Effectiveness of a bivalent mRNA vaccine dose against symptomatic SARS-CoV-2 infection among U.S. Healthcare personnel, September 2022-May 2023

BACKGROUND

Bivalent mRNA vaccines were recommended since September 2022. However, coverage with a recent vaccine dose has been limited, and there are few robust estimates of bivalent VE against symptomatic SARS-CoV-2 infection (COVID-19). We estimated VE of a bivalent mRNA vaccine dose against COVID-19 among eligible U.S. healthcare personnel who had previously received monovalent mRNA vaccine doses.

METHODS

We conducted a case-control study in 22 U.S. states, and enrolled healthcare personnel with COVID-19 (case-participants) or without COVID-19 (control-participants) during September 2022-May 2023. Participants were considered eligible for a bivalent mRNA dose if they had received 2-4 monovalent (ancestral-strain) mRNA vaccine doses, and were ≥67 days after the most recent vaccine dose. We estimated VE of a bivalent mRNA dose using conditional logistic regression, accounting for matching by region and four-week calendar period. We adjusted estimates for age group, sex, race and ethnicity, educational level, underlying health conditions, community COVID-19 exposure, prior SARS-CoV-2 infection, and days since the last monovalent mRNA dose.

RESULTS

Among 3,647 healthcare personnel, 1,528 were included as case-participants and 2,119 as control-participants. Participants received their last monovalent mRNA dose a median of 404 days previously; 1,234 (33.8%) also received a bivalent mRNA dose a median of 93 days previously. Overall, VE of a bivalent dose was 34.1% (95% CI, 22.6%-43.9%) against COVID-19 and was similar by product, days since last monovalent dose, number of prior doses, age group, and presence of underlying health conditions. However, VE declined from 54.8% (95% CI, 40.7%-65.6%) after 7-59 days to 21.6% (95% CI 5.6%-34.9%) after ≥60 days.

CONCLUSIONS

Bivalent mRNA COVID-19 vaccines initially conferred approximately 55% protection against COVID-19 among U.S. healthcare personnel. However, protection waned after two months. These findings indicate moderate initial protection against symptomatic SARS-CoV-2 infection by remaining up-to-date with COVID-19 vaccines.

Novel measures to assess ventricular assist device patient-reported outcomes: Findings from the MCS A-QOL study

BACKGROUND

Generic and heart failure-specific measures do not capture unique aspects of living with a ventricular assist device (VAD). Using state-of-the-science psychometric measurement methods, we developed a measurement system to assess post-ventricular assist device adjustment and health-related quality of life (HRQOL).

METHODS

Patients were recruited from 10/26/16-2/29/20 from 12 U.S. VAD programs. We created a dataset of participants (n = 620) enrolled before left (L)VAD implantation, with data at 3- or 6- months post-implantation (group1 [n = 154]), and participants enrolled after LVAD implantation, with data at one timepoint (group 2 [n = 466]). We constructed 5 item banks: 3 modified from existing measures and 2 new measures. Analyses included item response theory (IRT) modeling, differential item functioning tests for systematic measurement bias, and indicators of reliability and validity.

RESULTS

Of 620 participants, 56% (n = 345) were implanted as destination therapy, 51% (n = 316) were <12 months post-implantation, mean age = 57.3 years, 78% (n = 485) male, 70% (n = 433) White, 58% (n = 353) married/partnered, and 58% (n = 357) with >high school education. We developed 5 new VAD item banks/measures: 6-item VAD Team Communication; 12-item Self-efficacy Regarding VAD Self-care; 11-item Being Bothered by VAD Self-care and Limitations; 7-item Satisfaction with Treatment; and 11-item Stigma. Cronbach's alpha reliability ranged from good (≥0.80) to excellent (≥0.90) for item banks/measures. All measures, except VAD Team Communication, demonstrated at least moderate correlations (≥0.30) with construct validity indicators.

CONCLUSIONS

These measures meet IRT modeling assumptions and requirements; scores demonstrate reliability and validity. Use of these measures may assist VAD clinicians to inform patients about VADs as a treatment option and guide post-VAD interventions.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022

Background

Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant.

Methods

We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates.

Results

Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants.

Conclusions

A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

PROMIS: Physical, Mental and Social Health Outcomes Improve From Before to Early After LVAD Implant: Findings From the Mechanical Circulatory Support: Measures of Adjustment and Quality of Life (MCS A-QOL) Study

Study participants (n = 272) completed 12 Patient-Reported Outcomes Measurement Information System (PROMIS) physical, mental and social health measures (questionnaires) prior to implantation of a left ventricular assist device (LVAD) and again at 3 and 6 months postimplant. All but 1 PROMIS measure demonstrated significant improvement from pre-implant to 3 months; there was little change between 3 and 6 months. Because PROMIS measures were developed in the general population, patients with an LVAD, their caregivers and their clinicians can interpret the meaning of PROMIS scores in relation to the general population, helping them to monitor a return to normalcy in everyday life.

Validity of Patient-Reported Outcomes Measurement Information System Physical, Mental, and Social Health Measures After Left Ventricular Assist Device Implantation and Implications for Patient Care

BACKGROUND

A better understanding is needed of the burdens and benefits of left ventricular assist device (LVAD) implantation on patients' physical, mental, and social well-being. The purpose of this report was to evaluate the validity of Patient-Reported Outcomes Measurement Information System (PROMIS) measures for LVAD patients and to estimate clinically important score differences likely to have implications for patient treatment or care.

METHODS

Adults from 12 sites across all US geographic regions completed PROMIS measures ≥3 months post-LVAD implantation. Other patient-reported outcomes (eg, Kansas City Cardiomyopathy Questionnaire-12 item), clinician ratings, performance tests, and clinical adverse events were used as validity indicators. Criterion and construct validity and clinically important differences were estimated with Pearson correlations, ANOVA methods, and Cohen d effect sizes.

RESULTS

Participants' (n=648) mean age was 58 years, and the majority were men (78%), non-Hispanic White people (68%), with dilated cardiomyopathy (55%), long-term implantation strategy (57%), and New York Heart Association classes I and II (54%). Most correlations between validity indicators and PROMIS measures were medium to large (≥0.3; p<0.01). Most validity analyses demonstrated medium-to-large effect sizes (≥0.5) and clinically important differences in mean PROMIS scores (up to 14.8 points). Ranges of minimally important differences for 4 PROMIS measures were as follows: fatigue (3-5 points), physical function (2-3), ability to participate in social roles and activities (3), and satisfaction with social roles and activities (3-5).

CONCLUSIONS

The findings provide convincing evidence for the relevance and validity of PROMIS physical, mental, and social health measures in patients from early-to-late post-LVAD implantation. Findings may inform shared decision-making when patients consider treatment options. Patients with an LVAD, their caregivers, and their clinicians should find it useful to interpret the meaning of their PROMIS scores in relation to the general population, that is, PROMIS may help to monitor a return to normalcy in everyday life.

Computer adaptive testing to assess impairing behavioral health problems in emergency department patients with somatic complaints

Objectives

To assess: (1) the prevalence of mental health and substance use in patients presenting to the emergency department (ED) through use of a computer adaptive test (CAT‐MH), (2) the correlation among CAT‐MH scores and self‐ and clinician‐reported assessments, and (3) the association between CAT‐MH scores and ED utilization in the year prior and 30 days after enrollment.

Methods

This was a single‐center observational study of adult patients presenting to the ED for somatic complaints (97%) from May 2019 to March 2020. The main outcomes were computer‐adaptive‐assessed domains of suicidality, depression, anxiety, post‐traumatic stress disorder (PTSD), and substance use. We conducted Pearson correlations and logistic regression for objectives 2 and 3, respectively.

Results

From a sample of 794 patients, the proportion of those at moderate/severe risk was: 24.1% (suicidality), 8.3% (depression), 16.5% (anxiety), 12.3% (PTSD), and 20.4% (substance use). CAT‐MH domains were highly correlated with self‐report assessments (r = 0.49–0.79). Individuals who had 2 or more ED visits in the prior year had 62% increased odds of being in the intermediate‐high suicide risk category (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.07–2.44) compared to those with zero prior ED visits. Individuals who scored in the intermediate‐high‐suicide risk group had 63% greater odds of an ED visit within 30 days after enrollment compared to those who scored as low risk (OR, 1.63; 95% CI, 1.09, 2.44).

