Bayesian methods: a potential path forward for sepsis trials

BACKGROUND

Given the success of recent platform trials for COVID-19, Bayesian statistical methods have become an option for complex, heterogenous syndromes like sepsis. However, study design will require careful consideration of how statistical power varies using Bayesian methods across different choices for how historical data are incorporated through a prior distribution and how the analysis is ultimately conducted. Our objective with the current analysis is to assess how different uses of historical data through a prior distribution, and type of analysis influence results of a proposed trial that will be analyzed using Bayesian statistical methods.

METHODS

We conducted a simulation study incorporating historical data from a published multicenter, randomized clinical trial in the US and Canada of polymyxin B hemadsorption for treatment of endotoxemic septic shock. Historical data come from a 179-patient subgroup of the previous trial of adult critically ill patients with septic shock, multiple organ failure and an endotoxin activity of 0.60-0.89. The trial intervention consisted of two polymyxin B hemoadsorption treatments (2 h each) completed within 24 h of enrollment.

RESULTS

In our simulations for a new trial of 150 patients, a range of hypothetical results were observed. Across a range of baseline risks and treatment effects and four ways of including historical data, we demonstrate an increase in power with the use of clinically defensible incorporation of historical data. In one possible trial result, for example, with an observed reduction in risk of mortality from 44 to 37%, the probability of benefit is 96% with a fixed weight of 75% on prior data and 90% with a commensurate (adaptive-weighting) prior; the same data give an 80% probability of benefit if historical data are ignored.

CONCLUSIONS

Using Bayesian methods and a biologically justifiable use of historical data in a prior distribution yields a study design with higher power than a conventional design that ignores relevant historical data. Bayesian methods may be a viable option for trials in critical care medicine where beneficial treatments have been elusive.

Society of Critical Care Medicine Clinical Practice Guidelines for Rapid Sequence Intubation in the Critically Ill Adult Patient

RATIONALE

Controversies and practice variations exist related to the pharmacologic and nonpharmacologic management of the airway during rapid sequence intubation (RSI).

OBJECTIVES

To develop evidence-based recommendations on pharmacologic and nonpharmacologic topics related to RSI.

DESIGN

A guideline panel of 20 Society of Critical Care Medicine members with experience with RSI and emergency airway management met virtually at least monthly from the panel's inception in 2018 through 2020 and face-to-face at the 2020 Critical Care Congress. The guideline panel included pharmacists, physicians, a nurse practitioner, and a respiratory therapist with experience in emergency medicine, critical care medicine, anesthesiology, and prehospital medicine; consultation with a methodologist and librarian was available. A formal conflict of interest policy was followed and enforced throughout the guidelines-development process.

METHODS

Panelists created Population, Intervention, Comparison, and Outcome (PICO) questions and voted to select the most clinically relevant questions for inclusion in the guideline. Each question was assigned to a pair of panelists, who refined the PICO wording and reviewed the best available evidence using predetermined search terms. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was used throughout and recommendations of "strong" or "conditional" were made for each PICO question based on quality of evidence and panel consensus. Recommendations were provided when evidence was actionable; suggestions, when evidence was equivocal; and best practice statements, when the benefits of the intervention outweighed the risks, but direct evidence to support the intervention did not exist.

RESULTS

From the original 35 proposed PICO questions, 10 were selected. The RSI guideline panel issued one recommendation (strong, low-quality evidence), seven suggestions (all conditional recommendations with moderate-, low-, or very low-quality evidence), and two best practice statements. The panel made two suggestions for a single PICO question and did not make any suggestions for one PICO question due to lack of evidence.

CONCLUSIONS

Using GRADE principles, the interdisciplinary panel found substantial agreement with respect to the evidence supporting recommendations for RSI. The panel also identified literature gaps that might be addressed by future research.

Performance of a Standardized Clinical Assay for Urinary C-C Motif Chemokine Ligand 14 (CCL14) for Persistent Severe Acute Kidney Injury

Background

Clinical use of biomarkers requires the development of standardized assays and establishment of cutoffs. Urinary C-C motif chemokine ligand 14 (CCL14) has been validated to predict persistent severe AKI in critically ill patients with established AKI. We now report on the performance of standardized cutoffs using a clinical assay.

Methods

A second aim of the multicenter RUBY Study was to establish two cutoffs for the prediction of persistent severe AKI (defined as KDIGO stage 3 AKI for at least 72 consecutive hours). Patients who received renal replacement therapy (RRT) or died before achieving 72 hours in stage 3 AKI were also considered to have reached the end point.

Results

A cutoff value for urinary CCL14 of 1.3 ng/ml was determined to achieve high sensitivity (91%; 95% CI, 84% to 96%), and 13 ng/ml achieved high specificity (93%; 95% CI, 89% to 96%). The cutoff of 1.3 ng/ml identifies the majority (91%) of patients who developed persistent severe AKI with a negative predictive value of 92%. The cutoff at 13 ng/ml had a positive predictive value of 72% (with a negative predictive value of 75%). In multivariable adjusted analyses, a CCL14 concentration between 1.3 and 13 ng/ml had an adjusted odds ratio (aOR) of 3.82 (95% CI, 1.73 to 9.12; P=0.001) for the development of persistent severe AKI compared with those with a CCL14 ≤1.3 ng/ml, whereas a CCL14 >13 ng/ml had an aOR of 10.4 (95% CI, 3.89 to 29.9; P<0.001).

Conclusions

Using a clinical assay, these standardized cutoffs (1.3 and 13 ng/ml) allow for the identification of patients at high risk for the development of persistent severe AKI. These results have immediate utility in helping to guide AKI patient care and may facilitate future clinical trials.Clinical Trial registry name and registration number: Identification and Validation of Biomarkers of Acute Kidney Injury Recovery, NCT01868724.

