Ventilator alternatives ease shortages
Less invasive therapies are proving effective
The nightmare of doctors in overwhelmed Italian hospitals being forced to ration ventilators, choosing who would live and who would die, has been an ever-present fear since before the coronavirus hit the United States.
Avoiding that bleak scenario has made getting more ventilators a priority.
But as physicians have learned more about COVID-19, the disease caused by the SARS-CoV-2 virus, they are finding that less-invasive and less-risky therapies may be as effective and can help some patients heal faster. Doctors are becoming more conservative about putting severely ill patients on ventilators.
“The strategy right now is to be not as aggressive with the mechanical ventilation and trying other measures first,” said Marcus Schabacker, a physician and president and CEO of ECRI, an international, nonprofit organization based in the Philadelphia area that evaluates medical devices.
Simply putting patients on their side or stomach – a therapy long used to allow air to get into other parts of the lung – has shown promising results in some COVID-19 patients.
Also in recent weeks, physicians have found that patients with extremely low levels of oxygen can be treated with a deceptively simple-looking tube that sits in the patient’s nostrils.
Because of these discoveries, doctors – locally and nationally – are beginning to feel increasingly confident they will have enough ventilators to help keep COVID-19 and other patients alive.
The reduced use of ventilators is good news for patients and hospitals.
Mechanical ventilation – which involves heavily sedating a patient and threading a tube down the throat, also known as intubation – can damage the lungs, increase the risk of infection and cause cognitive impairments. Most patients don’t survive.
“Mechanical ventilation is not benign,” said Rahul Nanchal, director of the medical intensive care unit at Froedtert Hospital and a professor at the Medical College of Wisconsin. “It is associated with a lot of risks and many of these risks can be substantial.”
All of this is still evolving. There are no clear clinical guidelines. And Nanchal and other physicians stressed that there will always be some patients who need to be on ventilators.
New perspectives on quirks
The increased use of less-invasive therapies is based partly on a growing understanding about the characteristics of the disease.
Severely ill patients have signs of what is known as acute respiratory distress syndrome, or ARDS, such as extremely low blood oxygen levels, heavy breathing, fatigue and fogginess. Yet, to the surprise of doctors, the patients are not gasping for air and appear relatively comfortable and alert.
It’s a condition some doctors have dubbed “happy hypoxemia,” the medical term for low blood oxygen.
Doctors have found that many of these patients, who normally would be put on a ventilator, are doing well when treated with a medical device known as a high flow nasal cannula. The device delivers heated and humidified oxygen through a thin tube, or cannula, inserted in the nostrils.
“That’s in my mind, unquestionably, the best option,” said Joshua Glazer, an emergency and critical care physician treating coronavirus patients in UW Health’s intensive care unit.
The results have been surprising. Doctors at the University of Chicago Medicine, for instance, said outcomes for patients on high flow nasal cannulas have been “truly remarkable,” according to a news release Friday. The hospital used the cannulas on dozens of patients. Only one subsequently required a ventilator.
The therapy is typically paired with time placing the patient on his or her side or stomach.
Another option for some patients is a face mask connected to a breathing machine, though the devices pose a threat to hospital staff because they can aerosolize the virus, dispersing viral particles into the air.
High flow nasal cannula, which can also pose risk of aerosolization, is recommended for patients over these other devices in guidelines released last week by the National Institutes of Health.
Schabacker stressed that there is no recommended therapy for COVID-19 patients based on clinical evidence.
Establishing treatment guidelines takes years of study, and physicians, for now, are relying largely on closely monitoring what they’re seeing in their own patients. Patients who deteriorate can do so rapidly and sometimes unexpectedly. But the high flow nasal cannula treatments appear to be working better than expected.
“That’s probably preventing a significant number of patients from needing to be intubated and put on a ventilator,” said Lucian Durham, a Froedtert physician and the hospital’s director of mechanical and circulatory support.
Simple techniques working
The success of turning patients on their side or stomach is adding to the growing confidence that hospitals will have enough ventilators.
At Ascension St. Francis Hospital, the practice is part of patient treatment whenever possible, said Catherine Zyniecki, a clinical nurse specialist in the intensive care unit.
When a person is lying on his or her back for long periods of time, it enables fluids to accumulate and pressure to compress parts of the lung, a bit like a wet squeezed sponge. Remove the pressure and the sponge will expand.
Turning the patient allows the thin blood vessels that run along the alveoli — tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place — to open up. This allows additional areas of the lungs to be brought into better use, boosting the oxygen that gets into the bloodstream.
“You’re almost moving these patients like a rotisserie-style, trying to make sure you get the blood to circulate properly through the lungs,” said Ron Pasewald, respiratory care manager at Ascension St. Francis Hospital.
The simple step has shown surprising results in some patients.
“They’re doing terrific,” Zyniecki said, “and we’re seeing better outcomes than we expected.”
Schabacker, of ECRI, said some patients can show improvements within minutes, with blood oxygen levels rising 20% to 30%.
Prone positioning, putting patients on their stomach, has been shown to benefit patients on ventilators. The NIH guidelines updated last week recommend those patients be prone for 12 to 16 hours a day.
But what’s becoming increasingly clear is the combination of high flow nasal cannulas and keeping patients in a prone position is helping to keep them off ventilators.
The University of Chicago Medicine reported the combination has increased oxygen levels in patients to 80% and 90% from 40%.