Cardiopulmonary testing in long COVID-19 versus non-COVID-19 patients with undifferentiated Dyspnea on exertion.

BACKGROUND: Dyspnea and fatigue are characteristics of long SARS-CoV-2 (COVID)-19. Cardiopulmonary exercise testing (CPET) can be used to better evaluate such patients. RESEARCH QUESTION: How significantly and by what mechanisms is exercise capacity impaired in patients with long COVID who are coming to a specialized clinic for evaluation? STUDY DESIGN AND METHODS: We performed a cohort study using the Mayo Clinic exercise testing database. Subjects included consecutive long COVID patients without prior history of heart or lung disease sent from the Post-COVID Care Clinic for CPET. They were compared to a historical group of non-COVID patients with undifferentiated dyspnea also without known cardiac or pulmonary disease. Statistical comparisons were performed by t-test or Pearson's chi2 test controlling for age, sex, and beta blocker use where appropriate. RESULTS: We found 77 patients with long COVID and 766 control patients. Long COVID patients were younger (47 ± 15 vs 50 ± 10 years, P < .01) and more likely female (70% vs 58%, P < .01). The most prominent difference on CPETs was lower percent predicted peak V̇O2 (73 ± 18 vs 85 ± 23%, p < .0001). Autonomic abnormalities (resting tachycardia, CNS changes, low systolic blood pressure) were seen during CPET more commonly in long COVID patients (34 vs 23%, P < .04), while mild pulmonary abnormalities (mild desaturation, limited breathing reserve, elevated V̇E/V̇CO2) during CPET were similar (19% in both groups) with only 1 long COVID patient showing severe impairment. INTERPRETATION: We identified severe exercise limitation among long COVID patients. Young women may be at higher risk for these complications. Though mild pulmonary and autonomic impairment were common in long COVID patients, marked limitations were uncommon. We hope our observations help to untangle the physiologic abnormalities responsible for the symptomatology of long COVID.

Supporting Professionals in Critical Care Medicine: Burnout, Resiliency, and System-Level Change.

Burnout is occurring in epidemic proportions among intensive care unit physicians and other health-care professionals-accelerated by pandemic-driven stress. The impact of burnout is far-reaching, threatening the health of individual workers, the safety and quality of care our patients receive, and eroding the infrastructure of health care in general. Drivers of burnout include excessive quantity of work (nights, weekends, and acuity surges); excessive menial tasks; incivility, poor communication, and challenges to team success; and frequent moral distress and end-of-life issues. This article provides system-based practice and individual strategies to address these drivers and improve the well-being of our team and our patients.

Critical Care Staffing in Pandemics and Disasters: A Consensus Report From a Subcommittee of the Task Force for Mass Critical Care - Systems Strategies to Sustain the Health Care Workforce.

BACKGROUND: The COVID-19 pandemic has led to unprecedented mental health disturbances, burnout, and moral distress among health care workers, affecting their ability to care for themselves and their patients. RESEARCH QUESTION: In health care workers, what are key systemic factors and interventions impacting mental health and burnout? STUDY DESIGN AND METHODS: The Workforce Sustainment subcommittee of the Task Force for Mass Critical Care (TFMCC) utilized a consensus development process, incorporating evidence from literature review with expert opinion through a modified Delphi approach to determine factors affecting mental health, burnout, and moral distress in health care workers, to propose necessary actions to help prevent these issues and enhance workforce resilience, sustainment, and retention. RESULTS: Consolidation of evidence gathered from literature review and expert opinion resulted in 197 total statements that were synthesized into 14 major suggestions. These suggestions were organized into three categories: (1) mental health and well-being for staff in medical settings; (2) system-level support and leadership; and (3) research priorities and gaps. Suggestions include both general and specific occupational interventions to support health care worker basic physical needs, lower psychological distress, reduce moral distress and burnout, and foster mental health and resilience. INTERPRETATION: The Workforce Sustainment subcommittee of the TFMCC offers evidence-informed operational strategies to assist health care workers and hospitals plan, prevent, and treat the factors affecting health care worker mental health, burnout, and moral distress to improve resilience and retention following the COVID-19 pandemic.

