The authors provide a comprehensive review of the pathophysiology, diagnostic issues, pharmacology, mechanical pulmonary, cardiac support and COVID -19 ASAIO Recommendations emphasizing the treatments for ARDS. The latter topics are what make this document most useful and educational for all clinicians. These latter topics are the focus of the Key Points.
- There are tradeoffs between optimal and what’s available. What follows is a stepwise outline of therapies reflecting the usual progression recognizing variation occur which require modifications.
- Pulmonary Support
- Non-invasive (ex. CPAP/BIPAP) is acceptable for moderate hypoxemia.
- Invasive ventilation with limits on end tidal volume and pressure in ARDS.
- Prone position mechanical ventilation is often used for ARDS to improve basal lung aeration.
- Pulmonary and cardiac support
- Persistent hypoxemia – consider extracorporeal and membrane oxygenation for systemic oxygenation commonly provided by V-V ECMO.
- Cardiogenic shock occurs in a subset of COVID – 19 patients and in salvageable patients warrants focus on left ventricular function which is not always accurately portrayed by LVEF alone, prompting a clinical assessment of adequacy of both right and left cardiac performance.
- While V-V ECMO supports oxygenation in the setting of cor pulmonale, direct RV support is necessary to increase right sided output. Likewise, LV support is needed for cardiogenic shock and maybe provided by V-A ECMO as well as biventricular support using V-V ECMO and pVAD (Impella) for LV support.
- Conversely if total support is provided by V-A ECMO, use of pVAD (Impella) is ideal to unload the LV; the so-called ECPELLA configuration. The Impella use provides an opportunity for prolonged LV support, while potentially minimizing complications.
- These are challenging, often prolonged cases in patients who commonly have significant co-morbidities. Institutions are somewhat limited by their capabilities and realistic expectations for an individual patient’s probable recovery.