Point-of-care testing at triage decreases time to lactate level in septic patients

Portable Near-Infrared Fluorometer for a Liposomal Blood Lactate Assay

In sepsis, plasma lactate is a key biomarker of disease severity, prognosis, and treatment success. However, the median time to result for clinical lactate tests is 3 h. We recently reported a near-infrared fluorescent (NIRF) blood lactate assay that relies on a two-step enzymatic reaction in a liposomal reaction compartment. This assay was optimized in human blood and was capable of quantifying lactate in fresh capillary blood from human volunteers at clinically relevant concentrations in 2 min. However, these studies were performed with a tabletop fluorescence plate reader. For translation to the point of care, the liposomal lactate assay needs to be combined with a small portable NIR fluorometer. Portable NIR fluorometers were successfully used for the analysis of skin and soil samples, but reports for blood metabolite assays are scarce. We aimed at testing the performance of the liposomal lactate assay in combination with a commercial small portable NIR fluorometer. First, we tested the fluorophore of the liposomal lactate assay using the NIR dye sulfo-cyanine 7; we observed strong fluorescence signals and high linearity. Second, we performed the liposomal lactate assay in lactate-spiked human arterial blood using the portable fluorometer as the detector and observed strong and highly linear lactate sensing at clinically relevant lactate concentrations after 2 min. Finally, spiking fresh mouse blood with three clinically relevant lactate concentrations led to a significantly different response to all three concentrations after 5 min. These results highlight the usefulness of the tested portable NIR fluorometer for the liposomal lactate assay and motivate a clinical evaluation of this rapid and easy-to-use lactate assay.

Vesicular Diagnostics: A Spotlight on Lactate- and Ammonia-Sensing Systems

Liposomes are a highly successful drug delivery system with over 15 FDA-approved formulations. Beyond delivering drugs, lipid and polymer vesicles have successfully been used for diagnostic applications. These applications range from more traditional uses, such as releasing diagnostic agents in a controlled manner, to leveraging the unique membrane properties to separate analytes and provide isolated reaction compartments in complex biological matrices. In this Spotlight on Applications, I highlight the complexities in the development and translation of diagnostic vesicles with two case studies, a liposomal reaction compartment for lactate sensing and a transmembrane pH-gradient polymersome for ammonia sensing.

Advanced Triage Protocol: The Role of an Automated Lactate Order in Expediting Rapid Identification of Patients at Risk of Sepsis in the Emergency Department

We undertook a process improvement initiative to expedite rapid identification of potential sepsis patients based on triage chief complaint, vital signs, and initial lactate level.

A Point-of-Care Serum Lactate Level and Mortality in Adult Sepsis Patients: A Community Hospital Setting

Introduction:

Sepsis is a serious and emergency condition that may lead to acute circulatory failure associated with infection. Serum lactate level of over 4 mmol/L is associated with sepsis mortality. However, there is limited data on using a point of care (POC) for fingertip lactate level on sepsis mortality in community hospital setting. This study aimed to evaluate roles of POC for serum lactate with combination of clinical factors on mortality prediction in sepsis patients.

Methods:

This was a retrospective cohort study conducted at 7 community hospitals. The inclusion criteria were adult patients with diagnosis of sepsis who were tested for POC lactate level. Electronic chart reviews of eligible patients were performed. Predictors for mortality were computed using clinical factors and POC lactate level.

Results:

There were 1641 patients met the study criteria. The mortality rate was 8.96% (147 patients). There were 3 independent factors associated with mortality: age, co-morbid diseases, and POC lactate level. The adjusted odds ratio (95% CI) of POC lactate level was 1.025 (1.002, 1.048). The cut point of serum lactate was 1.6 mmol/L gave sensitivity of 79.59% and specificity of 32.10%.

Conclusion:

POC serum lactate level may be associated with mortality in sepsis patients at community hospitals. Lactate level of 1.6 mmol/L may be an indicator for mortality with good sensitivity. Physicians may consider more aggressive and prompt management in individuals with sepsis and POC serum lactate of 1.6 mmol/L or over.

Near-Infrared Fluorescence Hydrogen Peroxide Assay for Versatile Metabolite Biosensing in Whole Blood

In emergency medicine, blood lactate levels are commonly measured to assess the severity and response to treatment of hypoperfusion-related diseases (e.g., sepsis, trauma, cardiac arrest). Clinical blood lactate testing is conducted with laboratory analyzers, leading to a delay of 3 h between triage and lactate result. Here, a fluorescence-based blood lactate assay, which can be utilized for bedside testing, based on measuring the hydrogen peroxide generated by the enzymatic oxidation of lactate is described. To establish a hydrogen peroxide assay, near-infrared cyanine derivatives are screened and sulfo-cyanine 7 is identified as a new horseradish peroxidase (HRP) substrate, which loses its fluorescence in presence of HRP and hydrogen peroxide. As hydrogen peroxide is rapidly cleared by erythrocytic catalase and glutathione peroxidase, sulfo-cyanine 7, HRP, and lactate oxidase are encapsulated in a liposomal reaction compartment. In lactate-spiked bovine whole blood, the newly developed lactate assay exhibits a linear response in a clinically relevant range after 10 min. Substituting lactate oxidase with glucose and alcohol oxidase allows for blood glucose, ethanol, and methanol biosensing, respectively. This easy-to-use, rapid, and versatile assay may be useful for the quantification of a variety of enzymatically oxidizable metabolites, drugs, and toxic substances in blood and potentially other biological fluids.

Sepsis alerts in EMS and the results of pre-hospital ETCO2

BACKGROUND

Field sepsis alerts have the ability to expedite initial ED sepsis treatment. Our hypothesis is that in patients that meet EMS sepsis alert criteria there is a strong relationship between prehospital end-tidal carbon dioxide (ETCO2) readings and the outcome of diagnosed infection.

METHODS

In 2014, our EMS service initiated a protocol requiring hospitals to receive notification of a "sepsis alert" on all suspected sepsis patients. The EMS service transports 70,000 patients/year to a number of urban centers. All patients transported to our major urban teaching hospital by our EMS service in one year in which a sepsis alert was announced were included in this study. The primary outcome variable was diagnosed infection and secondary outcomes were hospital admission, ICU admission and mortality. Positive lactate was defined as >4.0 mmol/L. ROC curve analysis was used to define the best cutoff for ETCO2.

RESULTS

351 patients were announced as EMS sepsis alert patients and transported to our center over a one year period. Positive outcomes were as follows: diagnosed infection in 28% of patients, hospital admission in 63% and ICU admission in 11%. The correlation between lactate and ETCO2 was -0.45. A ROC curve analysis of ETCO2 vs. lactate >4 found that the best cutoff to predict a high lactate was an ETCO2 of 25 or less, which was considered a positive ETCO2 (AUC = 0.73). 27% of patients had a positive ETCO2 and 24% had a positive lactate. A positive ETCO2 predicted a positive lactate with 76% accuracy, 63% sensitivity and 80% specificity. 27% of those with a positive ETCO2 and 44% of those with a positive lactate had a diagnosed infection. 59% of those with a positive ETCO2 and 89% of those with a positive lactate had admission to the hospital. 15% of those with a positive ETCO2 and 18% of those with a positive lactate had admission to the ICU. Neither lactate nor ETCO2 were predictive of an increased risk for diagnosed infection, hospital admission or ICU admission in this patient population.

CONCLUSION

While ETCO2 predicted the initial ED lactate levels it did not predict diagnosed infection, admission to the hospital or ICU admission in our patient population but did predict mortality.

Integrating Point-of-care Testing Into a Community Emergency Department: A Mixed-methods Evaluation

OBJECTIVE

Point-of-care testing (POCT) is a commonly used technology that hastens the time to laboratory results in emergency departments (ED). We evaluated an ED-based POCT program on ED length of stay (LOS) and time to care, coupled with qualitative interviews of local ED stakeholders.

