A Blinded Randomized Trial Comparing Standard Activated Clotting Time Heparin Management to High Target Active Clotting Time and Individualized Hepcon HMS Heparin Management in Cardiopulmonary Bypass Cardiac Surgical Patients.

PURPOSE: High-dose heparin has been suggested to reduce consumption coagulopathy. MATERIALS AND METHODS: In a randomized, blinded, prospective trial of patients undergoing elective, complex cardiac surgery with cardiopulmonary bypass, patients were randomized to one of three groups: 1) high-dose heparin (HH) receiving an initial heparin dose of 450 u/kg, 2) heparin concentration monitoring (HC) with Hepcon Hemostasis Management System (HMS; Medtronic, Minneapolis, MN, USA) monitoring, or 3) a control group (C) receiving a standard heparin dose of 300 u/kg. Primary outcome measures were blood loss and transfusion requirements. RESULTS: There were 269 patients block randomized based on primary versus redo sternotomy to one of the three groups from August 2001 to August 2003. There was no difference in operative bleeding between the groups. Chest tube drainage did not differ between treatment groups at 8 hours (median [25th percentile, 75th percentile] for control group was 321 [211, 490] compared to 340 [210, 443] and 327 [250, 545], p = 0.998 and p = 0.540, for HH and HC treatment groups, respectively). The percentage of patients receiving transfusion was not different among the groups. CONCLUSION: Higher heparin dosing accomplished by either activated clot time or HC monitoring did not reduce 24-hour intensive care unit blood loss or transfusion requirements.

Validation of a Point-of-Care Analyzer for Determining Anticoagulation Status During Air Transport.

OBJECTIVE: We evaluated a point-of-care prothrombin time (PT)/international normalized ratio (INR) cartridge-based analyzer for its feasibility, accuracy, and value in critical care air transport. METHODS: In this prospective study, blood samples from 10 randomly selected adult patients were tested with the cartridge during transport to determine feasibility. The cartridge results were compared with the laboratory results for the same samples. Similarly, blood samples from an additional 20 randomly selected adult patients were tested to determine test accuracy. A chart review identified 110 adult patients with PT/INR cartridge results to determine the clinical value of those results. RESULTS: Data from the first group of 10 patients showed that vibration did not affect use of the cartridge. The average bias between the 2 testing methods was 0.0 INR units. A comparison of the PT/INR cartridge results and the laboratory results from the group of 20 patients showed that 73% of the cartridge values were within 0.2 of the laboratory values, 83% were within 0.4, and 93% were within 0.6. Of the 110 patients whose charts showed PT/INR cartridge results, 23% received blood products (45 trauma patients and 65 medical patients). CONCLUSION: The PT/INR cartridge withstands the rigors of rotor wing transport and provides accurate, valuable results for making clinical decisions.

Point-of-care washing of allogeneic red blood cells for the prevention of transfusion-related respiratory complications (WAR-PRC): a protocol for a multicenter randomised clinical trial in patients undergoing cardiac surgery.

INTRODUCTION: The transfusion-related respiratory complications, transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO), are leading causes of transfusion-related morbidity and mortality. At present, there are no effective preventive strategies with red blood cell (RBC) transfusion. Although mechanisms remain incompletely defined, soluble biological response modifiers (BRMs) within the RBC storage solution may play an important role. Point-of-care (POC) washing of allogeneic RBCs may remove these BRMs, thereby mitigating their impact on post-transfusion respiratory complications. METHODS AND ANALYSIS: This is a multicenter randomised clinical trial of standard allogeneic versus washed allogeneic RBC transfusion for adult patients undergoing cardiac surgery testing the hypothesis that POC RBC washing is feasible, safe, and efficacious and will reduce recipient immune and physiologic responses associated with transfusion-related respiratory complications. Relevant clinical outcomes will also be assessed. This investigation will enrol 170 patients at two hospitals in the USA. Simon's two-stage design will be used to assess the feasibility of POC RBC washing. The primary safety outcomes will be assessed using Wilcoxon Rank-Sum tests for continuous variables and Pearson chi-square test for categorical variables. Standard mixed modelling practices will be employed to test for changes in biomarkers of lung injury following transfusion. Linear regression will assess relationships between randomised group and post-transfusion physiologic measures. ETHICS AND DISSEMINATION: Safety oversight will be conducted under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained by the DSMB as well as the institutional review boards at each institution prior to enrolling the first study participant. This study aims to provide important information regarding the feasibility of POC washing of allogeneic RBCs and its potential impact on ameliorating post-transfusion respiratory complications. Additionally, it will inform the feasibility and scientific merit of pursuing a more definitive phase II/III clinical trial. REGISTRATION: ClinicalTrials.gov registration number is NCT02094118 (Pre-results).

