Guide to Lung-Protective Ventilation in Cardiac Patients

The incidence of acute respiratory insufficiency has continued to increase among patients admitted to modern-day cardiovascular intensive care units. Positive pressure ventilation (PPV) remains the mainstay of treatment for these patients. Alterations in intrathoracic pressure during PPV has distinct effects on both the right and left ventricles, affecting cardiovascular performance. Lung-protective ventilation (LPV) minimizes the risk of further lung injury through ventilator-induced lung injury and, hence, an understanding of LPV and its cardiopulmonary interactions is beneficial for cardiologists.

Risk of Major Bleeding Associated with Concomitant Direct-Acting Oral Anticoagulant and Clopidogrel Use: A Retrospective Cohort Study

BACKGROUND AND AIM

Combined anticoagulant-antiplatelet therapy is often indicated in adults with cardiovascular disease and atrial fibrillation or venous thromboembolism. The study aim was to assess the comparative risk of bleeding between rivaroxaban and apixaban when combined with clopidogrel.

METHODS

We conducted a retrospective cohort study of commercially insured US adults newly treated with a combination of rivaroxaban+clopidogrel or apixaban+clopidogrel (2015-2018) using Merative™ Marketscan Research Databases. We used propensity score-based inverse probability of treatment weighting (IPTW) to balance the treatment groups. Weighted Cox proportional hazards regression was used to estimate the risk of major bleeding.

RESULTS

The study cohort included 2895 rivaroxaban+clopidogrel users and 3628 apixaban+clopidogrel users. The median (range) duration of follow up was 61 (73) days. Rivaroxaban+clopidogrel users had a similar risk of major bleeding compared with apixaban+clopidogrel users (IPTW incidence rate per 100 person-years 7.96 vs 7.38; IPTW hazard ratio [HR] 1.13 [95% CI 0.78-1.63]). In the subcohort of adults who were treated with DOAC or clopidogrel monotherapy prior to the combined therapy, the risk of major bleeding did not differ by the drug of monotherapy (IPTW HR for rivaroxaban+clopidogrel group: 0.66 [95% CI 0.33-1.32]; IPTW HR for apixaban+clopidogrel group: 1.10 [95% CI 0.55-2.23]) CONCLUSIONS: In our study of commercially insured US adults, the concomitant use of rivaroxaban+clopidogrel and apixaban+clopidogrel conferred a similar risk of major bleeding. DOAC versus clopidogrel monotherapy prior to the concomitant therapy did not influence the risk of major bleeding.

Assessment of the U.S. Food and Drug Administration's risk evaluation and mitigation strategy (REMS) for prasugrel (EFFIENT): A narrative review

Background

Prasugrel, first approved in 2009, was subject to a US Food and Drug Administration (FDA) Risk Evaluation and Mitigation Strategy (REMS) to mitigate the risk of bleeding associated with its use.

Methods

We performed a narrative review of FDA documents obtained through a Freedom of Information Act request. Document classification and primary evidence extraction was performed by three authors (TM, JC, and SL).

Results

The prasugrel REMS consists of a medication guide and a communication plan. Assessment of the REMS was via patient and clinician surveys. 1560 patients were invited to participate and 212 individuals (13.6 %) completed the survey. Rates of awareness among respondents varied across key messages and were highest for those examining the risks of premature discontinuation (96 % and 88 % of respondents), while lower for those regarding the importance of perioperative discontinuation (66 %) and contraindications posed by a history of stroke (16 %) or transient ischemic attack (17 %). Of the 6000 clinicians invited to participate in the survey, 201 (3.4 %) agreed to take part. Four of 11 key risk messages did not meet prespecified acceptable levels of comprehension. No prespecified levels of patient or provider knowledge were required for the retirement of the REMS, which took place on March 23, 2012 based on the sponsor's request.

Conclusions

The prasugrel REMS consisted of passive educational materials whose adequacy was evaluated using highly limited, one-time, cross-sectional surveys. Our assessment adds to evidence suggesting the importance of improving the quality and impact of the FDA's post-approval activities to maximize drug safety.

