiac arrest. Older people who are CPR trained perform CPR when witnessing a cardiac arrest. OBJECTIVE: To assess whether elderly adults (>55 years) who receive chest-compression only cardiopulmonary resuscitation (CC-CPR) training display equivalent skill retention rates compared with those who receive traditional CPR instruction. We also identified factors associated with 3 months skill retention at 3 months in both groups. METHODS: Older adults in a suburban hospital Older Adult Services program were invited to participate in an experimental CPR course. The 2 h course was modelled after the AHA Friends and Family course, and used one of two standardized video scenarios. Seventy four subjects were randomized to CC-CPR (n=36) or traditional CPR (n=38) training. Participation consisted of initial training, followed by a 3 months return videotaped assessment. Three months skill competence was assessed either by consensus between two video evaluators, or the on-site evaluator. Chi square and Kappa tests were used for analysis, and unadjusted odds ratios and 95% confidence intervals are reported. RESULTS: Skill retention assessments were completed on 29 (81%) CC-CPR and 26 (68%) CPR trainees. Subjects were elderly (71.5+/-6.69 years), and had a high rate of previous CPR training (58.0%). Groups were similar in demographic characteristics. After training, participants exhibited high rates of perceived competence (86.4%), although the overall 3 months skill retention was low (43.6%). CC-CPR training resulted in equivalent skill retention rates as compared with traditional CPR training (51.7 vs. 44.4%; P=0.586). No participant factors were associated with skill retention, including age, previous CPR training, education level, medical history, or perceived physical ability to perform. CONCLUSION: We identified low rates of CPR skill retention in this elderly population. CC-CPR instruction was associated with equivalent skill retention rates compared with traditional CPR instruction. No demographic factors were associated with successful skill retention.

Estimated cost effectiveness of a police automated external defibrillator program in a suburban community: 7 years experience.

OBJECTIVE: To estimate the cost effectiveness of a 7-year police automatic external defibrillator (AED) program in four suburban communities. METHOD: 10-year retrospective study (7/89-7/99) of patients of four suburban communities during two study periods: (1) police first response and advanced life support (ALS) care (No-AED) and; (2) AED equipped police first response (P-AED) with subsequent ALS care. Using the perspective of the communities, we obtained costs of AED program from police agencies. We estimated cost/life saved and cost/year lives saved using decreased time to VF shock by EMS. We performed a sensitivity analysis for estimates of potential benefit using estimated improved survival as a result of decreased EMS response interval and obtained survival data. We used literature-based estimates of life expectancy after cardiac arrest survival to estimate cost/year life saved. We used student's t-test and chi(2) to estimate differences between groups. RESULTS: During the 10-year study period 208 patients met study criteria; (81 No-AED, 128 P-AED). The two groups were not different by patient age, ALS response interval, percent in VF, percent witnessed (WIT), or arrest location. Interval to first defibrillator equipped EMS vehicle arrival was less in the P-AED group (2.0 vs. 5.4 min, P<0.001) as was the interval from the emergency (911) call to first VF shock (6.6 vs. 8.4 min, P=0.02). Survival to DC was not statistically different with P-AED (11.9 vs. 9.9%, P=0.66) but this study was not powered to detect a difference. Estimated cost per life saved with P-AED varied from $23542 to $70342 and cost per year life saved ranged from $1582 to $16060. CONCLUSION: Police AED appears to be a cost-effective intervention in these suburban communities which have relatively rapid EMS response intervals.

Intramuscular versus oral dexamethasone for the treatment of moderate-to-severe croup: a randomized, double-blind trial.

UNLABELLED: Glucocorticoids are an effective treatment for croup, although the most beneficial route of administration remains unclear. Recent studies have concluded that both intramuscular dexamethasone and oral dexamethasone are effective treatments, but there are few data directly comparing the two for moderate-to-severe croup. OBJECTIVES: The authors' primary objective was to determine whether there is a difference in proportion of children with resolution of symptoms attributable to croup at 24 hours, when treated with oral or intramuscular dexamethasone. Secondarily, the authors sought to estimate whether there is a difference in proportion of children with resolution of symptoms attributable to croup at 10 days and to estimate the interval to complete resolution of symptoms between these two routes. METHODS: The authors performed a prospective, randomized, double-blind trial involving children aged 3-84 months with moderate-to-severe croup, presenting to a suburban teaching emergency department (ED). Patients were eligible for enrollment if they had inspiratory stridor or a barky cough and a croup score of 2 or greater after 10-15 minutes of cool mist therapy. The patients were randomized to one of two intervention groups. In both groups, the parents were not present in the treatment room during study drug administration. One group received 0.6 mg/kg of intramuscular dexamethasone and an oral placebo, while the other group received 0.6 mg/kg of oral dexamethasone and direct pressure on their thigh with the hub of a syringe. A nurse placed a Band-Aid on the site of the real or mock injection. Parents were contacted by telephone approximately 1 and 10 days after the index visit to ask about their child's symptoms using a standardized questionnaire. Data were analyzed using an intention-to-treat approach. RESULTS: Of 126 patients eligible, 96 were recruited, with complete follow-up on 95. The groups were similar in all baseline characteristics, treatments received in the ED, and disposition. At 24 hours and 10 days after the visit, there were no statistical differences between the groups for the proportion with stridor, expiratory sounds, barky cough, sleep pattern, the degree of improvement, or the proportion with complete resolution of symptoms at one day. CONCLUSIONS: No statistical differences for any parameters were observed between intramuscular and oral dexamethasone treatments for children with moderate-to-severe croup at 24 hours or at any time the week after treatment. The durations of symptoms were similar between the treatment groups.