Looking Under the Streetlight? A Framework for Differentiating Performance Measures by Level of Care in a Value-Based Payment Environment.

The majority of quality measures used to assess providers and hospitals are based on easily obtained data, focused on a few dimensions of quality, and developed mainly for primary/community care and population health. While this approach supports efforts focused on addressing the triple aim of health care, many current quality report cards and assessments do not reflect the breadth or complexity of many referral center practices.In this article, the authors highlight the differences between population health efforts and referral care and address issues related to value measurement and performance assessment. They discuss why measures may need to differ across the three levels of care (primary/community care, secondary care, complex care) and illustrate the need for further risk adjustment to eliminate referral bias.With continued movement toward value-based purchasing, performance measures and reimbursement schemes need to reflect the increased level of intensity required to provide complex care. The authors propose a framework to operationalize value measurement and payment for specialty care, and they make specific recommendations to improve performance measurement for complex patients. Implementing such a framework to differentiate performance measures by level of care involves coordinated efforts to change both policy and operational platforms. An essential component of this framework is a new model that defines the characteristics of patients who require complex care and standardizes metrics that incorporate those definitions.

Relation of Activated Clotting Times During Percutaneous Coronary Intervention to Outcomes.

Monitoring anticoagulation using the activated clotting time (ACT) in patients treated with heparin and undergoing percutaneous coronary intervention (PCI) is one of the most frequently used tests in invasive cardiology. However, despite its widespread use and guideline endorsement, uncertainty remains regarding the association of ACT with outcomes in contemporary practice. We reviewed all PCI procedures performed at the Mayo Clinic (Rochester, Minnesota) from October 2001 to December 2012 and evaluated the association between the ACT before device activation and in-hospital and 1-year outcomes. ACT values were grouped into tertiles for descriptive purposes and analyzed as a continuous variable for assessment of outcomes. We used logistic and Cox proportional hazards regression models to estimate the association of ACT and outcomes. Of the 12,055 patients who underwent PCI with an ACT value before device activation, 3,977 (33.0%) had an ACT <227, 4,046 (33.6%) had an ACT 227 to 285, and 4,032 (33.4%) had an ACT >285. Baseline and procedural characteristics were similar across ACT tertiles. In unadjusted analysis, higher ACT values were associated with death (p <0.001), bleeding (p = 0.024), procedural complication (p <0.001), and higher 1-year events (cardiac death, p <0.001; cardiac death/myocardial infarction, p = 0.022). After multivariable adjustment for baseline and procedural characteristics, ACT was not independently associated with in-hospital or 1-year ischemic, thrombotic, or bleeding outcomes. In conclusion, ACT values before device activation are not independently associated with clinically important outcomes in contemporary PCI practice.

Inclusion of short-term care patients affects the perceived performance of specialists: a retrospective cohort study.

BACKGROUND: Current publicly reported quality performance measures directly compare primary care to specialty care. Specialists see short-term patients referred due to poor control of their disease who then return to their local provider. Our study looked to determine if outcomes measured in short-term care patients differed from those in long-term care patients and what impact those differences may have on quality performance profiles for specialists. METHODS: Retrospective cohort from a large academic medical Center. Performance was measured as "Optimal Care"--all or none attainment of goals. Patients with short-term care (<90 days contact) versus long-term care (>90 days contact) were evaluated for both specialty and primary care practices during the year 2008. RESULTS: Patients with short-term care had significantly lower "Optimal Care": 7.2% vs. 19.7% for optimal diabetes care in endocrinology and 41.3% vs. 53.1% for optimal ischemic vascular disease care in cardiology (p < 0.001). Combining short and long term care patients lowered overall perceived performance for the specialty practice. CONCLUSIONS: Factors other than quality affect the perceived performance of the specialty practice. Extending current primary care quality measurement to short-term specialty care patients without adjustment produces misleading results.