Conclusion

The CAT‐MH documented that a considerable proportion of ED patients presenting for somatic problems had mental health conditions, even if mild. Mental health problems were also associated with ED utilization.

Estimation of Respiratory Rate from Breathing Audio

The COVID-19 pandemic has fueled exponential growth in the adoption of remote delivery of primary, specialty, and urgent health care services. One major challenge is the lack of access to physical exam including accurate and inexpensive measurement of remote vital signs. Here we present a novel method for machine learning-based estimation of patient respiratory rate from audio. There exist non-learning methods but their accuracy is limited and work using machine learning known to us is either not directly useful or uses non-public datasets. We are aware of only one publicly available dataset which is small and which we use to evaluate our algorithm. However, to avoid the overfitting problem, we expand its effective size by proposing a new data augmentation method. Our algorithm uses the spectrogram representation and requires labels for breathing cycles, which are used to train a recurrent neural network for recognizing the cycles. Our augmentation method exploits the independence property of the most periodic frequency components of the spectrogram and permutes their order to create multiple signal representations. Our experiments show that our method almost halves the errors obtained by the existing (non-learning) methods. Clinical Relevance- We achieve a Mean Absolute Error (MAE) of 1.0 for the respiratory rate while relying only on an audio signal of a patient breathing. This signal can be collected from a smartphone such that physicians can automatically and reliably determine respiratory rate in a remote setting.

Preoperative Assessment of Anxiety and Depression Using Computerized Adaptive Screening Tools: A Pilot Prospective Cohort Study

BACKGROUND

Serious mental health conditions (eg, anxiety and depression) are common in surgical patients, yet likely underassessed due to the time-consuming and cumbersome traditional screening process. A recently developed computerized adaptive mental health assessment tool (computerized adaptive test-mental health [CAT-MH]) allows rapid, precise, and accurate assessment of numerous mental health disorders, including anxiety and depression, without the need for a trained interviewer. The goal of this investigation was to determine the feasibility of administering CAT-MH for anxiety and depression in the preoperative setting and to obtain preliminary evidence of the prevalence of anxiety and depression in preoperative patients.

METHODS

In this prospective cohort study, 100 adult patients scheduled for elective surgery were enrolled and asked to complete the CAT-MH in the preoperative clinic. Urgent and emergency surgeries were excluded as were pregnant patients. Primary feasibility outcomes were completion rate and time to completion. Secondary outcomes were prevalence estimates of anxiety and depression.

RESULTS

All 100 enrolled patients completed the study. All patients were able to complete the mental health assessment (mean time: 3.6 ± 1.8 minutes standard deviation). Sixteen patients (16%) screened positive for anxiety (severity: mild, n = 7 [7%]; moderate, n = 7 [7%]); severe, n = 2 [2%]); 12 of 16 (75%) did not have a previous diagnosis of anxiety disorder. Twenty-eight (28%) patients screened positive for depression (severity: mild, n = 26 [26%]; moderate and severe, n = 1 each [1%]); 23 of 28 (82%) had no previous diagnosis of depressive disorder. Nineteen patients (19%) met the screening criteria for major depressive disorder; 14 of 19 (74%) of which had no previous diagnosis of major depressive disorder.

CONCLUSIONS

The results of this pilot study support the feasibility of using CAT-MH in a preoperative evaluation and indicate that there is a substantial prevalence of undiagnosed anxiety and depression in surgical patients.

Effectiveness of mRNA Covid-19 Vaccine among U.S. Health Care Personnel

BACKGROUND

The prioritization of U.S. health care personnel for early receipt of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), allowed for the evaluation of the effectiveness of these new vaccines in a real-world setting.

METHODS

We conducted a test-negative case-control study involving health care personnel across 25 U.S. states. Cases were defined on the basis of a positive polymerase-chain-reaction (PCR) or antigen-based test for SARS-CoV-2 and at least one Covid-19-like symptom. Controls were defined on the basis of a negative PCR test for SARS-CoV-2, regardless of symptoms, and were matched to cases according to the week of the test date and site. Using conditional logistic regression with adjustment for age, race and ethnic group, underlying conditions, and exposures to persons with Covid-19, we estimated vaccine effectiveness for partial vaccination (assessed 14 days after receipt of the first dose through 6 days after receipt of the second dose) and complete vaccination (assessed ≥7 days after receipt of the second dose).

RESULTS

The study included 1482 case participants and 3449 control participants. Vaccine effectiveness for partial vaccination was 77.6% (95% confidence interval [CI], 70.9 to 82.7) with the BNT162b2 vaccine (Pfizer-BioNTech) and 88.9% (95% CI, 78.7 to 94.2) with the mRNA-1273 vaccine (Moderna); for complete vaccination, vaccine effectiveness was 88.8% (95% CI, 84.6 to 91.8) and 96.3% (95% CI, 91.3 to 98.4), respectively. Vaccine effectiveness was similar in subgroups defined according to age (<50 years or ≥50 years), race and ethnic group, presence of underlying conditions, and level of patient contact. Estimates of vaccine effectiveness were lower during weeks 9 through 14 than during weeks 3 through 8 after receipt of the second dose, but confidence intervals overlapped widely.

CONCLUSIONS

The BNT162b2 and mRNA-1273 vaccines were highly effective under real-world conditions in preventing symptomatic Covid-19 in health care personnel, including those at risk for severe Covid-19 and those in racial and ethnic groups that have been disproportionately affected by the pandemic. (Funded by the Centers for Disease Control and Prevention.).

Predicting 30-day return hospital admissions in patients with COVID-19 discharged from the emergency department: A national retrospective cohort study

OBJECTIVES

Identification of patients with coronavirus disease 2019 (COVID-19) at risk for deterioration after discharge from the emergency department (ED) remains a clinical challenge. Our objective was to develop a prediction model that identifies patients with COVID-19 at risk for return and hospital admission within 30 days of ED discharge.

METHODS

We performed a retrospective cohort study of discharged adult ED patients (n = 7529) with SARS-CoV-2 infection from 116 unique hospitals contributing to the National Registry of Suspected COVID-19 in Emergency Care. The primary outcome was return hospital admission within 30 days. Models were developed using classification and regression tree (CART), gradient boosted machine (GBM), random forest (RF), and least absolute shrinkage and selection (LASSO) approaches.

RESULTS

Among patients with COVID-19 discharged from the ED on their index encounter, 571 (7.6%) returned for hospital admission within 30 days. The machine-learning (ML) models (GBM, RF, and LASSO) performed similarly. The RF model yielded a test area under the receiver operating characteristic curve of 0.74 (95% confidence interval [CI], 0.71-0.78), with a sensitivity of 0.46 (95% CI, 0.39-0.54) and a specificity of 0.84 (95% CI, 0.82-0.85). Predictive variables, including lowest oxygen saturation, temperature, or history of hypertension, diabetes, hyperlipidemia, or obesity, were common to all ML models.

CONCLUSIONS

A predictive model identifying adult ED patients with COVID-19 at risk for return for return hospital admission within 30 days is feasible. Ensemble/boot-strapped classification methods (eg, GBM, RF, and LASSO) outperform the single-tree CART method. Future efforts may focus on the application of ML models in the hospital setting to optimize the allocation of follow-up resources.

Early Convalescent Plasma for High-Risk Outpatients with Covid-19

BACKGROUND

Early administration of convalescent plasma obtained from blood donors who have recovered from coronavirus disease 2019 (Covid-19) may prevent disease progression in acutely ill, high-risk patients with Covid-19.

METHODS

In this randomized, multicenter, single-blind trial, we assigned patients who were being treated in an emergency department for Covid-19 symptoms to receive either one unit of convalescent plasma with a high titer of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or placebo. All the patients were either 50 years of age or older or had one or more risk factors for disease progression. In addition, all the patients presented to the emergency department within 7 days after symptom onset and were in stable condition for outpatient management. The primary outcome was disease progression within 15 days after randomization, which was a composite of hospital admission for any reason, seeking emergency or urgent care, or death without hospitalization. Secondary outcomes included the worst severity of illness on an 8-category ordinal scale, hospital-free days within 30 days after randomization, and death from any cause.

