The exponential increase in the number of patients with COVID-19 continues to pressure capacity in hospitals across the United States, including Colorado. The disease has posed a powerful challenge to intensive care units, where the growing ranks of critically ill patients threaten to overwhelm the supply of ventilators needed to sustain them.
In many cases, the battle against COVID-19 in ICUs is centered on a condition called acute respiratory distress syndrome, or ARDS, first described by groundbreaking University of Colorado pulmonologist Dr. Tom Petty in 1967.
In patients with ARDS, the tiny air sacs in the lungs called alveoli fill with fluid. The fluid makes it hard for oxygen to get into the blood system, and that can result in respiratory failure. Some of the causes of ARDS include sepsis, pneumonia and trauma. We can add COVID-19 to that list, said Dr. Marc Moss, head of the Division of Pulmonary Sciences and Critical Care Medicine at the University of Colorado School of Medicine.
“We’re seeing many more ARDS cases than we normally would because of COVID-19,” Moss said. He explained that the virus that causes the disease, SARS-CoV-2, infects the cells of the lungs, breaks down the barrier between the lung’s alveoli and capillaries, and allows fluid to flood the air sacs – the hallmark of ARDS.
UCHealth has cared for more than 600 patients as of April 9, many of whom needed intensive care, including younger people who are generally considered at lower risk than the elderly and/or people with other serious medical conditions.
Most ICU patients suffer from ARDS, and nearly all require ventilator support, he added. For now, at least, UCH has adequate supplies of ventilators to meet the challenge. However, the ways providers manage that support could spell the difference between life and death for many people.
Managing the flow of COVID, ARDS patients
The ICUs at UCHealth follow an evidence-based protocol for treating ARDS that a 2000 study showed decreased patient mortality by nearly a quarter, from 40 percent to 31 percent. The key element of the protocol, Moss said, is protecting the lungs by conservatively managing tidal volume: the volume of air the ventilator delivers to the lungs. With ARDS, more air isn’t better. To the contrary, low tidal volume, based on the patient’s weight and other characteristics, is less likely to damage already vulnerable lung tissue.
“The study showed that low tidal volume is the standard of care for patients with ARDS,” Moss said, adding that it is the “default strategy” at UCH. “It’s transformed the way we deliver care to people in the ICU who have ARDS and has saved many lives.”
Another method for managing ARDS is positive end expiratory pressure, or PEEP, a technique pioneered by Dr. Petty and his team. The idea is to use airway pressure to keep the air sacs open when the ventilated patient exhales. Doing so alleviates the stress placed on air sacs that would otherwise have to open and close repeatedly, creating stress, Moss said.
“What PEEP does is when [the patient] exhales all the way, positive air pressure keeps the sacs open, which decreases injury to the lungs that repetitive opening and closing causes,” he said.
A third element of the ARDS management strategy is “fluid conservation,” Moss said. If a patient’s blood pressure stabilizes, he explained, providers begin using diuretics to safely remove fluid, another potential source of lung stress. A 2015 study showed the approach can decrease patients’ time on the ventilator by an average of two days, Moss said, decreasing the risk of pneumonia and other bacterial infections.
Critical care combination for COVID-related ARDS
The challenge of combating ARDS is ongoing at UCH, with many specialties involved, said Dr. Todd Bull, a pulmonary disease and critical-care medicine specialist who is medical director for the UCHealth Comprehensive Lung and Breathing (CLB) program, which provides coordinated specialty care for a wide variety of lung and respiratory problems.
“The ARDS response at this moment is really a critical-care multidisciplinary effort that includes pulmonologists, anesthesiologists, surgeons, nurses, respiratory therapists, and many other specialties helping as consultants,” Bull said.
In the coming days, Bull added, the CLB plans to start a post-ICU clinic to extend care to patients who survive ARDS and other respiratory challenges. “We have decided to fast-forward the opening of this multidisciplinary clinic due to COVID-19,” Bull said, adding that it will headed by Dr. Sarah Jolley, a pulmonologist with the CLB.
The fight against ARDS extends beyond UCH. It is one of six hospitals in Colorado and 73 nationwide that belong to 12 clinical centers comprising the Prevention and Early Treatment of Acute Lung Injury (PETAL) Network. The network, which is funded by the National Heart, Lung and Blood Institute (NHLBI), develops and runs randomized clinical trials to test treatments for ARDS and other lung diseases. Moss said the network recently received approval and funding for a clinical trial of hydroxychloroquine to treat patients who have tested positive for COVID-19. The trial, which Moss said should start soon, will include UCH as a trial site.
The use of the anti-malarial drug hydroxychloroquine to treat COVID-19 has been controversial, as it’s been touted as potentially effective without evidence to back up the claim. Even so, the Food and Drug Administration on March 29 issued an emergency authorization for use of hydroxychloroquine and chloroquine to treat patients hospitalized with COVID-19.
“Anecdotal reports suggest that these drugs may offer some benefit in the treatment of hospitalized COVID-19 patients. Clinical trials are needed to provide scientific evidence that these treatments are effective,” the Department of Health and Human Services said in announcing the move.
The PETAL Network’s aim is precisely to move from unproven anecdotal reports of hydroxychloroquine’s effectiveness as an anti-viral to testing it against the rigors of a randomized trial, Moss said.
“There are no known medications to treat COVID-19,” he said. “We are trying the best we can to expedite clinical trials so we use evidence-based practice to find medications that we know work or don’t work.”
For all updates and to read more articles about the new coronavirus, please visit uchealth.org/covid19
Absent definitive results from the PETAL Network’s trial and the mountain of others now underway, ICU providers can save lives now with proven methods for treating and managing ARDS. But he acknowledged that his own work shows that many hospitals and providers still have work to do in improving their recognition of the condition and following protocols like low tidal volume, PEEP and fluid conservation to manage it.
“That’s an important area that we need to address,” Moss said. “Hopefully, the COVID-19 pandemic might increase the recognition of ARDS, even in patients who don’t have the infection. That might help with implementing better ventilation practices around the country.”