The Case for Passive Ventilation Alternative for COVID-19

He ordered that positive end-expiratory pressure (PEEP) be set to zero, inspiratory time to 1.4 seconds, pCO2 to less than 35 mmHg, and that tidal volume be increased to at least 800 mL. The regimen runs in direct contrast with widely held ventilation strategies and current guidance on COVID-19 treatment.

APRIL 30, 2020 -- Over 48 hours, eight patients arrived at the COVID-19 unit in Neustadt, Germany — four from an overwhelmed hospital in Strasbourg, France, and four who were transferred from other hospitals across Germany. All were critically ill, deeply sedated, and receiving lung-protective ventilation. It was clear to Gerhard Laier-Groeneveld, MD, a pulmonologist specializing in respiratory failure, that for all eight of his new patients, the long-trusted ventilation protocol wasn't working. So, he made a controversial call.

He ordered that positive end-expiratory pressure (PEEP) be set to zero, inspiratory time to 1.4 seconds, pCO2 to less than 35 mmHg, and that tidal volume be increased to at least 800 mL. The regimen runs in direct contrast with widely held ventilation strategies and current guidance on COVID-19 treatment.

Within 20 hours of passive ventilation, one of the French patients, a woman who had been intubated for 14 days, was able to be extubated. Another was extubated on the second day. The remaining six are doing well in the ICU but are too weak to breathe on their own for more than a few hours, owing to the fact that they arrived under such heavy sedation. After 2½ weeks without any deaths, Groeneveld decided to share his strategy via Medscape Consult, a crowdsourced social media platform where clinicians share and discuss real cases.

"COVID-19 is not ARDS [acute respiratory distress syndrome]," Groeneveld posted. "And it does need a different strategy of ventilation," he added later in an interview with Medscape Medical News. Although his patients were hypoxemic, CT scans showed pneumonia "with some homogeneous air space consolidation that does not respond to PEEP or prone positioning," he wrote. Physicians from all over the world responded, thanking him for his advice and asking for clarifications.

It's now been 4 weeks since the first patients arrived from France, and still there there have been no mortalities at the Neustadt COVID-19 unit. But many physicians are wary of abandoning decades of research-backed practices for this new approach in the face of a little-known virus. Still, Groeneveld insists the current protocols are inadequate, even dangerous, for treating COVID-19. And he's not alone.

Groeneveld posted to Consult just days after Luciano Gattinoni, MD, and his colleagues wrote an editorial arguing that COVID-19 has two distinct phenotypes, type L and type H. Type H, which is similar in pathology and treatment to ARDS, was only present in 20% to 30% of their 150 patients. Gattinoni argues that for the remaining 70% with type L, standard ventilation protocols are not productive and may even create injuries that cause COVID-19 to progress. The difference, Groeneveld says, between Gattinoni's approach, detailed in a recent JAMA editorial, and his own is that Groeneveld believes passive ventilation is the best course of treatment for all patients, even ARDS-like type H.

A physician on the front line in New York City has also questioned ventilation protocols because he found that COVID-19 symptoms could often present more like high-altitude pulmonary edema (HAPE) than ARDS. However, clinicians with experience treating both HAPE and COVID-19 have pushed back on this observation and have argued that the comparison between the diseases is potentially risky.

Other experts say it's too soon to abandon ventilation strategies that have been established through years of clinical trials. "Regardless of whether COVID-19 behaves like ARDS or not, we as physicians have been thinking about judicious use of mechanical ventilation for several decades," William Checkley, MD, PhD, a pulmonologist and critical care specialist at Johns Hopkins, told Medscape. "I don't think we should stray away from some principles of mechanical ventilation."

The Case for Passive Ventilation

Since 2011, Groeneveld has been researching an alternative to lung-protective ventilation — a way to relieve pressure on the respiratory muscles and avoid sedation using noninvasive oxygen therapies. Long before the current pandemic, he regarded the mortality rates among ARDS patients who undergo lung-protective ventilation — 35% to 50% — as unacceptable.

Now with COVID-19, the mortality rates are far worse. The UK's Intensive Care National Audit and Research Center (ICNARC) reported higher than normal mortalities: more than two thirds of 1053 COVID-19 patients who underwent mechanical ventilation died. This is almost twice the mortality rate of patients who received mechanical ventilation for viral pneumonia between 2017 and 2019.

"If we are to believe our colleagues in New York, 80% of the patients die on ventilator therapy. We have to change this therapy right now," Groeneveld told Medscape.

He's been testing passive ventilation without sedation in patients with respiratory failure for almost a decade and says he has achieved mortality rates as low as 2% to 8%. So when the pandemic hit Europe, he suspected his treatment approach could help. He left his job and home in Oberhausen, Germany, because the hospital there wouldn't admit foreign COVID-19 patients. In Neustadt, he could treat patients coming in from overwhelmed hospitals in Italy, Spain, and France.

Patients who arrive at Neustadt for COVID-19 are "treated with oxygen, mask ventilation, and high tidal volumes to meet respiratory drive," he said. Groeneveld and his team avoid intubation, regardless of saturated oxygen levels, until mental function is compromised. "We are sure that noninvasive ventilation is very effective and many people do not need intubation and sedatives," he said.

Still, many physicians, such as Johns Hopkins' Checkley, are resistant to forgo ARDS protocols.

"The importance of limiting tidal volumes in mechanically ventilated patients," Checkley said, "is to avoid creating volume trauma ? same goes with pressure. The risk of liberalizing the amount of tidal volume delivered could be problematic in the sense that you could induce injury." For patients with adequate respiratory system compliance, Checkley doesn't think physicians should increase tidal volumes above 8 mL/kg of predicted body weight.

Todd Rice, MD, a pulmonologist and critical care specialist at Vanderbilt University, is more skeptical. "To me, in my hospital it doesn't matter if you have ARDS. We do lung-protective ventilation on everybody because that's what the research supports," he said in an interview. In lung-protective studies, high tidal volume is often the control arm, Rice said. "High tidal volumes look better, their oxygen and CO2 levels are often better. But when the studies were done, we saw they died more often," he said.

It's true that studies from the ARDS Network show a higher mortality rate with tidal volume at 12 mL/kg of body weight, but Groeneveld argues that the high tidal volumes used in these studies are not a proxy for his strategy. In these studies, all patients were sedated and were receiving excessive fluids, and no one was extubated early. His approach uses highly individualized tidal volumes (usually >800 mL) determined on the basis of the disease, not body weight. The priority is to keep patients awake and passively ventilated so they aren't breathing on their own and to extubate as soon as possible.

Despite controversy around the elevated tidal volume and low PEEP associated with Groeneveld's approach, most physicians agree that limiting sedation as much as possible and delaying intubation is best for the patient.

For Groeneveld's patients still in the ICU, daily T-piece trials are being conducted, and when the trials are successful, they proceed with extubation. There are now seven patients in the ICU. All underwent intubation before arriving at Neustadt, and there still have been no mortalities. But this victory isn't enough to change the scientific community's opinion, Groeneveld acknowledges. There needs to be a direct comparison between the two ventilation protocols. So, on May 1, he's again moving, this time to the University of Göttingen, where there are more COVID-19 patients and he can compare the two protocols in the same disease. If the medical community doesn't adjust now, Groeneveld says, "will we repeat this disaster every couple of years when a new virus arrives?"

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