RESULTS

A total of 511 patients were enrolled in the trial (257 in the convalescent-plasma group and 254 in the placebo group). The median age of the patients was 54 years; the median symptom duration was 4 days. In the donor plasma samples, the median titer of SARS-CoV-2 neutralizing antibodies was 1:641. Disease progression occurred in 77 patients (30.0%) in the convalescent-plasma group and in 81 patients (31.9%) in the placebo group (risk difference, 1.9 percentage points; 95% credible interval, -6.0 to 9.8; posterior probability of superiority of convalescent plasma, 0.68). Five patients in the plasma group and 1 patient in the placebo group died. Outcomes regarding worst illness severity and hospital-free days were similar in the two groups.

CONCLUSIONS

The administration of Covid-19 convalescent plasma to high-risk outpatients within 1 week after the onset of symptoms of Covid-19 did not prevent disease progression. (SIREN-C3PO ClinicalTrials.gov number, NCT04355767.).

Building and experimenting with an agent-based model to study the population-level impact of CommunityRx, a clinic-based community resource referral intervention

CommunityRx (CRx), an information technology intervention, provides patients with a personalized list of healthful community resources (HealtheRx). In repeated clinical studies, nearly half of those who received clinical "doses" of the HealtheRx shared their information with others ("social doses"). Clinical trial design cannot fully capture the impact of information diffusion, which can act as a force multiplier for the intervention. Furthermore, experimentation is needed to understand how intervention delivery can optimize social spread under varying circumstances. To study information diffusion from CRx under varying conditions, we built an agent-based model (ABM). This study describes the model building process and illustrates how an ABM provides insight about information diffusion through in silico experimentation. To build the ABM, we constructed a synthetic population ("agents") using publicly-available data sources. Using clinical trial data, we developed empirically-informed processes simulating agent activities, resource knowledge evolution and information sharing. Using RepastHPC and chiSIM software, we replicated the intervention in silico, simulated information diffusion processes, and generated emergent information diffusion networks. The CRx ABM was calibrated using empirical data to replicate the CRx intervention in silico. We used the ABM to quantify information spread via social versus clinical dosing then conducted information diffusion experiments, comparing the social dosing effect of the intervention when delivered by physicians, nurses or clinical clerks. The synthetic population (N = 802,191) exhibited diverse behavioral characteristics, including activity and knowledge evolution patterns. In silico delivery of the intervention was replicated with high fidelity. Large-scale information diffusion networks emerged among agents exchanging resource information. Varying the propensity for information exchange resulted in networks with different topological characteristics. Community resource information spread via social dosing was nearly 4 fold that from clinical dosing alone and did not vary by delivery mode. This study, using CRx as an example, demonstrates the process of building and experimenting with an ABM to study information diffusion from, and the population-level impact of, a clinical information-based intervention. While the focus of the CRx ABM is to recreate the CRx intervention in silico, the general process of model building, and computational experimentation presented is generalizable to other large-scale ABMs of information diffusion.

Emergency Department-initiated High-flow Nasal Cannula for COVID-19 Respiratory Distress

INTRODUCTION

Patients with coronavirus disease 2019 (COVID-19) can develop rapidly progressive respiratory failure. Ventilation strategies during the COVID-19 pandemic seek to minimize patient mortality. In this study we examine associations between the availability of emergency department (ED)-initiated high-flow nasal cannula (HFNC) for patients presenting with COVID-19 respiratory distress and outcomes, including rates of endotracheal intubation (ETT), mortality, and hospital length of stay.

METHODS

We performed a retrospective, non-concurrent cohort study of patients with COVID-19 respiratory distress presenting to the ED who required HFNC or ETT in the ED or within 24 hours following ED departure. Comparisons were made between patients presenting before and after the introduction of an ED-HFNC protocol.

RESULTS

Use of HFNC was associated with a reduced rate of ETT in the ED (46.4% vs 26.3%, P <0.001) and decreased the cumulative proportion of patients who required ETT within 24 hours of ED departure (85.7% vs 32.6%, P <0.001) or during their entire hospitalization (89.3% vs 48.4%, P <0.001). Using HFNC was also associated with a trend toward increased survival to hospital discharge; however, this was not statistically significant (50.0% vs 68.4%, P = 0.115). There was no impact on intensive care unit or hospital length of stay. Demographics, comorbidities, and illness severity were similar in both cohorts.

CONCLUSIONS

The institution of an ED-HFNC protocol for patients with COVID-19 respiratory distress was associated with reductions in the rate of ETT. Early initiation of HFNC is a promising strategy for avoiding ETT and improving outcomes in patients with COVID-19.

The utility of computed tomography to evaluate thoracic complications after cardiopulmonary resuscitation

Background

Cardiopulmonary resuscitation (CPR) in adults following non-traumatic out of hospital cardiac arrest (OHCA) can cause thoracic complications including rib fractures, sternal fractures, and pneumothorax. Post-CPR complication rates are poorly studied and the optimum imaging modality to detect these complications post-resuscitation has not been established.

Methods

We performed a retrospective review of adult patients transported to a single, urban, academic hospital following atraumatic OHCA between September 2015 and January 2020. Patients who achieved sustained return of spontaneous circulation (ROSC) and who underwent computed tomography (CT) imaging of the chest following radiographic chest x-ray were included in the analyses. Patient demographics and prehospital data were collected. Descriptive statistics and multivariate logistic regression analysis were performed. Sensitivity and specificity of chest x-ray for the detection of thoracic injury in this population were estimated.

Results

786 non-traumatic OHCA patients were transported to the ED, 417 of whom obtained sustained ROSC and were admitted to the hospital (53%). 137 (32.9%) admitted patients underwent CT imaging of the chest in the ED. Of these imaged patients median age was 62 years old (IQR 53–70) with 54.0% female and 38.0% of patients having received bystander CPR. 40/137 (29.2%) patients had skeletal fractures noted on CT imaging and 12/137 (8.8%) had pneumothorax present on CT imaging. X-ray yielded a sensitivity of 7.5% for rib fracture and 50% for pneumothorax with a specificity of 100% for both. Logistic regression analysis revealed no significant association between age, sex, bystander CPR, or resuscitation length with thoracic fractures or pneumothorax.

Conclusions

Complications from OHCA CPR were high with 29.2% of CT imaged patients having rib fractures and 8.8% having pneumothoraces. X-ray had poor sensitivity for these post-resuscitation complications. Post-CPR CT imaging of the chest should be considered for detecting post-CPR complications.

Clinical prediction rule for SARS-CoV-2 infection from 116 U.S. emergency departments 2-22-2021

Objectives

Accurate and reliable criteria to rapidly estimate the probability of infection with the novel coronavirus-2 that causes the severe acute respiratory syndrome (SARS-CoV-2) and associated disease (COVID-19) remain an urgent unmet need, especially in emergency care. The objective was to derive and validate a clinical prediction score for SARS-CoV-2 infection that uses simple criteria widely available at the point of care.

Methods

Data came from the registry data from the national REgistry of suspected COVID-19 in EmeRgency care (RECOVER network) comprising 116 hospitals from 25 states in the US. Clinical variables and 30-day outcomes were abstracted from medical records of 19,850 emergency department (ED) patients tested for SARS-CoV-2. The criterion standard for diagnosis of SARS-CoV-2 required a positive molecular test from a swabbed sample or positive antibody testing within 30 days. The prediction score was derived from a 50% random sample (n = 9,925) using unadjusted analysis of 107 candidate variables as a screening step, followed by stepwise forward logistic regression on 72 variables.

Results

Multivariable regression yielded a 13-variable score, which was simplified to a 13-point score: +1 point each for age>50 years, measured temperature>37.5°C, oxygen saturation<95%, Black race, Hispanic or Latino ethnicity, household contact with known or suspected COVID-19, patient reported history of dry cough, anosmia/dysgeusia, myalgias or fever; and -1 point each for White race, no direct contact with infected person, or smoking. In the validation sample (n = 9,975), the probability from logistic regression score produced an area under the receiver operating characteristic curve of 0.80 (95% CI: 0.79–0.81), and this level of accuracy was retained across patients enrolled from the early spring to summer of 2020. In the simplified score, a score of zero produced a sensitivity of 95.6% (94.8–96.3%), specificity of 20.0% (19.0–21.0%), negative likelihood ratio of 0.22 (0.19–0.26). Increasing points on the simplified score predicted higher probability of infection (e.g., >75% probability with +5 or more points).

Conclusion

Criteria that are available at the point of care can accurately predict the probability of SARS-CoV-2 infection. These criteria could assist with decisions about isolation and testing at high throughput checkpoints.

