Myoglobin for Early Risk Stratification of Emergency Department Patients with Possible Myocardial Ischemia

OBJECTIVES: To determine and compare the prognostic abilities of early, single-sample myoglobin measurement with that of creatine kinase-MB (CK-MB), with cardiac troponin T (cTnT), and with physician judgment in the absence of marker results among emergency department (ED) patients with possible myocardial ischemia. METHODS: Prospective collection of clinical and serologic data using an identity-unlinked technique from patients with possible myocardial ischemia at two urban EDs. Outcome data concerning the occurrence of adverse events (AEs) during the 14 days after enrollment were used to calculate and compare the relative risks (RRs) and predictive values (with 95% confidence intervals) of the various markers for predicting AEs. RESULTS: Among 396 analyzed patients, 65 (16.4%) accrued 104 AEs, including 13 deaths (3.3%) and 31 (7.8%) myocardial infarctions. Myoglobin predicted AEs (RR = 3.36 [95% CI = 2.19 to 5.15]) with significantly higher sensitivity (50.8% [95% CI = 38.6 to 62.9]) than either CK-MB (15.4% [95% CI = 6.6 to 24.2]) or cTnT (24.6% [95% CI = 14.1 to 35.1]), but with lower specificity (81.9% [95% CI = 77.7 to 86.0]; CK-MB = 99.7% [95% CI = 99.1 to 100]; cTnT = 93.1% [95% CI = 90.3 to 95.8]). Myoglobin had prognostic ability among patients with chest pain (3.86 [95% CI = 2.39 to 6.22]) and atypical (non-chest pain) presentations (2.71 [95% CI = 1.09 to 6.71]), including those with a nondiagnostic electrocardiogram (3.11 [95% CI = 1.44 to 6.69]). The combination of myoglobin and physician decision making identified 63 of the 65 patients (96.9% [95% CI = 92.7 to 100]) with subsequent AEs. CONCLUSIONS: The early prognostic sensitivity of myoglobin may allow identification of some high-risk patients missed by physician judgment, CK-MB, and cTnT. Myoglobin should be considered for use in the ED based on both its diagnostic and prognostic abilities.     

The Prognostic Significance of Troponin I and Troponin T

Abstract. Objectives : To determine and compare the prognostic abilities of early, single-sample measurements of cardiac troponin I (cTn-I), cardiac troponin T (cTn-T), creatine kinase-MB (CK-MB) among ED patients with possible myocardial ischemia. Methods : Prospective collection of clinical and serologic data using an identity-unlinked technique from patients with possible myocardial ischemia at 2 urban EDs. Outcome data concerning the occurrence of adverse events (AEs) during the 14 days after enrollment were used to calculate and compare the relative risks (RRs) and predictive values (with 95% confidence intervals) of the 3 markers for predicting AEs. Results : Among the 401 study patients, 105 AEs occurred in 67 patients. cTn-I, cTn-T, and CK-MB were all significantly predictive of AEs, with RRs of 3.87 (2.39, 6.26), 3.03 (1.92, 4.79), and 6.45 (4.74, 8.77), respectively. For prediction of AEs, sensitivity for each of the 3 markers was low (cTn-I = 15.38, cTn-T = 24.62, CK-MB = 15.38), while specificity was high (cTn-I = 97.62, cTn-T = 93.15, CK-MB = 99.70). No significant difference in predictive ability was found between cTn-I and cTn-T. However, a positive CK-MB result was a stronger predictor of AEs than either cTn-I (p = 0.01) or cTn-T (p = 0.001). Conclusions : No significant difference in predictive abilities was found between cTn-I and cTn-T. However, routine testing for both CK-MB and either of the troponins may optimize early identification of high-risk patients so they may be targeted for a higher level of care and consideration of more aggressive therapies.     

Bedside Transorbital Ultrasound in the Clinical Evaluation of Pediatric Optic Neuritis in the Emergency Department

Background

Headache and monocular visual disturbance are worrisome pediatric presenting complaints in the emergency department. Appropriate and timely initial evaluation is critical. Most would opt for urgent computer tomography in such cases. Pediatric optic neuritis is a rare condition and is better evaluated by magnetic resonance imaging. With the increase in the use and scope of bedside ultrasound, there might be a potential role for transorbital ultrasound to be part of the emergency department evaluation of pediatric optic neuritis.

