Emergency Department Management of Severe Hypoxemic Respiratory Failure in Adults with COVID-19

Wilcox, Susan R.; Condella, Anna

Background While emergency physicians are familiar with the management of hypoxemic respiratory failure, management of mechanical ventilation and advanced therapies for oxygenation in the emergency department (ED) have become essential with the pandemic of COVID-19. Objective of the Review: To review current evidence on hypoxemia in COVID-19 and place it in the context of known evidence-based management of hypoxemic respiratory failure in the ED. Discussion COVID-19 causes mortality primarily through the development of acute respiratory distress syndrome (ARDS), with hypoxemia arising from shunt, a mismatch of ventilation and perfusion. Management of patients developing ARDS should focus on mitigating derecruitment and avoiding volutrauma or barotrauma. Conclusions High flow nasal cannula (HFNC) and non-invasive positive pressure ventilation (NIPPV) have a more limited role in COVID-19 due to risk of aerosolization and minimal benefit in severe cases but can be considered. Stable patients who can tolerate repositioning should be placed in prone position while awake. Once intubated, patients should be managed with ventilation strategies appropriate for ARDS, including targeting lung-protective volumes and low pressures. Increasing positive end-expiratory pressure (PEEP) can be beneficial. Inhaled pulmonary vasodilators do not decrease mortality but may be given to improve refractory hypoxemia. Prone positioning of intubated patients is associated with a mortality reduction in ARDS and can be considered for patients with persistent hypoxemia. Neuromuscular blockade should also be administered in patients who remain dyssynchronous with the ventilator despite adequate sedation. Finally, patients with refractory severe hypoxemic respiratory failure in COVID-19 should be considered for veno-venous extracorporeal membrane oxygenation (VV-ECMO).