Extracorporeal Cardiopulmonary Resuscitation for Refractory Out-of-Hospital Cardiac Arrest (EROCA): Results of a Randomized Feasibility Trial of Expedited Out-of-Hospital Transport

STUDY OBJECTIVE

Outcomes of extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest depend on time to therapy initiation. We hypothesize that it would be feasible to select refractory out-of-hospital cardiac arrest patients for expedited transport based on real-time estimates of the 911 call to the emergency department (ED) arrival interval, and for emergency physicians to rapidly initiate ECPR in eligible patients.

METHODS

In a 2-tiered emergency medical service with an ECPR-capable primary destination hospital, adults with refractory shockable or witnessed out-of-hospital cardiac arrest were randomized 4:1 to expedited transport or standard care if the predicted 911 call to ED arrival interval was less than or equal to 30 minutes. The primary outcomes were the proportion of subjects with 911 call to ED arrival less than or equal to 30 minutes and ED arrival to ECPR flow less than or equal to 30 minutes.

RESULTS

Of 151 out-of-hospital cardiac arrest 911 calls, 15 subjects (10%) were enrolled. Five of 12 subjects randomized to expedited transport had an ED arrival time of less than or equal to 30 minutes (overall mean 32.5 minutes [SD 7.1]), and 5 were eligible for and treated with ECPR. Three of 5 ECPR-treated subjects had flow initiated in less than or equal to 30 minutes of ED arrival (overall mean 32.4 minutes [SD 10.9]). No subject in either group survived with a good neurologic outcome.

CONCLUSION

The Extracorporeal Cardiopulmonary Resuscitation for Refractory Out-of-Hospital Cardiac Arrest trial did not meet predefined feasibility outcomes for selecting out-of-hospital cardiac arrest patients for expedited transport and initiating ECPR in the ED. Additional research is needed to improve the accuracy of predicting the 911 call to ED arrival interval, optimize patient selection, and reduce the ED arrival to ECPR flow interval.

Use of Biomarkers to Identify Acute Kidney Injury to Help Detect Sepsis in Patients With Infection

OBJECTIVES

Although early recognition of sepsis is vital to improving outcomes, the diagnosis may be missed or delayed in many patients. Acute kidney injury is one of the most common organ failures in patients with sepsis but may not be apparent on presentation. Novel biomarkers for acute kidney injury might improve organ failure recognition and facilitate earlier sepsis care.

DESIGN

Retrospective, international, Sapphire study.

SETTING

Academic Medical Center.

PATIENTS

Adults admitted to the ICU without evidence of acute kidney injury at time of enrollment.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We stratified patients enrolled in the Sapphire study into three groups-those with a clinical diagnosis of sepsis (n = 216), those with infection without sepsis (n = 120), and those without infection (n = 387) at enrollment. We then examined 30-day mortality stratified by acute kidney injury within each group. Finally, we determined the operating characteristics for kidney stress markers (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) for prediction of acute kidney injury as a sepsis-defining organ failure in patients with infection without a clinical diagnosis of sepsis at enrollment. Combining all groups, 30-day mortality was 23% for patients who developed stage 2-3 acute kidney injury within the first 3 days compared with 14% without stage 2-3 acute kidney injury. However, this difference was greatest in the infection without sepsis group (34% vs 11%; odds ratio, 4.09; 95% CI, 1.53-11.12; p = 0.005). Using a (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) cutoff of 2.0 units, 14 patients (11.7%), in the infection/no sepsis group, tested positive of which 10 (71.4%) developed stage 2-3 acute kidney injury. The positive test result occurred a median of 19 hours (interquartile range, 0.8-34.0 hr) before acute kidney injury manifested by serum creatinine or urine output. Similar results were obtained using a cutoff of 1.0 for any stage of acute kidney injury.

CONCLUSIONS

Use of the urinary (tissue inhibitor of metalloproteinases-2) × (insulin-like growth factor binding protein 7) test could identify acute kidney injury in patients with infection, possibly helping to detect sepsis, nearly a day before acute kidney injury is apparent by clinical criteria.

Effect of an emergency department intensive care unit on medical intensive unit admissions and care: A retrospective cohort study

OBJECTIVE

Evaluate the impact of an emergency critical care center (EC3) on the admissions of critically ill patients to a critical care medicine unit (CCMU) and their outcomes.

METHODS

This was a retrospective before/after cohort study in a tertiary university teaching hospital. To improve the care of critically ill patients in the emergency department (ED), a 9-bed EC3 was opened in the ED in February 2015. All critically ill patients in the emergency department must receive intensive support in EC3 before being considered for admission to the CCMU for further treatment. Patients from the emergency department account for a significant proportion of the patients admitted to the CCMU. The proportions of patients admitted to the CCMU from the ED were analyzed 1 year before and 1 year after the opening of the EC3. We also compared the admission data, demographic data, APACHE III scores and patient outcomes among patients admitted from ED to the CCMU in the year before and the year after the opening of the EC3.

RESULT

The establishment of the EC3 was associated with a decreased proportion of patients admitted to the CCMU from the ED (OR 0.73 95% CI 0.63-0.84, p < 0.01), a decrease in the proportion of patients with sepsis admitted from the ED (OR 0.68, 95% CI, 0.54-0.87, p < 0.01) and a decrease in the proportion of patients with gastrointestinal bleeding admitted from the ED (OR 0.49, 95% CI 0.28-0.84, p < 0.05). Following the establishment of the EC3, patients admitted to the CCMU had a higher APACHE III score in 2015 (74.85 ± 30.42 vs 72.39 ± 29.64, p = 0.015). Fewer low-risk patients were admitted to the CCMU for monitoring following the opening of the EC3 (112 [6.8%] vs. 181 [9.3%], p < 0.01). Propensity score matching analysis showed that the opening of the EC3 was associated with improved 60-day survival (HR 0.84, 95% CI 0.70-0.99, p = 0.046).

