Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by intractable fatigue, postexertional malaise, and orthostatic intolerance, but its pathophysiology is poorly understood. Pharmacologic cholinergic stimulation was used to test the hypothesis that neurovascular dysregulation underlies exercise intolerance in ME/CFS.

Atrial fibrillation (AF) is a common complication of sepsis. It is unclear whether norepinephrine, an α- and β-agonist, and phenylephrine, an α-agonist, are associated with different heart rates among patients with sepsis and AF.

Mortality historically has been the primary outcome of choice for acute and critical care clinical trials. However, undue reliance on mortality can limit the scope of trials that can be performed. Large sample sizes are usually needed for trials powered for a mortality outcome, and focusing solely on mortality fails to recognize the importance that reducing morbidity can have on patients' lives. The COVID-19 pandemic has highlighted the need for rapid, efficient trials to rigorously evaluate new therapies for hospitalized patients with acute lung injury. Oxygen-free days (OFDs) is a novel outcome for clinical trials that is a composite of mortality and duration of new supplemental oxygen use. It is designed to characterize recovery from acute lung injury in populations with a high prevalence of new hypoxemia and supplemental oxygen use. In these populations, OFDs captures two patient-centered consequences of acute lung injury: mortality and hypoxemic lung dysfunction. Power to detect differences in OFDs typically is greater than that for other clinical trial outcomes, such as mortality and ventilator-free days. OFDs is the primary outcome for the Fourth Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV-4) Host Tissue platform, which evaluates novel therapies targeting the host response to COVID-19 among adults hospitalized with COVID-19 and new hypoxemia. This article outlines the rationale for use of OFDs as an outcome for clinical trials, proposes a standardized method for defining and analyzing OFDs, and provides a framework for sample size calculations using the OFD outcome.

Accurate assessment of maximum respiratory pressure is vital when tracking disease progression and devising treatment strategies. Previous studies indicate a learning effect when undertaking maximum respiratory pressure measurements. The extent of this learning effect and methodologies undertaken to mitigate this learning effect have not been investigated systematically.

Chronic refractory cough significantly impairs the psychological and social aspects of quality of life. Loss of inhibitory control is suggested as a potential central neurobiological mechanism underlying chronic refractory cough.

The current approach to interpretation of lung function measurements assumes that differences in lung function between racial and ethnic groups represent inherent and biological differences. Observed differences in lung function between White and Black populations are often attributed to physiological differences in body proportions (eg, chest size, leg length); however, most studies investigating the observed differences have not considered the impact of socioeconomic status (SES).

Echocardiographic parameters are used as prognostic markers in patients with pulmonary arterial hypertension (PAH) receiving parenteral (IV or subcutaneous [IV/SC]) prostacyclin therapy. However, data on how posttreatment echocardiographic results associate with outcomes are limited.

The Veterans Health Administration issued policy for lung cancer screening resources at eight Veterans Affairs Medical Centers (VAMCs) in a demonstration project (DP) from 2013 through 2015.

SARS-CoV-2-related ARDS is associated with endothelial dysfunction and profound dysregulation of the thrombotic-fibrinolytic pathway. Defibrotide is a polyanionic compound with fibrinolytic, antithrombotic, and antiinflammatory properties.

Acute exacerbations of COPD (AECOPD) are associated with high morbidity and mortality and frequent readmissions.

Prior studies in the civilian population have reported racial disparities in lung cancer outcomes following surgical treatment, including inferior quality of care and worse survival. It is unclear if racial disparities exist in the Veterans Health Administration (VHA), the largest integrated health care system in the United States.

Idiopathic pulmonary fibrosis (IPF) is a progressive, often fatal form of interstitial lung disease (ILD) characterized by the absence of a known cause and usual interstitial pneumonitis (UIP) pattern on chest CT imaging and/or histopathology. Distinguishing UIP/IPF from other ILD subtypes is essential given different treatments and prognosis. Lung biopsy is necessary when noninvasive data are insufficient to render a confident diagnosis.