Perceived self-efficacy in performing and willingness to learn cardiopulmonary resuscitation in an elderly population in a suburban community.

BACKGROUND: Older persons are the group most likely to respond to cardiac arrests in private residences. OBJECTIVE: To characterize the knowledge about, attitudes toward, and perceived self-efficacy of older persons in learning and providing cardiopulmonary resuscitation. METHODS: A total of 2743 surveys were mailed to adults 55 years and older who resided in a single Michigan suburb. Data were collected on demographics, medical history, training in and willingness to provide cardiopulmonary resuscitation, and concerns about providing this intervention. RESULTS: The 631 persons (24.6%) who responded were elderly (mean age, 73.5 years) and had a mean of 1.7 occupants per household. More than one third lived alone. Of all respondents, 275 (43.6%) had received training in cardiopulmonary resuscitation, 370 (58.6%) indicated a willingness to learn cardiopulmonary resuscitation, and 412 (65.3%) thought that they had the ability to perform this intervention. Respondents 80 years or younger were significantly more likely than respondents more than 80 years old to be willing to learn cardiopulmonary resuscitation (65.7% vs 19.0%, P < .001) and perceived themselves as able to perform it (73.0% vs 34.0%, P < .001). The absence of mouth-to-mouth ventilation as part of training had minimal impact on the willingness of either age group to receive training (61.2% vs 58.6%, P = .19). Perceived ability to learn and perform cardiopulmonary resuscitation did not vary with the medical history of the respondent or the respondent's spouse. CONCLUSION: Adults 56 to 80 years old perceive themselves as able to perform cardiopulmonary resuscitation and are interested in receiving training.

Diagnostic parameters of CK-MB and myoglobin related to chest pain duration.

OBJECTIVE: Cardiac marker sensitivity depends on chest pain duration at the time of sampling. Our objective was to estimate the sensitivity, specificity, and likelihood ratios of early CK-MB and myoglobin assays in patients presenting to the emergency department (ED) with nondiagnostic ECGs, stratified by the duration of ongoing chest pain at the time of ED assessment. METHODS: This was a prospective observational study carried out in 10 US and 2 Canadian EDs. Patients >25 years of age with ongoing chest pain and nondiagnostic ECGs were stratified by pain duration (0-4 h, 4-8 h, 8-12 h, >12 h). CK-MB and myoglobin assays were drawn at T = 0 (ED assessment) and T = 1 hr. Patients were followed for 7-14 days to identify all cases of acute myocardial infarction (AMI). ED test results were correlated with patient outcomes. RESULTS: Of 5005 eligible patients, 565 had AMI. Pain duration was 0-4 h in 3014 patients, 4-8 h in 961, 8-12 h in 487, and >12 h in 543. Marker sensitivity increased with pain duration, ranging from 28%-77% for CK-MB and 39%-73% for myoglobin. The maximal sensitivity achieved by a T = 0 assay was 73%, and this was in patients with 8-12 or >12 h of ongoing pain. No combination of tests achieved 90% sensitivity in any pain duration strata. CONCLUSIONS: Regardless of chest pain duration, single assays and early serial markers (0+1 hr) do not rule out AMI; therefore, serial assays over longer observation periods are required. Likelihood ratios derived in this study will help physicians who use Bayesian analysis to determine post-test AMI likelihood in patients with chest pain.

Directed evolution of copy number of a broad host range plasmid for metabolic engineering.

Random mutagenesis and directed evolution has been successfully used to improve desired properties of enzymes for biocatalysis and metabolic engineering. Here we employ the method to increase copy number of a pBBR-based broad host range plasmid, which can be used to express desired enzymes in a variety of microbial hosts. Localized random mutagenesis was performed in the replication control region of a pBBR-derived plasmid containing a beta-carotene reporter. Mutant plasmids were isolated that showed increased beta-carotene production. Real-time PCR analysis confirmed that the copy number of the mutant plasmids increased 3-7 fold. Sequence of the 10 mutant plasmids indicated that each plasmid contained single or multiple mutations in the rep gene or the flanking regions. Single amino acid change of serine to leucine at codon 100 of the replication protein and single nucleotide change of C to T at 46 bp upstream of the rep gene caused the increase of plasmid copy number. The utility of the mutant plasmids for metabolic engineering were further demonstrated by increased beta-carotene production, when an isoprenoid pathway gene (dxs) was co-expressed on a compatible plasmid. The mutant plasmids were tested in Agrobacterium tumefaciens. Increase of plasmid copy number and beta-carotene production was also observed in the non-Escherichia coli host.