CONCLUSION

Following the opening of the EC3, the proportion of CCMU admissions from the ED decreased. The EC3 may be most effective at reducing the admission of lower-acuity patients with GI bleeding and possibly sepsis. The EC3 may be associated with improved survival in ED patients.

Angiotensin II Infusion for Shock: A Multicenter Study of Postmarketing Use

BACKGROUND

Vasodilatory shock refractory to catecholamine vasopressors and arginine vasopressin is highly morbid and responsible for significant mortality. Synthetic angiotensin II is a potent vasoconstrictor that may be suitable for use in these patients.

RESEARCH QUESTION

What is the safety and effectiveness of angiotensin II and what variables are associated with a favorable hemodynamic response?

STUDY DESIGN AND METHODS

We performed a multicenter, retrospective study at five tertiary medical centers in the United States. The primary end point of hemodynamic responsiveness to angiotensin II was defined as attainment of mean arterial pressure (MAP) of ≥ 65 mm Hg with a stable or reduced total vasopressor dosage 3 h after drug initiation.

RESULTS

Of 270 included patients, 181 (67%) demonstrated hemodynamic responsiveness to angiotensin II. Responders showed a greater increase in MAP (+10.3 mm Hg vs +1.6 mm Hg, P < .001) and reduction in vasopressor dosage (-0.20 μg/kg/min vs +0.04 μg/kg/min; P < .001) compared with nonresponders at 3 h. Variables associated with favorable hemodynamic response included lower lactate concentration (OR 1.11; 95% CI, 1.05-1.17, P < .001) and receipt of vasopressin (OR, 6.05; 95% CI, 1.98-18.6; P = .002). In severity-adjusted multivariate analysis, hemodynamic responsiveness to angiotensin II was associated with reduced likelihood of 30-day mortality (hazard ratio, 0.50; 95% CI, 0.35-0.71; P < .001). Arrhythmias occurred in 28 patients (10%) and VTE was identified in 4 patients.

INTERPRETATION

In postmarketing use for vasopressor-refractory shock, 67% of angiotensin II recipients demonstrated a favorable hemodynamic response. Patients with lower lactate concentrations and those receiving vasopressin were more likely to respond to angiotensin II. Patients who responded to angiotensin II experienced reduced mortality.

Emergency Department-based Intensive Care Unit Use Peaks Near Emergency Department Shift Turnover

Introduction

The Emergency Critical Care Center (EC3) is an emergency department-based intensive care unit (ED-ICU) designed to improve timely access to critical care for ED patients. ED patients requiring intensive care are initially evaluated and managed in the main ED prior to transfer to a separate group of ED-ICU clinicians. The timing of patient transfers to the ED-ICU may decrease the number of handoffs between main ED teams and have an impact on both patient outcomes and optimal provider staffing models, but has not previously been studied. We aimed to analyze patterns of transfer to the ED-ICU and the relationship with shift turnover times in the main ED. We hypothesized that the number of transfers to the ED-ICU increases near main ED shift turnover times.

Methods

An electronic health record search identified all patients managed in the ED and ED-ICU in 2016 and 2017. We analyzed the number of ED arrivals per hour, the number of ED-ICU consults per hour, the time interval from ED arrival to ED-ICU consult, the distribution throughout the day, and the relationship with shift turnover times in the main ED.

Results

A total of 160,198 ED visits were queried, of which 5308 (3.3%) were managed in the ED-ICU. ED shift turnover times were 7 am, 3 pm, and 11 pm. The mean number of ED-ICU consults placed per hour was 221 (85 standard deviation), with relative maximums occurring near ED turnover times: 10:31 pm–11:30 pm (372) and 2:31 pm–3:30 pm (365). The minimum was placed between 7:31 am – 8:30 am (88), shortly after the morning ED turnover time. The median interval from ED arrival time to ED-ICU consult order was 161 minutes (range 6–1,434; interquartile range 144–174). Relative minimums were observed for patients arriving shortly prior to ED turnover times: 4:31 am – 5:30 am (120 minutes [min]), 12:31 pm – 1:30 pm (145 min), and 9:31 pm – 10:30 pm (135 min). Relative maximums were observed for patients arriving shortly after ED turnover times: 7:31 am – 8:30 am (177 min), 4:31 pm – 5:30 pm (218 min), and 11:31 pm – 12:30 am (179 min).

Conclusion

ED-ICU utilization was highest near ED shift turnover times, and utilization was dissimilar to overall ED arrival patterns. Patients arriving immediately prior to ED shift turnover received earlier consults to the ED-ICU, suggesting these patients may have been preferentially transferred to the ED-ICU rather than signed out to the next team of emergency clinicians. These findings may guide operational planning, staffing models, and timing of shift turnover for other institutions implementing ED-ICUs. Future studies could investigate whether an ED-ICU model improves critically ill patients’ outcomes by minimizing ED provider handoffs.

An Emergency Department-Based Intensive Care Unit is Associated with Decreased Hospital and Intensive Care Unit Utilization for Diabetic Ketoacidosis

BACKGROUND

Many emergency department (ED) patients in diabetic ketoacidosis (DKA) are admitted to an inpatient intensive care unit (ICU), while ICU capacity is under increasing strain. The Emergency Critical Care Center (EC3), a hybrid ED-ICU setting, opened with the goal of providing rapid initiation of ICU care in the ED.

OBJECTIVE

We sought to evaluate the impact of an ED-ICU on disposition and safety outcomes for adult ED patients in DKA.

METHODS

This was a retrospective pre-post cohort of ED visits from 2012-2018 at a single academic medical center. Adult ED patients in DKA (pH < 7.30, HCO₃ < 18 mEq/L, anion gap > 14, and glucose > 250 mg/dL) immediately before (pre-EC3) and after (post-EC3) opening of an ED-ICU were identified. ED disposition and safety data were collected and analyzed.