METHODS

We conducted a mixed-methods study (2012-2016) to examine the impact of POCT in a single, community ED. The quantiative analysis involved an observational before-after study comparing time to laboratory test result (POC troponin or POC chemistry) and ED LOS after implementation of POCT, using a propensity-weighted interrupted time series analysis (ITSA). A complementary qualitative analysis involved five semistructured interviews with staff using grounded theory on the benefits and challenges to ED POCT.

RESULTS

A total of 47,399 ED visits were included in the study (24,705 in the preintervention period and 22,694 in the postintervention period). After POCT implementation, overall laboratory testing increased marginally from 61% to 62%. Central laboratory troponin and chemistry declined by > 50% and was replaced by POCT. Prior to POCT implementation, time to troponin and chemistry had declined steadily due to other improvements in laboratory efficiency. After POCT implementation, there was an immediate 20-minute further decline (p < 0.001) in both time to troponin and time to chemistry results using the propensity-weighted comparisons. However, the declining trend observed prior to POCT implementation did not continue at the same rate after implementation. Similarly, prior to POCT implementation, ED LOS declined due to other quality improvements. After POCT implementation, LOS continued declined at a similar rate. Because of this prior trend, the ITSA did not show a significant decline in LOS attributable to POCT. Common benefits of POCT perceived by staff in qualitative interviews included improved quality of care (64%) and reductions in time to test results (44%). Common challenges included concerns over POCT accuracy (32%) and technical barriers (29%).

CONCLUSION

In the study ED, implementation of POCT was associated with a reduction in time to test result for both troponin and chemistry. Local staff felt that faster time to test result improved quality of care; however, concerns were raised with POCT accuracy.

Influence du dosage systématique par biologie délocalisée du lactate sur le temps de passage des patients admis en salle d’accueil des urgences vitales

Objectif : L’objectif de notre étude était d’évaluer l’impact d’un dosage systématique par biologie délocalisée du lactate (DDL) sur le temps de passage en salle d’accueil des urgences vitales (SAUV).

Méthode : Il s’agit d’une étude prospective bicentrique de type avant/après réalisée dans deux services d’urgences universitaires. Deux phases ont été comparées. Lors de la première phase (septembre à décembre 2014), tous les patients d’âge supérieur ou égal à 18 ans orientés dès l’arrivée par l’infirmière organisatrice de l’accueil (IOA) en SAUV ont été inclus et ont bénéficié d’un DDL systématique. Pendant la seconde (mars à avril 2015) phase, pour les patients d’âge supérieur ou égal à 18 ans orientés dès l’arrivée par l’IOA en SAUV, le dosage du lactate a été laissé à l’appréciation du senior responsable et réalisé au laboratoire central.

Résultats : Les données sont exprimées en moyenne ± ET médiane [interquartile]. Huit cent trente-trois patients ont été inclus dont 397 dans la phase 1 et 436 dans la phase 2 (âge moyen de 63 ± 23 vs 59 ± 24 ans, p = 0,03), dont 16%ont été transférés en réanimation. Dans la phase 1 (avec DDL), la valeur moyenne du lactate (n = 397) était de 2,0 ± 1,9 mmol/l et dans la phase 2 (n = 70/436) de 2,2 ± 1,9 mmol/l (p = 0,55). La durée médiane de passage en SAUV n’était pas significativement diminuée avec DDL (165 [95–265] vs 170 [100–260] minutes, p = 0,76).

Conclusion : Notre étude n’a pas pu démontrer que l’introduction d’un DDL systématique réduit le temps de passage des patients admis en SAUV.

Early Point-of-Care Testing at Triage Reduces Care Time in Stable Adult Emergency Department Patients

BACKGROUND

Core laboratory testing may increase length of stay and delay care.

OBJECTIVES

We compared length of emergency department (ED) care in patients receiving point-of-care testing (POCT) at triage vs. traditional core laboratory testing.

METHODS

We conducted a prospective, case-controlled trial of adult patients with prespecified conditions requiring laboratory testing and had POCT performed by a nurse after triage for: a basic metabolic panel, troponin I, lactate, INR (i-STAT System), urinalysis (Beckman Coulter Icon), or urine pregnancy test. Study patients were matched with controls based on clinical condition, gender, age, and time to be seen. Groups were compared with Wilcoxon rank-sum or Fisher's exact tests.

RESULTS

We matched 52 POCT study patients with 52 controls. Groups were similar in age, gender, clinical condition, time to be seen by a physician (3.3 h, 95% confidence interval [CI] 2.2-4.4, vs. 3.1 h, 95% CI 2.2-4.5 h, in POCT and control patients, respectively; p = 0.84), use of imaging, and disposition. Of 52 study patients, 3 (5.8%, 95% CI 2.0-15.9) were immediately transferred to the critical care area to be urgently seen by an emergency physician. POCT patients had a significantly shorter median (interquartile range [IQR]) ED care time than matched controls (7.6, 95% CI 5.1-9.5 vs. 8.5, 6.2-11.3 h, respectively; p = 0.015). Median [IQR] ED length of stay was similar in study patients and controls (9.6, 95% CI 7.9-14.5 vs. 12.5, 8.2-21.2 h, respectively; p = 0.15).

CONCLUSIONS

Among stable adult patients presenting to the ED with one of the prespecified conditions, early POCT at triage, compared with traditional core laboratory testing after evaluation by an ED provider, reduced ED care time by approximately 1 h.

Capillary and venous lactate measurements with a handheld device compared to venous blood-gas analysis for emergency patients

Background/aim

Early identification of lactate levels may have a large impact on triage classification and assist in identifying critically ill patients. A handheld device provides a rapid and timesaving measurement of lactate levels adapted to work in a prehospital care setting. I.e., the device is small, fast, and easy-to-use. The aim of this study was to evaluate the Accutrend Plus handheld lactate analyzer in comparison to the reference in-hospital method.

Methods

Patients triaged as minimum yellow according to the RETTS System (Rapid Emergency Triage and Treatment System) and transported to hospital by ambulance were selected and a written consent to participate was obtained prior to inclusion in the study. Capillary (CAP) and venous (VEN) blood were analyzed with Accutrend Plus (AP). Venous blood samples were analyzed at the local hospital laboratory (GEM premier 4000) within 20 min from sampling. All sampling was conducted by two registered nurses specially trained in prehospital care.

Results

480 lactate measurements were performed in 160 patients. The mean difference between measurements in capillary blood compared with the reference method was 0.7 mmol/L and for venous blood 0.9 mmol/L. The limits of agreement from the Bland-Altman plot was − 0.9 to + 2.5 mmol/L and and − 0.1 to + 1.9 mmol/L, for CAP and VEN compared with GEM.

Conclusion

Our results shows low accuracy and low precision with VEN / CAP measurements of lactate compared to reference GEM.

The Utility of Point-of-Care Testing at Emergency Department Triage by Nurses in Simulated Scenarios

We developed and tested simulated patient scenarios to assess how normal or abnormal point-of-care (POC) test results at triage change prioritization decisions. This was a cross-sectional study where our team developed simulated scenarios and presented them to triage nurses from 3 academic medical centers. Twenty-four scenarios were constructed on the basis of 12 clinical indications from a protocol previously developed by our team. In each scenario, nurses were presented with 2 patients with the same Emergency Severity Index Version 4 (ESI v.4; Agency for Healthcare Research and Quality, Rockville, MD) triage level (Level 2 or Level 3). One of the patients met the inclusion criteria for POC testing under the protocol (cases), whereas the other patient did not (controls). Nurses were asked which of the 2 patients to prioritize first in 3 separate rounds: first without any POC test results, once with abnormal POC test results for case patients, and once with normal POC test results for case patients. Prioritization decisions that changed on the basis of abnormal POC results were defined as "up-triage" and prioritization decisions that changed on the basis of normal results were defined as "down-triage." A total of 39 nurses completed 468 scenarios. In scenarios without any POC test results, 42.3% of case patients were prioritized first. When POC test results were abnormal, 71.6% of cases were prioritized first. When POC test results were normal, 32.7% of case patients were prioritized first. An abnormal POC test resulted in up-triage in 32.5% of the scenarios. When POC test results were normal, there was down-triage in 18.6% of the scenarios. Up- and down-triage rates varied considerably by scenario and clinical indication. Point-of-care testing at emergency department triage results in reasonably high rates of up- and down-triage in simulated scenarios; however, POC tests for specific indications appear to be more useful than others.