Use of a Viral Filter to Reduce Exposure to Exhaled Aerosol Does Not Affect Methacholine Dose Delivery During Bronchoprovocation Testing.

BACKGROUND: Methacholine challenge testing (MCT) is a common bronchoprovocation technique used to assess airway hyper-responsiveness. We previously demonstrated that the addition of a viral filter to the nebulizer exhalation limb substantially reduced expelled particles during MCT. Our aim was to evaluate whether this modification affects the delivered dose of methacholine. METHODS: A mechanical ventilator was connected to a lung simulator with breathing frequency 15 breaths/min, tidal volume 500 mL, inspiratory-expiratory ratio 1:1, with a sinusoidal waveform. We compared methacholine dose delivery using the Hudson Micro Mist or AeroEclipse II BAN nebulizers powered by either a dry gas source or a compressor system. A filter placed in line between the nebulizer and test lung was weighed before and after 1 min of nebulized methacholine delivery. Mean inhaled mass was measured with and without a viral filter on the exhalation limb. Dose delivery was calculated by multiplying the mean inhaled mass by the respirable fraction (particles < 5 µm) and inhalation time. Unpaired t test was used to compare methacholine dose delivery with and without viral filter placement. RESULTS: The addition of a viral filter did not significantly affect methacholine dose delivery across all devices tested. Using a 50-psi dry gas source, dose delivered with or without a viral filter did not differ with the Hudson (422.3 µg vs 282.0 µg, P = .11) or the AeroEclipse nebulizer (563.0 µg vs 657.6 µg, P = .59). Using the compressor, dose delivered with and without a viral filter did not differ with the Hudson (974.0 µg vs 868.0 µg, P = .03) or the AeroEclipse nebulizer (818.0 µg vs 628.5 µg, P = .42). CONCLUSIONS: The addition of a viral filter to the nebulizer exhalation limb did not affect methacholine dose during bronchoprovocation testing. Routine use of a viral filter should be considered to improve pulmonary function technician safety and infection control measures during the ongoing COVID-19 pandemic.

International Virtual Simulation Education in Critical Care During COVID-19 Pandemic: Preliminary Description of the Virtual Checklist for Early Recognition and Treatment of Acute Illness and iNjury Program.

SUMMARY STATEMENT: The Checklist for Early Recognition and Treatment of Acute Illness and iNjury program is a well-established, interactive, and simulation-based program designed to improve the quality of care delivered in intensive care units. The COVID-19 pandemic created an overwhelming surge of critically ill patients worldwide, and infection control concerns limited healthcare providers' access to in-person and hands-on simulation training when they needed it the most. Virtual simulation offers an alternative to in-person training but is often complex and expensive. We describe our successful development and initial implementation of an inexpensive, simulation-based virtual Checklist for Early Recognition and Treatment of Acute Illness and iNjury program to address the pressing need for effective critical care training in various resource-limited settings both within and outside of the United States. The overall satisfaction rate ("excellent" or "very good" responses) was 94.4% after the virtual simulation workshop. Our initial experience suggests that virtual interactions can be engaging and build strong relationships, like in-person continuing professional education, even using relatively simple technology. This knowledge-to-practice improvement platform can be readily adapted to other disciplines beyond critical care medicine.

Aerosol Generation and Mitigation During Methacholine Bronchoprovocation Testing: Infection Control Implications in the Era of COVID-19.