RESULTS

We identified 631 patient encounters: 217 pre-EC3 and 414 post-EC3. Baseline demographics were similar between cohorts. Fewer patients in the post-EC3 cohort were admitted to an ICU (11.6% vs. 23.5%, p < 0.001, number needed to treat [NNT] = 8) or general floor bed (58.0% vs. 73.3%, p < 0.001, NNT = 6), and more were discharged from the ED (27.1% vs. 1.4%, p < 0.001, NNT = 4). Rates of hypokalemia (10.1% vs. 6.0%, p = 0.08) and admission to non-ICU with transfer to ICU within 24 h (0.5% vs. 0%, p = 0.30) did not differ.

CONCLUSION

Management of patients with DKA in an ED-ICU was associated with decreased ICU and hospital utilization with similar safety outcomes. Managing rapidly reversible critical illnesses in an ED-ICU may help obviate increasing strain facing many health care systems.

Association of an Emergency Department-Based Intensive Care Unit With Survival and Inpatient Intensive Care Unit Admissions

IMPORTANCE

Increased patient acuity, decreased intensive care unit (ICU) bed availability, and a shortage of intensivist physicians have led to strained ICU capacity. The resulting increase in emergency department (ED) boarding time for patients requiring ICU-level care has been associated with worse outcomes.

OBJECTIVE

To determine the association of a novel ED-based ICU, the Emergency Critical Care Center (EC3), with 30-day mortality and inpatient ICU admission.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used electronic health records of all ED visits between September 1, 2012, and July 31, 2017, with a documented clinician encounter at a large academic medical center in the United States with approximately 75 000 adult ED visits per year. The pre-EC3 cohort included ED patients from September 2, 2012, to February 15, 2015, when the EC3 opened, and the post-EC3 cohort included ED patients from February 16, 2015, to July 31, 2017. Data analyses were conducted from March 2, 2018, to May 28, 2019.

EXPOSURES

Implementation of EC3, an ED-based ICU designed to provide rapid initiation of ICU-level care in the ED setting and seamless transition to inpatient ICUs.

MAIN OUTCOMES AND MEASURES

The main outcomes were 30-day mortality among ED patients and rate of ED to ICU admission.

RESULTS

A total of 349 310 visits from a consecutive sample of ED patients (mean [SD] age, 48.5 [19.7] years; 189 709 [54.3%] women) were examined; the pre-EC3 cohort included 168 877 visits and the post-EC3 cohort included 180 433 visits. Implementation of EC3 was associated with a statistically significant reduction in risk-adjusted 30-day mortality among all ED patients (pre-EC3, 2.13%; post-EC3, 1.83%; adjusted odds ratio, 0.85; 95% CI, 0.80-0.90; number needed to treat, 333 patient encounters; 95% CI, 256-476). The risk-adjusted rate of ED admission to ICU decreased with implementation of EC3 (pre-EC3, 3.2%; post-EC3, 2.7%; adjusted odds ratio, 0.80; 95% CI, 0.76-0.83; number needed to treat, 179 patient encounters; 95% CI, 149-217).

CONCLUSIONS AND RELEVANCE

Implementation of a novel ED-based ICU was associated with improved 30-day survival and reduced inpatient ICU admission. Additional research is warranted to further explore the value of this novel care delivery model in various health care systems.

Simulation training enables emergency medicine providers to rapidly and safely initiate extracorporeal cardiopulmonary resuscitation (ECPR) in a simulated cardiac arrest scenario

BACKGROUND

Extracorporeal cardiopulmonaryresuscitation (ECPR) is emerging as a viable rescue strategy for refractory out-of-hospital cardiac arrest. In the U.S., limited training of emergency medicine providers is a barrier to widespread implementation.

AIMS

Test the hypothesis that emergency medicine physicians and nurses can acquire and retain the skills to rapidly and safely initiate ECPR using high-fidelity simulation.

STUDY DESIGN

Prospective interventional study.

SETTING

U.S. tertiary academic medical center.

SUBJECTS

Emergency medicine physicians and nurses with no prior ECPR/ECMO experience.

METHODS

Teams of three physicians and three nurses underwent a two-day ECPR training course including didactics, hands-on training, and simulation. Teams were videotaped initiating ECPR in a high-fidelity simulation scenario before and after simulation training. The primary outcome was the proportion of simulations in which full ECPR support was achieved within 30 min of patient arrival.

RESULTS

Five teams completed the entire study. Full ECPR support was achieved within 30 min of patient arrival in 11/15, 15/15, and 15/15 attempts at baseline (B), post-testing (PT) and 3-month post-testing (3-PT), respectively (p = 0.06). Intervals (mean ± sd) required to achieve full ECPR support at B, PT, and 3-PT were 25.8±5.3, 17.2±4.6, and 19.2±1.9 min respectively (p < 0.05 for B vs. PT and 3-PT).

CONCLUSION

High fidelity simulation training is effective in preparing emergency medicine physicians and nurses to rapidly and safely initiate ECPR in a simulated cardiac arrest scenario, and should be considered when implementing an ED-based ECPR program.

The Two-Bag Method for Treatment of Diabetic Ketoacidosis in Adults

BACKGROUND

The "two-bag method" of management of diabetic ketoacidosis (DKA) allows for titration of dextrose delivery by adjusting the infusions of two i.v. fluid bags of varying dextrose concentrations while keeping fluid, electrolyte, and insulin infusion rates constant.

OBJECTIVE

We aimed to evaluate the feasibility and potential benefits of this strategy in adult emergency department (ED) patients with DKA.