Impact of a Low-Intensity Resource Referral Intervention on Patients' Knowledge, Beliefs, and Use of Community Resources: Results from the CommunityRx Trial

BACKGROUND

Connecting patients to community-based resources is now a cornerstone of modern healthcare that supports self-management of health. The mechanisms that link resource information to behavior change, however, remain poorly understood.

OBJECTIVE

To evaluate the impact of CommunityRx, an automated, low-intensity resource referral intervention, on patients' knowledge, beliefs, and use of community resources.

DESIGN

Real-world controlled clinical trial at an urban academic medical center in 2015-2016; participants were assigned by alternating week to receive the CommunityRx intervention or usual care. Surveys were administered at baseline, 1 week, 1 month, and 3 months.

PARTICIPANTS

Publicly insured adults, ages 45-74 years.

INTERVENTION

CommunityRx generated an automated, personalized list of resources, known as HealtheRx, near each participant's home using condition-specific, evidence-based algorithms. Algorithms used patient demographic and health characteristics documented in the electronic health record to identify relevant resources from a comprehensive, regularly updated database of health-related resources in the study area.

MAIN MEASURES

Using intent-to-treat analysis, we examined the impact of HealtheRx referrals on (1) knowledge of the most commonly referred resource types, including healthy eating classes, individual counseling, mortgage assistance, smoking cessation, stress management, and weight loss classes or groups, and (2) beliefs about having resources in the community to manage health.

KEY RESULTS

In a real-world controlled trial of 374 adults, intervention recipients improved knowledge (AOR = 2.15; 95% CI, 1.29-3.58) and beliefs (AOR = 1.68; 95% CI, 1.07-2.64) about common resources in the community to manage health, specifically gaining knowledge about smoking cessation (AOR = 2.76; 95% CI, 1.07-7.12) and weight loss resources (AOR = 2.26; 95% CI 1.05-4.84). Positive changes in both knowledge and beliefs about community resources were associated with higher resource use (P = 0.02).

CONCLUSIONS

In a middle-age and older population with high morbidity, a low-intensity health IT intervention to deliver resource referrals promoted behavior change by increasing knowledge and positive beliefs about community resources for self-management of health.

NIH TRIAL REGISTRY

NCT02435511.

Cardiac Arrhythmia Following an Epileptic Seizure

Sudden unexplained death in epilepsy (SUDEP) refers to a death in a patient with epilepsy that is not due to trauma, drowning, status epilepticus, or another apparent cause. Although the pathophysiology of SUDEP is incompletely understood, growing evidence supports the role of seizure-associated arrhythmias as a potential etiology. We present a unique case of a patient presenting with ventricular tachycardia shortly following a seizure, along with corresponding laboratory data. Awareness of high risk arrhythmias in seizure patients could lead to advances in understanding pathophysiology and treatment of this complication of seizure disorder and ultimately prevention of SUDEP.

Depression in Emergency Department Patients and Association With Health Care Utilization

BACKGROUND

Depression is one of the most common illnesses in the United States, with increased prevalence among people with lower socioeconomic status and chronic mental illness who often seek care in the emergency department (ED). We sought to estimate the rate and severity of major depressive disorder (MDD) in a nonpsychiatric ED population and its association with subsequent ED visits and hospitalizations.

METHODS

This prospective cohort study enrolled a convenience sample of English-speaking adults presenting to an urban academic medical center ED without psychiatric complaints between January 1, 2015, and September 21, 2015. Patients completed a computerized adaptive depression diagnostic screen (CAD-MDD) and dimensional depression severity measurement test (CAT-DI) via tablet computer. Primary outcomes included number of ED visits and hospitalizations assessed from index visit until January 1, 2016. Negative binomial regression modeling was performed to assess associations between depression, depression severity, clinical covariates, and utilization outcomes.

RESULTS

Of 999 enrolled patients, 27% screened positive for MDD. The presence of MDD conveyed a 61% increase in the rate of ED visits (incidence rate ratio [IRR] = 1.61, 95% confidence interval [CI] = 1.27 to 2.03) and a 49% increase in the rate of hospitalizations (IRR = 1.49, 95% CI = 1.06-2.09). For each 10% increase in MDD severity, there was a 10% increase in the relative rate of subsequent ED visits (IRR = 1.10, 95% CI = 1.04 to 1.16) and hospitalizations (IRR = 1.10, 95% CI = 1.02 to 1.18). Across the range of the severity scale there was over a 2.5-fold increase in the rate of ED visits and hospitalization rates.

CONCLUSIONS

Rates of depression were high among a convenience sample of English-speaking adult ED patients presenting with nonpsychiatric complaints and independently associated with increased risk of subsequent ED utilization and hospitalization. Standardized assessment tools that provide rapid, accurate, and precise classification of MDD severity have the potential to play an important role in identifying ED patients in need of urgent psychiatric resource referral.

Development of a Computerized Adaptive Test Suicide Scale-The CAT-SS

OBJECTIVE

Current suicide risk screening and measurement are inefficient, have limited measurement precision, and focus entirely on suicide-related items. For this study, a psychometric harmonization between related suicide, depression, and anxiety symptom domains that provides a more balanced and complete spectrum of suicidal symptomatology was developed. The objective of this article is to describe the results of the early stages of computerized adaptive testing development for a suicide scale and pave the way for the final stage of validation.

METHODS

Data from psychiatric outpatients at the University of Pittsburgh and a community health clinic were collected from January 2010 through June 2012. 789 participants were enrolled in the calibration phase; 70% were female, and 30% were male. The rate of major depressive disorder as diagnosed by DSM-5 was 47%. The item bank contained 1,008 items related to depression, anxiety, and mania, including 11 suicide items. Data were analyzed using a bifactor model to identify a core dimension between suicidal ideation, depression, anxiety, and mania items. A computerized adaptive test was developed via simulation from the actual complete item responses in 308 subjects.

RESULTS

111 items were identified that provided an extension of suicidality assessment to include statistically related responses from depression and anxiety domains that are syndromally associated with suicidality. All items had high loadings on the primary suicide dimension (average = 0.67; range, 0.49-0.88). Analyses revealed that a mean of 10 items (5-20) had a correlation of 0.96 with the 111-item scale, with a precision of 5 points on a 100-point scale metric. Preliminary validation data based on 290 clinician interviews revealed a 52-fold increase in the likelihood of current suicidal ideation across the range of the Computerized Adaptive Test Suicide Scale (CAT-SS).

CONCLUSIONS

The CAT-SS is able to accurately measure the latent suicide dimension with a mean of 10 items in approximately 2 minutes. Further validation against an independent clinician-administered assessment of suicide risk (ideation and attempts) and prediction of suicidal behavior is underway.

Cost-utility of extracorporeal cardiopulmonary resuscitation in patients with cardiac arrest

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) is a resource-intensive tool that provides haemodynamic and respiratory support in patients who have suffered cardiac arrest. In this study, we investigated the cost-utility of ECPR (cost/QALY) in cardiac arrest patients treated at our institution.

METHODS

We performed a retrospective review of patients who received ECPR following cardiac arrest between 2012 and 2018. All medical care-associated charges with ECPR and subsequent hospital admission were recorded. The quality-of-life of survivors was assessed with the Health Utilities Index Mark II. The cost-utility of ECPR was calculated with cost and quality-of-life data.

RESULTS

ECPR was used in 32 patients (15/32 in-hospital, 47%) with a median age of 55.0 years (IQR 46.3-63.3 years), 59% male and 66% African American. The median duration of ECPR support was 2.1 days (IQR 0.9-3.8 days). Survival to hospital discharge was 16%. The median score of the Health Utilities Index Mark II at discharge for the survivors was 0.44 (IQR 0.32-0.52). The median operating cost for patients undergoing ECMO was $125,683 per patient (IQR $49,751-$206,341 per patient). The calculated cost-utility for ECPR was $56,156/QALY gained.

CONCLUSIONS

The calculated cost-utility is within the threshold considered cost-effective in the United States (<$150,000/QALY gained). These results are comparable to the cost-effectiveness of heart transplantation for end-stage heart failure. Larger studies are needed to assess the cost-utility of ECPR and to identify whether other factors, such as patient characteristics, affect the cost-utility benefit.

