But as the pandemic has continued, U.S. hospitals report much lower mortality rates, on par with mortality rates for patients with similar similar lung problems caused by other diseases.
Experts say it’s because clinicians have become more proficient and are implementing new tactics as they learn more about the covid-19 course; some use fans more selectively; many hospitals are less overwhelmed than when the virus first flooded Wuhan, parts of Italy and New York City; and the early data on ventilation and death did not present a real picture.
“Being on a ventilator right now in our hands is no different than it would be any day of the year,”
In a May 26 study in the journal Critical Care Medicine, Martin and a group of colleagues found that 35.7 percent of covid-19 patients who needed ventilators died – a significant but much lower percentage than the first reports that report the figure in the top 80 percent range.
The use of medications such as remdesivir, which shortens recovery times for some of the sicker patients, and the steroid dexamethasone also helped.
“We have learned a lot about covide since the beginning of the year,” said Russell G. Buhr, pulmonary and intensive care physician at Ronald Reagan’s UCLA Medical Center. “This means that we have a significantly better understanding of how to diagnose, recognize and manage this.”
Buhr hospital is still putting the data together, but said the mortality rate for ventilated patients is between 30% and 50%. This is roughly the same as the rate for people who develop acute respiratory distress syndrome, the dangerous accumulation of fluid in the small air pockets of the lungs caused by diseases such as pneumonia or injuries such as those suffered in road traffic accidents.
About 20 percent of covid-19 symptomatic patients require hospitalization and about 5 percent end up in intensive care. Most of those in ICU require fans. The devices essentially breathe for the patient, who is sedated with a long plastic tube placed in the throat and trachea.
Severely ill patients from 19 covids tend to dwell on ventilators longer than other intubated patients, some for weeks. The tube inflames the tissue, which can interfere with breathing, so later in the course of convalescence it can be removed and replaced by a smaller tube inserted through an incision in the trachea.
Although there is broad consensus that fans have saved many lives during the pandemic, clinicians discuss whether doctors turned to fans too often and too early, especially at the beginning of the pandemic.
“This is a brand new disease we have never seen before,” said Leora Horwitz, associate professor of health and medicine for the population at NYU Langone Health. “We are generally learning to recognize who is to be intubated and who is not. We avoid intubation where we can. We are learning proning,” the technique of putting patients on the stomach to help them breathe. “We are learning about blood clots.”
“It will never be 10 to 20 percent. Let’s not fool ourselves,” said Horwitz. “People who are sick enough to be put on a fan are really sick.”
Managing a patient on a ventilator is a delicate and time-consuming task that requires healthcare professionals to monitor and regulate the amount of oxygen a patient receives, the pressure in their lungs and the time between breaths, among others factors. Buhr said he could spend 30 to 45 minutes tweaking the ventilator settings for an individual patient.
When hospitals in China, Italy and New York City were flooded with patients at the start of the pandemic, this was simply not possible. Some patients have been intubated in the emergency room instead of in intensive care, where nurses can pay more attention. Some hospitals in New York used older or back-up equipment designed for anesthesia. Others relied on staff who were less familiar with the devices or who came from other places.
Italy has fewer ICU beds per capita than the United States and a large elderly population.
Martin, of Emory, said there is no doubt that all of these factors increased mortality rates, mainly because hospitals saw older and more vulnerable patients when the pandemic hit their countries for the first time. In addition to age, underlying conditions such as heart disease and diabetes drastically increase the chances of dying from covid-19.
“The number of cases in New York has exceeded normal and conventional care capacity,” said Martin.
When a team of researchers led by Annemarie Docherty, an academic intensive care consultant at the University of Edinburgh, examined over 20,000 UK patients in the ISARIC registry, they found 1,658 that they needed fans. Of these, 17% were discharged alive, 37% died, and 46% were still in hospital on May 3.
In contrast, the first studies that showed higher mortality rates may have presented a distorted view of the data. A first report in Wuhan’s Lancet Respiratory Medicine put the mortality rate at 86%, but included only 22 ventilated patients.
And when Northwell Health, one of New York’s two largest medical systems, first reported the results of a patient review in April, it put the mortality rate for those who needed 88% ventilators. . The study received widespread coverage in the U.S. media.
But several days later, when researchers corrected their work to account for the large number of patients undergoing ventilation who were still in the hospital, they reduced the mortality rate to 25 percent.