Early Diagnostic Efficiency of Cardiac Troponin I and Troponin T for Acute Myocardial Infarction

Objective : To compare the early diagnostic efficiency of the cardiac troponin I (cTn-I) level with that of the cardiac troponin T (cTn-T) level, as well as the creatine kinase (CK), CK-MB, and myoglobin levels, for acute myocardial infarction (AMI) in patients without an initially diagnostic ECG presenting to the ED within 24 hours of the onset of their symptoms. Methods : A prospective, observational, cohort study was performed involving chest pain patients admitted to a large urban community hospital. Participants were consecutive consenting ED chest pain patients ≥30 years of age. Exclusions included duration of symptoms >24 hours, inability to complete data collection, receipt of CPR, and ST-segment elevation on the initial ECG. Measurements included levels of cTn-I, cTn-T, CK, CK-MB, and myoglobin at the time of presentation and 1, 2, 6, and 12–24 hours after presentation as well as presenting ECG and clinical follow-up. Confirmation of the diagnosis of AMI was based on World Health Organization criteria. Results : Of the 177 patients included in the study, 27 (15%) were diagnosed as having AMIs. The sensitivities of all 5 biochemical markers for AMI were poor at the time of ED presentation (3.7–33.3%) but rose significantly over the study period. The sensitivity of cTn-T was significantly better than that of cTn-I over the initial 2 hours, but both markers' sensitivities were low (<60%) during this time frame. The cTn-I was significantly more specific for AMI than was the cTn-T, but not significantly better than CK-MB or myoglobin. Likelihood ratio analysis showed that the biochemical markers with the highest positive likelihood ratios for AMI during the first 2 hours following ED presentation were myoglobin and CK-MB. From 6 through 24 hours, the positive likelihood ratios for cTn-I, CK-MB, and myoglobin were superior to those of CK and cTn-T. Conclusions : cTn-I, CK-MB, and myoglobin are significantly more specific for AMI than are CK and cTn-T. Myoglobin is the biochemical marker having the highest combination of sensitivity, specificity, and negative predictive value for AMI within 2 hours of ED presentation. Neither cTn-I nor cTn-T offers significant advantages over myoglobin and CK-MB in the early (≤2 hours) initial screening for AMI. The cardiac troponins are of benefit in identifying AMI ≤6 hours after presentation.     

Evaluation of a new automated system for the determination of ck-mb isoforms

We evaluated a new analyzer (Cardio REP) specifically designed for cardiac CK-MB isoenzyme and isoforms activity, with a performance time of 24 minutes. Ten AMI patients, with times elapsed between the onset of chest pain and admission to hospital ranging from 30 minutes to 4 hours, were monitored every 3–4 hours until the 16th hour of hospitalization. In each serum sample, in addition to total CK-MB and CK-MB isoforms measured by the Cardio REP analyzer, we also assayed total CK activity, CK-MB activity by immunoinhibition method, CK-MB mass concentration, CK-MB isoforms by REP method, troponin T, and myoglobin. The precision study demonstrated acceptable within assay and between assay CVs% for total CK-MB (8.1 and 10.4), MB₁ (9.1 and 14.2), and MB₂ (9.1 and 8.2) isoforms. The method was found to be linear up to 371 U/L for MB₂ isoform fraction and up to 516 U/L for total CK-MB. Results for CK-MB obtained with the Cardio REP correlated well with those for CK-MB activity obtained with the immunoinhibition method (r = 0.869) and those of CK-MB mass concentration (r = 0.923). The sensitivity of the Cardio REP CK isoforms method was found to be greater than that of the REP CK isoforms method. Time to first increased value of MB₂/MB₁ ratio and MB₂ isoform was earlier in comparison to that for CK-MB mass concentrations and similar to that for myoglobin, a marker that, however, lacks specificity. The diagnostic efficiency of CK-MB isoforms and the availability of a real-time, fully automated method for their measurement suggest the utilization of this biochemical marker in emergency for the early diagnosis of AMI.     

Bedside Use of Speckle Tracking Echocardiography in the Emergency Department to Identify Acute Myocardial Infarction

Background

Rapid diagnosis of acute myocardial infarction (AMI) in the emergency department (ED) is often hindered by the limitations of the electrocardiogram (ECG). Speckle tracking echocardiography (STEch) is a semiautomated, computer-assisted process that provides accurate detection of regional ventricular wall motion abnormalities and can be performed at the bedside by operators with limited experience.

