Signal Transceiver Transit Times and Propagation Delay Corrections for Ranging and Georeferencing Applications

The accuracy of ranging measurements depends critically on the knowledge of time delays undergone by signals when retransmitted by a remote transponder and due to propagation effects. A new method determines these delays for every single pulsed signal transmission. It utilizes four ground-based reference stations, synchronized in time and installed at well-known geodesic coordinates and a repeater in space, carried by a satellite, balloon, aircraft, and so forth. Signal transmitted by one of the reference bases is retransmitted by the transponder, received back by the four bases, producing four ranging measurements which are processed to determine uniquely the time delays undergone in every retransmission process. A minimization function is derived comparing repeater's positions referred to at least two groups of three reference bases, providing the signal transit time at the repeater and propagation delays, providing the correct repeater position. The method is applicable to the transponder platform positioning and navigation, time synchronization of remote clocks, and location of targets. The algorithm has been demonstrated by simulations adopting a practical example with the transponder carried by an aircraft moving over bases on the ground.CNPq Agency (Brazil)Brazil agency CNPqBrazil agency CAPESBrazil agency CAPE

Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

<p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

Temporal trends in characteristics and outcomes associated with in-hospital cardiac arrest: A 20-year analysis (1999-2018)

Background Despite advances in resuscitation medicine, the burden of in-hospital cardiac arrest (IHCA) remains substantial. The impact of these advances and changes in resuscitation guidelines on IHCA survival remains poorly defined. To better characterize evolving patient characteristics and temporal trends in the nature and outcomes of IHCA, we undertook a 20-year analysis of a national database. Methods and Results We analyzed the National Inpatient Sample (1999-2018) using International Classification of Diseases, Ninth Revision and Tenth Revision, Clinical Modification (ICD-9-CM and ICD-10-CM) codes to identify all adult patients suffering IHCA. Subgroup analysis was performed based on the type of cardiac arrest (ie, ventricular tachycardia/ventricular fibrillation or pulseless electrical activity-asystole). An age- and sex-adjusted model and a multivariable risk-adjusted model were used to adjust for potential confounders. Over the 20-year study period, a steady increase in rates of IHCA was observed, predominantly driven by pulseless electrical activity-asystole arrest. Overall, survival rates increased by over 10% after adjusting for risk factors. In recent years (2014-2018), a similar trend toward improved survival is noted, though this only achieved statistical significance in the pulseless electrical activity-asystole cohort. Conclusions Though the ideal quality metric in IHCA is meaningful neurological recovery, survival is the first step toward this. As overall IHCA rates rise, overall survival rates are improving in tandem. However, in more recent years, these improvements have plateaued, especially in the realm of ventricular tachycardia/ventricular fibrillation-related survival. Future work is needed to better identify characteristics of IHCA nonsurvivors to improve resource allocation and health care policy in this area

Painting profiles of ambulatory advanced heart failure: A report from the revival registry

Purpose: Ambulatory patients with advanced heartfailure (HF) are increasingly being considered for mechanical circulatory support. INTERMACS patient profiles are a commonly used short-hand for HF disease severity and describe clinical trajectory, but have not been validated for use in ambulatorypatients on oral medical therapy. Methods: REVIVAL, a prospective, observational study, enrolled 400 outpatients from 21 VAD/transplant centers in 2015-16. Subjects had NYHA Class II-IV systolic HF despite optimal medical and electrical therapies, as well as arecent HF hospitalization, transplant listing, functional limitation, or evidence of high neurohormonal activation. Exclusion criteria included inotropes, dialysis or creatinine \u3e 3mg/dL, or a non-cardiac disease limiting function or survival. Baseline characteristics, medications, and laboratories were evaluated according to INTERMACS profile assigned at enrollment by thetreating physician. Continuous data were compared by one way ANOVA or Wilcoxon rank sum, categorical data using Chi-square test. Results: Across INTERMACS patient profiles 4-7, there was no difference in age, gender, race, ejection fraction, blood pressure, jugular venous pressure, use ofguideline-directed medical therapy, or most laboratories. However, lower INTERMACS profile was associated with progressively shorter 6-minute walk distance, higher uric acid level, and higher anticipated mortality by the Seattle HF Model Score. (TABLE) Conclusion: Among ambulatory patients with advanced HF, lower INTERMACS profile was associated with increased disease severity as reflected by greater functional limitation and higher anticipated mortality. INTERMACS profiling is aconvenient short-hand that encapsulates relevant prognostic information across multiple clinical domains. These profiles may assist in identifying ambulatory patients for consideration of advancedor investigational therapies (Table presented)