A 12-Month Clinical Audit Comparing Point-of-Care Lactate Measurements Tested by Paramedics with In-Hospital Serum Lactate Measurements

Objective

Prehospital point-of-care lactate (pLA) measurement may be a useful tool to assist paramedics with diagnosing a range of conditions, but only if it can be shown to be a reliable surrogate for serum lactate (sLA) measurement. The aim of this study was to determine whether pLA is a reliable predictor of sLA.

Methods

This was a retrospective study of adult patients over a 12-month period who had pLA measured by paramedics in an urban Australian setting and were transported by ambulance to a tertiary hospital where sLA was measured. Patients were excluded if they suffered a cardiopulmonary arrest at any time, had missing data, or if sLA was not measured within 24 hours of arrival. Levels of agreement were determined using methods proposed by Bland and Altman.

Results

A total of 290 patients were transported with a pLA recorded. After exclusions, there were 155 patients (55.0% male; age 71 [SD=18] years) remaining who had sLA recorded within 24 hours. Elevated pLA (>2.0mMol/L) was associated with sLA measurement (76.1% vs 23.9%; OR 3.18; 95% CI, 1.88-5.37; P<.0001). Median time between measurements was 89 minutes (IQR=75). Overall, median pLA was higher than sLA (3.0 [IQR=2.0] mMol/L vs 1.7 [IQR=1.3]; P<.001). Bland-Altman analysis on all participants showed a mean difference of 1.48 mMol/L (95% CI, -3.34 to 6.31). Normal pLA was found to be a true negative in 82.9% of cases, and elevated pLA was a true positive in 48.3% of cases. When the time between measurements was less than 60 minutes (n=25), normal pLA predicted normal sLA with 100% accuracy, with a false-positive rate of 18.2%. As time between measurements increased, accuracy diminished and the false-positive rate increased.

Conclusions

Overall, the level of agreement between pLA and sLA was poor. Accuracy of pLA diminished markedly as the time between the two measurements increased. It may be possible to use pLA as a screening tool; when considered this way, pLA performed much better, though larger prospective trials would be needed to confirm this.

SwanKL, KeeneT, AvardBJ. A 12-month clinical audit comparing point-of-care lactate measurements tested by paramedics with in-hospital serum lactate measurements. Prehosp Disaster Med. 2018;33(1):36–42.

Point-of-care testing (POCT) and evidence-based laboratory medicine (EBLM) - does it leverage any advantage in clinical decision making?

Point-of-care testing (POCT) is the analysis of patient specimens outside the clinical laboratory, near or at the site of patient care, usually performed by clinical staff without laboratory training, although it also encompasses patient self-monitoring. It is able to provide a rapid result near the patient and which can be acted upon immediately. The key driver is the concept that clinical decision making may be delayed when samples are sent to the clinical laboratory. Balanced against this are considerations of increased costs for purchase and maintenance of equipment, staff training, connectivity to the laboratory information system (LIS), quality control (QC) and external quality assurance (EQA) procedures, all required for accreditation under ISO 22870. The justification for POCT depends upon being able to demonstrate that a more timely result (shorter turnaround times (TATs)) is able to leverage a clinically important advantage in decision making compared with the central laboratory (CL). In the four decades since POCT was adapted for the self-monitoring of blood glucose levels by subjects with diabetes, numerous new POCT methodologies have become available, enabling the clinician to receive results and initiate treatment more rapidly. However, these instruments are often operated by staff not trained in laboratory medicine and hence are prone to errors in the analytical phase (as opposed to laboratory testing where the analytical phase has the least errors). In some environments, particularly remote rural settings, the CL may be at a considerable distance and timely availability of cardiac troponins and other analytes can triage referrals to the main centers, thus avoiding expensive unnecessary patient transportation costs. However, in the Emergency Department, availability of more rapid results with POCT does not always translate into shorter stays due to other barriers to implementation of care. In this review, we apply the principles of evidence-based laboratory medicine (EBLM) looking for high quality systematic reviews and meta-analyses, ideally underpinned by randomized controlled trials (RCTs), looking for evidence of whether POCT confers any advantage in clinical decision making in different scenarios.

Prognostic Factors in Emergency Department Patients with Glyphosate Surfactant Intoxication: Point-of-Care Lactate Testing

An increasing number of suicide attempts involve the ingestion of glyphosate surfactant; hence, clinical toxicologists may encounter severe cases of glyphosate surfactant intoxication. In several other clinical conditions, serum lactate is used to predict outcome. We investigated the relationship between lactate levels and 30-day mortality from glyphosate surfactant poisoning. This retrospective analysis involved 232 patients who were admitted to the emergency department after acute glyphosate surfactant poisoning between January 2004 and June 2014. We used a receiver operating characteristic (ROC) curve to define the optimal cut-off point for lactate levels. A Kaplan-Meier 30-day survival curve was then analysed in terms of the defined cut-off level. We used multi-variate Cox proportional hazards regression analysis to determine the risk factors for 30-day mortality. Of the 232 patients, 29 died, yielding a case fatality rate of 12.5%. Lactate was significantly higher in non-survivors (6.5 ± 3.1 mmol/L) than in survivors (3.3 ± 2.2 mmol/L; p < 0.001), and elevated lactate was significantly associated with 30-day mortality. The area under the ROC curve of lactate levels was 0.836 [95% confidence interval (CI): 0.716-0.869]. Lactate levels higher than 4.7 mmol/L were associated with increased mortality in multi-variable analysis (hazard ratio: 3.2; 95% CI: 1.1-8.7). Besides lactate, age >59 years, corrected QT interval >495 ms and potassium >5.5 mmol/L were independent risk factors for 30-day mortality. Lactate is an independent predictor of 30-day mortality in patients with glyphosate surfactant poisoning. Early measurement of lactate levels may be a simple and practical way to assess the severity of intoxication.

Comparison between B·R·A·H·M·S PCT direct, a new sensitive point-of-care testing device for rapid quantification of procalcitonin in emergency department patients and established reference methods - a prospective multinational trial

BACKGROUND

Procalcitonin (PCT) is increasingly being used for the diagnostic and prognostic work up of patients with suspected infections in the emergency department (ED). Recently, B·R·A·H·M·S PCT direct, the first high sensitive point-of-care test (POCT), has been developed for fast PCT measurement on capillary or venous blood samples.

METHODS

This is a prospective, international comparison study conducted in three European EDs. Consecutive patients with suspicion of bacterial infection were included. Duplicate determination of PCT was performed in capillary (fingertip) and venous whole blood (EDTA), and compared to the reference method. The diagnostic accuracy was evaluated by correlation and concordance analyses.

RESULTS

Three hundred and three patients were included over a 6-month period (60.4% male, median age 65.2 years). The correlation between capillary or venous whole blood and the reference method was excellent: r2=0.96 and 0.97, sensitivity 88.1% and 93.0%, specificity 96.5% and 96.8%, concordance 93% and 95%, respectively at a 0.25 μg/L threshold. No significant bias was observed (-0.04 and -0.02 for capillary and venous whole blood) although there were 6.8% and 5.1% outliers, respectively. B·R·A·H·M·S PCT direct had a shorter time to result as compared to the reference method (25 vs. 144 min, difference 119 min, 95% CI 110-134 min, p<0.0001).

CONCLUSIONS

This study found a high diagnostic accuracy and a faster time to result of B·R·A·H·M·S PCT direct in the ED setting, allowing shortening time to therapy and a more wide-spread use of PCT.

