Background:

Acute respiratory distress syndrome (ARDS) is a condition associated with hypoxemia due to noncardiogenic causes with bilateral lung infiltrates on chest X-ray or CT imaging. 10% of all ICU admissions are ARDS patients, and the recent pandemic of the novel coronavirus has dramatically increased the number of ARDS patients in ICUs across the world. The international epidemiological study (2016) reported a mortality rate of 35-46% for ARDS, and this is very high mortality compared to other ICU diseases. Furthermore, ARDS survivors present with many functional impairments, including physical, cognitive, and psychiatric dysfunction (Post Intensive Care Syndrome, PICS), and their Activities of Daily Living (ADL) and Quality of Life (QOL) are impaired and many other functional impairments have been pointed out. Their inability to get their original life has attracted significant research attention and become a significantly important research topic. Many patients who are unable to return to work due to functional disability require nursing care, and there is concern about the increased burden on the patient, the family supporting the patient, and the social economy. Therefore, the development of effective strategies for patients with ARDS that take into account not only mortality but also functional prognosis is strongly needed.

Recent studies have shown that lung-protective ventilation (low tidal volume and airway pressure control), neuromuscular blocking agents, prone position, noninvasive mechanical ventilators, and extracorporeal membrane oxygenation (ECMO) have improved outcomes, including mortality, in patients with ARDS. However, the mortality of patients with ARDS is still as high as 40%. In addition, the complete reintegration ratio of patients with ARDS after 1 year of hospital discharge reported in 2003 was only 50%, and recent reports have shown little progress in this aspect. Strategies to improve outcomes (mortality and functional prognosis) of ARDS patients by improving not only treatment but also the quality of ICU care have become a hot topic in recent years. The previous paper showed that excessive sedation and absolute bed rest for the purpose of ventilation control and rest during intubation in ARDS patients correlated with delirium, prolonged duration of ventilation, and even increased mortality. Therefore, attempts have been explored to improve outcomes for ARDS patients by systematically providing sedation, analgesia, rehabilitation, spontaneous breathing and awaking tests, and delirium management during ICU admission. These attempts, known as the ABCDEF bundle, have been actively recommended by a number of academic societies to be introduced in ICUs as an attempt to improve outcomes of patients with ARDS and promote their reintegration into society. (ABCDEF bundle: A (Assess, prevent, and manage pain), B (Both spontaneous awakening trials (SAT) and spontaneous breathing trials (SBT)), C (Choice of analgesia and sedation), D (Delirium: assess, prevent, and manage), E (Early mobility and exercise), F (Family engagement and empowerment)), and even ICU care such as nutritional therapy and ICU diaries have been shown to improve outcomes for ICU patients, including ARDS, and are strongly recommended. (In this study, this ICU care is referred to as evidence-based ICU care.) On the other hand, our research team has reported that the overall implementation rate of these evidence-based ICU care, ABCDEF bundles, nutritional therapy, and ICU diaries in ICU patients is quite low, and the rate is significantly lower in mechanically ventilated patients. The reason for the low implementation rates is thought to be that the ventilator is a major barrier. Although many articles have proposed evidence-based ICU care, there is little evidence as to which of these should be prioritized and which should be combined to maximize patient outcomes. The reason for this may be that there is a lack of evidence on which of these should be prioritized and which should be combined to maximize patient outcomes. Implementation of evidence-based ICU care requires many resources and effort, and it is difficult to implement all of them simultaneously. Therefore, the purpose of this international multicenter study is to investigate the current epidemiology and treatment strategy given to the patients with ARDS after the two-year pandemic of the novel coronavirus, clarify the actual implementation of ICU care for ARDS patients who require ventilators at high frequency, and evaluate how the implementation of evidence-based ICU care is associated with patient outcomes.

Significance of the study This study has the potential to increase the generalizability of the results which will be obtained from all regions of the world, including Asia, Europe, North and South America, Oceania, and Africa. Therefore, the results will potentially contribute to improving patient treatment and outcomes in all regions of the world. Furthermore, the results obtained will provide a detailed picture of the current ICU care given to patients with ARDS in the ICU. The association/correlation analysis between its implementation and patient outcomes will identify the content of ICU care which can maximize improvement in outcomes for ARDS patients. As a result, this study will contribute to the development of ICU care guidelines and thereby improve the outcomes of patients with ARDS. The study will play a significant role in improving outcomes for patients with ARDS worldwide. In addition, the results of this study will serve as basement data for future interventional research.