CommunityRx: A Real-World Controlled Clinical Trial of a Scalable, Low-Intensity Community Resource Referral Intervention

OBJECTIVES

To test the effect of CommunityRx, a scalable, low-intensity intervention that matches patients to community resources, on mental health-related quality of life (HRQOL) (primary outcome), physical HRQOL, and confidence in finding resources.

METHODS

A real-world trial assigned publicly insured residents of Chicago, Illinois, aged 45 to 74 years to an intervention (n = 209) or control (n = 202) group by alternating calendar week, December 2015 to August 2016. Intervention group participants received usual care and an electronic medical record-generated, personalized list of community resources. Surveys (baseline, 1-week, 1- and 3-months) measured HRQOL and confidence in finding community resources to manage health.

RESULTS

At 3 months, there was no difference between groups in mental (-1.03; 95% confidence interval [CI] = -3.02, 0.96) or physical HRQOL (0.59; 95% CI = -0.98, 2.16). Confidence in finding resources was higher in the intervention group (odds ratio = 2.08; 95% CI = 1.18, 3.63); the effect increased at each successive time point. Among intervention group participants, 65% recalled receiving the intervention; 48% shared community resource information with others.

CONCLUSIONS

CommunityRx did not increase HRQOL, but its positive effect on confidence in finding resources for self-care suggests that this low-intensity intervention may have a role in population health promotion.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02435511.

Validation of the Computerized Adaptive Test for Mental Health in Primary Care

PURPOSE

The US Preventive Services Task Force recommends screening for depression in the general adult population. Although screening questionnaires for depression and anxiety exist in primary care settings, electronic health tools such as computerized adaptive tests based on item response theory can advance screening practices. This study evaluated the validity of the Computerized Adaptive Test for Mental Health (CAT-MH) for screening for major depressive disorder (MDD) and assessing MDD and anxiety severity among adult primary care patients.

METHODS

We approached 402 English-speaking adults for participation from a primary care clinic, of whom 271 adults (71% female, 65% black) participated. Participants completed modules from the CAT-MH (Computerized Adaptive Diagnostic Test for MDD, CAT-Depression Inventory, CAT-Anxiety Inventory); brief paper questionnaires (9-item Patient Health Questionnaire [PHQ-9], 2-item Patient Health Questionnaire [PHQ-2], Generalized Anxiety Disorder 7-item Scale [GAD-7]); and a reference-standard interview, the Structured Clinical Interview for DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) Diagnoses.

RESULTS

On the basis of the interview, 31 participants met criteria for MDD and 29 met criteria for GAD. The diagnostic accuracy of the Computerized Adaptive Diagnostic Test for MDD (area under curve [AUC] = 0.85) was similar to that of the PHQ-9 (AUC = 0.84) and higher than that of the PHQ-2 (AUC = 0.76) for MDD screening. Using the interview as the reference standard, the accuracy of the CAT-Anxiety Inventory (AUC = 0.93) was similar to that of the GAD-7 (AUC = 0.97) for assessing anxiety severity. The patient-preferred screening method was assessment via tablet/computer with audio.

CONCLUSIONS

Computerized adaptive testing could be a valid and efficient patient-centered screening strategy for depression and anxiety screening in primary care settings.

CommunityRx: A Population Health Improvement Innovation That Connects Clinics To Communities

The CommunityRx system, a population health innovation, combined an e-prescribing model and community engagement to strengthen links between clinics and community resources for basic, wellness, and disease self-management needs in Chicago. The components of CommunityRx were a youth workforce, whose members identified 19,589 public-serving entities in the 106-square-mile implementation region between 2012 and 2014; community health information specialists, who used the workforce's findings to generate an inventory of 14,914 health-promoting resources; and a health information technology (IT) platform that was integrated with three electronic health record systems at thirty-three clinical sites. By mapping thirty-seven prevalent social and medical conditions to community resources, CommunityRx generated 253,479 personalized HealtheRx prescriptions for more than 113,000 participants. Eighty-three percent of the recipients found the HealtheRx very useful, and 19 percent went to a place they learned about from the HealtheRx. All but one organization continued using the CommunityRx system after the study period ended. This study demonstrates the feasibility of using health IT and workforce innovation to bridge the gap between clinical and other health-promoting sectors.

Abstract 107: Mitochondrial Dysfunction Mediated Myocardial Stunning Following Resuscitation From Cardiac Arrest

Rationale: Severe myocardial contractile dysfunction following resuscitation from cardiac arrest (CA) is a major contributor to CA mortality. The pathophysiology and etiology of this dysfunction is not known and there are no pharmacological therapies known to improve outcomes. Previously, we demonstrated that Dynamin related protein 1 (Drp1) is activated and recruited to the mitochondria during CA and that the Drp1 inhibitor Mdivi-1 improves post CA survival.

Objective: To determine the effects of CA length on myocardial and mitochondrial function. We also sought to determine the effects of Mdivi-1 on post CA outcomes.

Methods and Results: Asystolic cardiac arrest (CA) was induced in mice by IV injection of 0.08 mg/g KCL. CPR begun at 4, 8, 12, and 16 minutes post-cardiac arrest had rates of return of spontaneous circulation (ROSC) of 100%(12/12), 93%(14/15), 71%(10/14), and 44% (4/9) and 2-hour survival of 100%(12/12), 67%(10/15), 50%(7/14), and 11%(1/9). Transthoracic echocardiography 15 min post-resuscitation demonstrated percent fractional shortening of 36±4% (Sham,n=6), 30±4% (4 minCA,n=11), 24±5% (8minCA,n=10), 15±2% (12minCA,n=12). In surviving animals, myocardial dysfunction persisted for 2 hours post-resuscitation, but slowly recovered to baseline by 72 hours. No evidence of myocardial necrosis, inflammation, or apoptosis was noted following resuscitation. Progressive increases in mitochondrial derived reactive oxygen species (ROS) during CA was observed by MitoSOX red myocardial tissue staining. Mitochondria isolated from 12 min CA hearts demonstrated decreased substrate coupled and uncoupled respiration. Mdivi-1, a mitochondrial inhibitor of division (fission), improved survival and neurological scores in mice following an 8 min cardiac arrest compared to controls.

Conclusions: Severe, time dependent myocardial stunning (contractile dysfunction in the absence of irreversible injury) was observed following asystolic cardiac arrest. This myocardial stunning was associated with mitochondrial injury and improved by an inhibitor of Drp1. Strategies targeting ischemia/reperfusion-induced changes in mitochondrial dynamics hold promise for improving myocardial function and survival following cardiac arrest.

A novel pharmacological strategy by PTEN inhibition for improving metabolic resuscitation and survival after mouse cardiac arrest

Sudden cardiac arrest (SCA) is a leading cause of death in the United States. Despite return of spontaneous circulation, patients die due to post-SCA syndrome that includes myocardial dysfunction, brain injury, impaired metabolism, and inflammation. No medications improve SCA survival. Our prior work suggests that optimal Akt activation is critical for cooling protection and SCA recovery. Here, we investigate a small inhibitor of PTEN, an Akt-related phosphatase present in heart and brain, as a potential therapy in improving cardiac and neurological recovery after SCA. Anesthetized adult female wild-type C57BL/6 mice were randomized to pretreatment of VO-OHpic (VO) 30 min before SCA or vehicle control. Mice underwent 8 min of KCl-induced asystolic arrest followed by CPR. Resuscitated animals were hemodynamically monitored for 2 h and observed for 72 h. Outcomes included heart pressure-volume loops, energetics (phosphocreatine and ATP from (31)P NMR), protein phosphorylation of Akt, GSK3β, pyruvate dehydrogenase (PDH) and phospholamban, circulating inflammatory cytokines, plasma lactate, and glucose as measures of systemic metabolic recovery. VO reduced deterioration of left ventricular maximum pressure, maximum rate of change in the left ventricular pressure, and Petco2 and improved 72 h neurological intact survival (50% vs. 10%; P < 0.05). It reduced plasma lactate, glucose, IL-1β, and Pre-B cell colony enhancing factor, while increasing IL-10. VO increased phosphorylation of Akt and GSK3β in both heart and brain, and cardiac phospholamban phosphorylation while reducing p-PDH. Moreover, VO improved cardiac bioenergetic recovery. We concluded that pharmacologic PTEN inhibition enhances Akt activation, improving metabolic, cardiovascular, and neurologic recovery with increased survival after SCA. PTEN inhibitors may be a novel pharmacologic strategy for treating SCA.