METHODS

This is a before-and-after comparison of a protocol using the two-bag method operationalized in our adult ED in 2015. A retrospective electronic medical record search identified adult ED patients presenting with DKA from January 1, 2013 to June 30, 2016. Clinical and laboratory data, timing of medical therapies, and safety outcomes were collected and analyzed.

RESULTS

Sixty-eight patients managed with the two-bag method (2B) and 107 patients managed with the one-bag method (1B) were identified. The 2B and 1B groups were similar in demographics and baseline metabolic derangements, though significantly more patients in the 2B group received care in a hybrid ED and intensive care unit setting (94.1% vs. 51.4%; p < 0.01). 2B patients experienced a shorter interval to first serum bicarbonate ≥ 18 mEq/L (13.4 vs. 20.0 h; p < 0.05), shorter duration of insulin infusion (14.1 vs. 21.8 h; p < 0.05), and fewer fluid bags were charged to the patient (5.2 vs. 29.7; p < 0.01). Frequency of any measured hypoglycemia or hypokalemia trended in favor of the 2B group (2.9% vs. 10.3%; p = 0.07; 16.2% vs. 27.1%; p = 0.09; respectively), though did not reach significance.

CONCLUSIONS

The 2B method appears feasible for management of adult ED patients with DKA, and use was associated with earlier correction of acidosis, earlier discontinuation of insulin infusion, and fewer i.v. fluid bags charged than traditional 1B methods, while no safety concerns were observed.

Practice characteristics of Emergency Department extracorporeal cardiopulmonary resuscitation (eCPR) programs in the United States: The current state of the art of Emergency Department extracorporeal membrane oxygenation (ED ECMO)

PURPOSE

To characterize the current scope and practices of centers performing extracorporeal cardiopulmonary resuscitation (eCPR) on the undifferentiated patient with cardiac arrest in the emergency department.

METHODS

We contacted all US centers in January 2016 that had submitted adult eCPR cases to the Extracorporeal Life Support Organization (ELSO) registry and surveyed them, querying for programs that had performed eCPR in the Emergency Department (ED ECMO). Our objective was to characterize the following domains of ED ECMO practice: program characteristics, patient selection, devices and techniques, and personnel.

RESULTS

Among 99 centers queried, 70 responded. Among these, 36 centers performed ED ECMO. Nearly 93% of programs are based at academic/teaching hospitals. 65% of programs are less than 5 years old, and 60% of programs perform ≤3 cases per year. Most programs (90%) had inpatient eCPR or salvage ECMO programs prior to starting ED ECMO programs. The majority of programs do not have formal inclusion and exclusion criteria. Most programs preferentially obtain vascular access via the percutaneous route (70%) and many (40%) use mechanical CPR during cannulation. The most commonly used console is the Maquet Rotaflow(®). Cannulation is most often performed by cardiothoracic (CT) surgery, and nearly all programs (>85%) involve CT surgeons, perfusionists, and pharmacists.

CONCLUSIONS

Over a third of centers that submitted adult eCPR cases to ELSO have performed ED ECMO. These programs are largely based at academic hospitals, new, and have low volumes. They do not have many formal inclusion or exclusion criteria, and devices and techniques are variable.

Extracorporeal membrane oxygenation (ECMO) for critically ill adults in the emergency department: history, current applications, and future directions

Extracorporeal membrane oxygenation (ECMO) is a mode of extracorporeal life support that augments oxygenation, ventilation and/or cardiac output via cannulae connected to a circuit that pumps blood through an oxygenator and back into the patient. ECMO has been used for decades to support cardiopulmonary disease refractory to conventional therapy. While not robust, there are promising data for the use of ECMO in acute hypoxemic respiratory failure, cardiac arrest, and cardiogenic shock and the potential indications for ECMO continue to increase. This review discusses the existing literature on the potential use of ECMO in critically ill patients within the emergency department.

Age-related differences in biomarkers of acute inflammation during hospitalization for sepsis

The authors aimed to evaluate age-related differences in inflammation biomarkers during the first 72 h of hospitalization for sepsis. This was a secondary analysis of a prospective observational cohort of adult patients (n = 855) from 10 urban academic emergency departments with confirmed infection and two or more systemic inflammatory response syndrome criteria. Six inflammation-related biomarkers were analyzed-chemokine (CC-motif) ligand-23, C-reactive protein, interleukin-1 receptor antagonist, neutrophil gelatinase-associated lipocalin (NGAL), peptidoglycan recognition protein, and tumor necrosis factor receptor-1a (TNFR-1a)-measured at presentation and 3, 6, 12, 24, 48, or 72 h later. The median age was 56 (interquartile range, 43 - 72) years, and sepsis severity was 38% sepsis, 16% severe sepsis without shock, and 46% septic shock; the overall 30-day mortality was 12%. Older age was associated with higher sepsis severity: 41% of subjects aged 18 to 34 years had severe sepsis or septic shock compared with 71% for those aged 65 years or older (P < 0.001). In longitudinal models adjusting for demographics, comorbidities, and infection source, older age was associated with higher baseline values for chemokine (CC-motif) ligand-23, interleukin-1 receptor antagonist, NGAL, and TNFR-1a (all P < 0.05). However, older adults had higher mean values during the entire 72-h period only for NGAL and TNFR-1a and higher final 72-h values only for TNFR-1a. Adjustment or stratification by sepsis severity did not change the age-inflammation associations. Although older adults had higher levels of inflammation at presentation and an increased incidence of severe sepsis and septic shock, these age-related differences in inflammation largely resolved during the first 72 h of hospitalization.

Discovery and validation of cell cycle arrest biomarkers in human acute kidney injury

INTRODUCTION

Acute kidney injury (AKI) can evolve quickly and clinical measures of function often fail to detect AKI at a time when interventions are likely to provide benefit. Identifying early markers of kidney damage has been difficult due to the complex nature of human AKI, in which multiple etiologies exist. The objective of this study was to identify and validate novel biomarkers of AKI.