Widely used track and trigger scores: are they ready for automation in practice?

INTRODUCTION: Early Warning Scores (EWS) are widely used for early recognition of patient deterioration. Automated alarm/alerts have been recommended as a desirable characteristic for detection systems of patient deterioration. We undertook a comparative analysis of performance characteristics of common EWS methods to assess how they would function if automated. METHODS: We evaluated the most widely used EWS systems (MEWS, SEWS, GMEWS, Worthing, ViEWS and NEWS) and the Rapid Response Team (RRT) activation criteria in use in our institution. We compared their ability to predict the composite outcome of Resuscitation call, RRS activation or unplanned transfer to the ICU, in a time-dependent manner (3, 8, 12, 24 and 36 h after the observation) by determining the sensitivity, specificity and positive predictive values (PPV). We used a large vital signs database (6,948,689 unique time points) from 34,898 unique consecutive hospitalized patients. RESULTS: PPVs ranged from less than 0.01 (Worthing, 3 h) to 0.21 (GMEWS, 36 h). Sensitivity ranged from 0.07 (GMEWS, 3 h) to 0.75 (ViEWS, 36 h). Used in an automated fashion, these would correspond to 1040-215,020 false positive alerts per year. CONCLUSIONS: When the evaluation is performed in a time-sensitive manner, the most widely used weighted track-and-trigger scores do not offer good predictive capabilities for use as criteria for an automated alarm system. For the implementation of an automated alarm system, better criteria need to be developed and validated before implementation.

Fresh and citrated whole-blood specimens can produce different thromboelastography results in patients on extracorporeal membrane oxygenation.

OBJECTIVES: To compare thromboelastography (TEG) tracings obtained from fresh and citrated whole-blood samples in patients on extracorporeal membrane oxygenation (ECMO) or after cardiopulmonary bypass and in healthy volunteers. METHODS: Samples of fresh and citrated whole blood were analyzed for 25 patients and 4 healthy volunteers. Thromboelastography analysis was performed in both plain and heparinase cups. RESULTS: In 5 of 6 patients on ECMO, use of citrated samples resulted in apparent partial or complete heparin reversal. In TEG tracings from patients following cardiopulmonary bypass, there was a slight hypercoagulable appearance in the citrated sample. No differences were noted between fresh and citrated samples from healthy volunteers whose blood was spiked with heparin. CONCLUSIONS: In some patients on ECMO, use of samples collected in sodium citrate tubes for TEG analysis results in significant artifacts, which could lead to heparin overdosing in these patients.

Treatment of chronic tendinopathy with ultrasound-guided needle tenotomy and platelet-rich plasma injection.

OBJECTIVE: To determine whether ultrasound (US)-guided percutaneous needle tenotomy followed by a platelet-rich plasma (PRP) injection would result in pain reduction, functional improvement, or structural alterations in patients with chronic, recalcitrant tendinopathy. DESIGN: Part A was a retrospective observational study. Part B was a prospective observational study. SETTING: Outpatient academic sports medicine center. PARTICIPANTS: Patients were required to have chronic (>3 months), recalcitrant tendinopathy treated with US-guided percutaneous tenotomy and PRP injection between January 2007 and October 2009. Fifty-one subjects met the inclusion criteria. Forty-one (80%) participated in part A of the study, whereas 34 subjects (67%) participated in part B. METHODS: In part A, subjects completed a survey obtaining anthropomorphic, demographic, pain, and functional data. Subjects' platelet, hemoglobin, and white blood cell concentrations from their whole-blood and PRP samples were also obtained. In part B, subjects returned to the clinic after US-guided percutaneous needle tenotomy and PRP injection for a diagnostic US, which was compared with their preprocedure diagnostic US. MAIN OUTCOME MEASURES: The main outcome measures included changes in pain, function, and tendon characteristics. RESULTS: The tendinopathy location was in the upper extremity in 10 subjects (24.4%), was in the lower extremity in 31 subjects (75.6%), and had been present for a mean of 40 months. The mean postprocedure follow-up was 14 months, and the maximum benefits occurred 4 months postprocedure. There were mean functional and worst-pain improvements of 68% and 58%, respectively. Eighty-three percent of subjects were satisfied with their outcomes and would recommend the procedure to a friend. Although no tendons demonstrated a normal sonographic appearance after the procedure, 84% of subjects had an improvement in echotexture, 64% had a resolution of intratendinous calcifications, and 82% had a decrease in intratendinous neovascularity. None of the variables analyzed in this study demonstrated a significant correlation with pain or functional outcome measures. CONCLUSIONS: In this case series, we found US-guided percutaneous needle tenotomy followed by PRP injection to be a safe and effective treatment for chronic, recalcitrant tendinopathy, and this treatment was associated with sonographically apparent improvements in tendon morphology. However, because of the intrinsic limitations of the study design and the heterogeneity of treated tendons, further research is required to corroborate our findings.

