One of the continuing mysteries of COVID-19 is how it can affect different people in different ways. How can some people survive with just mild symptoms, if they show any signs of illness at all, while others develop such damaging, deadly pneumonia? According to a paper accepted for publication in the journal Intensive Care Medicine and reported on in ZMEScience, COVID-19 may not be a single disease, but a syndrome—the pneumonia may fall into two categories, requiring different treatments.

Based on observations of several cases, the authors propose two primary “phenotypes” that describe the time-related disease spectrum of emergency department cases of COVID-19. 

These are “Type L”, which is characterized by low elastance, low ventilation to perfusion ratio, low lung weight, and low recruitability; and “Type H”, characterized by high elastance, high right-to-left shunt, high lung weight, and high recruitability.

Read more from ZMEScience and find the study in Intensive Care Medicine.  

Featured image:

Panel A: CT scan acquired during spontaneous breathing. The cumulative distribution of the CT number is shifted to the left (well aerated compartments), being the 0 to -100 HU compartment, the non- aerated tissue virtually 0. Indeed, the total lung tissue weight was 1108 g, 7.8% of which was not aerated and the gas volume was 4228 ml. Patient receiving oxygen with Venturi mask, inspired oxygen fraction of 0.8.

Panel B: CT acquired during mechanical ventilation at end-expiratory pressure at 5 cmH2O of PEEP. The cumulative distribution of the CT scan is shifted to the right (non-aerated compartments) while the left compartments are greatly reduced. Indeed, the total lung tissue weight was 2744 g, 54% of which was not aerated and the gas volume was 1360 ml. The patient was ventilated in Volume Controlled mode, 7.8 ml/kg of tidal volume, respiratory rate of 20 breaths per minute, inspired oxygen fraction of 0.7

Credit: Intensive Care Medicine.