Abstract 261: Best Practice Advisories Effects On Telemetry Ordering Habits

Background: Inpatient Telemetry detects dysrhythmias. However, data from telemetry influences management on < 1% of patients, and telemetry is often used in cases with no benefit. We are conducting a multi-center study to evaluate the impact of an EMR-based best practice advisory (BPA) on telemetry ordering practice

Methods: To assess the effectiveness of a BPA encouraging cessation of telemetry, we performed an analysis of time on telemetry and the number of BPA alerts before and after October 2019 [Figure 1]. We redesigned the telemetry BPA to restrict firing to the hours of (8 AM to 6 PM) and to restrict notifications to the first call and Attending provider. We used Epic-generated data from 88, 832 unique patient telemetry orders and 121, 621 BPA responses from 3 hospitals. The data was normalized for variation in patients hospitalized over time using admission contact serial numbers (CSN) and inpatient admission orders for non-ICU medicine floors.

Results: We analyzed data from 243,280 BPA alerts. Pre-BPA implementation mean alerts were 150.01 std 43.07 and post BPA implementation mean alerts were 76.33 std 33.461 p-value 0.00. Mean time on telemetry pre BPA 4481.262 mins std 6531.82 post BPA 4311.14 mins std 6011.18 mins p value 0.001

Conclusion: Despite practice standards, telemetry use outside of the ICU varies widely amongst providers. Reduction in the number of telemetry minutes can lead to a decrease in clinician telemetry review time and offer improvement in patient satisfaction and comfort by not being connected to the device.

Improving Risk Prediction for Pulmonary Embolism in COVID‐19 Patients using Echocardiography

SARS‐CoV‐2 infection is associated with increased risk for pulmonary embolism (PE), a fatal complication that can cause right ventricular (RV) dysfunction. Serum D‐dimer levels are a sensitive test to suggest PE, however lacks specificity in COVID‐19 patients. The goal of this study was to identify a model that better predicts PE diagnosis in hospitalized COVID‐19 patients using clinical, laboratory, and echocardiographic imaging predictors. We performed a cross‐sectional study of 302 adult patients admitted to the Johns Hopkins Hospital (March 2020–February 2021) for COVID‐19 infection who underwent transthoracic echocardiography and D‐dimer testing; 204 patients had CT angiography. Clinical, laboratory and imaging predictors including, but not limited to, D‐dimer and RV dysfunction were used to build prediction models for PE using logistic regression. Model discrimination was assessed using area under the receiver operator curve (AUC) and calibration using Hosmer‐Lemeshow χ² statistic. Internal validation was performed. The prevalence of PE was 7.6%. The model with positive D‐dimer above 5 mg/L, RV dysfunction on echocardiography, and troponin had an AUC of 0.77, and cross‐validated AUC of 0.74. D‐dimer (>5 mg/L) had a positive association with PE (adj odds ratio = 4.40; 95% confidence interval: [1.80, 10.78]). We identified a model including clinical, imaging and laboratory variables that predicted PE in hospitalized COVID‐19 patients. Positive D‐dimer >5, RV dysfunction on echocardiography, and troponin were important predictors for calculating likelihood of PE diagnosis. This approach may be useful to aid in clinical decision‐making related to diagnostic imaging and treatment. Prospective studies are needed to evaluate impact on patient outcomes.

Presentation and outcomes of sepsis in the cardiac intensive care unit

The prevalence of sepsis is increasing in subspecialty intensive care units, including the cardiac intensive care unit (CICU). The clinical characteristics and outcomes of CICU patients with sepsis are not well understood. We conducted a retrospective cohort study of sepsis patients in the CICU compared to other ICUs using the PROGRESS registry. CICU-sepsis patients were older with fewer acute organ failures (median 2 v. 3, p < 0.001), lower SOFA scores (median 7 v. 9, p < 0.001), and more comorbidities. The use of fluid resuscitation, mechanical ventilation, and renal replacement were similar. Mortality was 47.3% for CICU-sepsis patients compared to 43.6% for sepsis patients in other ICU (P = 0.37). We conclude that, in a prior cohort of septic patients, sepsis in CICU patients had outcomes that are comparably poor to sepsis in other ICUs. Septic CICU patients presented with fewer acute organ failures, but more chronic comorbidities. Contemporary data as well as novel interventions and investigations targeted specifically to cardiac patients with sepsis should be prioritized.