Alcohol consumption decreases lactate clearance in acutely injured patients

INTRODUCTION

Alcohol, a common risk factor for injury, has direct toxic effects on the liver. The use of lactate clearance has been well described as an indicator of the adequacy of resuscitation in injured patients. We investigated whether acutely injured patients with positive blood alcohol content (+BAC) had less lactate clearance than sober patients.

METHODS

We conducted a retrospective cohort study of acutely injured patients treated at an urban Level 1 trauma centre between January 2010 and December 2012. Blood alcohol and venous lactate levels were measured on all patients at the time of arrival. Study subjects were patients transported directly from the scene of injury, who had an elevated lactate concentration on arrival (≥3.0mmol/L) and at least one subsequent lactate measurement within 24h after admission. Lactate clearance ([Lactate1-Lactate2]/Lactate1) was calculated for all patients. Chi-squared tests were used to compare values from sober and intoxicated subjects. Lactate clearance was plotted against alcohol levels and stratified by age and Injury Severity Score (ISS).

RESULTS

Serial lactate concentration measurements were obtained in 3910 patients; 1674 of them had +BAC. Patients with +BAC were younger (mean age: 36.6 [SD 14.7] vs 41.0 [SD 19.9] years [p=0.0001]), were more often male (83.4% vs 75.9% [p=0.0001]), had more minor injuries (ISS<9) (33.8% vs 27.1% [p=0.0001]), had a lower in-hospital mortality rate (1.4% vs 3.9% [p=0.0001]), but also had lower average lactate clearance (37.8% vs 47.6% [p=0.0001]). The lactate clearance of the sober patients (47.6 [SD 33.5]) was twice that of those with +BAC >400 (23.5 [SD 6.5]). Lactate clearance decreased with increasing BAC irrespective of age and ISS.

CONCLUSIONS

In a large group of acutely injured patients, a dose-dependent decrease in lactate clearance was seen in those with elevated BAC. This relationship will cause a falsely elevated lactate reading or prolong lactate clearance and should be taken into account when evaluating patients with +BAC.

Prehospital Lactate Measurement by Emergency Medical Services in Patients Meeting Sepsis Criteria

Introduction

We aimed to pilot test the delivery of sepsis education to emergency medical services (EMS) providers and the feasibility of equipping them with temporal artery thermometers (TATs) and handheld lactate meters to aid in the prehospital recognition of sepsis.

Methods

This study used a convenience sample of prehospital patients meeting established criteria for sepsis. Paramedics received education on systemic inflammatory response syndrome (SIRS) criteria, were trained in the use of TATs and hand-held lactate meters, and enrolled patients who had a recent history of infection, met ≥ 2 SIRS criteria, and were being transported to a participating hospital. Blood lactate was measured by paramedics in the prehospital setting and again in the emergency department (ED) via usual care. Paramedics entered data using an online database accessible at the point of care.

Results

Prehospital lactate values obtained by paramedics ranged from 0.8 to 9.8 mmol/L, and an elevated lactate (i.e. ≥ 4.0) was documented in 13 of 112 enrolled patients (12%). The unadjusted correlation of prehospital and ED lactate values was 0.57 (p< 0.001). The median interval between paramedic assessment of blood lactate and the electronic posting of the ED-measured lactate value in the hospital record was 111 minutes. Overall, 91 patients (81%) were hospitalized after ED evaluation, 27 (24%) were ultimately diagnosed with sepsis, and 3 (3%) died during hospitalization. Subjects with elevated prehospital lactate were somewhat more likely to have been admitted to the intensive care unit (23% vs 15%) and to have been diagnosed with sepsis (38% vs 22%) than those with normal lactate levels, but these differences were not statistically significant.

Conclusion

In this pilot, EMS use of a combination of objective SIRS criteria, subjective assessment of infection, and blood lactate measurements did not achieve a level of diagnostic accuracy for sepsis that would warrant hospital prenotification and committed resources at a receiving hospital based on EMS assessment alone. Nevertheless, this work provides an early model for increasing EMS awareness and the implementation of novel devices that may enhance the prehospital assessment for sepsis. Additional translational research studies with larger numbers of patients and more robust methods are needed.

Cost-effectiveness analysis of early point-of-care lactate testing in the emergency department

PURPOSE

To determine the cost-effectiveness of implementing a point-of-care (POC) Lactate Program in the emergency department (ED) for patients with suspected sepsis to identify patients who can benefit from early resuscitation.

MATERIALS AND METHODS

We constructed a cost-effectiveness model to examine an ED with 30 000 patients annually. We evaluated a POC lactate program screening patients with suspected sepsis for an elevated lactate ≥4 mmol/L. Those with elevated lactate levels are resuscitated and their lactate clearance is evaluated by serial POC lactate measurements. The POC Lactate Program was compared with a Usual Care Strategy in which all patients with sepsis and an elevated lactate are admitted to the intensive care unit. Costs were estimated from the 2014 Medicare Inpatient and National Physician Fee schedules, and hospital and industry estimates.

RESULTS

In the base-case, the POC Lactate Program cost $39.53/patient whereas the Usual Care Strategy cost $33.20/patient. The screened patients in the POC arm resulted in 1.07 quality-adjusted life years for an incremental cost-effectiveness ratio of $31 590 per quality-adjusted life year gained, well below accepted willingness-to-pay-thresholds.

CONCLUSIONS

Implementing a POC Lactate Program for screening ED patients with suspected sepsis is a cost-effective intervention to identify patients responsive to early resuscitation.

Comparison of Result Times Between Urine and Whole Blood Point-of-care Pregnancy Testing

INTRODUCTION

Point-of-care (POC) pregnancy testing is commonly performed in the emergency department (ED). One prior study demonstrated equivalent accuracy between urine and whole blood for one common brand of POC pregnancy testing. Our study sought to determine the difference in result times when comparing whole blood versus urine for the same brand of POC pregnancy testing.

METHODS

We conducted a prospective, observational study at an urban, academic, tertiary care hospital comparing the turnaround time between order and result for urine and whole blood pregnancy tests collected according to standard protocol without intervention from the investigators. After the blood was collected, the nurse would place three drops onto a Beckman Coulter ICON 25 Rapid HCG bedside pregnancy test and set a timer for 10 minutes. At the end of the 10 minutes, the result and time were recorded on an encoded data sheet and not used clinically. The same make and model analyzer was also used for urine tests in the lab located within the ED. The primary outcome was the difference in mean turnaround time between whole blood in the ED and urine testing in the adjacent lab results. Concordance between samples was assessed as a secondary outcome.

RESULTS

265 total patients were included in the study. The use of whole blood resulted in a mean time savings of 21 minutes (95% CI 16-25 minutes) when compared with urine (p<0.001). There was 99.6% concordance between results, with one false negative urine specimen with a quantitative HCG level of 81 mIU/L.

CONCLUSION

Our results suggest that the use of whole blood in place of urine for bedside pregnancy testing may reduce the total result turnaround time without significant changes in accuracy in this single-center study.

Failure to clear elevated lactate predicts 24-hour mortality in trauma patients

BACKGROUND

Lactate clearance is a standard resuscitation goal in patients in nontraumatic shock but has not been investigated adequately as a tool to identify trauma patients at risk of dying. Our objective was to determine if trauma patients with impaired lactate clearance have a higher 24-hour mortality rate than patients whose lactate concentration normalizes.

METHODS

A retrospective chart review identified patients who were admitted directly from the scene of injury to an urban trauma center between 2010 and 2013 and who had at least one lactate concentration measurement within 24 hours. Transfers, patients without lactate measurement, and those who were dead on arrival were excluded. Of the 26,545 screened patients, 18,304 constituted the initial lactate measurement population, and 3,887 were the lactate clearance cohorts.

