Anecdotal evidence has increasingly demonstrated that this proposed physiological approach is associated with much lower mortality rates among COVID-19 patients, he said.
While not willing to name the hospitals at this time, he said that one center in Europe has had a 0% mortality rate among COVID-19 patients in the ICU when using this approach, compared with a 60% mortality rate at a nearby hospital using a protocol-driven approach.
In his editorial, Dr. Gattinoni disputed the recently published
recommendationfrom the Surviving Sepsis Campaign that “mechanically ventilated patients with COVID-19 should be managed similarly to other patients with acute respiratory failure in the ICU.”
“Yet, COVID-19 pneumonia, despite falling in most of the circumstances under the Berlin definition of ARDS, is a specific disease, whose distinctive features are severe hypoxemia often associated with near normal respiratory system compliance,” Dr. Gattinoni and colleagues wrote, noting that this was true for more than half of the 150 patients he and his colleagues had assessed, and that several other colleagues in northern Italy reported similar findings. “This remarkable combination is almost never seen in severe ARDS.”
Dr. Gattinoni and colleagues hypothesized that COVID-19 patterns at patient presentation depend on interaction between three sets of factors: 1) disease severity, host response, physiological reserve and comorbidities; 2) ventilatory responsiveness of the patient to hypoxemia; and 3) time elapsed between disease onset and hospitalization.
They identified two primary phenotypes based on the interaction of these factors: Type L, characterized by low elastance, low ventilator 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.
“Given this conceptual model, it follows that the respiratory treatment offered to Type L and Type H patients must be different,” Dr. Gattinoni said.
Patients may transition between phenotypes as their disease evolves. “If you start with the wrong protocol, at the end they become similar,” he said.
Rather, it is important to identify the phenotype at presentation to understand the pathophysiology and treat accordingly, he advised.
The phenotypes are best identified by CT scan, but signs implicit in each of the phenotypes, including respiratory system elastance and recruitability, can be used as surrogates if CT is unavailable, he noted.
“This is a kind of disease in which you don’t have to follow the protocol – you have to follow the physiology,” he said. “Unfortunately, many, many doctors around the world cannot think outside the protocol.”
In his interview with Dr. Whyte, Dr. Kyle-Sidell stressed that doctors must begin to consider other approaches. “We are desperate now, in the sense that everything we are doing does not seem to be working,” Dr. Kyle-Sidell said, noting that the first step toward improving outcomes is admitting that “this is something new.”
“I think it all starts from there, and I think we have the kind of scientific technology and the human capital in this country to solve this or at least have a very good shot at it,” he said.