Myocardial Work Efficiency, A Novel Measure of Myocardial Dysfunction, Is Reduced in COVID-19 Patients and Associated With In-Hospital Mortality

Background: Although troponin elevation is common in COVID-19, the extent of myocardial dysfunction and its contributors to dysfunction are less well-characterized. We aimed to determine the prevalence of subclinical myocardial dysfunction and its association with mortality using speckle tracking echocardiography (STE), specifically global longitudinal strain (GLS) and myocardial work efficiency (MWE). We also tested the hypothesis that reduced myocardial function was associated with increased systemic inflammation in COVID-19. Methods and Results: We conducted a retrospective study of hospitalized COVID-19 patients undergoing echocardiography (n = 136), of whom 83 and 75 had GLS (abnormal >-16%) and MWE (abnormal <95%) assessed, respectively. We performed adjusted logistic regression to examine associations of GLS and MWE with in-hospital mortality. Patients were mean 62 ± 14 years old (58% men). While 81% had normal left ventricular ejection fraction (LVEF), prevalence of myocardial dysfunction was high by STE; [39/83 (47%) had abnormal GLS; 59/75 (79%) had abnormal MWE]. Higher MWE was associated with lower in-hospital mortality in unadjusted [OR 0.92 (95% CI 0.85-0.99); p = 0.048] and adjusted models [aOR 0.87 (95% CI 0.78-0.97); p = 0.009]. In addition, increased systemic inflammation measured by interleukin-6 level was associated with reduced MWE. Conclusions: Subclinical myocardial dysfunction is common in COVID-19 patients with clinical echocardiograms, even in those with normal LVEF. Reduced MWE is associated with higher interleukin-6 levels and increased in-hospital mortality. Non-invasive STE represents a readily available method to rapidly evaluate myocardial dysfunction in COVID-19 patients and can play an important role in risk stratification.

The role of sex and inflammation in cardiovascular outcomes and mortality in COVID-19

OBJECTIVE

Higher mortality in COVID-19 in men compared to women is recognized, but sex differences in cardiovascular events are less well established. We aimed to determine the independent contribution of sex to stroke, myocardial infarction and death in the setting of COVID-19 infection.

METHODS

We performed a retrospective cohort study of hospitalized COVID-19 patients in a racially/ethnically diverse population. Clinical features, laboratory markers and clinical events were initially abstracted from medical records, with subsequent clinician adjudication.

RESULTS

Of 2060 patients, myocardial injury (32% vs 23%, p = 0.019), acute myocardial infarction (2.7% vs 1.6%, p = 0.114), and ischemic stroke (1.8% vs 0.7%, p = 0.007) were more common in men vs women. In-hospital death occurred in 160 men (15%) vs 117 women (12%, p = 0.091). Men had higher odds of myocardial injury (odds ratio (OR) 2.04 [95% CI 1.43-2.91], p < 0.001), myocardial infarction (1.72 [95% CI 0.93-3.20], p = 0.085) and ischemic stroke (2.76 [95% CI 1.29-5.92], p = 0.009). Despite adjustment for demographics and cardiovascular risk factors, male sex predicted mortality (HR 1.33; 95% CI:1.01-1.74; p = 0.041). While men had significantly higher markers of inflammation, in sex-stratified analyses, increase in interleukin-6, C-reactive protein, ferritin and d-dimer were predictive of mortality and myocardial injury similarly in both sexes.

CONCLUSIONS

Adjusted odds of myocardial injury, ischemic stroke and all-cause mortality, but not myocardial infarction, are significantly higher in men compared to women with COVID-19. Higher inflammatory markers are present in men but associated similarly with risk in both men and women. These data suggest that adverse cardiovascular outcomes in men vs. women are independent of cardiovascular comorbidities.

Trends in Therapy and Outcomes Associated With Respiratory Failure in Patients Admitted to the Cardiac Intensive Care Unit

PURPOSE

To describe the epidemiology, outcomes, and temporal trends of respiratory failure in the cardiac intensive care unit (CICU).

MATERIALS AND METHODS

Retrospective cohort analysis of 2,986 unique Mayo Clinic CICU patients from 2007 to 2018 with respiratory failure. Temporal trends were analyzed, along with hospital and 1-year mortality. Multivariable logistic regression was used to determine adjusted hospital mortality trends.

RESULTS

The prevalence of respiratory failure in the CICU increased from 15% to 38% during the study period (P < 0.001 for trend). Among patients with respiratory failure, the utilization of invasive ventilation decreased and noninvasive ventilation modalities increased over time. Hospital mortality and 1-year mortality were 24% and 54%, respectively, with variation according to the type of respiratory support (highest among patients receiving invasive ventilation alone: 35% and 46%, respectively). Hospital mortality was highest among patients with concomitant cardiac arrest and/or shock (52% for patients with both). Hospital mortality decreased in the overall population from 35% to 25% (P < 0.001 for trend), but was unchanged among patients receiving positive-pressure ventilation.