RESULTS

Initial lactate had an area under the receiver operating characteristic curve of 0.86 and 0.73 for mortality at 24 hours and in the hospital, respectively. An initial concentration of 3 mmol/L or greater had a sensitivity of 0.86 and a specificity of 0.73 for mortality at 24 hours. The mortality rate among patients with elevated lactate concentrations (n = 2,381; 5.6 [2.8] mmol/L) that did not decline to less than 2.0 mmol/L in response to resuscitative efforts (mean [SD] second measurement, 3.7 [1.9] mmol/L) was nearly seven times higher (4.1% vs. 0.6%, p < 0.001) than among those with an elevated concentration (n = 1,506, 5.3 [2.7] mmol/L) that normalized (1.4 [0.4] mmol/L). Logistic regression analysis showed that failure to clear lactate was associated with death more than any other feature (odds ratio, 7.4; 95% confidence interval, 1.5-35.5), except having an Injury Severity Score (ISS) greater than 25 (odds ratio, 8.2; 95% confidence interval, 2.7-25.2).

CONCLUSION

Failure to clear lactate is a strong negative prognostic marker after injury. An initial lactate measurement combined with a second measurement for high-risk individuals might constitute a useful method of risk stratifying injured patients.

LEVEL OF EVIDENCE

Prognostic study, level III.

The accuracy and timeliness of a Point Of Care lactate measurement in patients with Sepsis

BACKGROUND

The aims of this study were to a) compare the lactate measurement of a Point of Care (POC) handheld device to near patient blood gas analysers, and b) determine the differential reporting times between the analysers.

METHODS

A two-staged study; method comparison and prospective observational stages, was conducted. For the first stage, blood samples were analysed on the i-STAT handheld device and the near patient blood gas analysers (GEM 4000 and OMNI S). Results were compared using Pearson correlation coefficient and Bland-Altman tests. For the second stage, we examined the differential reporting times of the POC device compared to the near patient blood gas analysers in two Scottish hospitals. Differential reporting times were assessed using Mann-Whitney test and descriptive statistics were reported with quartiles.

RESULTS

Highly significant Pearson correlation coefficients (0.999 and 0.993 respectively) were found between i-STAT and GEM 4000 and OMNI S. The Bland-Altman agreement method showed bias values of -0.03 and -0.24, between i-STAT and GEM 4000 and OMNI S respectively. Median time from blood draw to i-STAT lactate results was 5 min (Q1-Q3 5-7). Median time from blood draw to GEM 4000 lactate results was 10 min (Q1-Q3 7.75-13). Median time from blood draw to OMNIS lactate results was 11 min (Q1-Q3 8-22). The i-STAT was significantly quicker than both the GEM 4000 and the OMNIS (each p-value < 0.001). In addition, 18 of our study samples were sent to the central laboratory for analysis due to a defect in the lactate module of OMNI S. The median time for these samples from blood draw to availability of the central laboratory results at the clinical area was 133 min.

CONCLUSIONS

The POC handheld device produced accurate, efficient and timely lactate measurements with the potential to influence clinical decision making sooner.

Comprehensive bedside point of care testing in critical ED patients: a before and after study

OBJECTIVE

We determined the effects of comprehensive point-of-care testing (POCT) on process of care in critically ill emergency department (ED) patients. We hypothesized that POCT would shorten ED length of stay (LOS), reduce time to test results, and reduce time to completion of intravenous (IV) contrast computed tomography (CT) imaging compared with central lab testing.

METHODS

A before and after study was performed in ED patients triaged to the critical care area. During the before period, traditional lab testing was performed, whereas in the after period, bedside POCT devices were introduced in all 15 critical care beds with 5 testing cartridges (chemistry with hemoglobin and hematocrit, troponin I, brain natriuretic peptide, lactate, and international normalized ratio [INR]). Clinical protocols indicated when POCT should be used.

RESULTS

The numbers of critical ED patients before and after introducing POCT were 1405 and 981 respectively. Test turnaround (minutes) was significantly reduced with bedside POCT for all five tests. Use of POCT reduced the median [interquartile range] time to completion of IV contrast CT by 81 minutes (96 [55-214] vs 177 [78-300]; P = .004). Point-of-care testing significantly reduced median ED LOS in patients who received an IV contrast CT (260 [180-410] vs 347 [347 (202-523]; P = .03).

CONCLUSIONS

Introduction of comprehensive bedside POCT in critical ED patients is associated with significant reductions in test turnaround, and time to completion of CT scanning when IV contrast is required. ED LOS was also reduced in the latter population.

EMS patients and walk-in patients presenting with severe sepsis: differences in management and outcome

OBJECTIVES

Sepsis is a significant problem. The differences between patients with sepsis who walk into the emergency department (ED) and those who are transported via emergency medical services (EMS) have not been clarified. The aim of the study was to determine whether there was a difference in outcome between patients arriving by EMS and those presenting directly to the ED.

METHODS

We prospectively collected and reviewed a cohort of all cases of severe sepsis and septic shock admitted to the medical intensive care unit from the ED from November 2009 to March 2012. Extracted data were basic demographic information (including mode of ED arrival), clinical data, and treatments. We calculated Systemic Inflammatory Response Syndrome criteria, Acute Physiology and Chronic Health Evaluation II scores, and Sequential Organ Failure Assessment (SOFA) scores. The primary outcome was mortality in severely ill patients with sepsis.

RESULTS

A total of 378 subjects (78%) presented by EMS and 107 subjects were walk-in patients (22%). Patients transported via EMS were older (P < 0.01), had fewer lactates >4 (P < 0.02), a more altered mental status (P < 0.01), and higher respiratory rates (P < 0.05) than did walk-in patients. Patients transported by EMS had worse disease severity when measured by an Acute Physiology and Chronic Health Evaluation II score (P < 0.01) but not by SOFA score. EMS patients had a shorter time to receiving antibiotics (P = 0.02) and central line placement (P < 0.01) than did walk-in patients. In a logistic model, mortality was associated with increasing age (adjusted odds ratio 1.3; 95% confidence interval [CI] 1.2-1.4), higher first-measured ED lactates (1.2; 95% CI 1.1-1.2), and increased initial SOFA score (adjusted odds ratio 1.2; 95% CI 1.1-1.3) but not EMS arrival or prehospital fluids.

CONCLUSIONS

Neither arrival by EMS nor fluid administration by EMS is associated with decreased mortality in severe sepsis.

Portable lactate analyzer for measuring lactate in cerebrospinal fluid (CSF) and plasma - method-comparison evaluations

Increased plasma lactate levels can indicate the presence of metabolic disorders in HIV infected individuals.

OBJECTIVE

To determine whether a portable analyzer is valid for measuring cerebrospinal fluid (CSF) and plasma lactate levels in HIV infected individuals.

METHOD

CSF and plasma were collected from 178 subjects. Samples tested by the Accutrend portable analyzer were compared to those tested by a reference device (SYNCHRON LX 20).

RESULTS

The portable analyzer had in plasma sensitivity of 0.95 and specificity 0.87. For CSF the specificity was 0.95; the sensitivity 0.33; the negative predictive value was 95% and the positive predictive value 33%.

CONCLUSIONS

These findings support the validity of the portable analyzer in measuring lactate concentrations in CSF that fall within the normal range. The relatively poor positive predictive value indicates that a result above the reference range may represent a "false positive test", and should be confirmed by the reference device before concluding abnormality.

Point-of-care testing in the overcrowded emergency department--can it make a difference?

Emergency departments (EDs) face several challenges in maintaining consistent quality care in the face of steadily increasing public demand. Improvements in the survival rate of critically ill patients in the ED are directly related to the advancement of early recognition and treatment. Frequent episodes of overcrowding and prolonged waiting times force EDs to operate beyond their capacity and threaten to impact upon patient care. The objectives of this review are as follows: (a) to establish overcrowding as a threat to patient outcomes, person-centered care, and public safety in the ED; (b) to describe scenarios in which point-of-care testing (POCT) has been found to ameliorate factors thought to contribute to overcrowding; and (c) to discuss how POCT can be used directly, and indirectly, to expedite patient care and improve outcomes. Various studies have shown that overcrowding in the ED has profound effects on operational efficiency and patient care. Several reports have quantified overcrowding in the ED and have described a relationship between heightened periods of overcrowding and delays in treatment, increased incidence of adverse events, and an even greater probability of mortality. In certain scenarios, POCT has been found to increase the number of patients discharged in a timely manner, expedite triage of urgent but non-emergency patients, and decrease delays to treatment initiation. This review concludes that POCT, when used effectively, may alleviate the negative impacts of overcrowding on the safety, effectiveness, and person-centeredness of care in the ED.