Evaluation of a New Assay for Cardiac Troponin I vs Creatine Kinase-MB for the Diagnosis of Acute Myocardial Infarction

Objective : To compare a new assay for cardiac troponin I (cTn-I) with an assay for creatine kinase-MB (CK-MB) for the diagnosis of acute myocardial infarction (AMI).
Methods : A prospective cross-sectional study of patients presenting with symptoms consistent with cardiac ischemia was performed at a university teaching hospital. Serum sampling for cTn-I and CK-MB was performed at 0, 1, 3, 8, and 16 hours after presentation. Normal values were defined as CK-MB ≤ 7 ng/mL and a relative index ≤ 2%, cTn-I ≤ 1.4 ng/mL. Final diagnosis was made using World Health Organization criteria, including standard enzyme sampling. Consecutive patients with AMI were compared with a randomly selected subset of patients without AMI to determine the sensitivity and specificity of the cTn-I and CK-MB assays for AMI, stratified by time from symptom onset. The ability of the biochemical cardiac markers obtained within 6 hours of symptom onset to predict later complications or need for interventions was assessed using odds ratios (ORs).
Results : Thirty-five patients who had AMI were compared with 136 patients who did not have AMI. The sensitivities and specificities of the cTn-I and CK-MB assays, stratified by time from symptom onset, were: Patients who had elevations in either CK-MB or cTn-I within 6 hours of symptom onset were at increased risk for cardiovascular complications and/or interventions (CK-MB, OR 5.8; cTn-I, OR 6.3).
Conclusion : cTn-I was as sensitive and specific for AMI as was CK-MB in ED patients who presented within 24 hours of symptom onset. However, cTn-I was more sensitive in patients who presented ≥ 24 hours after symptom onset. Elevations of either marker within 6 hours of symptom onset predict an increased risk of complications and/or need for interventions.     

Identifying Myocardial Ischemia due to Coronary Microvascular Dysfunction in the Emergency Department: Introducing a New Paradigm in Acute Chest Pain Evaluation

Chest pain stands as one of the most frequent patient presentations in the emergency department (ED). Despite established diagnostic algorithms for identifying several important causes of chest pain, such as acute myocardial infarction (AMI), aortic dissection, and pulmonary embolism, guidance on managing patients with recurrent chest pain, one of the top 3 reasons for repeated hospitalization in the United States, is less defined. The assessment of symptoms, serial ECG, and necrosis biomarkers plays a major role in patient management. Notably, the recently introduced high-sensitivity troponin T (hs-TnT) assay is helping to identify ischemia in patients previously undiagnosed by conventional testing. In Europe, with the use of this assay for over a decade, the identification of patients with AMI has substantially increased, particularly of patients with type 2 AMI, which is seen in the absence of atherosclerotic obstruction of the epicardial coronaries on angiography. Use of hs-TnT is in particular relevant in women, in whom the use of a sex-specific threshold for elevated hs-TnT has almost doubled the diagnosis of AMI. With the advent of the hs-TnT assay in the United States in 2017, a similar phenomenon is expected. Thus, it is important to learn from the European experience and to develop sex-specific nuanced algorithms for the evaluation of additional causes of myocardial ischemia/necrosis, such as coronary artery vasomotor disorders and coronary microvascular dysfunction. The latter has a high prevalence among symptomatic women presenting to the ED, a group in whom recurrent chest pain is common. This commentary describes the tools available for diagnosing epicardial- and non–epicardial-related myocardial ischemia in patients with recurrent chest pain in the ED setting. A sex-specific, nuanced approach applied to select groups of patients being observed in the ED has the potential to reduce admissions and to allow for the initiation of timely, appropriate medical treatment and outpatient follow-up in an at-risk population. The costs and availability of advanced diagnostics may pose some limitation to the widespread adoption of such protocols.     

Development and Implementation of a Model to Improve Identification of Patients Infected with HIV Using Diagnostic Rapid Testing in the Emergency Department