Use of an autologous blood recovery system during emergency pericardiocentesis in the electrophysiology laboratory.

INTRODUCTION: Emergency pericardiocentesis during electrophysiology procedures is often associated with significant aspiration of pericardial blood, requiring transfusion. We sought to assess the feasibility of urgent use of an autologous blood recovery system in the electrophysiology laboratory to autotransfuse blood aspirated from the pericardium. METHODS AND RESULTS: We retrospectively analyzed Mayo Clinic electrophysiology records for patients who had ablation procedure-related pericardial effusions requiring emergency pericardial drainage during an 8-month period. An autologous blood recovery system was used during pericardiocentesis to separate and clean packed red blood cells from the pericardial aspirate. These cells were returned acutely to the patient intravenously. The procedural safety, aspirated and autotransfused volumes, and efficacy of this approach were evaluated. During the study period, nine patients underwent pericardial drainage with autotransfusion using a cell-salvage instrument during electrophysiology procedures. The mean aspirated volume was 1,078 mL, with a mean autotransfused volume of 390 mL. For four patients, all with aspirated volumes of 1,100 mL or less, autotransfusion alone was sufficient to maintain hemodynamic stability and avoid allogeneic transfusion. One patient required surgical intervention because of ongoing pericardial bleeding. The ablation procedure was completed after aspiration in two patients. No procedural complications related to the use of the cell-salvage system occurred. CONCLUSION: Autologous blood recovery during pericardiocentesis is safe, convenient, and feasible. With early use it may decrease or eliminate the need for allogeneic blood transfusion and, in selected cases, may permit completion of the ablation procedure.

Correlation of point-of-care International Normalized Ratio to laboratory International Normalized Ratio in hemodialysis patients taking warfarin.

BACKGROUND AND OBJECTIVES: To determine whether point-of-care (POC) International Normalized Ratio (INR) test results correlate with plasma INR measures in intermittent hemodialysis (IHD) patients on warfarin. Anemia is thought to reduce the accuracy of POC INR assay results. Whether POC INR testing could be implemented for hemodialysis patients on chronic warfarin, who are often anemic despite hematopoietic therapy, has not been established. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Thirty-seven chronic hemodialysis patients on warfarin contributed sets of three consecutive blood samples for INR comparison immediately before hemodialysis: one finger stick, two from hemodialysis access (arteriovenous graft, fistula, or catheter). POC INR testing was performed using CoaguChek S device. Anemia was defined as hematocrit < 32%. RESULTS: Pairwise comparison and correlation of 258 INR results showed high correlation for POC versus laboratory INR (r = 0.94; P < 0.001). Of these, 16 (6%) differed by >0.6 INR units, four (1.6%) differed by >0.8 INR units, and one differed by >1.0 INR units. Resulting pairwise correlation analyses between samples were: for anemic patients (0.96; P < 0.001), nonanemic patients (0.93; P < 0.001), and for those obtained from arteriovenous grafts (0.94; P < 0.001). POC INR samples from dialysis catheters correlated poorly with laboratory INR results. CONCLUSIONS: POC INR correlates well with plasma INR measures in IHD patients requiring chronic warfarin, and anemia did not influence this reliability. Blood sampling from finger stick or arteriovenous graft or fistula showed excellent correlation with laboratory INR, whereas sampling from dialysis catheters was unsatisfactory, likely from heparin contamination.

Left ventricular function and heart failure in myocardial infarction: impact of the new definition in the community.