Inhibition of sphingosine-1-phosphate lyase rescues sphingosine kinase-1-knockout phenotype following murine cardiac arrest

AIMS

To test the role of sphingosine-1-phosphate (S1P) signaling system in the in vivo setting of resuscitation and survival after cardiac arrest.

MAIN METHODS

A mouse model of potassium-induced cardiac arrest and resuscitation was used to test the importance of S1P homeostasis in resuscitation and survival. C57BL/6 and sphingosine kinase-1 knockout (SphK1-KO) female mice were arrested for 8 min then subjected to 5 minute CPR with epinephrine bolus given at 90s after the beginning of CPR. Animal survival was monitored for 4h post-resuscitation. Upregulation of tissue and circulatory S1P levels were achieved via inhibition of S1P lyase by 2-acetyl-5-tetrahydroxybutyl imidazole (THI). Plasma and heart tissue S1P and ceramide levels were quantified by targeted ESI-LC/MS/MS.

KEY FINDINGS

Lack of SphK1 and low tissue/circulatory S1P levels in SphK1-KO mice led to poor animal resuscitation after cardiac arrest and to impaired survival post-resuscitation. Inhibition of S1P lyase in SphK1-KO mice drastically improved animal resuscitation and survival. Improved resuscitation and survival of THI-treated SphK1-KO mice were better correlated with cardiac dihydro-S1P (DHS1P) than S1P levels. The lack of SphK1 and the inhibition of S1P lyase by THI were accompanied by modulation in cardiac S1PR1 and S1PR2 expression and by selective changes in plasma N-palmitoyl- and N-behenoyl-ceramide levels.

SIGNIFICANCE

Our data provide evidence for the crucial role for SphK1 and S1P signaling system in resuscitation and survival after cardiac arrest, which may form the basis for development of novel therapeutic strategy to support resuscitation and long-term survival of cardiac arrest patients.

Genetic deletion of NOS3 increases lethal cardiac dysfunction following mouse cardiac arrest

STUDY AIMS

Cardiac arrest mortality is significantly affected by failure to obtain return of spontaneous circulation (ROSC) despite cardiopulmonary resuscitation (CPR). Severe myocardial dysfunction and cardiovascular collapse further affects mortality within hours of initial ROSC. Recent work suggests that enhancement of nitric oxide (NO) signaling within minutes of CPR can improve myocardial function and survival. We studied the role of NO signaling on cardiovascular outcomes following cardiac arrest and resuscitation using endothelial NO synthase knockout (NOS3(-/-)) mice.

METHODS

Adult female wild-type (WT) and NOS3(-/-) mice were anesthetized, intubated, and instrumented with left-ventricular pressure-volume catheters. Cardiac arrest was induced with intravenous potassium chloride. CPR was performed after 8min of untreated arrest. ROSC rate, cardiac function, whole-blood nitrosylhemoglobin (HbNO) concentrations, heart NOS3 content and phosphorylation (p-NOS3), cyclic guanosine monophosphate (cGMP), and phospho-troponin I (p-TnI) were measured.

RESULTS

Despite equal quality CPR, NOS3(-/-) mice displayed lower rates of ROSC compared to WT (47.6% [10/21] vs. 82.4% [14/17], p<0.005). Among ROSC animals, NOS3(-/-) vs. WT mice exhibited increased left-ventricular dysfunction and 120min mortality. Prior to ROSC, myocardial effectors of NO signaling including cGMP and p-TnI were decreased in NOS3(-/-) vs. WT mice (p<0.05). Following ROSC in WT mice, significant NOS3-dependent increases in circulating HbNO were seen by 120min. Significant increases in cardiac p-NOS3 occurred between end-arrest and 15min post-ROSC, while total NOS3 content was increased by 120min post-ROSC (p<0.05).

CONCLUSIONS

Genetic deletion of NOS3 decreases ROSC rate and worsens post-ROSC left-ventricular function. Poor cardiovascular outcomes are associated with differences in NOS3-dependent myocardial cGMP signaling and circulating NO metabolites.

Akt1 genetic deficiency limits hypothermia cardioprotection following murine cardiac arrest

Therapeutic hypothermia (TH) cardioprotection has recently been associated with increased Akt signaling in a rat model of cardiac arrest. However, it is not known whether Akt is required for this beneficial effect of TH. We used a mouse model of cardiac arrest demonstrating TH cardioprotection to study the response of mice deficient in an Akt1 allele. We hypothesized that Akt1 mediates TH cardioprotection and that decreases in Akt1 content would diminish such protection. Adult C57BL/6 wild-type (WT) mice underwent an 8-min cardiac arrest. After 6 min, the mice were randomized to normothermia (WT(NT), 37 degrees C) or TH (WT(TH), 30 degrees C). Following cardiopulmonary resuscitation and the return of spontaneous circulation (ROSC), the animals were hemodynamically monitored for 240 min (R240). At R240, cardiac tissue Akt content and phosphorylation were assayed. Studies were repeated in Akt1 heterozygous (Akt1(+/-)) mice. As a result, baseline characteristics and ROSC rates were equivalent across groups. At R240, WT(TH) mice exhibited lower heart rate, larger stroke volume, and higher cardiac output than WT(NT) animals (P < 0.05). Cardioprotection in WT(TH) at R240 was associated with increased cardiac Akt phosphorylation at Ser473 and Thr308 compared with that in WT(NT) (P < 0.05). TH-associated alterations in Akt phosphorylation, stroke volume, heart rate, and cardiac output were abrogated in Akt1(+/-) animals. In conclusion, TH improves post-ROSC cardiac function and increases Akt phosphorylation in WT, but not Akt1(+/-), mice. The Akt1 isoform appears necessary for TH-mediated cardioprotection.

Plasma and myocardial visfatin expression changes are associated with therapeutic hypothermia protection during murine hemorrhagic shock/resuscitation

AIM

Cytokine production during hemorrhagic shock (HS) could affect cardiac function during the hours after resuscitation. Visfatin is a recently described protein that functions both as a proinflammatory plasma cytokine and an intracellular enzyme within the nicotinamide adenine dinucleotide (NAD(+)) salvage pathway. We developed a mouse model of HS to study the effect of therapeutic hypothermia (TH) on hemodynamic outcomes and associated plasma and tissue visfatin content.

METHODS

Mice were bled and maintained at a mean arterial pressure (MAP) of 35 mmHg. After 30 min, animals (n=52) were randomized to normothermia (NT, 37+/-0.5 degrees C) or TH (33+/-0.5 degrees C) followed by rewarming at 60 min following resuscitation. After 90 min of HS (S90), mice were resuscitated and monitored for 180 min (R180). Visfatin, interleukin 6 (IL-6), keratinocyte-derived chemokine (KC), tumor necrosis factor-alpha (TNF-alpha), and myoglobin were measured by ELISA.

RESULTS

Compared to NT, TH animals exhibited improved R180 survival (23/26 [88.5%] vs. 13/26 [50%]; p=0.001). Plasma visfatin, IL-6, KC, and TNF-alpha increased by S90 in both groups (p<0.05). TH attenuated S90 plasma visfatin and, after rewarming, decreased R180 plasma IL-6, KC, and myoglobin (p<0.05) relative to NT. Heart and gut KC increased at S90 while IL-6 increases were delayed until R180 (p<0.05). NT produced sustained elevations of myocardial KC but decreased visfatin by R180, effects abrogated by TH (p<0.05).

CONCLUSIONS

In a mouse model of HS, TH improves hemodynamics and alters plasma and tissue proinflammatory cytokines including the novel cytokine visfatin. TH modulation of cytokines may attenuate cardiac dysfunction following HS.

Nitrite therapy after cardiac arrest reduces reactive oxygen species generation, improves cardiac and neurological function, and enhances survival via reversible inhibition of mitochondrial complex I

BACKGROUND

Three-fourths of cardiac arrest survivors die before hospital discharge or suffer significant neurological injury. Except for therapeutic hypothermia and revascularization, no novel therapies have been developed that improve survival or cardiac and neurological function after resuscitation. Nitrite (NO(2)(-)) increases cellular resilience to focal ischemia/reperfusion injury in multiple organs. We hypothesized that nitrite therapy may improve outcomes after the unique global ischemia/reperfusion insult of cardiopulmonary arrest.