Objectives Infection with the human immunodeficiency virus (HIV) continues to expand in nontraditional risk groups, and the prevalence of undiagnosed infection remains relatively high in the patient populations of urban emergency departments (EDs). Unfortunately, HIV testing in this setting remains uncommon. The objectives of this study were 1) to develop a physician‐based diagnostic rapid HIV testing model, 2) to implement this model in a high‐volume urban ED, and 3) to prospectively characterize the patients who were targeted by physicians for testing and determine the proportions who completed rapid HIV counseling, testing, and referral; tested positive for HIV infection; and were successfully linked into medical and preventative care. Methods An interdisciplinary group of investigators developed a model for performing physician‐based diagnostic rapid HIV testing in the ED. This model was then evaluated using a prospective cohort study design. Emergency physicians identified patients at risk for undiagnosed HIV infection using clinical judgment and consensus guidelines. Testing was performed by the hospital's central laboratory, and clinical social workers performed pretest and posttest counseling and provided appropriate medical and preventative care referrals, as defined by the model. Results Over the 30‐month study period, 105,856 patients were evaluated in the ED. Of these, 681 (0.64%; 95% confidence interval [CI] = 0.60% to 0.69%) were identified by physicians and completed rapid HIV counseling, testing, and referral. Of the 681 patients, 15 (2.2%; 95% CI = 1.2% to 3.6%) patients tested positive for HIV infection and 12 (80%; 95% CI = 52% to 96%) were successfully linked into care. Conclusions A physician‐based diagnostic HIV testing model was developed, successfully implemented, and sustained in a high‐volume, urban ED setting. While the use of this model successfully identified patients with undiagnosed HIV infection in the ED, the overall level of testing remained low. Innovative testing programs, such as nontargeted screening, more specific targeted screening, or alternative hybrid methods, are needed to more effectively identify undiagnosed HIV infection in the ED patient population.     

Variance Cardiography for Emergency Department Evaluation of Chest Pain Patients

Objective: To determine the test performance of 24–lead variance cardiography (VC), an ECG technique that measures QRS morphologic variability, for ED evaluation of chest pain associated with coronary artery disease (CAD).
Methods: A prospective, single–blind study of VC was performed in a community teaching hospital ED. All chest pain patients (>30 years of age) who, after initial emergency physician evaluation, were believed to have pain of potential cardiac etiology and were admitted to the hospital were eligible. Exclusion criteria included obvious noncardiac etiology for discomfort, bundle–branch block, atrial fibrillation, and incomplete subsequent cardiac evaluation. After initial evaluation and stabilization, VC was obtained. The numerical output of VC was a CAD index (CADI). Serum myoglobin and creatine kinase (CK)–MB levels were obtained at the time of presentation and after one, two, and six hours. Hospital records were reviewed to determine final diagnosis and in–hospital evaluation results.
Results: Fifty–two of 75 eligible patients had complete data. Final diagnoses were as follows: 27/52 (52%), noncardiac; 13/52 (25%), acute myocardial infarction (AMI); and 12/52 (23%), unstable angina due to CAD. Twenty–three percent (12/52) of the patients had CADIs < 75. Eleven of these were found to have noncardiac origins for their chest pain. The twelfth patient had a 12–lead ECG revealing AMI and had been given thrombolytic therapy with subsequent reperfusion prior to VC. Using a CADI < 75 as the cutoff for a negative study, VC alone had a negative predictive value of 92%, a sensitivity of 96%, a positive predictive value of 60%, and a specificity of 41%.
Conclusion: A CADI < 75, in addition to clinical impression and initial ECG, may identify chest pain patients who do not have significant CAD. Further prospective assessment of VC is warranted.     

The T2Bacteria Assay Is a Sensitive and Rapid Detector of Bacteremia That Can Be Initiated in the Emergency Department and Has Potential to Favorably Influence Subsequent Therapy

BackgroundBacteremia causes a major worldwide burden, in terms of financial and productivity costs, as well the morbidity and mortality it can ultimately cause. Proper treatment of bacteremia is a challenge because of the species-dependent response to antibiotics. The T2Bacteria Panel is a U.S. Food and Drug Administration–cleared and culture-independent assay for detection of bacteremia, including common ESKAPE pathogens—Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa—and provides species identification in as little as 3.6 h directly from blood.ObjectiveOur aim was to evaluate the T2Bacteria assay performance and potential to affect patient care in the emergency department (ED).MethodsED patients from a Louisiana and Florida center were enrolled as part of the T2Bacteria Panel clinical study, which was prospective and noninterventional. Blood samples for blood culture (BC) and T2Bacteria were matched in time and anatomic location.ResultsData from 137 ED patients were evaluated. Relative to BC, T2Bacteria showed 100% positive percent agreement and 98.4% negative percent agreement. In addition, for species on the T2Bacteria Panel, the T2Bacteria assay detected 25% more positives associated with infection, and on average identified the infectious species 56.6 h faster. The T2Bacteria assay covered 70.5% of all species detected by BC. Finally, relative to actual care, the T2Bacteria assay could have potentially focused therapy in 8 patients, reduced time to a species-directed therapy in 4 patients, and reduced time to effective therapy in 4 patients.ConclusionsIn this ED population, the T2Bacteria assay was a rapid and sensitive detector of bacteremia from common ESKAPE pathogens and showed the theoretical potential to influence subsequent patient therapy, ranging from antibiotic de-escalation to faster time to effective therapy.     