Impact of socioeconomic factors on patient desire for LVAD therapy

Purpose: While increased heart failure (HF) severity and poor quality of life (QOL) have been associated with the decision to receive a left ventricular assist device (LVAD), we examined if socioeconomic factors were associated with patient willingness to accept an LVAD. Methods: We studied ambulatory patients with advanced HF (n= 400) from the REVIVAL Registry. Subjects were classified into 3 groups based on their responses after receiving basic information about benefits and risks of LVAD therapy: 1-wanting LVAD, 2-unsure, 3-not wanting LVAD to treat their current level ofHF. Logistic regression analysis was performed to identify clinical and demographic predictors of wanting an LVAD. Results: Patient characteristics are shown in Table 1. Lower education level, lower income, worse QOL and higher NYHA class were significant univariable predictors of patients wanting LVAD (p\u3c 0.05 for all). In the multivariable model, higher NYHA class and lower income remained significant independent predictors (p= 0.003 and 0.041, respectively). Every unit increase in NYHA class was associated with a 1.79 times higher odds of wanting LVAD vs. combined unsure and not wanting LVAD. Compared to those with income \u3e $80K, patients with income \u3c$40K and those with income $40K-80K were 2.28 and 2.17 times more likely to want LVAD vs. combined unsure and not wanting LVAD(Table 2). Conclusion: Patients preference for LVAD is influenced by level of income independently of severity ofHF, with greater preference for LVAD among lower and middle tier income groups. Understanding impact ofsocioeconomic factors on patients desire to accept LVADmay help tailor discussion to individual needs (Table presented)

Insurance Status and Quality of Diabetes Care in Community Health Centers

Objectives. We sought to compare quality of diabetes care by insurance type in federally funded community health centers

Caregiver burden before heart transplantation and long-term mechanical circulatory support: Findings from the Sustaining Quality of Life of the Aged: Transplant or Mechanical Support (SUSTAIN-IT) study

Background: Caregiving for heart failure (HF) patients is burdensome. We examined differences in caregiver burden for three groups of older advanced HF patients: (1) supported with mechanical circulatory support (MCS) before heart transplantation (HT MCS), (2) awaiting transplant without MCS (HT non-MCS), and (3) prior to long-term MCS and factors associated with burden. Methods: From 10/1/15-12/31/18, we enrolled 276 caregivers for HF patients from 13 U.S. sites: 85 HT MCS, 96 HT non-MCS, and 95 prior to long-term MCS. At enrollment, caregivers completed the Oberst Caregiving Burden Scale (15 items, 2 subscales: time (range=1-5; higher score=more time spent on task) and difficulty (range=1-5; higher score=higher difficulty of task) and other measures. Statistical analyses included descriptive statistics, ANOVA, chi-square tests, and linear regression. Results: Overall, caregivers were aged 60.8±9.8 years and predominantly white, female, spouses, well educated, and reported ≥1 comorbidities. Caregivers overall reported a moderate amount of time spent on tasks and slight task difficulty. Caregivers for HT non-MCS candidates reported significantly less perceived time spent on tasks than caregivers for HT MCS candidates and caregivers for patients prior to long-term MCS (2.2±0.74 vs 2.4±0.74 vs 2.5±0.71, respectively, p=0.02) and less perceived difficulty of tasks (1.2±0.33 vs 1.4±0.53 vs 1.4±0.54, respectively, p=0.01). Caregiver and patient factors were associated with caregiver burden. Conclusions: Prior to HT and long-term MCS, caregiver burden was low to moderate. Caregiver factors were predominantly associated with caregiver burden. Understanding caregiver burden and factors affecting caregiver burden may enhance preoperative advanced therapies discussions and guide caregiver support