Severe COVID-19 : current challenges and future perspectives

<p>At the end of 2019, a novel coronavirus was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the Hubei Province of China.　It rapidly spread, resulting in an epidemic throughout China, followed by an increasing number of cases in other countries throughout the world.　Coronavirus disease 2019 （COVID-19） can progress in a subset of patients to acute respiratory distress syndrome （ARDS） and has had a catastrophic effect on the world’s demographics resulting in more than 6 million deaths worldwide.</p><p>The major morbidity and mortality from COVID-19 is largely due to acute viral pneumonia that evolves to ARDS.　Most patients who are mechanically ventilated due to COVID-19-related ARDS should be managed in accordance with evidence-based ARDS strategies, including low tidal volume ventilation with permissive hypercapnia, prone positioning or extracorporeal membrane oxygenation （ECMO）.　In recent years, it has revealed that excessive respiratory effort exacerbates lung injury, which called patient self-inflicted lung injury （P-SILI）, and the importance of controlling excessive respiratory effort has been recognized.</p><p>Although infection with the SARS-CoV2 Omicron variant is associated with less severe disease compared with the Alpha and Delta variants, Omicron is spreading faster than any previous variant.　The overall risk related to this variant remains very high because its infection also extends to the patients with severe underlying disease or immune-compromised host including patients with chemotherapy or organ transplant recipients.　COVID-19 survivor, especially with ARDS, are at high risk for long term physical and mental impairments, and a multidisciplinary approach is essential for critical illness recovery.</p>