Development of in-airway laser absorption spectroscopy for respiratory based measurements of cardiac output.

Nicholas M J Smith, John Couper, Graham Richmond, Dominic Sandhu, Gus Hancock, Peter A Robbins, Grant A D Ritchie

Abstract read

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Article in Scientific reports, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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5 · Who and what money

Authors and funding

7 authors.

Nicholas M J SmithDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.

John CouperDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.

Graham RichmondDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.

Dominic SandhuDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.

Gus HancockDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.

Peter A RobbinsDepartment of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.

Grant A D RitchieDepartment of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK. Grant.Ritchie@chem.ox.ac.uk.

Funding

Medical Research Council MC_PC_15029

6 · The paper itself

Abstract

Respiratory approaches to determining cardiac output in humans are securely rooted in mass balance and therefore potentially highly accurate. To address existing limitations in the gas analysis, we developed an in-airway analyser based on laser absorption spectroscopy to provide analyses every 10 ms. The technique for estimating cardiac output requires both a relatively soluble and insoluble tracer gas, and we employed acetylene and methane for these, respectively. A multipass cell was used to provide sufficient measurement sensitivity to enable analysis directly within the main gas stream, thus avoiding errors introduced by sidestream gas analysis. To assess performance, measurements of cardiac output were made during both rest and exercise on five successive days in each of six volunteers. The measurements were extremely repeatable (coefficient of variation ~ 7%). This new measurement technology provides a stable foundation against which the algorithm to calculate cardiac output can be further developed.

Indexed as

RespirationCardiac OutputExerciseHumansLasersOxygen ConsumptionRespiratory SystemRestSpectrum AnalysisThorax

Identifiers

PMID33664377

DOI10.1038/s41598-021-84649-0

PMCPMC7970843

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