Plasma lactate concentrations in septic peritonitis: A retrospective study of 83 dogs (2007-2012)

OBJECTIVE

To determine if absolute plasma lactate concentration or lactate clearance in dogs with septic peritonitis is associated with morbidity or mortality.

DESIGN

Retrospective cohort study from 2007 to 2012.

SETTING

University teaching hospital.

ANIMALS

Eighty-three dogs with septic peritonitis were included. Patients had at least 1 plasma lactate measurement during the course of the hospitalization.

RESULTS

Sixty-four percent of the patients survived to discharge, 22% were euthanized, and 14% died during hospitalization. Plasma lactate concentration >2.5 mmol/L on admission (29% of the patients) was associated with mortality (P = 0.001). Median admission plasma lactate concentration (n = 81) was significantly different between nonsurvivors (2.5 mmol/L, range 0.5-8.4) and survivors (1.4 mmol/L, range 0.5-9.7; P = 0.007). Admission plasma lactate concentration >4 mmol/L yielded a sensitivity of 36% and a specificity of 92% for nonsurvival. The inability to normalize plasma lactate concentration within 6 hours of admission (n = 10/24) yielded a sensitivity of 76% and specificity of 100% for nonsurvival. Postoperative hyperlactatemia (plasma lactate concentration >2 mmol/L; n = 18/76) had a sensitivity of 46% and specificity of 88% for nonsurvival. Persistent postoperative hyperlactatemia (n = 11/18) had a sensitivity of 92% and a specificity of 100% for nonsurvival. Lactate clearance less than 21% at 6 hours (n = 20) had a sensitivity of 54% and specificity of 91% for nonsurvival. Lactate clearance less than 42% at 12 hours (n = 18) had a sensitivity of 82% and a specificity of 100% for nonsurvival.

CONCLUSIONS

Admission plasma lactate concentration and lactate clearance were good prognostic indicators in dogs with septic peritonitis.

Diagnostic characteristics of a clinical screening tool in combination with measuring bedside lactate level in emergency department patients with suspected sepsis

BACKGROUND

Early identification of sepsis and initiation of aggressive treatment saves lives. However, the diagnosis of sepsis may be delayed in patients without overt deterioration. Clinical screening tools and lactate levels may help identify sepsis patients at risk for adverse outcomes.

OBJECTIVES

The objective was to determine the diagnostic characteristics of a clinical screening tool in combination with measuring early bedside point-of-care (POC) lactate levels in emergency department (ED) patients with suspected sepsis.

METHODS

This was a prospective, observational study set at a suburban academic ED with an annual census of 90,000. A convenience sample of adult ED patients with suspected infection were screened with a sepsis screening tool for the presence of at least one of the following: temperature greater than 38°C or less than 36°C, heart rate greater than 90 beats/min, respiratory rate greater than 20 breaths/min, or altered mental status. Patients meeting criteria had bedside POC lactate testing following triage, which was immediately reported to the treating physician if ≥2.0 mmol/L. Demographic and clinical information, including lactate levels, ED interventions, and final diagnosis, were recorded. Outcomes included presence or absence of sepsis using the American College of Chest Physicians/Society of Critical Care Medicine consensus conference definitions and intensive care unit (ICU) admissions, use of vasopressors, and mortality. Diagnostic test characteristics were calculated using 2-by-2 tables with their 95% confidence intervals (CIs). The association between bedside lactate and ICU admissions, use of vasopressors, and mortality was determined using logistic regression.

RESULTS

A total of 258 patients were screened for sepsis. Their mean (± standard deviation [SD]) age was 64 (±19) years; 46% were female, and 82% were white. Lactate levels were 2.0 mmol/L or greater in 80 (31%) patients. Patients were confirmed to meet sepsis criteria in 208 patients (81%). The diagnostic characteristics for sepsis of the combined clinical screening tool and bedside lactates were sensitivity 34% (95% CI = 28% to 41%), specificity 82% (95% CI = 69% to 90%), positive predictive value 89% (95% CI = 80% to 94%), and negative predictive value 23% (95% CI = 17% to 30%). Bedside lactate levels were associated with sepsis severity (p < 0.001), ICU admission (odds ratio [OR] = 2.01; 95% CI = 1.53 to 2.63), and need for vasopressors (OR = 1.54; 95% CI = 1.13 to 2.12).

CONCLUSIONS

Use of a clinical screening tool in combination with early bedside POC lactates has moderate to good specificity but low sensitivity in adult ED patients with suspected sepsis. Elevated bedside lactate levels are associated with poor outcomes.

Monitoring systems and quantitative measurement of biomolecules for the management of trauma

Continued high morbidity and complications due to trauma related hemorrhage underscores the fact that our understanding of the detailed molecular events of trauma are inadequate to bring life-saving changes to practice. The current state of efficacy and advances in biomedical microdevice technology for trauma diagnostics concerning hemorrhage and hemorrhagic shock was considered with respect to vital signs and metabolic biomarkers. Tachycardia and hypotension are markers of hemorrhagic shock in decompensated trauma patients. Base deficit has been predicative of injury severity at hospital admission. Tissue oxygen saturation has been predicative of onset of multiple organ dysfunction syndrome. Blood potassium levels increase with onset of hemorrhagic shock. Lactate is a surrogate for tissue hypoxia and its clearance predicts mortality. Triage glucose measurements have been shown to be specific in predicting major injuries. No vital sign has yet to be proven effective as an independent predictor of trauma severity. Point of care (POC) devices allow for rapid results, easy sample preparation and processing, small sample volumes, small footprint, multifunctional analysis, and low cost. Advances in the field of in-vivo biosensors has provided a much needed platform by which trauma related metabolites can be monitored easily, rapidly and continuously. Multi-analyte monitoring biosensors have the potential to explore areas still undiscovered in the realm of trauma physiology.

Diagnostic accuracy of a single point-of-care prehospital serum lactate for predicting outcomes in pediatric trauma patients

BACKGROUND

Preliminary evidence suggests that a single prehospital lactate level (pLA) improves prediction of morbidity and mortality in adult trauma patients independent of vital signs. However, the value of pLA for pediatric trauma patients is unknown. Our objective was to determine whether pLA is associated with the need for critical care in pediatric trauma patients.

METHODS

We conducted a cohort study of 217 patients transported by helicopter to a level I pediatric trauma center over 24 months. The primary outcome was the need for predefined critical care measures. Covariates included vital signs and Glasgow Coma Scale (GCS) scores documented by prehospital providers.

RESULTS

Forty-one subjects required critical care. Abnormal prehospital vital signs were not associated with need for critical care. Overall, median pLA level for patients who required critical care was 2.1 mmol/L (interquartile range [IQR], 1.6-2.7 mmol/L) versus 1.7 mmol/L (IQR, 1.2-2.2 mmol/L) for those who did not (P = 0.01). In addition, there were 85 subjects who had normal vital signs and a normal GCS during transport. Of these, 11 (13%) required critical care. In the subset of patients with normal prehospital vital signs and GCS, median pLA level for patients who required critical care was 2.6 mmol/L (IQR, 1.8-2.6 mmol/L) versus 1.7 mmol/L (IQR, 1-2.1 mmol/L) for those who did not (P = 0.01).

CONCLUSIONS

Prehospital lactate level was higher in pediatric trauma patients who required critical care, including those who had normal prehospital vital signs and GCS. In this cohort, lactate was an early identifier of children with severe traumatic injuries.