Proposed involvement of a soluble methane monooxygenase homologue in the cyclohexane-dependent growth of a new Brachymonas species.

High-throughput mRNA differential display (DD) was used to identify genes induced by cyclohexane in Brachymonas petroleovorans CHX, a recently isolated beta-proteobacterium that grows on cyclohexane. Two metabolic gene clusters were identified multiple times in independent reverse transcription polymerase chain reactions (RT-PCR) in the course of this DD experiment. These clusters encode genes believed to be required for cyclohexane metabolism. One gene cluster (8 kb) encodes the subunits of a multicomponent hydroxylase related to the soluble butane of Pseudomonas butanovora and methane monooxygenases (sMMO) of methanotrophs. We propose that this butane monooxygenase homologue carries out the oxidation of cyclohexane into cyclohexanol during growth. A second gene cluster (11 kb) contains almost all the genes required for the oxidation of cyclohexanol to adipic acid. Real-time PCR experiments confirmed that genes from both clusters are induced by cyclohexane. The role of the Baeyer-Villiger cyclohexanone monooxygenase of the second cluster was confirmed by heterologous expression in Escherichia coli.

An emergency department observation unit protocol for acute-onset atrial fibrillation is feasible.

STUDY OBJECTIVE: We sought to describe the feasibility of an emergency department observation unit (EDOU) treatment protocol for the management of uncomplicated acute-onset atrial fibrillation (AAF). METHODS: This descriptive case series took place at a major suburban, university-affiliated teaching hospital. Patients were prospectively enrolled in an EDOU treatment protocol if they had uncomplicated AAF that failed initial ED attempts to convert to sinus rhythm. In the EDOU, patients underwent ECG monitoring, serial creatine kianse MB measurements, and further rate control with optional electrical cardioversion. Primary outcomes measured were EDOU rate of conversion to sinus rhythm, rate of discharge home, length of stay, positive diagnostic outcomes, complications of AAF, and 7-day return visits. RESULTS: Sixty-seven patients were studied. Patients were symptomatic for a median of 4.0 hours, had mean initial ED pulse rates of 137+/-23 beats/min, and spent 4.7+/-2.2 hours in the ED before transfer to the EDOU. While in the EDOU, 55 (82%) patients converted to sinus rhythm. Five (7%) patients were admitted because of positive test results: 2 for myocardial infarction, 2 for fever, and 1 for ventricular tachycardia. Twelve (18%) patients remained in atrial fibrillation, with 9 admitted and 3 discharged. Overall, 81% of patients were discharged in 11.8+/-7.0 hours, and 19% were admitted after 17.6+/-9.5 hours of observation. Three discharged patients returned within 7 days, 2 for uncomplicated recurrent AAF and 1 for chest pain subsequently found to be noncardiac in origin. There were no major complications attributable to the EDOU protocol. CONCLUSION: Selected patients with AAF for whom initial ED management fails can subsequently be managed in an EDOU with a high short-term conversion and discharge rate.

Criteria for the safe use of D-dimer testing in emergency department patients with suspected pulmonary embolism: a multicenter US study.

STUDY OBJECTIVE: We derive a decision rule to partition emergency department patients with suspected pulmonary embolism (PE) into a small, high-risk group (>40% pretest probability) that is unsafe for D -dimer testing and a larger group that is safe to have PE ruled out with either a whole-blood D -dimer plus alveolar deadspace measurement or a quantitative D -dimer assay. METHODS: Nine hundred thirty-four patients with suspected PE were studied at 7 urban EDs in the United States. Patients were prospectively interviewed and examined for recognized symptoms, signs, and risk factors associated with PE. These data were collected before standard objective imaging for PE. Selected variables were analyzed by multivariate logistic analysis to determine factors associated with PE (P <.05). A decision rule was then constructed to categorize approximately 80% of ED patients as safe for D -dimer testing. RESULTS: Pretest prevalence of PE was 19.4% (181/934; 95% confidence interval [CI] 16.3% to 21.7%). Six variables found to be significant on multivariate analysis were used to construct the decision rule. Unsafe patients had either a shock index (heart rate/systolic blood pressure) more than 1.0 or age older than 50 years, together with any one of the following conditions: unexplained hypoxemia (SaO (2) <95%; no prior lung disease), unilateral leg swelling, recent major surgery, or hemoptysis. These criteria were met by 197 (21.0%) of 934 patients, and 83 of 197 (42.1%; 95% CI 35.3% to 49.6%) patients had PE. Exclusion of these 197 unsafe patients significantly decreased the probability of PE in the remaining 737 (79.0%) safe patients to 13.3% (95% CI 10.9% to 15.9%). CONCLUSION: Simple clinical criteria can permit safe D -dimer testing in the majority of ED patients with suspected PE. These criteria warrant prospective validation.