CONCLUSIONS

The prevalence of respiratory failure in CICU more than doubled during the last decade. The use of noninvasive respiratory support increased, while overall mortality declined over time. Cardiac arrest and shock accounted for the majority of deaths. Further research is needed to optimize the outcomes of high-risk CICU patients with respiratory failure.

Rationale and Design of the Aspirin Dosing-A Patient-Centric Trial Assessing Benefits and Long-term Effectiveness (ADAPTABLE) Trial

Importance

Determining the right dosage of aspirin for the secondary prevention treatment of atherosclerotic cardiovascular disease (ASCVD) remains an unanswered and critical question.

Objective

To report the rationale and design for a randomized clinical trial to determine the optimal dosage of aspirin to be used for secondary prevention of ASCVD, using an innovative research method.

Design, Setting, and Participants

This pragmatic, open-label, patient-centered, randomized clinical trial is being conducted in 15 000 patients within the National Patient-Centered Clinical Research Network (PCORnet), a distributed research network of partners including clinical research networks, health plan research networks, and patient-powered research networks across the United States. Patients with established ASCVD treated in routine clinical practice within the network are eligible. Patient recruitment began in April 2016. Enrollment was completed in June 2019. Final follow-up is expected to be completed by June 2020.

Interventions

Participants are randomized on a web platform in a 1:1 fashion to either 81 mg or 325 mg of aspirin daily.

Main Outcomes and Measures

The primary efficacy end point is the composite of all-cause mortality, hospitalization for nonfatal myocardial infarction, or hospitalization for a nonfatal stroke. The primary safety end point is hospitalization for major bleeding associated with a blood-product transfusion. End points are captured through regular queries of the health systems' common data model within the structure of PCORnet's distributed data environment.

Conclusions and Relevance

As a pragmatic study and the first interventional trial conducted within the PCORnet electronic data infrastructure, this trial is testing several unique and innovative operational approaches that have the potential to disrupt and transform the conduct of future patient-centered randomized clinical trials by evaluating treatments integrated in clinical practice while at the same time determining the optimal dosage of aspirin for secondary prevention of ASCVD.

Trial Registration

ClinicalTrials.gov Identifier: NCT02697916.

Transition From an Open to Closed Staffing Model in the Cardiac Intensive Care Unit Improves Clinical Outcomes

Background Several studies have shown improved outcomes in closed compared with open medical and surgical intensive care units. However, very little is known about the ideal organizational structure in the modern cardiac intensive care unit (CICU). Methods and Results We retrospectively reviewed consecutive unique admissions (n=3996) to our tertiary care CICU from September 2013 to October 2017. The aim of our study was to assess for differences in clinical outcomes between an open compared with a closed CICU. We used multivariable logistic regression adjusting for demographics, comorbidities, and severity of illness. The primary outcome was in-hospital mortality. We identified 2226 patients in the open unit and 1770 in the closed CICU. The unadjusted in-hospital mortality in the open compared with closed unit was 9.6% and 8.9%, respectively (P=0.42). After multivariable adjustment, admission to the closed unit was associated with a lower in-hospital mortality (odds ratio [OR], 0.69; 95% CI: 0.53-0.90, P=0.007) and CICU mortality (OR, 0.70; 95% CI, 0.52-0.94, P=0.02). In subgroup analysis, admissions for cardiac arrest (OR, 0.42; 95% CI, 0.20-0.88, P=0.02) and respiratory insufficiency (OR, 0.43; 95% CI, 0.22-0.82, P=0.01) were also associated with a lower in-hospital mortality in the closed unit. We did not find a difference in CICU length of stay or total hospital charges (P>0.05). Conclusions We found an association between lower in-hospital and CICU mortality after the transition to a closed CICU. These results may help guide the ongoing redesign in other tertiary care CICUs.

Incidence, predictors and prognosis of respiratory support in non-ST segment elevation myocardial infarction

BACKGROUND

The incidences of invasive mechanical ventilation and non-invasive ventilation among patients with non-ST segment elevation myocardial infarction and associated prognosis are not well characterized.

