Experts review evolution of approaches to mechanical ventilator liberation

Liberation from mechanical ventilation represents a daily challenge for physicians practicing in the ICU. Since the publication of the CHEST/ATS Guideline on Liberation From Mechanical Ventilation in Critically Ill Adults in 2017, evidence-based approaches to mechanical ventilator liberation continue to evolve.

During the session Novel Strategies to Liberate Patients From Mechanical Ventilation, members of the expert panel that authored the 2017 guideline reviewed and updated attendees on the use of several strategies that have been shown to facilitate ventilator liberation. The session is available on demand for registered CHEST 2021 attendees through October 1, 2022.

“Ventilator liberation is one of the most important problems and biggest challenges that physicians in the ICU encounter because we know that every additional day that a patient remains on a mechanical ventilator, their mortality rate increases,” said session chair Daniel R. Ouellette, MD, MS, FCCP, Associate Professor of Medicine at Wayne State University School of Medicine and Director of the Pulmonary General Practice Unit at Henry Ford Hospital in Detroit.

“At the same time, we understand that when a patient is liberated from the ventilator, if that liberation effort is unsuccessful and the patient has to go back on the ventilator within 48 hours, their risk of not surviving the hospitalization is very high,” he added. “There’s a difficult balance between trying to liberate patients both successfully and quickly, so the assessment of when to liberate patients from the ventilator becomes critical.”

Among the strategies discussed by the panel, which also featured Jonathon Truwit, MD, and Sangeeta Mehta, MD, was the use of various noninvasive ventilation modes following extubation that have been shown to decrease the likelihood of re-intubation.

“In patients who are at high risk of being re-intubated following their liberation, studies have shown that patients treated with a mask ventilation device had improved outcomes, were less likely to have to go back on the ventilator, and had improved mortality,” Dr. Ouellette said. “Another noninvasive strategy that has been shown to be effective and is being used more and more commonly, particularly during the COVID-19 pandemic, is the delivery of high-flow oxygen through a nasal cannula.”

Dr. Ouellette also said that spontaneous breathing trials (SBTs) can help to assess whether the patient is ready to be liberated from the ventilator.

“There are a couple of ways of doing a spontaneous breathing trial, but one decision point is whether to use augmented airway pressures during the test,” he said. “What we found in our data analysis for the guideline was that augmented pressures led to patients being more successful at completing their SBT, thus leading to earlier extubation from the ventilator.”

The panel also discussed recommendations related to use of the cuff leak test, which is commonly done in association with SBTs.

“The cuff leak test is used to assess whether there is edema, stricture, or some sort of closure present in the airway, before making the decision to extubate,” Dr. Ouellette said. “The problem with the cuff leak test is that, quite frankly, it is not a very good test. It’s often used, but it’s difficult to interpret and may or may not have implications for the liberation decision.”

The panel also reviewed key considerations and strategies for patients who remain supported by mechanical ventilation, including the importance of sedation profiles.

“We want to sedate our patients, so they have limited discomfort when they’re on the ventilator, but we know that if we sedate them too heavily, then they are less likely to be easily liberated from the ventilator,” Dr. Ouellette said. “Sedation strategies that involve daily interruption to allow the patient to wake up and let us to assess them, as well as strategies that focus on minimizing sedation wherever possible, are very important.”