METHODS AND RESULTS

We developed a mouse model of cardiac arrest characterized by 12 minutes of normothermic asystole and a high cardiopulmonary resuscitation rate. In this model, global ischemia and cardiopulmonary resuscitation were associated with blood and organ nitrite depletion, reversible myocardial dysfunction, impaired alveolar gas exchange, neurological injury, and an approximately 50% mortality. A single low dose of intravenous nitrite (50 nmol=1.85 micromol/kg=0.13 mg/kg) compared with blinded saline placebo given at cardiopulmonary resuscitation initiation with epinephrine improved cardiac function, survival, and neurological outcomes. From a mechanistic standpoint, nitrite treatment restored intracardiac nitrite and increased S-nitrosothiol levels, decreased pathological cardiac mitochondrial oxygen consumption resulting from reactive oxygen species formation, and prevented oxidative enzymatic injury via reversible specific inhibition of respiratory chain complex I.

CONCLUSIONS

Nitrite therapy after resuscitation from 12 minutes of asystole rapidly and reversibly modulated mitochondrial reactive oxygen species generation during early reperfusion, limiting acute cardiac dysfunction, death, and neurological impairment in survivors.

Derangements in blood glucose following initial resuscitation from in-hospital cardiac arrest: a report from the national registry of cardiopulmonary resuscitation

STUDY AIMS

Hyperglycemia is associated with poor outcomes in critically ill patients. We examined blood glucose values following in-hospital cardiac arrest (IHCA) to (1) characterize post-arrest glucose ranges, (2) develop outcomes-based thresholds of hyperglycemia and hypoglycemia, and (3) identify risk factors associated with post-arrest glucose derangements.

METHODS

We retrospectively studied 17,800 adult IHCA events reported to the National Registry of Cardiopulmonary Resuscitation (NRCPR) from January 1, 2005 through February 1, 2007.

RESULTS

Data were available from 3218 index events. Maximum blood glucose values were elevated in diabetics (median 226 mg/dL [IQR, 165-307 mg/dL], 12.5 mmol/L [IQR 9.2-17.0 mmol/L]) and non-diabetics (median 176 mg/dL [IQR, 135-239 mg/dL], 9.78 mmol/L [IQR 7.5-13.3 mmol/L]). Unadjusted survival to hospital discharge was higher in non-diabetics than diabetics (45.5% [95% CI, 43.3-47.6%] vs. 41.7% [95% CI, 38.9-44.5%], p=0.037). Non-diabetics displayed decreased adjusted survival odds for minimum glucose values outside the range of 71-170 mg/dL (3.9-9.4 mmol/L) and maximum values outside the range of 111-240 mg/dL (6.2-13.3 mmol/L). Diabetic survival odds decreased for minimum glucose greater than 240 mg/dL (13.3 mmol/L). In non-diabetics, arrest duration was identified as a significant factor associated with the development of hypo- and hyperglycemia.

CONCLUSIONS

Hyperglycemia is common in diabetics and non-diabetics following IHCA. Survival odds in diabetics are relatively insensitive to blood glucose with decreased survival only associated with severe (>240 mg/dL, >13.3 mmol/dL) hyperglycemia. In non-diabetics, survival odds were sensitive to hypoglycemia (<70 mg/dL, <3.9 mmol/L).

Cardiac catheterization is underutilized after in-hospital cardiac arrest

BACKGROUND

Indications for immediate cardiac catheterization in cardiac arrest survivors without ST elevation myocardial infarction (STEMI) are uncertain as electrocardiographic and clinical criteria may be challenging to interpret in this population. We sought to evaluate rates of early catheterization after in-hospital ventricular fibrillation (VF) arrest and the association with survival.

METHODS

Using a billing database we retrospectively identified cases with an ICD-9 code of cardiac arrest (427.5) or VF (427.41). Discharge summaries were reviewed to identify in-hospital VF arrests. Rates of catheterization on the day of arrest were determined by identifying billing charges. Unadjusted analyses were performed using Chi-square, and adjusted analyses were performed using logistic regression.

RESULTS

One hundred and ten in-hospital VF arrest survivors were included in the analysis. Cardiac catheterization was performed immediately or within 1 day of arrest in 27% (30/110) of patients and of these patients, 57% (17/30) successfully received percutaneous coronary intervention. Of those who received cardiac catheterization the indication for the procedure was STEMI or new left bundle branch block (LBBB) in 43% (13/30). Therefore, in the absence of standard ECG data suggesting acute myocardial infarction, 57% (17/30) received angiography. Patients receiving cardiac catheterization were more likely to survive than those who did not receive catheterization (80% vs. 54%, p<.05).

CONCLUSION

In patients receiving cardiac catheterization, more than half received this procedure for indications other than STEMI or new LBBB. Cardiac catheterization was associated with improved survival. Future recommendations need to be established to guide clinicians on which arrest survivors might benefit from immediate catheterization.

Intra-arrest cooling with delayed reperfusion yields higher survival than earlier normothermic resuscitation in a mouse model of cardiac arrest

BACKGROUND

Therapeutic hypothermia (TH) represents an important method to attenuate post-resuscitation injury after cardiac arrest. Laboratory investigations have suggested that induction of hypothermia before return of spontaneous circulation (ROSC) may confer the greatest benefit. We hypothesized that a short delay in resuscitation to induce hypothermia before ROSC, even at the expense of more prolonged ischemia, may yield both physiological and survival advantages.

METHODS

Cardiac arrest was induced in C57BL/6 mice using intravenous potassium chloride; resuscitation was attempted with CPR and fluid administration. Animals were randomized into three groups (n=15 each): a normothermic control group, in which 8 min of arrest at 37 degrees C was followed by resuscitation; an early intra-arrest hypothermia group, in which 6.5 min of 37 degrees C arrest were followed by 90s of cooling, with resuscitation attempted at 30 degrees C (8 min total ischemia); and a delayed intra-arrest hypothermia group, with 90s cooling begun after 8 min of 37 degrees C ischemia, so that animals underwent resuscitation at 9.5 min.

RESULTS

Animals treated with TH demonstrated improved hemodynamic variables and survival compared to normothermic controls. This was the case even when comparing the delayed intra-arrest hypothermia group with prolonged ischemia time against normothermic controls with shorter ischemia time (7-day survival, 4/15 vs. 0/15, p<0.001).

CONCLUSIONS

Short resuscitation delays to allow establishment of hypothermia before ROSC appear beneficial to both cardiac function and survival. This finding supports the concept that post-resuscitation injury processes begin immediately after ROSC, and that intra-arrest cooling may serve as a useful therapeutic approach to improve survival.

Altering CO2 during reperfusion of ischemic cardiomyocytes modifies mitochondrial oxidant injury

OBJECTIVE

Acute changes in tissue CO2 and pH during reperfusion of the ischemic heart may affect ischemia/reperfusion injury. We tested whether gradual vs. acute decreases in CO2 after cardiomyocyte ischemia affect reperfusion oxidants and injury.

DESIGN

Comparative laboratory investigation.

SETTING

Institutional laboratory.

SUBJECTS

Embryonic chick cardiomyocytes.

INTERVENTIONS

Microscope fields of approximately 500 chick cardiomyocytes were monitored throughout 1 hr of simulated ischemia (PO2 of 3-5 torr, PCO2 of 144 torr, pH 6.8), followed by 3 hrs of reperfusion (PO2 of 149 torr, PCO2 of 36 torr, pH 7.4), and compared with cells reperfused with relative hypercarbia (PCO2 of 71 torr, pH 6.8) or hypocarbia (PCO2 of 7 torr, pH 7.9).

MEASUREMENTS AND MAIN RESULTS

The measured outcomes included cell viability (via propidium iodide) and oxidant generation (reactive oxygen species via 2',7'-dichlorofluorescin oxidation and nitric oxide [NO] via 4,5-diaminofluorescein diacetate oxidation). Compared with normocarbic reperfusion, hypercarbia significantly reduced cell death from 54.8% +/- 4.0% to 26.3% +/- 2.8% (p < .001), significantly decreased reperfusion reactive oxygen species (p < .05), and increased NO at a later phase of reperfusion (p < .01). The NO synthase inhibitor N-nitro-L-arginine methyl ester (200 microM) reversed this oxidant attenuation (p < .05), NO increase (p < .05), and the cardioprotection conferred by hypercarbic reperfusion (increasing death to 54.3% +/- 6.0% [p < .05]). Conversely, hypocarbic reperfusion increased cell death to 80.4% +/- 4.5% (p < .01). It also increased reactive oxygen species by almost two-fold (p = .052), without affecting the NO level thereafter. Increased reactive oxygen species was attenuated by the mitochondrial complex III inhibitor stigmatellin (20 nM) when given at reperfusion (p < .05). Cell death also decreased from 85.9% +/- 4.5% to 52.2% +/- 6.5% (p < .01). The nicotinamide adenine dinucleotide phosphate oxidase inhibitor apocynin (300 microM) had no effect on reperfusion reactive oxygen species.

