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POS-ARI-ER publication: A closer look at respiratory support failure in COVID-19 patients

The coronavirus causing COVID-19 has infected over 500 million people worldwide, and resulted in more than 6 million deaths. The most severe presentation of the disease is acute respiratory distress syndrome. Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas, non-invasive mechanical ventilation, or invasive mechanical ventilation. However, the use and need for support have changed over time depending on COVID-19 vaccination coverage, circulating viral variants, an evolving treatment evidence base and practice variation.

A new peer-reviewed paper published in Critical Care dives deeper into this issue. The study, which was supported by the POS-ARI-ER team, aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients with severe COVID-19 during the first two years of the pandemic in high-income countries and low middle-income countries.

A total of 66,565 patients treated with one of the three types of support within the first 24 hours of hospital admission were included in this study. Patients in high-income countries were more frequently treated with nasal cannulas (48.0%), followed by non-invasive mechanical ventilation (38.6%) and invasive mechanical ventilation (13.4%). In contrast, patients admitted in lower- and middle-income countries were less frequently treated with nasal cannulas (16.1%) and the majority received invasive mechanical ventilation (59.1%).

The failure rate of non-invasive respiratory support was 15.5%, more than two-thirds of which were from wealthier countries. Higher leucocyte count, tachypnoea, and treatment in a poorer country were identified as risk factors for failure of nasal cannulas and non-invasive mechanical ventilation. Importantly, these two treatments' failure was related to worse clinical outcomes, such as 28-day mortality.

The authors concluded that non-invasive respiratory treatments could be used as the first respiratory support in patients with severe COVID-19. However, it is crucial to identify patients at risk of failing because delaying invasive mechanical ventilation may be associated with worse clinical outcomes. 


Establishing the cause of Acute Respiratory Infections (ARI) at the time of presentation is difficult with currently available diagnostic approaches, resulting in unnecessary use of antibiotics in many patients and enhancing antimicrobial resistance. The Perpetual Observational Study (POS) among patients with ARI covers pathogens with proven epidemic potential, such as influenza viruses and coronaviruses. The primary objective of this study is to provide an infrastructure capable of rapidly implementing randomised controlled trials and other clinical studies related to the diagnosis and treatment of ARI in emergency rooms. Read more about POS-ARI-ER here.