METHODS

We performed two multicenter observational studies in critically ill patients at risk for AKI - discovery and validation. The top two markers from discovery were validated in a second study (Sapphire) and compared to a number of previously described biomarkers. In the discovery phase, we enrolled 522 adults in three distinct cohorts including patients with sepsis, shock, major surgery, and trauma and examined over 300 markers. In the Sapphire validation study, we enrolled 744 adult subjects with critical illness and without evidence of AKI at enrollment; the final analysis cohort was a heterogeneous sample of 728 critically ill patients. The primary endpoint was moderate to severe AKI (KDIGO stage 2 to 3) within 12 hours of sample collection.

RESULTS

Moderate to severe AKI occurred in 14% of Sapphire subjects. The two top biomarkers from discovery were validated. Urine insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, a key mechanism implicated in AKI, together demonstrated an AUC of 0.80 (0.76 and 0.79 alone). Urine [TIMP-2]·[IGFBP7] was significantly superior to all previously described markers of AKI (P <0.002), none of which achieved an AUC >0.72. Furthermore, [TIMP-2]·[IGFBP7] significantly improved risk stratification when added to a nine-variable clinical model when analyzed using Cox proportional hazards model, generalized estimating equation, integrated discrimination improvement or net reclassification improvement. Finally, in sensitivity analyses [TIMP-2]·[IGFBP7] remained significant and superior to all other markers regardless of changes in reference creatinine method.

CONCLUSIONS

Two novel markers for AKI have been identified and validated in independent multicenter cohorts. Both markers are superior to existing markers, provide additional information over clinical variables and add mechanistic insight into AKI.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT01209169.

Relationship between B-type natriuretic peptide and adverse outcome in patients with clinical evidence of sepsis presenting to the emergency department

OBJECTIVES

Myocardial dysfunction is an important aspect of sepsis pathophysiology. B-type natriuretic peptide (BNP) is a neurohormone released from the ventricles in response to myocardial stretch and volume overload. The authors hypothesized that an elevated BNP in patients presenting to the emergency department (ED) with suspected sepsis are at increased risk for development of adverse events.

METHODS

This was a prospective, observational, multicenter cohort study in 10 EDs. Patients were eligible if they were older than 18 years, had two or more systemic inflammatory response syndrome (SIRS) criteria, and had suspected infection or a serum lactate level > 2.5 mmol/L. Patients were excluded if they were pregnant, had do-not-attempt-resuscitation status, sustained a cardiac arrest prior to hospital arrival, had known chronic renal insufficiency, or were on dialysis. BNP levels were obtained at arrival. The primary outcome was a composite of severe sepsis, septic shock within 72 hours, or in-hospital mortality.

RESULTS

There were 825 patients enrolled (mean ± standard deviation [SD] age = 53.5 ± 19.6 years; 51% were female and 37% were African American). The area under the curve (AUC) for BNP to predict the triple composite outcome was 0.69, and the optimal cut-point of BNP was 49 pg/mL. Patients with a BNP > 49 pg/mL had a greater mortality rate (11.6% vs. 2.1%; p = 0.0001), a greater risk of development of severe sepsis (67.7% vs. 36.8%; p = 0.0001) and septic shock (51.7% vs. 26.4%; p = 0.0001), and a higher rate of the triple composite outcome (69% vs. 37%; unadjusted odds ratio [OR] = 1.9, 95% confidence interval [CI] = 1.6 to 2.1; p < 0.001). The sensitivity was 63% (95% CI = 58% to 67%), specificity was 69% (95% CI = 65% to 73%), negative predictive value (NPV) was 63% (95% CI = 58% to 67%), and positive predictive value (PPV) was 69% (95% CI = 65% to 74%). In multivariate modeling, after adjusting for age, sex, heart rate, white blood cell count, and creatinine, an elevated BNP was associated with increased odds of having the composite outcome. The outcome was similar in the subset of patients who did not have severe sepsis or septic shock upon arrival.

CONCLUSIONS

In patients who present to the ED with SIRS criteria and suspected infection, an elevated BNP is associated with a worse prognosis but has limited diagnostic utility.

Current practice, demographics, and trends of critical care trained emergency physicians in the United States

OBJECTIVES

Critical care medicine (CCM) is of growing interest among emergency physicians (EPs), but the number of CCM-trained EPs and their postfellowship practice is unknown. This study's purpose was to conduct a descriptive census survey of EPs who have completed or are currently in a CCM fellowship.

METHODS

The authors created a Web-based survey, and requests to participate were sent to EPs who have completed or are currently in a CCM fellowship. Responses were collected over a 12-month period. Physicians were located via multiple whom electronic mailing lists, including the Emergency Medicine Section of the Society of Critical Care Medicine, Critical Care Section of the American College of Emergency Physicians, and the Emergency Medicine Residents' Association. The authors also contacted CCM fellowship coordinators and used informal networking. Data were collected on emergency medicine (EM) and other residency training; discipline, duration, and year of CCM fellowship; current practice setting; and board certification status, including the European Diploma in Intensive Care (EDIC).

RESULTS

A total of 104 physicians completed the survey (97% response rate), of whom 73 had completed fellowship at the time of participation, and 31 of whom were in fellowship training. Of those who completed fellowship, 36/73 (49%) practice both EM and CCM, and 45/73 (62%) practice in academic institutions. Multiple disciplines of fellowship were represented: multidisciplinary (39), surgical (28), internal medicine (16), anesthesia (14), and other (4). Together, the CCM fellowships at the University of Maryland R Adams Cowley Shock Trauma Center and the University of Pittsburgh have trained 42% of all EM-CCM physicians, with 38 other institutions training from one to four fellows each. The number of EPs completing CCM fellowships has risen: from 1974 to 1989, 12 EPs; from 1990 to 1999, 15 EPs; and from 2000 to 2007, 43 EPs.