The Etiology and Prognostic Significance of Cardiac Troponin I Elevation in Unselected Emergency Department Patients

Background: Cardiac troponin elevations are associated not only with acute coronary syndromes (ACS) but also with multiple other cardiac and non-cardiac conditions. Study Objectives: To investigate the etiology and clinical significance of cardiac troponin I elevations in an unselected Emergency Department (ED) patient cohort. Methods: The study population consisted of 991 consecutive troponin-positive patients admitted to the ED of a university hospital with ACS as the presumptive diagnosis. Cardiac troponin I was measured on admission and a follow-up sample was obtained at 6–12 h. Clinical diagnosis was ascertained retrospectively using all the available information including electrocardiogram, clinical data, laboratory tests, and available coronary angiograms. Results: At admission, 805 (81.2%) patients were already troponin positive; of these, the troponin elevation was related to myocardial infarction (MI) in 654 (81.2%) patients. Finally, 83.0% of the troponin elevations were due to MI, 7.9% were related to other cardiac causes, and 9.1% to non-cardiac diseases. The leading non-cardiac causes were pulmonary embolism, renal failure, pneumonia, and sepsis. Non-cardiac patients with elevated troponin I at admission showed significantly higher in-hospital mortality (26.7% vs. 13.4%, p = 0.002) compared to cardiac patients. Conclusion: Elevated troponin levels for reasons other than MI are common in the ED and are a marker of poor in-hospital prognosis.     

Emergency Provider Attitudes and Barriers to Universal HIV Testing in the Emergency Department

Background: The Centers for Disease Control and Prevention (CDC) recently published recommendations for routine, voluntary human immunodeficiency virus (HIV) testing of adults in all health care settings, including the emergency department (ED). Study Objective: The objective of this study was to examine the willingness of ED providers to offer HIV testing, as well as their perceived barriers to implementation of these guidelines. Methods: Before the establishment of a routine HIV testing program in the ED, a 21-item survey was used to assess ED providers' knowledge, attitudes, and perceived challenges to HIV testing. Six months after program initiation, the identical survey was re-administered to determine whether HIV testing program experience altered providers' perceptions. Results: There were 108 of 146 (74%) providers who completed both the pre- and post-implementation surveys. Although the majority of emergency providers at 6 months were supportive of an ED-based HIV testing program (59/108 [55%]), only 38% (41/108) were willing to offer the HIV test most or all of the time. At 6 months, the most frequently cited barriers to offering a test were: inadequate time (67/108 [62%]), inadequate resources (65/108 [60%]), and concerns regarding provision of follow-up care (64/108 [59%]). Conclusions: After the implementation of a large-scale HIV testing program in an ED, the majority of emergency providers were supportive of routine HIV testing. Nevertheless, 6 months after program initiation, providers were still reluctant to offer the test due to persistent barriers. Further studies are needed to identify feasible implementation strategies that minimize barriers to routine HIV testing in the ED.     

Implementing Bedside Handoff in the Emergency Department: A Practice Improvement Project

Introduction

Handoff in the emergency department is considered a high-risk period for medical errors to occur. In response to concerns about the effectiveness of the nursing handoff in the emergency department of a Midwestern trauma center, a practice improvement project was implemented. The process change required nursing handoff at shift changes to be conducted at the bedside, using an adapted situation, background, assessment, recommendation (SBAR) communication tool.

A Survey of Bedside Ultrasound Use by Emergency Physicians in California

Objective. The purpose of this study was to investigate the current practice of emergency physician–performed bedside ultrasound examinations in California and to assess differences between academic and community practice. Methods. We queried all emergency departments (EDs) in California to determine whether bedside ultrasound was used by emergency physicians. Among EDs that were using bedside ultrasound, we administered a survey to assess use patterns, credentialing criteria, and quality assurance (QA) programs. Results. We contacted all eligible EDs (n = 293) by telephone and had a 100% response rate for our primary question: 101 EDs (34%) reported use of bedside ultrasound. Of these 101 EDs, 97 (96%) responded to the secondary survey, showing the following: (1) 48% of physicians at each site were credentialed to use ultrasound in at least 1 modality; (2) 70% of EDs used American College of Emergency Physicians (ACEP) criteria for credentialing guidelines; and (3) 33% had an ultrasound QA program. Comparing practice settings, 68% of academic departments used bedside ultrasound compared with 29% of community departments (difference, 39%; 95% confidence interval [CI], 23% to 54%; P < .0001). In academic departments, a mean of 60% of physicians were credentialed, compared with 41% in community EDs (difference, 19%; 95% CI, 2.5% to 35%; P = .036). Conclusions. Most California EDs do not use bedside ultrasound. Although most EDs using ultrasound report that they follow ACEP emergency ultrasound guidelines, most do not have a QA program as recommended by these guidelines. Compared with community EDs, academic EDs are more likely to use bedside ultrasound, have physicians credentialed in ultrasound use, and have QA programs.     