METHODS

We conducted a retrospective cohort study of patients with admission diagnosis of non-ST segment elevation myocardial infarction using the US National Inpatient Sample database between 2002-2014. The exposure variable was invasive mechanical ventilation or non-invasive ventilation within 24 h of admission, compared to no respiratory support. The primary outcome was in-hospital mortality. We determined the association between respiratory support and mortality using Cox proportional hazard models.

RESULTS

A total of 4,152,421 non-ST segment elevation myocardial infarction hospitalizations were identified, among whom 1.3% required non-invasive ventilation and 1.9% required invasive mechanical ventilation. Non-invasive ventilation use increased over time (0.4% in 2002 to 2.4% in 2014, p<0.001) while there was no definite trend in invasive mechanical ventilation use. Revascularization was lower for non-ST segment elevation myocardial infarction hospitalizations including invasive mechanical ventilation (23.9%) and non-invasive ventilation (14.5%) compared to 36.5% of those without respiratory support (p<0.001). In-hospital mortality was 3.1% for non-ST segment elevation myocardial infarction without respiratory support compared to 9.2% with non-invasive ventilation (adjusted hazard ratio 1.86, 95% confidence interval 1.74-1.98) and 37.2% with invasive mechanical ventilation (adjusted hazard ratio 3.03, 95% confidence interval 2.88-3.19). Mortality for non-ST segment elevation myocardial infarction-non-invasive ventilation is improving over time while mortality for non-ST segment elevation myocardial infarction-invasive mechanical ventilation is increasing over time.

CONCLUSION

Mechanical respiratory support in non-ST segment elevation myocardial infarction is used in an important minority of cases, is increasing and is independently associated with mortality. Studies of the optimal management of acute coronary syndrome complicated by respiratory failure are needed to improve outcomes.

Racial Disparity in Cardiac Surgery Risk and Outcome: Report From a Statewide Quality Initiative

BACKGROUND

Racial disparities persist in health care. Our study objective was to evaluate racial disparity in cardiac surgery in Maryland.

METHODS

A statewide database was used to identify patients. Demographics, comorbidities, and predicted risk of death were compared between races. Crude mortality and incidence of complications were compared between groups, as were risk-adjusted odds for mortality and major morbidity or mortality.

RESULTS

The study included 23,094 patients. Most patients were white (75.8%), followed by African American (16.3%), Asian (3.8%), and other races (4.1%). African Americans had a higher preoperative risk for mortality based on The Society of Thoracic Surgeons predictive models compared with white patients (3.0% vs 2.3%, P < .001). African Americans also had higher prevalence of diabetes mellitus, hypertension, peripheral vascular disease, and cerebral vascular disease than white patients. After adjustment for preoperative risk, there was no difference in 30-day mortality between African Americans (odds ratio [OR], 1.26; 95% confidence interval [CI], 0.99-1.59), Asians (OR, 1.22; 95% CI, 0.75-1.97), and other races (OR, 1.18; 95% CI, 0.74-1.89) compared with whites. African Americans had lower risk-adjusted odds of major morbidity or mortality compared with whites (OR, 0.83; 95% CI, 0.75-0.93).

CONCLUSIONS

African American cardiac surgical patients have the highest preoperative risk in Maryland. Patients appeared to receive excellent cardiac surgical care, regardless of race, as risk-adjusted mortality did not differ between groups, and African American patients had lower risk-adjusted odds of major morbidity or mortality than white patients. Future interventions in Maryland should be aimed at reducing preoperative risk disparity in cardiac surgical patients.

Noteworthy Literature published in 2017 for Perioperative Echocardiography

In this inaugural review, we present noteworthy advances in perioperative echocardiography relevant to the cardiac anesthesiologist. These studies come from different clinical realms including advances in mitral valve imaging, perioperative echocardiographic evaluation, and critical care echocardiography. The importance of perioperative echocardiography continues to grow with cardiac anesthesiologists positioned in a critical role throughout the perioperative care continuum.

Dynamic Changes in High-Sensitivity Cardiac Troponin I Are Associated with Dynamic Changes in Sum Absolute QRST Integral on Surface Electrocardiogram in Acute Decompensated Heart Failure

BACKGROUND

A three-dimensional electrocardiographic (ECG) metric, the sum absolute QRST integral (SAI QRST), predicts ventricular arrhythmias in heart failure (HF) patients with implantable cardioverter defibrillator and mechanical response to cardiac resynchronization therapy. We hypothesized that there is an association between patient-specific changes in SAI QRST and myocardial injury as measured by high-sensitivity troponin I (hsTnI).

