The effect of mild to moderate COVID-19 infection on the cardiorespiratory fitness of firefighters.

Introduction: An adequate level of cardiorespiratory fitness (CRF) is critical for firefighters to perform the strenuous and physiologically demanding work of firefighting safely and effectively. The coronavirus disease 2019 (COVID-19) has been shown to negatively impact CRF in both the acute phase and longer-term following infection. This study aimed to determine changes to the CRF of firefighters pre- to post-mild to moderate COVID-19 infection and to investigate the impact of days past COVID-19 infection on change in CRF. Methods: CRF measures from cardiopulmonary exercise testing (CPET) at annual occupational health exams that occurred pre-COVID-19 infection in 2019 were obtained for firefighters from seven Arizona fire departments. Measures were compared to CPET evaluations from annual health exams the following year in a cohort of firefighters who self-reported mild to moderate illness following COVID-19 infection between exams. Results: Among a cohort of 103 firefighters, mean age 40 ± 9 years, CRF [as measured by peak oxygen consumption (VO2)] declined by an average of 2.55 ml·kg-1·min-1 or 7.3% (d = -0.38, p < 0.001) following COVID-19 infection (mean time from COVID-19 infection to CPET was 110 ± 78 days). The number of days past COVID-19 infection showed a small, yet significant, relationship to peak VO2 (r = 0.250, p = 0.011). Estimated marginal effects indicated that when biological sex, age, and BMI are controlled for, predicted peak VO2 returned to pre-COVID-19 values ~300 days after COVID-19 infection. Conclusion: Peak VO2 (ml·kg-1·min-1) declined 7.3% among firefighters an average of 110 days past reporting mild to moderate COVID-19 infection. This decrease has implications for the operational readiness and safety of firefighters.

Database derived from an electronic medical record-based surveillance network of US emergency department patients with acute respiratory illness.

BACKGROUND: For surveillance of episodic illness, the emergency department (ED) represents one of the largest interfaces for generalizable data about segments of the US public experiencing a need for unscheduled care. This protocol manuscript describes the development and operation of a national network linking symptom, clinical, laboratory and disposition data that provides a public database dedicated to the surveillance of acute respiratory infections (ARIs) in EDs. METHODS: The Respiratory Virus Laboratory Emergency Department Network Surveillance (RESP-LENS) network includes 26 academic investigators, from 24 sites, with 91 hospitals, and the Centers for Disease Control and Prevention (CDC) to survey viral infections. All data originate from electronic medical records (EMRs) accessed by structured query language (SQL) coding. Each Tuesday, data are imported into the standard data form for ARI visits that occurred the prior week (termed the index file); outcomes at 30 days and ED volume are also recorded. Up to 325 data fields can be populated for each case. Data are transferred from sites into an encrypted Google Cloud Platform, then programmatically checked for compliance, parsed, and aggregated into a central database housed on a second cloud platform prior to transfer to CDC. RESULTS: As of August, 2023, the network has reported data on over 870,000 ARI cases selected from approximately 5.2 million ED encounters. Post-contracting challenges to network execution have included local shifts in testing policies and platforms, delays in ICD-10 coding to detect ARI cases, and site-level personnel turnover. The network is addressing these challenges and is poised to begin streaming weekly data for dissemination. CONCLUSIONS: The RESP-LENS network provides a weekly updated database that is a public health resource to survey the epidemiology, viral causes, and outcomes of ED patients with acute respiratory infections.

Towards optical frequency geopotential difference measurements via a flying drone.

Geopotential and orthometric height differences between distant points can be measured via timescale comparisons between atomic clocks. Modern optical atomic clocks achieve statistical uncertainties on the order of 10-18, allowing height differences of around 1 cm to be measured. Frequency transfer via free-space optical links will be needed for measurements where linking the clocks via optical fiber is not possible, but requires line of sight between the clock locations, which is not always practical due to local terrain or over long distances. We present an active optical terminal, phase stabilization system, and phase compensation processing method robust enough to enable optical frequency transfer via a flying drone, greatly increasing the flexibility of free-space optical clock comparisons. We demonstrate a statistical uncertainty of 2.5×10-18 after 3 s of integration, corresponding to a height difference of 2.3 cm, suitable for applications in geodesy, geology, and fundamental physics experiments.

Demonstration of 100 Gbps coherent free-space optical communications at LEO tracking rates.

Free-space optical communications are poised to alleviate the data-flow bottleneck experienced by spacecraft as traditional radio frequencies reach their practical limit. While enabling orders-of-magnitude gains in data rates, optical signals impose much stricter pointing requirements and are strongly affected by atmospheric turbulence. Coherent detection methods, which capitalize fully on the available degrees of freedom to maximize data capacity, have the added complication of needing to couple the received signal into single-mode fiber. In this paper we present results from a coherent 1550 nm link across turbulent atmosphere between a deployable optical terminal and a drone-mounted retroreflector. Through 10 Hz machine vision optical tracking with nested 200 Hz tip/tilt adaptive optics stabilisation, we corrected for pointing errors and atmospheric turbulence to maintain robust single mode fiber coupling, resulting in an uninterrupted 100 Gbps optical data link while tracking at angular rates of up to 1.5 deg/s, equivalent to that of spacecraft in low earth orbit. With the greater data capacity of coherent communications and compatibility with extant fiber-based technologies being demonstrated across static links, ground-to-low earth orbit links of Terabits per second can ultimately be achieved with capable ground stations.

Angle-of-arrival variability of retroreflected lasers despite atmospheric reciprocity.