OBJECTIVES: The aim of this study is to evaluate ventricular function and the occurrence of heart failure (HF) among persons with myocardial infarction (MI) meeting only troponin criteria compared to persons meeting creatine kinase and its MB fraction (CK-MB) criteria. BACKGROUND: The 2000 American College of Cardiology/European Society of Cardiology MI definition enabled identification of MIs meeting only troponin-based criteria. Data on ventricular function and HF among these are lacking. METHODS: Between November 2002 and May 2006, we prospectively identified 835 persons with MI in the community using standardized criteria including cardiac pain, electrocardiogram, and biomarkers. Troponin and CK-MB were prospectively measured in all; each patient was classified according to the criteria met. RESULTS: We performed echocardiograms (median of 1 day post-MI) in 482 patients (age 68+/-15 years; 45% women); 363 patients met CK-MB criteria, whereas 119 met only troponin criteria. The latter had lower wall motion score index (1.3+/-0.4 vs 1.5+/-0.5 for CK-MB; P<.01). Diastolic dysfunction was similar in both groups. After 1 year of follow up, 142 patients developed post-MI HF. Patients meeting only troponin criteria had a lower risk of HF after adjustment for age, sex, comorbidity (hazard ratio 0.56, 95% confidence interval 0.37-0.85, P<.01), which persisted after further adjustments for systolic or diastolic function. CONCLUSIONS: In the community, the prospective application of the new MI definition identifies patients meeting only troponin criteria with better systolic function than cases meeting CK-MB criteria. Such MIs have a lower risk of subsequent HF. These findings are important for risk stratification in clinical practice.

Evaluation of the BiliChek noninvasive bilirubin analyzer for prediction of serum bilirubin and risk of hyperbilirubinemia.

We identified clinical and laboratory variables affecting the relationship between transcutaneous and serum bilirubin levels and determined whether transcutaneous bilirubin values could be used to predict the risk of hyperbilirubinemia. Median bias between transcutaneous and diazo serum bilirubin was 2.0 mg/dL (34.2 micromol/L), while median bias between transcutaneous and the Vitros (Ortho Clinical Diagnostics, Rochester, NY) serum bilirubin values was 1.3 mg/dL (22.2 micromol/L). The mother's ethnicity, the gestational age, and postnatal age did not impact the relationship between transcutaneous and serum bilirubin values. In contrast, the serum bilirubin method (diazo vs Vitros) and collection container (clear vs amber tube) significantly impacted the relationship between transcutaneous and serum bilirubin values. Transcutaneous bilirubin was a sensitive but not specific predictor of the risk of hyperbilirubinemia using a conventional risk nomogram. Because systematic differences between serum bilirubin methods and local laboratory practices impact the relationship between transcutaneous and serum bilirubin values, the effectiveness of transcutaneous prediction of the serum bilirubin risk zone will vary by institution.

Accuracy of capillary whole blood international normalized ratio on the CoaguChek S, CoaguChek XS, and i-STAT 1 point-of-care analyzers.

We evaluated the accuracy of capillary whole blood international normalized ratio (INR) on the CoaguChek S (Roche Diagnostics, Indianapolis, IN), CoaguChek XS (Roche Diagnostics), and i-STAT 1 (i-STAT, East Windsor, NJ) point-of-care (POC) analyzers compared with venous plasma INRs determined by a reference laboratory method. Overall agreement between POC and laboratory plasma INR was very good, with median bias between capillary whole blood and laboratory plasma INRs varying from 0.0 to -0.2 INR units on all devices. More than 90% of results on the CoaguChek XS and i-STAT 1 and 88% of CoaguChek S results were within 0.4 INR units of the reference laboratory method. The CoaguChek XS and i-STAT 1 demonstrated greater accuracy than the CoaguChek S as measured by the number of results that differed by more than 0.5 INR units from the reference method. Median bias between CoaguChek S capillary whole blood and laboratory plasma INRs changed over time, demonstrating the need for ongoing quality assurance measures for POC INR programs.

In-patient international normalized ratio self-testing instruction after mechanical heart valve implantation.

