Type L and Type H COVID-19 Phenotypes

Type L and Type H COVID-19.

You may have heard the Type L and Type H phenotypes mentioned during recent discussions about the current COVID-19 pandemic. These terms were coined by Luciano Gattinoni et al in an attempt to describe the two main manifestations that they were seeing while treating COVID-19 infected patients in their Intensive Care Units. In the Emergency Department, we see a variety of phenotypes, with many atypical and low acuity presentations, but those admitted for respiratory support, often eventually progress to these two phenotypes.

The Type L phenotype is characterized by normally compliant lungs but with profound hypoxemia. This is often the initial phenotype, but Type L occasionally progresses to the more severe Type H. The Type H phenotype is similar to ARDS in that the lungs demonstrate low compliance, significant edema, and high recruitability.

Type L COVID-19 Phenotype

Type H COVID-19 Phenotype

Identifying these phenotypes is important for determining the best way to manage these patients. Type H is managed like ARDS, while the Type L is managed very differently. Not understanding these differences could easily lead to harm and iatrogenic injury in patients who fit into the Type L phenotype. Below is a lengthy, but enlightening discussion on the management considerations from multiple critical care gurus around the world. Enjoy.

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