CONCLUSIONS

Emergency physicians are entering CCM fellowships in increasing numbers. Almost half of these EPs practice both EM and CCM.

Antithrombotic therapy for the CardioWest temporary total artificial heart

The CardioWest temporary total artificial heart serves as a viable bridge to orthotopic heart transplantation in patients who are experiencing end-stage refractory biventricular heart failure. This device is associated with a low, albeit still substantial, risk of thrombosis. Platelet interactions with artificial surfaces are complex and result in continuous activation of contact proteins despite therapeutic anticoagulation. We searched the medical literature (publication dates, January 1962-October 2009) in order to evaluate means of mitigating adverse events that have occurred after implantation of the CardioWest temporary total artificial heart.We conclude that the use of a multitargeted antithrombotic approach, involving anticoagulation (bivalirudin and warfarin) and antiplatelet therapy (dipyridamole and aspirin), can mitigate the procoagulative effects of mechanical circulatory assist devices, particularly those that are associated with the CardioWest temporary total artificial heart. Careful monitoring with use of a variant multisystem approach, involving efficacy tests (thrombelastography and light transmittance aggregometry), safety tests (laboratory analyses), and warfarin genomics, may maximize the therapeutic actions and minimize the bleeding risks that are associated with the multitargeted antithrombotic approach. The development and monitoring of individualized antithrombotic regimens require that informed health professionals appreciate the complexities and grasp the hazards that are associated with these therapies.

Effects of hypercapnia on BP in hypoalbuminemic and Nagase analbuminemic rats

STUDY OBJECTIVE

To determine if animals with abnormally low albumin levels are more susceptible to the effects of hypercapnia on BP compared to normal animals.

DESIGN

Prospective, controlled laboratory experiment.

SETTING

University research laboratory.

ANIMALS

Eighteen male Sprague-Dawley rats: 6 rats 10 to 12 weeks old (young Sprague-Dawley [YSD]), 6 rats 6 to 9 months old (old Sprague-Dawley [OSD]), and 6 rats 10 to 12 weeks old (Nagase analbuminemic mutant Sprague-Dawley [NAR]).

METHODS

Under general anesthesia and paralysis, we varied the Paco(2) by changing the respiratory rate on mechanical ventilation. Mean arterial pressure (MAP) was monitored in a continuous fashion. We obtained arterial blood for blood gas and electrolyte analysis, and nitric oxide (NO) production.

RESULTS

OSD rats had reduced serum albumin, while NAR rats were analbuminemic. Although NAR animals had a decreased buffer capacity compared to age-matched control animals (0.010 vs 0.013, p < 0.05), the MAP decreased in an identical fashion in all three groups. NO production increased with hypercapnia but was similar in all three groups. However, NAR rats had consistently higher plasma strong ion gap (2.8 to 4.1 mEq/L greater) compared to either YSD or OSD rats (p < 0.01), and baseline strong ion difference (mean +/- SD) was significantly lower in NAR rats (28.7 +/- 2.1 mEq/L) compared to either YSD rats (33.0 +/- 5.1 mEq/L) or OSD rats (31.2 +/- 5.1 mEq/L) [p < 0.05].

CONCLUSIONS

These findings suggest that analbuminemic or hypoalbuminemic rats are not more susceptible to hypercapnia-induced hemodynamic instability. Baseline values for apparent strong ion difference are lower in NA rats consistent with a reduced buffer base resulting from analbuminemia.

Early goal-directed therapy in severe sepsis and septic shock revisited: concepts, controversies, and contemporary findings

Studies of acute myocardial infarction, trauma, and stroke have been translated into improved outcomes by earlier diagnosis and application of therapy at the most proximal stage of hospital presentation. Most therapies for these diseases are instituted prior to admission to an ICU; this approach to the sepsis patient has been lacking. In response, a trial comparing early goal-directed therapy (EGDT) vs standard care was performed using specific criteria for the early identification of high-risk sepsis patients, verified definitions, and a consensus-derived protocol to reverse the hemodynamic perturbations of hypovolemia, vasoregulation, myocardial suppression, and increased metabolic demands. Five years after the EGDT publication, there has been much discussion generated with regard to the concepts of EGDT, as well as debate fueled regarding diagnostic and therapeutic interventions. However, during this time period further investigations by the primary investigators and others have brought additional contemporary findings. EGDT modulates some of the components of inflammation, as reflected by improved organ function. The end points used in the EGDT protocol, the outcome results, and the cost-effectiveness have subsequently been externally validated, revealing similar or even better findings than those from the original trial. Although EGDT is faced with challenges, a coordinated approach to sepsis management is necessary to duplicate the progress in outcomes seen in patients with conditions such as acute myocardial infarction, stroke, and trauma.

Lactate versus non-lactate metabolic acidosis: a retrospective outcome evaluation of critically ill patients

Introduction

Acid–base abnormalities are common in the intensive care unit (ICU). Differences in outcome exist between respiratory and metabolic acidosis in similar pH ranges. Some forms of metabolic acidosis (for example, lactate) seem to have worse outcomes than others (for example, chloride). The relative incidence of each type of disorder is unknown. We therefore designed this study to determine the nature and clinical significance of metabolic acidosis in critically ill patients.

Methods

An observational, cohort study of critically ill patients was performed in a tertiary care hospital. Critically ill patients were selected on the clinical suspicion of the presence of lactic acidosis. The inpatient mortality of the entire group was 14%, with a length of stay in hospital of 12 days and a length of stay in the ICU of 5.8 days.

