BACKGROUND: In the early stages of COVID-19 pneumonia, hypoxemia has been described in absence of dyspnea ("silent" or "happy" hypoxemia). Our aim was to report its prevalence and outcome in a series of hypoxemic patients upon Emergency Department admission.METHODS: In this retrospective observational cohort study we enrolled a study population consisting of 213 COVID-19 patients with PaO2/FiO2 ratio <300 mmHg at hospital admission. Two groups (silent and dyspneic hypoxemia) were defined. Symptoms, blood gas analysis, chest X-ray (CXR) severity, need for intensive care and outcome were recorded.RESULTS: Silent hypoxemic patients (68-31.9%) compared to the dyspneic hypoxemic patients (145-68.1%) showed greater frequency of extra respiratory symptoms (myalgia, diarrhea and nausea) and lower plasmatic LDH. PaO2/FiO2 ratio was 225±68 mmHg and 192±78 mmHg in silent and dyspneic hypoxemia respectively (P=0.002). Eighteen percent of the patients with PaO2/FiO2 from 50 to 150 mmHg presented silent hypoxemia. Silent and dyspneic hypoxemic patients had similar PaCO2 (34.2±6.8 mmHg vs. 33.5±5.7 mmHg, P=0.47) but different respiratory rates (24.6±5.9 bpm vs. 28.6±11.3 bpm respectively, P=0.002). Even when CXR was severely abnormal, 25% of the population was silent hypoxemic. Twenty-six point five percent and 38.6% of silent and dyspneic patients were admitted to the ICU respectively (P=0.082). Mortality rate was 17.6% and 29.7% (log-rank P=0.083) in silent and dyspneic patients.CONCLUSIONS: Silent hypoxemia is remarkably present in COVID-19. The presence of dyspnea is associated with a more severe clinical condition.

Prevalence and outcome of silent hypoxemia in COVID-19 / M. Busana, A. Gasperetti, L. Giosa, G.B. Forleo, M. Schiavone, G. Mitacchione, C. Bonino, P. Villa, M. Galli, C. Tondo, A. Saguner, P. Steiger, A. Curnis, A. Dello Russo, F. Pugliese, M. Mancone, J.J. Marini, L. Gattinoni. - In: MINERVA ANESTHESIOLOGY. - ISSN 2724-4407. - 87:3(2021), pp. 325-333. [10.23736/S0375-9393.21.15245-9]

Prevalence and outcome of silent hypoxemia in COVID-19

M. Busana
Primo
;
A. Gasperetti
Secondo
;
M. Schiavone;C. Bonino;P. Villa;M. Galli;C. Tondo;L. Gattinoni
Ultimo
2021

Abstract

BACKGROUND: In the early stages of COVID-19 pneumonia, hypoxemia has been described in absence of dyspnea ("silent" or "happy" hypoxemia). Our aim was to report its prevalence and outcome in a series of hypoxemic patients upon Emergency Department admission.METHODS: In this retrospective observational cohort study we enrolled a study population consisting of 213 COVID-19 patients with PaO2/FiO2 ratio <300 mmHg at hospital admission. Two groups (silent and dyspneic hypoxemia) were defined. Symptoms, blood gas analysis, chest X-ray (CXR) severity, need for intensive care and outcome were recorded.RESULTS: Silent hypoxemic patients (68-31.9%) compared to the dyspneic hypoxemic patients (145-68.1%) showed greater frequency of extra respiratory symptoms (myalgia, diarrhea and nausea) and lower plasmatic LDH. PaO2/FiO2 ratio was 225±68 mmHg and 192±78 mmHg in silent and dyspneic hypoxemia respectively (P=0.002). Eighteen percent of the patients with PaO2/FiO2 from 50 to 150 mmHg presented silent hypoxemia. Silent and dyspneic hypoxemic patients had similar PaCO2 (34.2±6.8 mmHg vs. 33.5±5.7 mmHg, P=0.47) but different respiratory rates (24.6±5.9 bpm vs. 28.6±11.3 bpm respectively, P=0.002). Even when CXR was severely abnormal, 25% of the population was silent hypoxemic. Twenty-six point five percent and 38.6% of silent and dyspneic patients were admitted to the ICU respectively (P=0.082). Mortality rate was 17.6% and 29.7% (log-rank P=0.083) in silent and dyspneic patients.CONCLUSIONS: Silent hypoxemia is remarkably present in COVID-19. The presence of dyspnea is associated with a more severe clinical condition.
COVID-19; Emergency service; Hospital; Hypoxia; Respiratory distress syndrome
Settore MED/11 - Malattie dell'Apparato Cardiovascolare
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/827645
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