Corner cube retroreflectors are commonly used as cooperative targets in free-space laser applications. The previous literature suggests that due to path reciprocity, a retroreflected beam is self-corrected across a turbulent atmosphere and should show no angle-of-arrival variability in the near field. This is at odds with recent experiments that rely on angle-of-arrival measurements in retroreflected beams for effective tip/tilt correction. In this Letter we investigate the mechanism behind observed angle-of-arrival variability using numerical field propagation to model various transceiver and retroreflector geometries. We determine that asymmetric truncation of a curved wavefront at the retroreflector, transceiver, or both, results in a difference in tip/tilt between the transmitted and reflected wavefronts. This difference propagates as angle-of-arrival variation at the transceiver despite reciprocity, providing the error signal necessary for adaptive optics tip/tilt correction without a remote beacon.

Oral Antiplatelet Therapy Administered Upstream to Patients With NSTEMI.

OBJECTIVE: To describe from a noninterventional registry (Utilization of Ticagrelor in the Upstream Setting for Non-ST-Segment Elevation Acute Coronary Syndrome), the short-term ischemic and hemorrhagic outcomes in patients with non-ST elevation myocardial infarction (MI) are managed with a loading dose (LD) of a P2Y12 inhibitor (P2Y12i) given at least 4 hours before diagnostic angiography and delineation of coronary anatomy. Prior data on the effects of such "upstream loading" have been inconsistent. METHODS: In 53 US hospitals, we evaluated the in-hospital care and outcomes of patients with confirmed non-ST elevation MI managed with an interventional strategy and loaded upstream (at least 4 h before diagnostic angiography) with oral P2Y12i therapy. Patients entered into the database were grouped into 1 of 4 cohorts for analysis: (1) overall cohort, (2) thienopyridine (clopidogrel or prasugrel) load, (3) ticagrelor load, and (4) ticagrelor-consistent. The fourth cohort is a subset of cohort 3 that received ticagrelor throughout the index hospital stay and at discharge. We evaluated in-hospital clinical course and ischemic and bleeding outcomes in all patients and also 30-day outcomes in the ticagrelor-consistent cohort. RESULTS: A total of 3355 patients were enrolled, of whom 1087 had 30-day follow-up. The mean (±SD) age was 63.3 ± 12.5 years, and 62.6% were male. Thrombolysis in MI and Global Registry of Acute Coronary Events scores placed these patients in the intermediate risk range, and CRUSADE scores were in the moderate risk range. The LD in Utilization of Ticagrelor in the Upstream Setting for Non-ST-Segment Elevation Acute Coronary Syndrome was clopidogrel in 45.6%, ticagrelor in 53.6%, and prasugrel in 0.8%. The median upstream interval (LD to angiography) was 17:27 hours and did not change appreciably over the course of the data collection period (2/15-10/19). Access was radial in 48.6% and femoral in 51.4%. Postangiography management was medical only in 32.3%, percutaneous coronary intervention in 59.4%, and coronary artery bypass grafting in 8.3%. Median length of stay was 2.7 days, and median time from angiography to coronary artery bypass grafting was 3.6 days. In-hospital mortality was 0.51%, and major bleeding (thrombolysis in MI) was 0.24%; the in-hospital major adverse cardiovascular events rate was 0.7%, and stent thrombosis occurred in 0.18%. No significant differences were seen between the ticagrelor and clopidogrel cohorts in hospital, but 16% received more than 1 P2Y12i in-hospital. On follow-up (93.2% response), 86.7% of patients reported taking ticagrelor as directed. CONCLUSIONS: Upstream loading of P2Y12i was associated with very low rates of bleeding and short length of stay in a large cohort of non-ST elevation MI (NSTEMI) patients managed invasively.

The safety of oral anticoagulants registry (SOAR): A national, ED-based study of the evaluation and management of bleeding and bleeding concerns due to the use of oral anticoagulants.

OBJECTIVE: The Safety of Oral Anticoagulants Registry (SOAR) was designed to describe the evaluation and management of patients with oral anticoagulant (OAC)-related major bleeding or bleeding concerns who present to the emergency department (ED) with acute illness or injury. Patients in the ED are increasingly taking anticoagulants, which can cause bleeding-related complications as well as impact the acute management of related or unrelated clinical issues that prompt presentation. Modifications of emergency evaluation and management due to anticoagulation have not previously been studied. METHODS: This was a multicenter observational in-hospital study of patients who were judged to be experiencing an active OAC effect and had (a) an obvious bleeding event or (b) were deemed at risk for serious bleeding spontaneously, after injury, or during an indicated invasive procedure. Diagnostic testing, therapies employed, and clinical outcomes were collected. RESULTS: Thirty-one US hospitals contributed data to SOAR. Of 1513 subjects, acute hemorrhage (AH) qualified 78%, while 22% had a bleeding concern (BC). Warfarin was the index OAC in 37.3%, dabigatran in 13.3%, and an anti-Factor Xa in 49.4%. The most common sites of AH were gastrointestinal (51.0%) and intracranial (26.8%). In warfarin-treated patients, the mean (IQR) presenting INR was 3.1 (2.2, 4.8) in AH patients and 3.9 (2.4, 7.2) in BC patients. Three-fifths of SOAR patients were treated with factor repletion or specific reversal agents, and those patients had a longer length of stay. In addition, seven (0.76%) of the treated patients experienced an in-hospital thrombotic complication; two of these seven died on the index admission, both of fatal pulmonary embolism. Vitamin K was used and dosed inconsistently in both warfarin and NOAC cohorts. CONCLUSION: Care of anticoagulated patients in the acute care setting is inconsistent, reflecting the diversity of presentation. As the prevalence of OAC use increases with the aging of the US population, further study and targeted educational efforts are needed to drive more evidence-based care of these patients.