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Your search keyword '"Snapper R. M. Magor-Elliott"' showing total 2 results
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2 results on '"Snapper R. M. Magor-Elliott"'

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

Author

Nicholas M. J. Smith, Snapper R. M. Magor-Elliott, Christopher J. Fullerton, John H. Couper, Graham Richmond, Gus Hancock, Grant A. D. Ritchie, Peter A. Robbins, Nick P. Talbot, and Nayia Petousi

Subjects
COPD-chronic obstructive pulmonary disease, respiratory physiology, lung inhomogeneity, respiratory disease, translational physiology, Physiology, QP1-981
Abstract

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. It also provides parameter estimates for total anatomical deadspace and functional residual capacity (FRC). We demonstrate that these parameters are robust and sensitive, and that they can distinguish between healthy individuals and those with mild-moderate COPD (stage 1–2), as well as distinguish between mild-moderate COPD (stage 1–2) and more severe (stage 3–4) COPD. In particular, σCL, a measure of unevenness in lung inflation/deflation, could represent a more sensitive non-invasive marker of early or mild COPD. In addition, by providing a multi-dimensional assessment of lung physiology, this technique may also give insight into the underlying pathophysiological phenotype for individual patients. These preliminary results warrant further investigation in larger clinical research studies, including interventional trials.

Published
2022
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2. Altered lung physiology in two cohorts after COVID-19 infection as assessed by computed cardiopulmonography

Author

Snapper R. M. Magor-Elliott, Asma Alamoudi, Rebecca R. Chamley, Haopeng Xu, Tishan Wellalagodage, Rory P. McDonald, David O’Brien, Jonathan Collins, Ben Coombs, James Winchester, Ed Sellon, Cheng Xie, Dominic Sandhu, Christopher J. Fullerton, John H. Couper, Nicholas M. J. Smith, Graham Richmond, Mark P. Cassar, Betty Raman, Nick P. Talbot, Alexander N. Bennett, Edward D. Nicol, Grant A. D. Ritchie, Nayia Petousi, David A. Holdsworth, and Peter A. Robbins

Subjects
Physiology, Physiology (medical), Respiration, Humans, COVID-19, Respiration, Artificial, Lung, Respiratory Function Tests
Abstract

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. The first is collection of highly precise, highly time-resolved measurements of gas exchange with a purpose-built molecular flow sensor based around laser absorption spectroscopy. The second component is estimation of physiological parameters by fitting a cardiopulmonary model to the data set. The measurement protocol involved 7 min of breathing air followed by 5 min of breathing pure O2. One hundred seventy-eight participants were studied, with 97 returning for a repeat assessment. One hundred twenty-six arterial blood gas samples were drawn from MCOVID participants. For participants who had required intensive care and/or invasive mechanical ventilation, there was a significant increase in anatomical dead space of ∼30 mL and a significant increase in alveolar-to-arterial Po2 gradient of ∼0.9 kPa relative to control participants. Those who had been hospitalized had reductions in functional residual capacity of ∼15%. Irrespectively of COVID-19 severity, participants who had had COVID-19 demonstrated a modest increase in ventilation inhomogeneity, broadly equivalent to that associated with 15 yr of aging. This study illustrates the capability of CCP to study aspects of lung function not so easily addressed through standard clinical lung function tests. However, without measurements before infection, it is not possible to conclude whether the findings relate to the effects of COVID-19 or whether they constitute risk factors for more serious disease. NEW & NOTEWORTHY This study used a novel technique, computed cardiopulmonography, to study the lungs of patients who have had COVID-19. Depending on severity of infection, there were increases in anatomical dead space, reductions in absolute lung volumes, and increases in ventilation inhomogeneity broadly equivalent to those associated with 15 yr of aging. However, without measurements taken before infection, it is unclear whether the changes result from COVID-19 infection or are risk factors for more severe disease.

Published
2022

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