CONCLUSIONS

Altering CO2 content during reperfusion can significantly affect myocardial postresuscitation injury, in part by modifying mitochondrial oxidants and NO synthase-induced NO production.

A pilot study of ice-slurry application for inducing laparoscopic renal hypothermia

OBJECTIVE

To assess, in a pilot study, the feasibility of delivering a microparticulate ice slurry (MPS) to provide regional hypothermia, as renal cooling during laparoscopic procedures is cumbersome and inefficient.

MATERIALS AND METHODS

An ex vivo preparation was used to simulate the boundary conditions of a kidney. Four pig kidneys were placed onto a thin membrane overlying a constant temperature bath (37 degrees C) with parenchymal thermocouples. Renal surfaces were coated with MPS and temperatures recorded. In an in vivo pig model we assessed laparoscopic delivery and cooling ability of the MPS under physiological conditions. Kidneys in two pigs were laparoscopically exposed; thermocouple probes were placed throughout the kidney and the hilum was clamped. MPS was delivered through a modified 5-mm laparoscopic suction/irrigation cannula. Cortical and core body temperatures were measured.

RESULTS

In the ex vivo study, the mean (sd) initial temperature was 37.1 (0.4) degrees C; the mean time to reach 15 degrees C was 10.3 (2.6) min and the mean nadir temperature was 13.0 (1.5) degrees C. In vivo, the MPS was delivered with no technical difficulty; the mean renal unit starting temperature and core body temperature were 37.2 degrees C and 37.0 degrees C, respectively. The mean (range) time to reach 15 degrees C was 16.5 (5.5-28.6) min. The mean nadir core body temperature was 34.0 degrees C.

CONCLUSION

This initial study showed efficient and rapid induction of renal hypothermia using MPS delivered through 5-mm laparoscopic ports, with no technical difficulty. These exploratory pilot findings support further, larger scale, histopathological and renal functional investigations of topical ice slurries as a means of providing renal hypothermia in laparoscopic procedures.

Clinical and hemodynamic comparison of 15:2 and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation*

OBJECTIVE

To compare cardiopulmonary resuscitation (CPR) with a compression to ventilation (C:V) ratio of 15:2 vs. 30:2, with and without use of an impedance threshold device (ITD).

DESIGN

Prospective randomized animal and manikin study.

SETTING

Animal laboratory and emergency medical technician training facilities.

SUBJECTS

Twenty female pigs and 20 Basic Life Support (BLS)-certified rescuers.

INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS

ANIMALS

Acid-base status, cerebral, and cardiovascular hemodynamics were evaluated in 18 pigs in cardiac arrest randomized to a C:V ratio of 15:2 or 30:2. After 6 mins of cardiac arrest and 6 mins of CPR, an ITD was added. Compared to 15:2, 30:2 significantly increased diastolic blood pressure (20 +/- 1 to 26 +/- 1; p < .01); coronary perfusion pressure (18 +/- 1 to 25 +/- 2; p = .04); cerebral perfusion pressure (16 +/- 3 to 18 +/- 3; p = .07); common carotid blood flow (48 +/- 5 to 82 +/- 5 mL/min; p < .001); end-tidal CO2 (7.7 +/- 0.9 to 15.7 +/- 2.4; p < .0001); and mixed venous oxygen saturation (26 +/- 5 to 36 +/- 5, p < .05). Hemodynamics improved further with the ITD. Oxygenation and arterial pH were similar. Only one of nine pigs had return of spontaneous circulation with 15:2, vs. six of nine with 30:2 (p < 0.03). HUMANS: Fatigue and quality of CPR performance were evaluated in 20 BLS-certified rescuers randomized to perform CPR for 5 mins at 15:2 or 30:2 on a recording CPR manikin. There were no significant differences in the quality of CPR performance or measurement of fatigue. Significantly more compressions per minute were delivered with 30:2 in both the animal and human studies.

CONCLUSIONS

These data strongly support the contention that a ratio of 30:2 is superior to 15:2 during manual CPR and that the ITD further enhances circulation with both C:V ratios.

Induced hypothermia by central venous infusion: Saline ice slurry versus chilled saline

OBJECTIVE

Surface cooling improves outcome in selected comatose survivors of cardiac arrest. Internal cooling with considerable volumes of intravenous cold saline may accelerate hypothermia induction. This study compares core temperatures in swine after central catheter infusions of saline ice slurry (saline with smoothed 100-microm-size ice particles) vs. an equal volume of chilled saline. We hypothesized that slurry would achieve core hypothermia (32-34 degrees C) more consistently and at a faster rate.

DESIGN

A total of 11 swine were randomized to receive microparticulate ice slurry, chilled saline infusion, or anesthesia alone in a monitored laboratory setting.

INTERVENTIONS

Intravenous bolus (50 mL/kg) of slurry or chilled 1.5% NaCl saline. Slurry was composed of a 1:1 mixture of ice and distilled H2O plus NaCl.

MEASUREMENTS

Cerebral cortex, tympanic membrane, inferior vena cava, rectal temperatures, electrocardiogram, arterial blood pressure, and arterial oxygen saturation were recorded for 1 hr after bolus.

MAIN RESULTS

Compared with anesthetized controls, core brain temperatures of the saline and slurry groups dropped by 3.4 +/- 0.4 degrees C and 5.3 +/- 0.7 degrees C (p = .009), respectively. With an infusion rate of 120 mL/min, cooling rates for the saline and slurry groups were -11.6 +/- 1.8 degrees C/hr and -18.2 +/- 2.9 degrees C/hr, respectively, during the first 20 mins. Four of four animals in the slurry group vs. zero of four animals in the saline group achieved target cortical temperatures of <34 degrees C.

CONCLUSIONS

Cold intravenous fluids rapidly induce hypothermia in swine with intact circulation. A two-phase (liquid plus ice) saline slurry cools more rapidly than an equal volume of cold saline at 0 degrees C. Ice-slurry could be a significant improvement over other cooling methods when rate of cooling and limited infusion volumes are important to the clinician.

Model of cortical-basal ganglionic processing: encoding the serial order of sensory events

Several lines of evidence suggest that the prefrontal (PF) cortex and basal ganglia are important in cognitive aspects of serial order in behavior. We present a modular neural network model of these areas that encodes the serial order of events into spatial patterns of PF activity. The model is based on the topographically specific circuits linking the PF with the basal ganglia. Each module traces a pathway from the PF, through the basal ganglia and thalamus, and back to the PF. The complete model consists of an array of modules interacting through recurrent corticostriatal projections and collateral inhibition between striatal spiny units. The model's architecture positions spiny units for the classification of cortical contexts and events and provides bistable cortical-thalamic loops for sustaining a representation of these contextual events in working memory activations. The model was tested with a simulated version of a delayed-sequencing task. In single-unit studies, the task begins with the presentation of a sequence of target lights. After a short delay, the monkey must touch the targets in the order in which they were presented. When instantiated with randomly distributed corticostriatal weights, the model produces different patterns of PF activation in response to different target sequences. These patterns represent an unambiguous and spatially distributed encoding of the sequence. Parameter studies of these random networks were used to compare the computational consequences of collateral and feed-forward inhibition within the striatum. In addition, we studied the receptive fields of 20,640 model units and uncovered an interesting set of cue-, rank- and sequence-related responses that qualitatively resemble responses reported in single unit studies of the PF. The majority of units respond to more than one sequence of stimuli. A method for analyzing serial receptive fields is presented and utilized for comparing the model units to single-unit data.

Network models of the basal ganglia

Over the past year, a number of conceptual and mathematical models of the basal ganglia and their interactions with other areas of the brain have appeared in the literature. Even though the models each differ in significant ways, several computational principles, such as convergence, recurrence and competition, appear to have emerged as common themes of information processing in the basal ganglia. Simulation studies of these models have provoked new types of questions at the many levels of inquiry linking biophysics to behavior.