BACKGROUND: Patient self-testing of the international normalized ratio (INR) has been shown to improve management of anticoagulation with warfarin and reduce risks of thromboembolism and bleeding. Self-testing instruction usually begins several weeks after hospital discharge. We evaluated the feasibility of in-hospital INR self-testing instruction in patients recovering from valve replacement. METHODS: We instituted an education program on a self-testing device before hospital discharge in 50 adult patients (median age, 54 years; 66% men) undergoing cardiac valve replacement with mechanical prostheses. Patients were monitored for 1 month to assess their ability to self-test and the accuracy of the INR measurements. RESULTS: Self-testing instruction began on postoperative day 4 (range, 1 to 8 days). Each patient had an average of 3.5 teaching sessions; each session lasted approximately 20 minutes. One month after discharge, all patients (98%) but 1 were able to self-test. No patient required interval instruction. One bleeding episode occurred in a patient whose INR exceeded the therapeutic range. Once warfarin doses were stabilized, 5 patients had subtherapeutic INR values on self-testing. The mean INR test result obtained from the coagulometer correlated well with values obtained by laboratory determination (r = 0.79). CONCLUSIONS: This evaluation of an in-hospital education program demonstrates that patients are able to learn INR self-testing and that most will continue to use the method without the need for interval instruction. Improved anticoagulation management by early introduction of INR self-testing should reduce thromboembolic and hemorrhagic complications after valve replacement.

Aspirin responsiveness in healthy volunteers measured with multiple assay platforms.

BACKGROUND: We evaluated the sensitivity, precision, and concordance of 4 assays designed to detect aspirin responsiveness or resistance. METHODS: Twenty-nine healthy laboratory volunteers took 80 mg aspirin for 7 days, and a subset of volunteers took 325 mg aspirin for an additional 7 days. We measured platelet function by light transmission aggregometry with arachidonic acid, PFA-100, and VerifyNow. PFA-100 and VerifyNow assays were performed in duplicate to assess method imprecision. Some volunteers had samples taken within 2-4 h of the final dose of aspirin and again within 20-24 h of the final dose. We measured urinary 11-dehydro-thromboxane B(2) at baseline and after 80 or 325 mg aspirin. RESULTS: No volunteers were nonresponsive to aspirin therapy as measured by the PFA-100. One of 29 participants demonstrated lack of response to aspirin as measured by VerifyNow and urinary 11-dehydro-thromboxane B(2); 2 of 29 demonstrated lack of response as measured by light transmission aggregometry. Imprecision was <10% for the PFA-100 and VerifyNow. Concordance was high (>90%) between all assays. Neither aspirin dose (80 vs 325 mg) nor timing between final dose of aspirin and blood draw (2-4 vs 20-24 h) affected any of the assays. CONCLUSIONS: Light transmission aggregometry, PFA-100, VerifyNow, and urinary 11-dehydro-thromboxane B(2) are all sensitive to the effects of aspirin in healthy individuals. Variables such as aspirin dose, timing between final dose of aspirin and blood collection, and imprecision do not affect the ability of the assays to detect aspirin effect on platelet function.

Evaluation of the impact of hematocrit and other interference on the accuracy of hospital-based glucose meters.

BACKGROUND: Most glucose meter comparisons to date have focused on performance specifications likely to impact subcutaneous dosing of insulin. We evaluated four hospital-based glucose meter technologies for accuracy, precision, and analytical interferences likely to be encountered in critically ill patients, with the goal of identifying and discriminating glucose meter performance specifications likely to impact intensive intravenous insulin dosing. METHODS: Precision, both within-run and day-to-day, was evaluated on all four glucose meters. Accuracy (bias) of the meters and analytical interference were evaluated by comparing results obtained on whole blood specimens to plasma samples obtained from these whole blood specimens run on a hexokinase reference method. RESULTS: Precision was acceptable and differed little between meters. There were significant differences in the degree to which the meters correlated with the reference hexokinase method. Ascorbic acid showed significant interference with three of the four meters. Hematocrit also affected the correlation between whole blood and plasma hexokinase glucose on three of the four glucose meters tested, with the magnitude of this interference also varying by glucose meter technology. CONCLUSIONS: Correlation to plasma hexokinase values and hematocrit interference are the main variables that differentiate glucose meters. Meters that correlate with plasma glucose measured by a reference method over a wide range of glucose concentrations and minimize the effects of hematocrit will allow better glycemic control for critically ill patients.

Comparison of lactate values between point-of-care and central laboratory analyzers.