Rapid Progression of Wellens Syndrome in the Emergency Department

Background: In 1982, Wellens and colleagues described characteristic electrocardiogram (ECG) findings in angina patients virtually pathognomonic for significant stenosis of the proximal left anterior descending coronary artery and associated with a high risk of acute anterior wall myocardial infarction. Case Report: We present the case of a 74-year-old emergency department patient with classic ECG findings of Wellens syndrome and progression to acute ST elevation within 55 min. Summary: We present this case to increase awareness among emergency physicians of the characteristic findings of Wellens syndrome.     

Introduction of a Stat Laboratory Reduces Emergency Department Length of Stay

Objectives:  Emergency department (ED) length of stay (LOS) impacts patient satisfaction and overcrowding. Laboratory turnaround time (TAT) is a major determinant of ED LOS. The authors determined the impact of a Stat laboratory (Stat lab) on ED LOS. The authors hypothesized that a Stat lab would reduce ED LOS for admitted patients by 1 hour.
Methods:  This was a before-and-after study conducted at an academic suburban ED with 75,000 annual patient visits. All patients presenting to the ED during the months of August and October 2006 were considered. A Stat lab located within the central laboratory was introduced in September 2006 to reduce laboratory TAT. The test TATs and ED LOS before (August 2006) and after (October 2006) implementing the Stat lab for all ED patients were the data of interest. ED LOS before and after the Stat lab was introduced was compared with the Mann-Whitney U-test. A sample size of 5,000 patients in each group had 99% power to detect a 1-hour difference in ED LOS.
Results:  There were 5,631 ED visits before and 5,635 visits after implementing the Stat lab. Groups were similar in age (34 years vs. 36 years) and gender (51% males in both). The percentages of patients with laboratory tests before and after Stat lab implementation were 68.7 and 71.3%, respectively. Test TATs for admitted patients were significantly improved after the Stat lab introduction. Implementation of the Stat lab was associated with a significant reduction in the median ED LOS from 466 (interquartile range [IQR] = minutes before to 402 (IQR = 296–553) minutes after implementing the Stat lab. The effects of the Stat lab on ED LOS were less marked for discharged patients.
Conclusions:  Introduction of a Stat lab dedicated to the ED within the central laboratory was associated with shorter laboratory TATs and shorter ED LOS for admitted patients, by approximately 1 hour.     

Evaluation of a Portable Clinical Blood Analyzer in the Emergency Department

Objective: To assess the potential effects of rapid bedside blood analysis on patient management in the ED.
Methods: A prospective, nonrandomized clinical study was conducted over a consecutive ten-month period (August 1992 to May 1993). Blood samples drawn from a convenience sample of 960 patients for analysis of Na ⁺, K ⁺, Cl^-, BUN, glucose, and/or hematocrit (Hct) were simultaneously analyzed by portable clinical analyzer (PCA) and by routine methods in the central laboratory. Caregivers were blinded to the PCA values; patient care was based solely on central laboratory results. Physicians were surveyed after the completion of patient care.
Results: The PCA results were available 31 minutes (mean) sooner than were the central laboratory results for Hct, 43 minutes faster for Na ⁺, K⁺, and Cl^-, and 44 minutes faster for BUN and glucose. Except for Hct and glucose, the values obtained from the PCA were not significantly different from the central clinical blood analyzer laboratory values. When surveyed, the physicians caring for the patients reported that had the PCA results been available, a different or an earlier therapeutic approach would have resulted in 9.5% of the cases. The decision to release or admit the patient was based on one or more of the laboratory values for 10.7% of patients sampled. In no case in this series did a physician report that final ED clinical outcome would have been affected.
Conclusions: In our ED, the PCA yielded faster reporting of laboratory values. These earlier results might have reduced the length of stay in the ED for 17.3% of patients studied. Selective use of a handheld portable analyzer might decrease time to therapeutic interventions and time to disposition.