An interprofessional process to improve early identification and treatment for sepsis

The course of sepsis is rapid. Patient outcomes improve when sepsis is diagnosed and treated quickly. The clinical goals of the evidence-based bundled strategies from the International consortium Surviving Sepsis Campaign (SSC) include optimizing timeliness in the delivery of care and creating a continuum for sepsis management that runs from the emergency department (ED) to the acute and critical care settings. Successful implementation of processes that integrate sepsis bundles can improve patient mortality and hospital costs. Improving interprofessional education and collaboration are necessary to facilitate the effective use of bundled strategies. An intervention that included interprofessional education resulted in a statistically significant difference between the three phases studied. There was a statistically significant improvement between the phases for lactate completion X(2) = 16.908 (p < .01) after education. Frequency of blood cultures being obtained before antibiotic administration was nearing statistical significance (p < .054). There was an improvement in time to antibiotic administration between phase 2 (182.09 mean average minutes, SD = 234.06) and phase 3 (91.62 mean average minutes, SD = 167.99).

Accuracy of Handheld Point-of-Care Fingertip Lactate Measurement in the Emergency Department

Introduction: Early recognition of elevated lactate levels in sepsis may hasten the detection of those patients eligible for aggressive resuscitation. Point-of-care (POC) testing is now increasingly available for use in the emergency department (ED). We examined the accuracy and time-saving effect of a handheld POC device for the measurement of fingertip and whole blood lactate as compared with reference laboratory testing in critically ill ED patients.

Methods: A convenience sample of adult ED patients receiving serum lactate testing was prospectively enrolled at an urban, tertiary care US hospital. Consenting patients underwent fingertip POC lactate measurement with a portable device and simultaneous whole blood sampling for analysis by both the POC device and standard laboratory analyzer (“reference method”). Lactate measurements were compared by intraclass correlation (ICC) and Bland and Altman plots. Differences in time to test result were compared by paired t test.

Results: Twenty-four patients, 19 (79%) with sepsis and 21 (88%) with lactate levels below 4 mmol/L, were included from April 2005 to May 2005. Fingertip POC and whole blood POC lactate measurements each correlated tightly with the reference method (ICC = 0.90 and ICC = 0.92, respectively). Mean time between obtaining fingertip lactate samples and whole blood reference lactate samples was 8 ± 13 minutes. Mean time between obtaining POC and reference laboratory lactate results was 65 minutes (95% confidence interval, 30–103).

Conclusion: Fingertip POC lactate measurement is an accurate method to determine lactate levels in infected ED patients with normal or modestly elevated lactate values and significantly decreases time to test results. These findings should be verified in a larger, more critically ill, ED population.

Severe sepsis in pre-hospital emergency care: analysis of incidence, care, and outcome

RATIONALE

Severe sepsis is common and highly morbid, yet the epidemiology of severe sepsis at the frontier of the health care system-pre-hospital emergency care-is unknown.

OBJECTIVES

We examined the epidemiology of pre-hospital severe sepsis among emergency medical services (EMS) encounters, relative to acute myocardial infarction and stroke.

METHODS

Retrospective study using a community-based cohort of all nonarrest, nontrauma King County EMS encounters from 2000 to 2009 who were transported to a hospital.

MEASUREMENTS AND MAIN RESULTS

Overall incidence rate of hospitalization with severe sepsis among EMS encounters, as well as pre-hospital characteristics, admission diagnosis, and outcomes. Among 407,176 EMS encounters, we identified 13,249 hospitalizations for severe sepsis, of whom 2,596 died in the hospital (19.6%). The crude incidence rate of severe sepsis was 3.3 per 100 EMS encounters, greater than for acute myocardial infarction or stroke (2.3 per 100 and 2.2 per 100 EMS encounters, respectively). More than 40% of all severe sepsis hospitalizations arrived at the emergency department after EMS transport, and 80% of cases were diagnosed on admission. Pre-hospital care intervals, on average, exceeded 45 minutes for those hospitalized with severe sepsis. One-half or fewer of patients with severe sepsis were transported by paramedics (n = 7,114; 54%) or received pre-hospital intravenous access (n = 4,842; 37%).

CONCLUSIONS

EMS personnel care for a substantial and increasing number of patients with severe sepsis, and spend considerable time on scene and during transport. Given the emphasis on rapid diagnosis and intervention for sepsis, the pre-hospital interval may represent an important opportunity for recognition and care of sepsis.

End-tidal carbon dioxide is associated with mortality and lactate in patients with suspected sepsis

OBJECTIVE

Exhaled end-tidal carbon dioxide (ETCO(2)) concentration is associated with lactate levels in febrile patients. We assessed the association of ETCO(2) with mortality and lactate levels in patients with suspected sepsis.

METHODS

This was a prospective observational study. We enrolled 201 adult patients presenting with suspected infection and 2 or more systemic inflammatory response syndrome criteria. Lactate and ETCO(2) were measured and analyzed with patient outcomes.

RESULTS

The area under the receiver operator characteristics curve (AUC) was 0.75 (confidence interval [CI], 0.65-0.86) for lactate and mortality and 0.73 (CI, 0.61-0.84) for ETCO(2) and mortality. When analyzed across the different categories of sepsis, the AUCs for lactate and mortality were 0.61 (CI, 0.36-0.87) for sepsis, 0.69 (CI, 0.48-0.89) for severe sepsis, and 0.74 (CI, 0.55-0.93) for septic shock. The AUCs for ETCO(2) and mortality were 0.60 (CI, 0.37-0.83) for sepsis, 0.67 (CI, 0.46-0.88) for severe sepsis, and 0.78 (CI, 0.59-0.96) for septic shock. There was a significant inverse relationship between ETCO(2) and lactate in all categories, with correlation coefficients of -0.421 (P < .001) in the sepsis group, -0.597 (P < .001) in the severe sepsis group, and -0.482 (P = .011), respectively. Adjusted odds ratios were calculated, demonstrating 3 significant predictors of mortality: use of vasopressors 16.4 (95% CI, 1.80-149.2), mechanical ventilation 16.4 (95% CI, 3.13-85.9), and abnormal ETCO(2) levels 6.48 (95% CI, 1.06-39.54).

CONCLUSIONS

We observed a significant association between ETCO(2) concentration and in-hospital mortality in emergency department patients with suspected sepsis across a range of disease severity.

Point-of-care capillary blood lactate measurements in human immunodeficiency virus-uninfected children with in utero exposure to human immunodeficiency virus and antiretroviral medications

OBJECTIVES

To estimate the prevalence of elevated point-of-care (POC) capillary blood lactate concentrations in human immunodeficiency virus (HIV)-exposed, uninfected children (HEU) and to determine if POC lactate varies with in utero antiretroviral (ARV) exposure.

METHODS

The Surveillance Monitoring for Antiretroviral Therapy Toxicities protocol of the Pediatric HIV/AIDS Cohort Study enrolled 1934 children between 2007 and 2009, 0 to 12 years of age, born to HIV-infected mothers. POC lactate was measured annually on capillary blood using the Lactate Pro device. Associations of POC lactate with in utero ARV exposure and other characteristics were evaluated using logistic regression models, adjusting for maternal characteristics and other confounders.

RESULTS

Of 1641 children with POC measurements (median age, 3.0 years), 3.4% had POC lactate >3 mmol/L. Median POC lactate level decreased with age (1.9 mmol/L, 1.7 mmol/L, and 1.6 mmol/L for children 0-<6 months [99% ≤6 weeks of life], 6-<24 months, and ≥24 months of age, respectively; P < 0.001). Prevalence of elevated POC lactate did not differ by in utero ARV exposure drug class, but was significantly higher in children exposed in utero to emtricitabine or efavirenz, cocaine or opiates, and those of white race.

CONCLUSIONS

POC lactate testing is a useful rapid laboratory screening assay for HEU children with ARV exposure. ARV use during pregnancy has resulted in a dramatic decrease in mother-to-child transmission of HIV, and the risk of elevated lactate in HEU children is low. However, as new ARVs and more complex regimens are used during pregnancy by HIV-infected women, continued monitoring for infant toxicities is essential.