Measurement of lactate levels is important in the care of critically ill adult and pediatric patients. We compared 3 whole blood lactate methods (Radiometer ABL 725, Radiometer Medical A/S, Bronshoj, Denmark; i-STAT, i-STAT, East Windsor, NJ; and Nova Lactate Plus, Nova Biomedical, Waltham, MA) with 2 plasma-based methods (Roche Integra, Roche Diagnostics, Indianapolis, IN; and Vitros, Ortho Clinical Diagnostics, Rochester, NY). The Vitros LAC slide assay was used as the reference method. Results were compared by least squares regression and Bland-Altmann plots and by comparing concordance within clinically relevant lactate ranges. Correlation between lactate methods was good with slopes between 0.87 and 1.06 and intercepts of 0.9 to 1.8 mg/dL (0.1-0.2 mmol/L) of lactate for all 4 methods compared with the Vitros. At high (>54.1 mg/dL [6 mmol/L]) lactate values, the Radiometer and i-STAT methods reported lower lactate results compared with the Vitros and Integra. The Nova analyzer reported higher lactate results than either the Vitros or Integra. The negative bias in i-STAT and Radiometer results may confound the interpretation of patient condition if multiple methods are used within the same institution.

Accuracy of roche accu-chek inform whole blood capillary, arterial, and venous glucose values in patients receiving intensive intravenous insulin therapy after cardiac surgery.

Intravenous insulin protocols are increasingly common in the intensive care unit to maintain normoglycemia. Little is known about the accuracy of point-of-care glucometers for measuring glucose in this patient population or the impact of sample source (capillary, arterial, or venous whole blood) on the accuracy of glucometer results. We compared capillary, arterial, and venous whole blood glucose values with laboratory plasma glucose values in 20 patients after cardiac surgery. All 4 samples (capillary, arterial, and venous whole blood and laboratory plasma glucose) were analyzed hourly for the first 5 hours during intravenous insulin therapy in the intensive care unit. There were no significant differences between median capillary whole blood (149 mg/dL [8.3 mmol/L]) and laboratory plasma (151 mg/dL [8.4 mmol/L]) glucose levels. The median arterial (161 mg/dL [8.9 mmol/L]) and venous (162 mg/dL [9.0 mmol/L]) whole blood glucose levels were significantly higher than the median laboratory plasma glucose level. Capillary whole blood glucose levels correlate most closely with laboratory plasma glucose levels in patients receiving intensive intravenous insulin therapy after cardiac surgery.

Redefinition of myocardial infarction: prospective evaluation in the community.

BACKGROUND: The 2000 European Society of Cardiology/American College of Cardiology definition for myocardial infarction (MI) combines ischemic symptoms, electrocardiographic changes, and troponin rather than creatine kinase levels. The use of troponins will increase the detection of MI by a magnitude to be quantified, and the clinical acceptance of the new definition is unknown. METHOD AND RESULTS: Subjects presenting to an Olmsted County facility with a troponin T value > or = 0.03 ng/mL between November 2002 and March 2005 were prospectively classified through the use of standardized MI criteria, relying on cardiac pain, Minnesota coding of the ECG, and troponin, creatine kinase, and its MB fraction measured simultaneously. Through the use of dynamic changes in troponin, 538 MIs were identified versus 327 with creatine kinase and 427 with only the MB fraction of creatine kinase. This represents a 74% (95% confidence interval [CI], 69% to 79%) increase above the number of MIs identified with creatine kinase and a 41% (95% CI, 37% to 46%) increase above the number identified with criteria including only its MB fraction. When relying on single values of troponin, increases in the number of MIs were always large but varied widely according to the threshold used for troponin. Cases meeting only troponin-based criteria were less likely to have electrocardiographic ST-segment elevation and had better survival than those identified with previous criteria. Clinician diagnoses mentioned MI in 42% (95% CI, 34% to 49%) of cases meeting only troponin-based criteria versus 74% (95% CI, 69% to 78%) for MIs meeting the previous criteria (P < 0.001). CONCLUSIONS: The prospective application of the new criteria in the community results in a large increase in the number of MIs and a change in case mix. The clinical acceptance of the new criteria is incomplete, and studies that rely exclusively on dismissal diagnoses to assess MI rates may underestimate the burden of disease as presently defined.