Results

We reviewed records of 9,799 patients admitted to the ICUs at our institution between 1 January 2001 and 30 June 2002. We selected a cohort in which clinicians caring for patients ordered a measurement of arterial lactate level. We excluded patients in which any necessary variable required to characterize an acid–base disorder was absent. A total of 851 patients (9% of ICU admissions) met our criteria. Of these, 548 patients (64%) had a metabolic acidosis (standard base excess < -2 mEq/l) and these patients had a 45% mortality, compared with 25% for those with no metabolic acidosis (p < 0.001). We then subclassified metabolic acidosis cases on the basis of the predominant anion present (lactate, chloride, or all other anions). The mortality rate was highest for lactic acidosis (56%); for strong ion gap (SIG) acidosis it was 39% and for hyperchloremic acidosis 29% (p < 0.001). A stepwise logistic regression model identified serum lactate, SIG, phosphate, and age as independent predictors of mortality.

Conclusion

In critically ill patients in which a measurement of lactate level was ordered, lactate and SIG were strong independent predictors of mortality when they were the major source of metabolic acidosis. Overall, patients with metabolic acidosis were nearly twice as likely to die as patients without metabolic acidosis.

Clinical review: the meaning of acid-base abnormalities in the intensive care unit part I - epidemiology

Acid-base abnormalities are common in critically ill patients. Our ability to describe acid-base disorders must be precise. Small differences in corrections for anion gap, different types of analytical processes, and the basic approach used to diagnose acid-base aberrations can lead to markedly different interpretations and treatment strategies for the same disorder. By applying a quantitive acid-base approach, clinicians are able to account for small changes in ion distribution that may have gone unrecognized with traditional techniques of acid-base analysis. Outcome prediction based on the quantitative approach remains controversial. This is in part due to use of various technologies to measure acid-base variables, administration of fluid or medication that can alter acid-base results, and lack of standardized nomenclature. Without controlling for these factors it is difficult to appreciate the full effect that acid-base disorders have on patient outcomes, ultimately making results of outcome studies hard to compare.

Critical Care Medicine Training and Certification for Emergency Physicians

Demand for critical care services is increasing. Unless the supply of intensivists increases, critically ill patients will not have access to intensivists. Recent critical care society recommendations include increased graduate medical education support and expansion of the J-1 visa waiver program for foreign medical graduates. This article proposes additional recommendations, based on strengthening the relationship between emergency medicine and critical care medicine. Critical care is a continuum that includes out-of-hospital, emergency department (ED), and ICU care teams. Both emergency medicine and critical care medicine require expertise in treating life-threatening acute illness, with many critically ill patients often presenting first to the ED. Increased patient volumes and acuity have resulted in longer ED lengths of stay and more critical care delivery in the ED. However, the majority of critical care medicine fellowships do not accept emergency medicine residents, and those who do successfully complete a fellowship do not have access to a US certification examination in critical care medicine. Despite these barriers, interest in critical care medicine training among emergency physicians is increasing. Dual emergency medicine- and critical care medicine-trained physicians will not only help alleviate the intensivist shortage but also strengthen critical care delivery in the ED and facilitate coordination at the ED-ICU interface. We therefore propose that all accreditation bodies work cooperatively to create a route to critical care medicine certification for emergency physicians who complete a critical care fellowship.

Critical care medicine training and certification for emergency physicians*

Demand for critical care services is increasing. Unless the supply of intensivists increases, critically ill patients will not have access to intensivists. Recent critical care society recommendations include increased graduate medical education support and expansion of the J-1 visa waiver program for foreign medical graduates. This article proposes additional recommendations, based on strengthening the relationship between emergency medicine and critical care medicine. Demand for critical care services is increasing. Unless the supply of intensivists increases, critically ill patients will not have access to intensivists. Recent critical care society recommendations include increased graduate medical education support and expansion of the J-1 visa waiver program for foreign medical graduates. This article proposes additional recommendations, based on strengthening the relationship between emergency medicine (EM) and critical care medicine (CCM). Critical care is a continuum that includes prehospital, emergency department (ED), and intensive care unit (ICU) care teams. Both EM and CCM require expertise in treating life-threatening acute illness, with many critically ill patients often presenting first to the ED. Increased patient volumes and acuity have resulted in longer ED lengths of stay and more critical care delivery in the ED. However, the majority of CCM fellowships do not accept EM residents, and those who successfully complete a fellowship do not have access to a U.S. certification exam in CCM. Despite these barriers, interest in CCM training among EM physicians is increasing. Dual EM/CCM-trained physicians not only will help alleviate the intensivist shortage but also will strengthen critical care delivery in the ED and facilitate coordination at the ED-ICU interface. We therefore propose that all accreditation bodies work cooperatively to create a route to CCM certification for emergency physicians who complete a critical care fellowship.

Acid–base and electrolyte analysis in critically ill patients: are we ready for the new millennium?

PURPOSE OF REVIEW

Disorders of acid-base and electrolytes are commonly seen in critically ill patients. The presence of these disorders typically signals the development of an underlying pathology. These disturbances can be severe and are often associated with worse outcome. Indeed, metabolic acidosis is one of the ways we quantify organ failure. Although acid-base and electrolyte disorders may be a result of the underlying pathophysiology (eg, renal failure, respiratory failure, shock), they may also result from the way in which we manage critically ill patients.

RECENT FINDINGS

The application of the physical-chemical approach to acid-base analysis has led to recent developments in the identification and quantification and understanding of mechanisms for acid-base disorders commonly found in critically ill patients. Examples include a better understanding of the role of electrolytes (especially sodium and chloride) and weak acids in the pathophysiology of acid-base disorders, the implication of acid-base derangements on the inflammatory process and organ perfusion, and the importance of resuscitation fluid composition.

SUMMARY

By adopting a physical-chemical approach to acid-base analysis we are gaining insight to the complexities of acid-base disorders and how their treatments may affect outcome.