Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study

Objectives To evaluate oxygen saturation and vital signs measured in the community by emergency medical services (EMS) as clinical markers of COVID-19-positive patient deterioration.Design A retrospective data analysis.Setting Patients were conveyed by EMS to two hospitals in Hampshire, UK, between...

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Main Authors: John Black, Helen Pocock, Charles Deakin, Daniel Burns, Matthew Inada-Kim, Michael Boniface, Francis P Chmiel
Format: Article
Language:English
Published: BMJ Publishing Group 2024-01-01
Series:BMJ Open
Online Access:https://bmjopen.bmj.com/content/14/1/e067378.full
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author John Black
Helen Pocock
Charles Deakin
Daniel Burns
Matthew Inada-Kim
Michael Boniface
Francis P Chmiel
author_facet John Black
Helen Pocock
Charles Deakin
Daniel Burns
Matthew Inada-Kim
Michael Boniface
Francis P Chmiel
author_sort John Black
collection DOAJ
description Objectives To evaluate oxygen saturation and vital signs measured in the community by emergency medical services (EMS) as clinical markers of COVID-19-positive patient deterioration.Design A retrospective data analysis.Setting Patients were conveyed by EMS to two hospitals in Hampshire, UK, between 1 March 2020 and 31 July 2020.Participants A total of 1080 patients aged ≥18 years with a COVID-19 diagnosis were conveyed by EMS to the hospital.Primary and secondary outcome measures The primary study outcome was admission to the intensive care unit (ICU) within 30 days of conveyance, with a secondary outcome representing mortality within 30 days of conveyance. Receiver operating characteristic (ROC) analysis was performed to evaluate, in a retrospective fashion, the efficacy of different variables in predicting patient outcomes.Results Vital signs measured by EMS staff at the first point of contact in the community correlated with patient 30-day ICU admission and mortality. Oxygen saturation was comparably predictive of 30-day ICU admission (area under ROC (AUROC) 0.753; 95% CI 0.668 to 0.826) to the National Early Warning Score 2 (AUROC 0.731; 95% CI 0.655 to 0.800), followed by temperature (AUROC 0.720; 95% CI 0.640 to 0.793) and respiration rate (AUROC 0.672; 95% CI 0.586 to 0.756).Conclusions Initial oxygen saturation measurements (on air) for confirmed COVID-19 patients conveyed by EMS correlated with short-term patient outcomes, demonstrating an AUROC of 0.753 (95% CI 0.668 to 0.826) in predicting 30-day ICU admission. We found that the threshold of 93% oxygen saturation is prognostic of adverse events and of value for clinician decision-making with sensitivity (74.2% CI 0.642 to 0.840) and specificity (70.6% CI 0.678 to 0.734).
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spelling doaj-art-f3956fbbf0d64a58bb729acb2e7a8d0e2025-08-20T02:13:31ZengBMJ Publishing GroupBMJ Open2044-60552024-01-0114110.1136/bmjopen-2022-067378Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort studyJohn Black0Helen Pocock1Charles Deakin2Daniel Burns3Matthew Inada-Kim4Michael Boniface5Francis P Chmiel6South Central Ambulance Service NHS Foundation Trust, Otterbourne, UKSouth Central Ambulance Service NHS Foundation Trust, Otterbourne, UKSouth Central Ambulance Service NHS Foundation Trust, Otterbourne, UK1T-Cypher Bio Ltd, Oxford, Oxfordshire, UKDepartment of Acute Medicine, Hampshire Hospitals NHS Foundation Trust, Winchester, UKSchool of Electronics and Computer Science, University of Southampton, Southampton, UKSchool of Electronics and Computer Science, University of Southampton, Southampton, UKObjectives To evaluate oxygen saturation and vital signs measured in the community by emergency medical services (EMS) as clinical markers of COVID-19-positive patient deterioration.Design A retrospective data analysis.Setting Patients were conveyed by EMS to two hospitals in Hampshire, UK, between 1 March 2020 and 31 July 2020.Participants A total of 1080 patients aged ≥18 years with a COVID-19 diagnosis were conveyed by EMS to the hospital.Primary and secondary outcome measures The primary study outcome was admission to the intensive care unit (ICU) within 30 days of conveyance, with a secondary outcome representing mortality within 30 days of conveyance. Receiver operating characteristic (ROC) analysis was performed to evaluate, in a retrospective fashion, the efficacy of different variables in predicting patient outcomes.Results Vital signs measured by EMS staff at the first point of contact in the community correlated with patient 30-day ICU admission and mortality. Oxygen saturation was comparably predictive of 30-day ICU admission (area under ROC (AUROC) 0.753; 95% CI 0.668 to 0.826) to the National Early Warning Score 2 (AUROC 0.731; 95% CI 0.655 to 0.800), followed by temperature (AUROC 0.720; 95% CI 0.640 to 0.793) and respiration rate (AUROC 0.672; 95% CI 0.586 to 0.756).Conclusions Initial oxygen saturation measurements (on air) for confirmed COVID-19 patients conveyed by EMS correlated with short-term patient outcomes, demonstrating an AUROC of 0.753 (95% CI 0.668 to 0.826) in predicting 30-day ICU admission. We found that the threshold of 93% oxygen saturation is prognostic of adverse events and of value for clinician decision-making with sensitivity (74.2% CI 0.642 to 0.840) and specificity (70.6% CI 0.678 to 0.734).https://bmjopen.bmj.com/content/14/1/e067378.full
spellingShingle John Black
Helen Pocock
Charles Deakin
Daniel Burns
Matthew Inada-Kim
Michael Boniface
Francis P Chmiel
Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
BMJ Open
title Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
title_full Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
title_fullStr Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
title_full_unstemmed Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
title_short Validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed COVID-19: a retrospective cohort study
title_sort validation of oxygen saturations measured in the community by emergency medical services as a marker of clinical deterioration in patients with confirmed covid 19 a retrospective cohort study
url https://bmjopen.bmj.com/content/14/1/e067378.full
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