Long-term complications of COVID-19 in ICU survivors: what do we know?

Coronavirus disease 2019 (COVID-19) has caused more than 175 million persons infected and 3.8 million deaths so far and is having a devastating impact on both low and high-income countries, in particular on hospitals and Intensive Care Units (ICU). The ICU mortality during the first pandemic wave ranged from 40% to 85% during the busiest ICU period for admissions around the peak of the surge, and those surviving are frequently faced with impairments affecting physical, cognitive, and mental health status, complicating the postacute phase of COVID-19, which in the pre-COVID period, were defined collectively as postintensive care syndrome (PICS). Long COVID is defined as four weeks of persisting symptoms after the acute illness, and post-COVID syndrome and chronic COVID-19 are the proposed terms to describe continued symptomatology for more than 12 weeks. Overall, 50% of ICU survivors suffer from new physical, mental, and/or cognitive problems at 1 year after ICU discharge. The prevalence, severity, and duration of the various impairments in ICU survivors are poorly defined, with substantial variations among published series, and may reflect differences in the timing of assessment, the outcome measured, the instruments utilized, and thresholds adopted to establish the diagnosis, the qualification of personnel delivering the tests, the resource availability as well diversity in patients' case-mix. Future longitudinal studies of adequate sample size with repeated assessments of validated outcomes and comparison with non-COVID-19 ICU patients are needed to fully explore the long-term outcome of ICU patients with COVID-19. In this article, we focus on chronic COVID-19 in ICU survivors and present state-of-the-art data regarding long-term complications related to critical illness and the treatments and organ support received.