BACKGROUND: Methacholine bronchoprovocation or challenge testing (MCT) is commonly performed to assess airway hyper-responsiveness in the setting of suspected asthma. Nebulization is an aerosol-generating procedure, but little is known about the risks of MCT in the context of the ongoing coronavirus disease 2019 (COVID-19) pandemic. We aimed to quantify and characterize aerosol generation during MCT by using different delivery methods and to assess the impact of adding a viral filter. METHODS: Seven healthy subjects performed simulated MCT in a near particle-free laboratory space with 4 different nebulizers and with a dosimeter. Two devices continuously sampled the ambient air during the procedure, which detected ultrafine particles, from 0.02-1 µm, and particles of sizes 0.3, 0.5, 1.0, 2.0, 5.0, and 10 µm, respectively. Particle generation was compared among all the devices, with and without viral filter placement. RESULTS: Ultrafine-particle generation during simulated MCT was significant across all the devices. Ultrafine-particle (0.02-1 µm) concentrations decreased 77%-91% with the addition of a viral filter and varied significantly between unfiltered (P < .001) and filtered devices (P < .001). Ultrafine-particle generation was lowest when using the dosimeter with filtered Hudson nebulizer (1,258 ± 1,644 particle/mL). Ultrafine-particle concentrations with the filtered nebulizer devices using a compressor were higher than particle concentrations detected when using the dosimeter: Monaghan (3,472 ± 1,794 particles/mL), PARI (4,403 ± 2,948), Hudson (6,320 ± 1,787) and AirLife (9,523 ± 5,098). CONCLUSIONS: The high particle concentrations generated during MCT pose significant infection control concerns during the COVID-19 pandemic. Particle generation during MCT was significantly reduced by using breath-actuated delivery and a viral filter, which offers an effective mitigation strategy.

Mitigation of Aerosols Generated During Exercise Testing With a Portable High-Efficiency Particulate Air Filter With Fume Hood.

BACKGROUND: The role of portable high-efficiency particulate air (HEPA) filters for supplemental aerosol mitigation during exercise testing is unknown and might be relevant during COVID-19 pandemic. RESEARCH QUESTION: What is the effect of portable HEPA filtering on aerosol concentration during exercise testing and its efficiency in reducing room clearance time in a clinical exercise testing laboratory? STUDY DESIGN AND METHODS: Subjects were six healthy volunteers aged 20 to 56 years. In the first experiment, exercise was performed in a small tent with controlled airflow with the use of a stationary cycle, portable HEPA filter with fume hood, and particle counter to document aerosol concentration. Subjects performed a four-stage maximal exercise test that lasted 12 min plus 5 min of pretest quiet breathing and 3 min of active recovery. First, they exercised without mitigation then with portable HEPA filter running. In a separate experiment, room aerosol clearance time was measured in a clinical exercise testing laboratory by filling it with artificially generated aerosols and measuring time to 99.9% aerosol clearance with heating, ventilation, and air conditioning (HVAC) only or HVAC plus portable HEPA filter running. RESULTS: In the exercise experiment, particle concentrations reached 1,722 ± 1,484/L vs 96 ± 124/L (P < .04) for all particles (>0.3 µm), 1,339 ± 1,281/L vs 76 ± 104/L (P < .05) for smaller particles (0.3 to 1.0 µm), and 333 ± 209/L vs 17 ± 19/L (P < .01) for larger particles (1.0 to 5.0 µm) at the end of the protocol in a comparison of mitigation vs portable HEPA filter. Use of a portable HEPA filter in a clinical exercise laboratory clearance experiment reduced aerosol clearance time 47% vs HVAC alone. INTERPRETATION: The portable HEPA filter reduced the concentration of aerosols generated during exercise testing by 96% ± 2% for all particle sizes and reduced aerosol room clearance time in clinical exercise testing laboratories. Portable HEPA filters therefore might be useful in clinical exercise testing laboratories to reduce the risk of COVID-19 transmission.

Aerosol Generation During Peak Flow Testing: Clinical Implications for COVID-19.

