Early identification of acute respiratory distress syndrome in times of the COVID-19 pandemic

Acute respiratory distress syndrome(ARDS)was reported for the first time in 1967 in 12 patients with sudden respiratory failure due to a non-cardiogenic pulmonary edema.[1]Even though these patients had no underlying pulmonary disease,they rapidly developed severe hypoxemia,stiff lungs,and pulmonary bilateral infiltrates within a few days after a precipitating factor.Autopsy revealed a characteristic histological pattern of diffuse alveolar damage involving hyaline membranes,edema,necrosis,and cell proliferation.[2,3]The definition of ARDS evolved markedly over time and the Berlin definition,which was proposed in 2012,is currently the most recent one.[4]First,acute onset of respiratory symptoms appearing or worsening within 7 days of a clinical insult,thereby excluding patients who develop respiratory failure over more prolonged periods due to idiopathic pulmonary fibrosis,non-specific interstitial pneumonitis,organizing pneumonia,or pulmonary vasculitis.

Oxygenation strategies after extubation of critically ill and postoperative patients

In intensive care units(ICUs),the decision to extubate is a critical one because mortality is particularly high in case of reintubation.Around 15%of patients ready to be weaned offa ventilator experience extubation failure leading to reintubation.The use of high-flow nasal oxygen and non-invasive ventilation are two alternatives of standard oxygen supplementation that may help to prevent reintubation.High-flow nasal oxygen and non-invasive ventilation,may be used to prevent reintubation in patients with low(e.g.,patients without comorbidities and with short durations of mechanical ventilation)and high risk(e.g.,patients>65 years and those with underlying cardiac disease,chronic respiratory disorders,and/or hypercapnia at the time of extubation)of reintubation,respectively.However,non-invasive ventilation used as a rescue therapy to treat established post-extubation respiratory failure could increase mortality by delaying reintubation,and should therefore be used very carefully in this setting.The oxygenation strategy to be applied in postoperative patients is different from the patients who are extubated in the ICUs.Standard oxygen after a surgical procedure is adequate,even following major abdominal or cardio-thoracic surgery,but should probably be switched to high-flow nasal oxygen in patients with hypoxemic.Unlike in patients experiencing post-extubation respiratory failure in ICUs wherein non-invasive ventilation may have deleterious effects,it may actually improve the outcomes in postoperative patients with respiratory failure.This review discusses the different clinical situations with the aim of choosing the most effective oxygenation strategy to prevent post-extubation respiratory failure and to avoid reintubation.