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High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves

Background: High flow nasal oxygen (HFNO) is an accepted treatment for severe COVID-19 related acute hypoxaemic respiratory failure (AHRF) especially where limited access to intensive care unit (ICU) resources exists, and approximately halves the need for invasive mechanical ventilation. Objectives...

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Main Author: Audley, Gordon George
Other Authors: Calligaro, Gregory
Format: Thesis
Language:English
Published: Department of Medicine 2024
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access_status_str Open Access
author Audley, Gordon George
author2 Calligaro, Gregory
author_browse Audley, Gordon George
Calligaro, Gregory
author_facet Calligaro, Gregory
Audley, Gordon George
author_sort Audley, Gordon George
collection Thesis
description Background: High flow nasal oxygen (HFNO) is an accepted treatment for severe COVID-19 related acute hypoxaemic respiratory failure (AHRF) especially where limited access to intensive care unit (ICU) resources exists, and approximately halves the need for invasive mechanical ventilation. Objectives: To determine if treatment outcomes would be better in the third COVID wave (irrespective of differences in variant virulence; ancestral vs delta) due to increased institutional experience and capacity for HNFO and more restrictive admission criteria for respiratory high care wards and ICU dictated by the higher case load in the third wave. Methods: We included consecutive patients with COVID-19-related AHRF treated with HFNO during the first (7 May to 25 August 2020) and third COVID waves (4 July to 4 September 2021) at Groote Schuur Hospital. The primary endpoint was comparison of HFNO failure between the first and third waves of the COVID-19 pandemic. Findings: A total of 744 patients were included: 343 in the first, and 401 in the third COVIDwave. Patients treated with HFNO in the first wave had an older median (IQR) age (53 (46-61) vs 47 (40-56) years, p<0.001), and a higher prevalence of diabetes (46.9 vs. 36.9%, p=0.006), hypertension (51.0% vs 35.2%, p<0.001), obesity (33.5% vs 26.2%, p=0.029) and HIV infection (12.5% vs 5.5%, p<0.001). Median (IQR) arterial oxygen partial pressure to fraction inspired oxygen ratio (PaO2/FiO2) at HFNO initiation and the ratio of oxygen saturation/FiO2 to respiratory rate within 6 hours (ROX-6 score) after HFNO commencement were lower in the first wave compared with the third: 57.9 (47.3-74.3) vs 64.3 (51.2-79.0), p=0.005 and 3.19 (2.37-3.77) vs 3.43 (2.93-4.00), p<0.001, respectively. Despite these differences in comorbidities and baseline measures of oxygenation, the likelihood of HFNO failure (57.1% versus 59.6.1%, p=0.498) and mortality (52.1% vs 46.9%, p=0.159) did not differ between first and third waves the first and third COVID waves. Conclusion: Despite differences in overall case load, baseline patient characteristics, virulence of the circulating wave variant and institutional experience with HFNO, treatment outcomes were very similar in the first and third COVID waves. We conclude that once severe respiratory failure is established in COVID pneumonia, comorbidities and HFNO provider experience make little difference to outcome.
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provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
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spelling oai:open.uct.ac.za:11427/40754 High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves Audley, Gordon George Calligaro, Gregory General Medicine Background: High flow nasal oxygen (HFNO) is an accepted treatment for severe COVID-19 related acute hypoxaemic respiratory failure (AHRF) especially where limited access to intensive care unit (ICU) resources exists, and approximately halves the need for invasive mechanical ventilation. Objectives: To determine if treatment outcomes would be better in the third COVID wave (irrespective of differences in variant virulence; ancestral vs delta) due to increased institutional experience and capacity for HNFO and more restrictive admission criteria for respiratory high care wards and ICU dictated by the higher case load in the third wave. Methods: We included consecutive patients with COVID-19-related AHRF treated with HFNO during the first (7 May to 25 August 2020) and third COVID waves (4 July to 4 September 2021) at Groote Schuur Hospital. The primary endpoint was comparison of HFNO failure between the first and third waves of the COVID-19 pandemic. Findings: A total of 744 patients were included: 343 in the first, and 401 in the third COVIDwave. Patients treated with HFNO in the first wave had an older median (IQR) age (53 (46-61) vs 47 (40-56) years, p<0.001), and a higher prevalence of diabetes (46.9 vs. 36.9%, p=0.006), hypertension (51.0% vs 35.2%, p<0.001), obesity (33.5% vs 26.2%, p=0.029) and HIV infection (12.5% vs 5.5%, p<0.001). Median (IQR) arterial oxygen partial pressure to fraction inspired oxygen ratio (PaO2/FiO2) at HFNO initiation and the ratio of oxygen saturation/FiO2 to respiratory rate within 6 hours (ROX-6 score) after HFNO commencement were lower in the first wave compared with the third: 57.9 (47.3-74.3) vs 64.3 (51.2-79.0), p=0.005 and 3.19 (2.37-3.77) vs 3.43 (2.93-4.00), p<0.001, respectively. Despite these differences in comorbidities and baseline measures of oxygenation, the likelihood of HFNO failure (57.1% versus 59.6.1%, p=0.498) and mortality (52.1% vs 46.9%, p=0.159) did not differ between first and third waves the first and third COVID waves. Conclusion: Despite differences in overall case load, baseline patient characteristics, virulence of the circulating wave variant and institutional experience with HFNO, treatment outcomes were very similar in the first and third COVID waves. We conclude that once severe respiratory failure is established in COVID pneumonia, comorbidities and HFNO provider experience make little difference to outcome. 2024-11-28T08:32:37Z 2024-11-28T08:32:37Z 2024 2024-11-27T09:56:54Z Thesis / Dissertation Masters MMed http://hdl.handle.net/11427/40754 eng application/pdf Department of Medicine Faculty of Health Sciences University of Cape Town
spellingShingle General Medicine
Audley, Gordon George
High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
thesis_degree_str Master's
title High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
title_full High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
title_fullStr High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
title_full_unstemmed High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
title_short High flow nasal oxygen in resource constrained, non-intensive care high care wards for COVID-19 acute hypoxaemic respiratory failure: comparing outcomes of first versus third waves
title_sort high flow nasal oxygen in resource constrained non intensive care high care wards for covid 19 acute hypoxaemic respiratory failure comparing outcomes of first versus third waves
topic General Medicine
url http://hdl.handle.net/11427/40754
work_keys_str_mv AT audleygordongeorge highflownasaloxygeninresourceconstrainednonintensivecarehighcarewardsforcovid19acutehypoxaemicrespiratoryfailurecomparingoutcomesoffirstversusthirdwaves