BACKGROUND: Peak flow testing is a common procedure performed in ambulatory care. There are currently no data regarding aerosol generation during this procedure. Given the ongoing debate regarding the potential for aerosol transmission of SARS-CoV-2, we aimed to quantify and characterize aerosol generation during peak flow testing. METHODS: Five healthy volunteers performed peak flow maneuvers in a particle-free laboratory space. Two devices continuously sampled the ambient air during the procedure. One device can detect ultrafine particles 0.02-1 µm in diameter, while the second device can detect particles 0.3, 0.5, 1.0, 2.0, 5.0, and 10 µm in diameter. Five different peak flow meters were compared to ambient baseline during masked and unmasked tidal breathing. RESULTS: Ultrafine particles (0.02-1 µm) were generated during peak flow measurement. There was no significant difference in ultrafine particle mean concentration between peak flow meters (P = .23): Respironics (1.25 ± 0.47 particles/mL), Philips (3.06 ± 1.22), Clement Clarke (3.55 ± 1.22 particles/mL), Respironics Low Range (3.50 ± 1.52 particles/mL), and Monaghan (3.78 ± 1.31 particles/mL). Ultrafine particle mean concentration with peak flow testing was significantly higher than masked (0.22 ± 0.29 particles/mL) and unmasked tidal breathing (0.15 ± 0.18 particles/mL, P = .01), but the ultrafine particle concentrations were small compared to ambient particle concentrations in a pulmonary function testing room (89.9 ± 8.95 particles/mL). CONCLUSIONS: In this study, aerosol generation was present during peak flow testing, but concentrations were small compared to the background particle concentration in the ambient clinical environment. Surgical masks and eye protection are likely sufficient infection control measures during peak expiratory flow testing in asymptomatic patients with well controlled respiratory symptoms, but COVID-19 testing remains prudent in patients with acute respiratory symptoms prior to evaluation and peak expiratory flow assessment while the community prevalence of SARS-CoV-2 cases remains high.

Characterization of Aerosol Generation During Various Intensities of Exercise.

BACKGROUND: Characterization of aerosol generation during exercise can inform the development of safety recommendations in the face of COVID-19. RESEARCH QUESTION: Does exercise at various intensities produce aerosols in significant quantities? STUDY DESIGN AND METHODS: In this experimental study, subjects were eight healthy volunteers (six men, two women) who were 20 to 63 years old. The 20-minute test protocol of 5 minutes rest, four 3-minute stages of exercise at 25%, 50%, 75%, and 100% of age-predicted heart rate reserve, and 3 minutes active recovery was performed in a clean, controlled environment. Aerosols were measured by four particle counters that were place to surround the subject. RESULTS: Age averaged 41 ± 14 years. Peak heart rate was 173 ± 17 beat/min (97% predicted); peak maximal oxygen uptake was 33.9 ± 7.5 mL/kg/min; and peak respiratory exchange ratio was 1.22 ± 0.10. Maximal ventilation averaged 120 ± 23 L/min, while cumulative ventilation reached 990 ± 192 L. Concentrations increased exponentially from start to 20 minutes (geometric mean ± geometric SD particles/liter): Fluke >0.3 µm = 66 ± 1.8 → 1605 ± 3.8; 0.3-1.0 µm = 35 ± 2.2 → 1095 ± 4.6; Fluke 1.0-5.0 µm = 21 ± 2.0 → 358 ± 2.3; P-Trak anterior = 637 ± 2.3 → 5148 ± 3.0; P-Trak side = 708 ± 2.7 → 6844 ± 2.7; P-Track back = 519 ± 3.1 → 5853 ± 2.8. All increases were significant at a probability value of <.05. Exercise at or above 50% of predicted heart rate reserve showed statistically significant increases in aerosol concentration. INTERPRETATION: Our data suggest exercise testing is an aerosol-generating procedure and, by extension, other activities that involve exercise intensities at or above 50% of predicted heart rate reserve. Results can guide recommendations for safety of exercise testing and other indoor exercise activities.

Heated High-Flow Nasal Cannula Oxygen Therapy and Noninvasive Positive Pressure Ventilation

* Oxygen delivery by high-flow nasal cannula (HFNC) provides increased oxygenation by increasing the oxygen in the nasopharyngeal dead space. Patients are able to eat, drink, and talk, and, therefore, it is more comfortable than wearing an oxygen mask. * HFNC can be used in patients with COVID-19 as they develop acute respiratory failure. However, HFNC is not as efficient at removing carbon dioxide as intubation. * Initial settings include a flow rate of 30 mL/minute, which can be raised as tolerated by the patient. The maximum flow rate is 60 mL/minute. FiO2 can be set up to 100%. * Abdominal distention and barotrauma can occur from high flow settings. Introduction

Characterizing Particulate Generation During Cardiopulmonary Rehabilitation Classes With Patients Wearing Procedural Masks.

