Evidence map›Paper›PMID 36264932›Full record

ArticlePloS one2022

Intrapulmonary shunting is a key contributor to hypoxia in COVID-19: An update on the pathophysiology.

Nikhil Mayor, Harry Knights, Aleksandra Kotwica, Andrew Solomon Joseph Coppola, Harriet Hunter, Nathan Jeffreys, Alexander Morgan, Shivani Gupta, James Prentice, Rebecca Macfarlane and 3 more

Open access · goldAbstract read
In one paragraph

Article in PloS one, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 3 papers.

0numbers the graph read from it
0cells of the map it votes in
3citing papers in PubMed
0.2field-weighted citation impact, top 48% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

3 citing papers in PubMed, 1 citations in OpenAlex.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors at 6 institutions in 1 country.

Nikhil MayorRoyal Surrey NHS Foundation Trust, Guildford, Surrey, United Kingdom.ORCID 0000-0003-2681-2501
Harry KnightsEpsom & St Helier NHS Foundation Trust, Epsom, United Kingdom.ORCID 0000-0002-8184-7208
Aleksandra KotwicaLister Hospital, East and North Hertfordshire NHS Trust, Stevenage, United Kingdom.
Andrew Solomon Joseph CoppolaGuy's and St Thomas' NHS Foundation Trust, London, United Kingdom.
Harriet HunterRoyal Surrey NHS Foundation Trust, Guildford, Surrey, United Kingdom.
Nathan JeffreysRoyal Surrey NHS Foundation Trust, Guildford, Surrey, United Kingdom.
Alexander MorganEpsom & St Helier NHS Foundation Trust, Epsom, United Kingdom.
Shivani GuptaEpsom & St Helier NHS Foundation Trust, Epsom, United Kingdom.
James PrenticeEpsom & St Helier NHS Foundation Trust, Epsom, United Kingdom.
Rebecca MacfarlaneEpsom & St Helier NHS Foundation Trust, Epsom, United Kingdom.
Emma Russell-JonesKing's College London, London, United Kingdom.
Theodore DassiosKing's College London, London, United Kingdom.
David Russell-JonesRoyal Surrey NHS Foundation Trust, Guildford, Surrey, United Kingdom.
Royal Surrey NHS Foundation Trust · GBKing's College London · GBGuy's and St Thomas' NHS Foundation Trust · GBLister Hospital · GBUniversity College London · GBUniversity of Surrey · GB

Funding

Department of Health
6 · The paper itself

Abstract

backgroundThe pathophysiology of COVID-19 remains poorly understood. We aimed to estimate the contribution of intrapulmonary shunting and ventilation-to-perfusion (VA/Q) mismatch using a mathematical model to construct oxygen-haemoglobin dissociation curves (ODCs).

methodsODCs were constructed using transcutaneous pulse oximetry at two different fractions of inspired oxygen (FiO2). 199 patients were included from two large district general hospitals in the South East of England from 1st to 14th January 2021. The study was supported by the National Institute of Health Research (NIHR) Clinical Research Network.

resultsOverall mortality was 29%. Mean age was 68.2 years (SEM 1·2) with 46% female. Median shunt on admission was 17% (IQR 8-24.5); VA/Q was 0.61 (IQR 0.52-0.73). Shunt was 37.5% higher in deaths (median 22%, IQR 9-29) compared to survivors (16%, 8-21; p = 0.0088) and was a predictor of mortality (OR 1.04; 95% CI 1.01-1.07). Admission oxygen saturations were more strongly predictive of mortality (OR 0.91, 95% CI 0.87-0.96). There was no difference in VA/Q mismatch between deaths (0.60; IQR 0.50-0.73) and survivors (0.61; IQR 0.52-0.73; p = 0.63) and it was not predictive of mortality (OR 0.68; 95% CI 0.18-2.52; p = 0.55). Shunt negatively correlated with admission oxygen saturation (R -0.533; p<0.0001) whereas VA/Q was not (R 0.1137; p = 0.12).

interpretationShunt, not VA/Q mismatch, was associated with worsening hypoxia, though calculating shunt was not of prognostic value. This study adds to our understanding of the pathophysiology of hypoxaemia in COVID-19. Our inexpensive and reliable technique may provide further insights into the pathophysiology of hypoxia in other respiratory diseases.

Indexed as

COVID-19Lung DiseasesAgedFemaleHumansHypoxiaMaleOximetryOxygenVentilation-Perfusion RatioOxygen

Identifiers

PMID36264932
PMCPMC9584408
OpenAlexW4306898318

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.