Several drugs have been investigated in patients with ARDS, including epoprostenol, nitric oxide, statins, and methylprednisolone, but have not improved survival. Meduri et al. performed an RCT demonstrating that methylprednisolone was associated with a reduction in lung injury score and duration of mechanical ventilation. While not powered to evaluate mortality, this trial raised interest in the use of corticosteroid to mitigate inflammatory lung injury. The 2017 Guidelines from the Society of Critical Care Medicine (SCCM) and the European Society of Intensive Care Medicine (ESICM) recommend steroids for treatment of ARDS based on a meta-analysis of nine randomized controlled trials demonstrating reduction in markers of inflammation and duration of mechanical ventilation, although many of the trials had a small sample size and some were performed without lung protective ventilation. In March 2020, Villar et al. published the largest randomized control trial of corticosteroid therapy for moderate to severe ARDS investigating the impact of dexamethasone on survival and duration of mechanical ventilation.  

A 50-year-old man requires intubation for encephalopathy. His urine output is > 400 cc/hr and serum Na returns at 179 mEq/L. What is the most likely cause of his polyuria? 

We do not often give thought to the factors controlling our circadian rhythm. And yet the circadian system modulates many physiologic systems, including brain arousal, cardiovascular function, sympathetic tone, appetite, metabolism and immune system function. Similar to the sinoatrial node pacing the heart, the suprachiasmatic nucleus located in the hypothalamus serves as the central pacemaker for the circadian rhythm, directing sleep, motor activity, temperature and autonomic tone. Rhythmic release of melatonin from the pineal gland helps drive this central clock in addition to other circadian biomarkers, including cortisol and core body temperature. In healthy individuals, plasma melatonin concentrations typically measure 10-fold higher at night than during the daytime. How does critical illness affect circadian rhythm, specifically melatonin secretion?

As we learn more about the pathophysiology of COVID-19, alternative treatments are being explored for the severe sequelae of this disease. SARS-CoV-2 enters human cells via the ACE2 receptor, located in many organs, including the heart, vascular endothelium, and alveolar epithelium causing an inflammatory cascade that can lead to ARDS, vasodilatory shock, myocarditis, acute kidney injury and capillary leak. Given the relationship between SARS-CoV-2 and the RAAS, is there a role for angiotensin II in vasodilatory shock caused by COVID-19?