BACKGROUND: The clinical benefits of cardiopulmonary rehabilitation are extensive, including improvements in health-related quality of life, emotional condition, physical function, and overall mortality. The COVID-19 pandemic continues to have a negative impact on center-based cardiopulmonary rehabilitation. Justifiable concern exists that the exercise-related increase in pulmonary ventilation within the rehabilitation classes may lead to the generation of infectious respiratory particles. RESEARCH QUESTION: Is cardiopulmonary rehabilitation while wearing a procedural mask a particle-generating procedure? STUDY DESIGN AND METHODS: Data were collected prospectively at a cardiopulmonary rehabilitation facility with all patients wearing a procedural mask. Small (0.3-4.9 µm) and large (5-10 µm) particle generation was quantified using a light-scattering particle counter. Data were analyzed by time, exertion level, and number of participants. RESULTS: A total of 24 distinct patients attended two or more of the cardiopulmonary rehabilitation classes tested. Most of the patients were men (n = 16 [67%]) and were in rehabilitation because of cardiac disease. During the cardiopulmonary rehabilitation class, small and large micrometer-size particles increased with increasing class size. In classes with four patients or more, a significant increase was found from ambient levels in both small (four patients, P < .01; and five patients, P < .01) and large (four patients, P < .01; and five patients, P < .01) particle count that peaked at about 35 to 40 min during each class. INTERPRETATION: Using an airborne particle counter, we found significant exercise-related increases in both small and large micrometer-size particle generation during cardiopulmonary rehabilitation classes, with larger class sizes (ie, more patients), despite participants wearing a procedural mask.

Stress and Fear: Clinical Implications for Providers and Patients (in the Time of COVID-19 and Beyond).

In light of the coronavirus disease 2019 pandemic, we explore the role of stress, fear, and the impact of positive and negative emotions on health and disease. We then introduce strategies to help mitigate stress within the health care team, and provide a rationale for their efficacy. Additionally, we identify strategies to optimize patient care and explain their heightened importance in today's environment.

Anticoagulation in COVID-19: A Systematic Review, Meta-analysis, and Rapid Guidance From Mayo Clinic.

A higher risk of thrombosis has been described as a prominent feature of coronavirus disease 2019 (COVID-19). This systematic review synthesizes current data on thrombosis risk, prognostic implications, and anticoagulation effects in COVID-19. We included 37 studies from 4070 unique citations. Meta-analysis was performed when feasible. Coagulopathy and thrombotic events were frequent among patients with COVID-19 and further increased in those with more severe forms of the disease. We also present guidance on the prevention and management of thrombosis from a multidisciplinary panel of specialists from Mayo Clinic. The current certainty of evidence is generally very low and continues to evolve.

Triage of Scarce Critical Care Resources in COVID-19 An Implementation Guide for Regional Allocation: An Expert Panel Report of the Task Force for Mass Critical Care and the American College of Chest Physicians.

Public health emergencies have the potential to place enormous strain on health systems. The current pandemic of the novel 2019 coronavirus disease has required hospitals in numerous countries to expand their surge capacity to meet the needs of patients with critical illness. When even surge capacity is exceeded, however, principles of critical care triage may be needed as a means to allocate scarce resources, such as mechanical ventilators or key medications. The goal of a triage system is to direct limited resources towards patients most likely to benefit from them. Implementing a triage system requires careful coordination between clinicians, health systems, local and regional governments, and the public, with a goal of transparency to maintain trust. We discuss the principles of tertiary triage and methods for implementing such a system, emphasizing that these systems should serve only as a last resort. Even under triage, we must uphold our obligation to care for all patients as best possible under difficult circumstances.