Nearly 90% of Covid-19 patients placed on ventilators at a New York health system died, according to a study published Wednesday in JAMA, and a separate analysis published this week argues that some Covid-19 patients shouldn't be placed on ventilators at all.
For the study published Wednesday in JAMA, an international team of researchers examined the EHRs of 5,700 patients with Covid-19, the disease caused by the new coronavirus, who were treated at one of Northwell Health's 12 hospital locations in the New York area between March 1 and April 4. The researchers said records for 2,634 of those patients included known outcomes data, meaning the records indicated the patients either were discharged or died. The researchers used those records to calculate mortality rates.
The researchers found that 21% of the 2,634 patients died. According to the Washington Post, that percentage is similar to the average percentage of non-Covid-19 patients who died after being admitted to the hospital with respiratory issues before the new coronavirus epidemic.
But the researchers also found that about 88% of the 320 Covid-19 patients who were put on ventilators died. According to the Post, previous research has found that, before the Covid-19 epidemic, about 80% of patients who did not have Covid-19 and were placed on ventilators died.
Northwell Health researchers said, because the study only reports mortality rates among patients whose EHRs included known outcomes, "a longer-term study may find different mortality rates as different segments of the population are infected" with the new coronavirus.
In addition, Hassan Khouli, chair of critical care medicine at the Cleveland Clinic, said it's possible that, "for the most part," the mortality rate reported in the study is "not related to the ventilator."
The study noted that 57% of the 5,700 patients had hypertension, 41% were obese, and 34% had diabetes—all comorbidities that CDC has said can raise a patient's risk of developing a severe case of Covid-19.
Still, Karina Davidson, the study's lead author and a professor at the Feinstein Institutes for Medical Research at Northwell, said, "For those who have a severe enough course to require hospitalization through the [ED]," the 88% mortality rate "is a sad number."
Kevin Tracey, president and CEO of the Feinstein Institutes for Medical Research, said the study's findings "provide a crucial early insight into the front-line response to the Covid-19 outbreak in New York."
According to HealthDay, the findings support concerns voiced by some clinicians that putting critically ill Covid-19 patients on ventilators too soon—or at all—could result in more harm than benefits.
Udit Chaddha, an interventional pulmonologist with Mount Sinai Hospital who was not involved in the studies, said some ICUs are starting to delay putting Covid-19 patients on ventilators out of fear that the treatment could be causing damage. "There had been a tendency earlier on in the crisis for people to put patients on ventilators early, because patients were deteriorating very quickly," Chaddha said. "That is something that most of us have stepped away from doing."
A separate analysis published Tuesday in the American Journal of Tropical Medicine and Hygiene supports clinicians' efforts to move away from placing Covid-19 patients on ventilators.
In the analysis, an international group of physician-researchers reviewed and summarized current guidance on providing ventilator support with a particular focus on settings with limited resources.
The researchers said, during their review, they found that some Covid-19 patients who were put on ventilators did not need mechanical ventilation. Particularly, the researchers found that low levels of blood oxygen, or hypoxemia, in a Covid-19 patient did not necessarily indicate that the patient needed to be intubated. "In our personal experience, hypoxemia … is often remarkably well tolerated by Covid-19 patients" when compared with patients with traditional pneumonia, especially among patients younger than 60, the researchers wrote.
According to the researchers, that's because Covid-19 affects the lungs differently than conditions like traditional pneumonia or respiratory distress syndrome, and mechanical ventilation actually could cause further damage to the lungs in some Covid-19 patients. For instance, aside from patients experiencing the typical side effects of intubation—which can include weakening of the diaphragm, increased risk of infection, and swelling—Covid-19 can cause thick mucus to coat patients' lungs, which can prevent the lungs from taking in the oxygen delivered via ventilation. The sudden increase in oxygen therefore can cause leaks, inflammation, swelling, and other damage to patients' lungs, the researchers said.
Overall, the researchers wrote that only patients who are clearly struggling to breathe should be treated with ventilators.
"The trigger for intubation should, within certain limits, probably not be based on hypoxemia but more on respiratory distress and fatigue," said Marchus Schultz from the Amsterdam University Medical Centers, who coauthored the analysis.
The researchers concluded that other breathing support measures, such as oxygen-delivering nose prongs or face masks, might be safer treatment options for patients who are experiencing low oxygen levels. "[Patients] do not need to be intubated [unless levels are] getting too extremely low for too long," Schultz said (Cha, Washington Post, 4/22; Preidt, HealthDay/U.S. News & World Report, 4/22; Fox, CNN, 4/22; Begley, STAT News, 4/21).
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