Reasons for the Overuse of Sedatives and Deep Sedation for Mechanically Ventilated Coronavirus Disease 2019 Patients.

To the Editor:

We read with great interest the study by Wongtangman et al (1) published in a recent issue of Critical Care Medicine, which investigated the potential mediators of high mortality rate of coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome (ARDS). Sophisticated statistical methods including mediation analysis and propensity score matching were leveraged to make causal inference from observational dataset (2). The authors finally concluded that COVID-19 ARDS is more likely to die than other non-COVID-19 ARDS, even after adjusting for the severity of illness, and the effect was partially mediated thorough the use of sedatives and analgesics. In other words, the study supports previous findings that deep sedation with overdosing of sedatives is associated with increased risk of adverse clinical outcomes. Since many clinical guidelines have already recommended the use of light sedation for mechanically ventilated (MV) patients (3), why there are so many patients being deeply sedated during COVID-19 pandemic? Most probably, the management of MV patients with light sedation requires more labor force. The medical resources, including medical doctors, are in short during the pandemic (4). Thus, patients are more likely to be deeply sedated to avoid any adverse events associated with light sedation such as inadvertent tube removal and agitation (5). Another explanation for the overuse of sedatives is that COVID-19-related ARDS are more likely to develop refractory hypoxia, forcing physicians to use deep sedation and advanced ventilation support to improve oxygenation. It is well documented that low arterial blood oxygenation is the hallmark of COVID-19-related ARDS. However, one limitation is that the study did not report the level of mechanical ventilation such as the use of lung recruitment maneuvers, driving pressure, positive end-expiratory pressure, and mechanical power. High level of these ventilatory supports may require high dose of sedatives and even neuromuscular blockade.