Evidence-based diagnostics: adult septic arthritis

BACKGROUND

Acutely swollen or painful joints are common complaints in the emergency department (ED). Septic arthritis in adults is a challenging diagnosis, but prompt differentiation of a bacterial etiology is crucial to minimize morbidity and mortality.

OBJECTIVES

The objective was to perform a systematic review describing the diagnostic characteristics of history, physical examination, and bedside laboratory tests for nongonococcal septic arthritis. A secondary objective was to quantify test and treatment thresholds using derived estimates of sensitivity and specificity, as well as best-evidence diagnostic and treatment risks and anticipated benefits from appropriate therapy.

METHODS

Two electronic search engines (PUBMED and EMBASE) were used in conjunction with a selected bibliography and scientific abstract hand search. Inclusion criteria included adult trials of patients presenting with monoarticular complaints if they reported sufficient detail to reconstruct partial or complete 2 × 2 contingency tables for experimental diagnostic test characteristics using an acceptable criterion standard. Evidence was rated by two investigators using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS). When more than one similarly designed trial existed for a diagnostic test, meta-analysis was conducted using a random effects model. Interval likelihood ratios (LRs) were computed when possible. To illustrate one method to quantify theoretical points in the probability of disease whereby clinicians might cease testing altogether and either withhold treatment (test threshold) or initiate definitive therapy in lieu of further diagnostics (treatment threshold), an interactive spreadsheet was designed and sample calculations were provided based on research estimates of diagnostic accuracy, diagnostic risk, and therapeutic risk/benefits.

RESULTS

The prevalence of nongonococcal septic arthritis in ED patients with a single acutely painful joint is approximately 27% (95% confidence interval [CI] = 17% to 38%). With the exception of joint surgery (positive likelihood ratio [+LR] = 6.9) or skin infection overlying a prosthetic joint (+LR = 15.0), history, physical examination, and serum tests do not significantly alter posttest probability. Serum inflammatory markers such as white blood cell (WBC) counts, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) are not useful acutely. The interval LR for synovial white blood cell (sWBC) counts of 0 × 10(9)-25 × 10(9)/L was 0.33; for 25 × 10(9)-50 × 10(9)/L, 1.06; for 50 × 10(9)-100 × 10(9)/L, 3.59; and exceeding 100 × 10(9)/L, infinity. Synovial lactate may be useful to rule in or rule out the diagnosis of septic arthritis with a +LR ranging from 2.4 to infinity, and negative likelihood ratio (-LR) ranging from 0 to 0.46. Rapid polymerase chain reaction (PCR) of synovial fluid may identify the causative organism within 3 hours. Based on 56% sensitivity and 90% specificity for sWBC counts of >50 × 10(9)/L in conjunction with best-evidence estimates for diagnosis-related risk and treatment-related risk/benefit, the arthrocentesis test threshold is 5%, with a treatment threshold of 39%.

CONCLUSIONS

Recent joint surgery or cellulitis overlying a prosthetic hip or knee were the only findings on history or physical examination that significantly alter the probability of nongonococcal septic arthritis. Extreme values of sWBC (>50 × 10(9)/L) can increase, but not decrease, the probability of septic arthritis. Future ED-based diagnostic trials are needed to evaluate the role of clinical gestalt and the efficacy of nontraditional synovial markers such as lactate.

Out-of-hospital characteristics and care of patients with severe sepsis: a cohort study

PURPOSE

Early recognition and treatment in severe sepsis improve outcomes. However, out-of-hospital patient characteristics and emergency medical services (EMS) care in severe sepsis is understudied. Our goals were to describe out-of-hospital characteristics and EMS care in patients with severe sepsis and to evaluate associations between out-of-hospital characteristics and severity of organ dysfunction in the emergency department (ED).

MATERIALS AND METHODS

We performed a secondary data analysis of existing data from patients with severe sepsis transported by EMS to an academic medical center. We constructed multivariable linear regression models to determine if out-of-hospital factors are associated with serum lactate and sequential organ failure assessment (SOFA) in the ED.

RESULTS

Two hundred sixteen patients with severe sepsis arrived by EMS. Median serum lactate in the ED was 3.0 mmol/L (interquartile range, 2.0-5.0) and median SOFA score was 4 (interquartile range, 2-6). Sixty-three percent (135) of patients were transported by advanced life support providers and 30% (62) received intravenous fluid. Lower out-of-hospital Glasgow Coma Scale score was independently associated with elevated serum lactate (P < .01). Out-of-hospital hypotension, greater respiratory rate, and lower Glasgow Coma Scale score were associated with greater SOFA (P < .01).

CONCLUSIONS

Out-of-hospital fluid resuscitation occurred in less than one third of patients with severe sepsis, and routinely measured out-of-hospital variables were associated with greater serum lactate and SOFA in the ED.

Opportunities for Emergency Medical Services care of sepsis

OBJECTIVE

Emergency Medical Services (EMS) systems play key roles in the rapid identification and treatment of critical illness such as trauma, myocardial infarction and stroke. EMS often provides care for sepsis, a life-threatening sequelae of infection. In this study of Emergency Department patients admitted to the hospital with an infection, we characterized the patients receiving initial care by EMS.

METHODS

We prospectively studied patients with suspected infection presenting to a 50,000 visit urban, academic ED from September 16, 2005-September 30, 2006. We included patients who had abnormal ED vital signs or required hospital admission. We identified patients that received EMS care. Between EMS and non-EMS patients, we compared patient age, sex, nursing home residency, vital signs, comorbidities, source of infection, organ dysfunction, sepsis severity and mortality. We analyzed the data using univariate odds ratios, the Wilcoxon rank-sum test and multivariate logistic regression.

RESULTS

Of 4613 ED patients presenting with serious infections, 1576 (34.2%) received initial EMS care. The mortality rate among those transported by EMS was 126/1576 (8.0%) compared to 67/3037 (2.2%) in those who were not. Adjusted mortality was higher for EMS (OR 1.8, 95% CI: 1.3-2.6). Of patients who qualified for protocolized sepsis care in the ED, 99/162 (61.1%) were transported via EMS. EMS patients were more likely to present with severe sepsis (OR 3.9; 3.4-4.5) or septic shock (OR 3.6; 2.6-5.0). EMS patients had higher sepsis acuity (mortality in ED sepsis score 6 vs. 3, p<0.001).

CONCLUSIONS

EMS provides initial care for over one-third of ED infection patients, including the majority of patients with severe sepsis, septic shock, and those who ultimately die. EMS systems may offer important opportunities for advancing sepsis diagnosis and care.

The feasibility and accuracy of point-of-care lactate measurement in emergency department patients with suspected infection

BACKGROUND

Prior studies show that lactate is a useful prognostic marker in sepsis.

OBJECTIVE

To study the feasibility and accuracy of a point-of-care (POC) analyzer capable of performing bedside serum lactate measurements; and to determine if other measurements (pH, base excess) are predictive of mortality.

METHODS

DESIGN

prospective cohort study of adult (age 18 years or older) Emergency Department (ED) patients with suspected infection during the study period of May 2006 through March 2007.

SETTING

A 55,000-annual-visit urban tertiary care ED.

INTERVENTION

A point-of-care device (i-STAT, Abbott Point of Care Inc., Princeton, NJ) was deployed using a standardized training and quality assurance process. Using POC testing, we measured serum lactate, pH, and base excess, as well as concomitant lactate measurement via a central laboratory.

STATISTICS

Area under the curve (AUC) for receiver operator characteristic curve, Bland-Altman statistics along with a correlation coefficient, and relative risk with 95% confidence intervals reported.

RESULTS

There were 699 patients enrolled, of whom 34 (4.9%) died. The AUCs for mortality prediction were: POC lactate 0.72, laboratory lactate 0.70, pH measurement 0.60, and base excess 0.60. Bland-Altman showed that POC lactate was, on average, 0.32 (95% confidence interval -0.35-0.98) lower than laboratory lactate, with agreement kappa = 0.97.

CONCLUSIONS

A point-of-care testing device provides a reliable and feasible way to measure serum lactate at the bedside. The pH and base excess were less helpful.