METHODS

Sum absolute integral QRST on resting 12-lead ECG and hsTnI were measured simultaneously, every 3 hours, and during 12-hour observation period in a prospective cohort of emergency department patients (n = 398; mean age 57.8 ± 13.2 years; 54% female, 64% black), diagnosed with acute coronary syndrome (ACS, n = 28), acutely decompensated HF (acute decompensated heart failure, n = 35), cardiac non-ACS (n = 19), or noncardiac condition (n = 316). Random-effects linear regression analysis assessed the association of SAI QRST and myocardial injury, with adjustment for demographics (age, sex, race), prevalent cardiovascular disease (myocardial infarction, history of revascularization, stroke, and HF), risk factors (diabetes, smoking, hypercholesterolemia, hypertension, and cocaine use), and left bundle branch block.

RESULTS

Within the entire cohort, SAI QRST decreased by 3 (95%CI -5 to -1) mV*ms every 3 hours. A 10-fold increase in hsTnI was associated with a 7.7 (0.6-14.9) mV*ms increase in SAI QRST. In the subgroup of acutely decompensated HF patients (n = 35), a 10-fold increase in hsTnI was associated with a 61.0 (5.9-116.1) mV*ms increase in SAI QRST.

CONCLUSION

Patient-specific time-varying changes in the surface ECG scalar measure of global electrical heterogeneity, as measured by SAI QRST, and in myocardial injury as measured by hsTnI, are independently and directly associated with each other, likely reflecting a common underlying mechanism.

HIV and coronary arterial remodeling from the Multicenter AIDS Cohort Study (MACS)

OBJECTIVE

Positive remodeling (PR), a coronary artery characteristic associated with risk for myocardial infarction (MI), may be more prevalent in HIV-infected (HIV+) people. We evaluated the prevalence of PR using coronary CT angiography (CCTA) in HIV+ and HIV-uninfected (HIV-) men.

METHODS

Men enrolled in the Multicenter AIDS Cohort Study underwent CCTA if they were 40-70 years, had normal kidney function and no history of coronary revascularization. Multivariable logistic regression models were used to estimate the odds ratio (OR) of PR by HIV serostatus, adjusting for demographics and coronary artery disease (CAD) risk factors. Analysis of PR among atherosclerotic segments further adjusted for plaque type and stenosis.

RESULTS

The prevalence of PR was 8.4% versus 12.1% (p = 0.10) for HIV- and HIV + men, respectively. After demographic adjustment, HIV + men had twice the odds of PR [OR 2.01(95% CI 1.20-3.38)], which persisted after CAD risk factor adjustment [1.76(1.00-3.10)]. Higher systolic blood pressure, total cholesterol, diabetes medication use, older age, segment number with plaque present, mixed and non-calcified plaque, and stenosis>50%, were associated with increased odds of PR, while higher HDL cholesterol, higher nadir CD4 count, and black race were associated with lower PR odds. Among atherosclerotic segments, the association between HIV infection and PR persisted, but was not statistically significantly.

CONCLUSION

HIV+ men have more positively remodeled arterial segments, which may be due to more coronary segments with atherosclerosis or HIV-related immunosuppression. Further studies are needed to evaluate whether PR contributes to higher rates of MI in HIV+ individuals.

Lottery-based versus fixed incentives to increase clinicians' response to surveys

OBJECTIVE

To compare the effects of lottery-based and fixed incentives on clinicians' response to surveys.

DATA SOURCES

Three randomized trials with fixed payments and actuarially equivalent lotteries.

STUDY DESIGN

Trial 1 compared a low-probability/high-payout lottery, a high-probability/low-payout lottery, and no incentive. Trial 2 compared a moderate-probability/moderate-payout lottery with an unconditional fixed payment (payment sent with questionnaire). Trial 3 compared a moderate-probability/moderate-payout lottery with a conditional fixed payment (payment promised following response).

PRINCIPAL FINDINGS

Neither the low-probability nor high-probability lotteries improved response compared with no incentive. Unconditional fixed payments produced significantly greater response than actuarially equivalent lotteries, but conditional fixed payments did not.

CONCLUSIONS

Lottery-based incentives do not improve clinicians' response rates compared with no incentives, and they are inferior to unconditional fixed payments.