Alveolar deadspace and intrapulmonary shunt in healthy individuals and in individuals who have recovered from COVID-19 infection.

Following acute COVID-19 infection, unvaccinated patients have been reported to exhibit elevated alveolar deadspace (̇V/̇V) and intrapulmonary shunt (̇Q/̇Q) fractions. However, as there is uncertainty surrounding the upper limits of normal for ̇V/̇V and ̇Q/̇Q, we sought to replicate the findings from a separate, previously reported cohort of COVID-19 patients that also included a healthy control group never infected with COVID-19. Data from 81 participants, classified into four different groups based on the severity of prior COVID-19 infection, were used.

The Lognormal Lung: A new approach to quantifying lung inhomogeneity in COPD.

Early diagnosis and disease phenotyping in COPD are currently limited by the use of spirometry, which may remain normal despite significant small-airways disease and which may not fully capture a patient's underlying pathophysiology. In this study we explored the use of a new non-invasive technique that assesses gas-exchange inhomogeneity in patients with COPD of varying disease severity (according to GOLD Stage), compared with age-matched healthy controls. The technique, which combines highly accurate measurement of respiratory gas exchange using a bespoke molecular flow sensor and a mechanistic mathematical model of the lung, provides new indices of lung function: the parameters σCL, σCd, and σVD represent the standard deviations of distributions for alveolar compliance, anatomical deadspace and vascular conductance relative to lung volume, respectively.

Altered lung physiology in two cohorts after COVID-19 infection as assessed by computed cardiopulmonography.

The longer-term effects of COVID-19 on lung physiology remain poorly understood. Here, a new technique, computed cardiopulmonography (CCP), was used to study two COVID-19 cohorts (MCOVID and C-MORE-LP) at both ∼6 and ∼12 mo after infection. CCP is comprised of two components.

A dynamic model of the body gas stores for carbon dioxide, oxygen, and inert gases that incorporates circulatory transport delays to and from the lung.

Many models of the body's gas stores have been generated for specific purposes. Here, we seek to produce a more general purpose model that: ) is relevant for both respiratory (CO and O) and inert gases; ) is based firmly on anatomy and not arbitrary compartments; ) can be scaled to individuals; and ) incorporates arterial and venous circulatory delays as well as tissue volumes so that it can reflect rapid transients with greater precision. First, a "standard man" of 11 compartments was produced, based on data compiled by the International Radiation Protection Commission.