This article is part of Harvard Medical School’s continuing coverage of medicine, biomedical research, medical education and policy related to the SARS-CoV-2 pandemic and the disease COVID-19.
When the drive to breathe is very high, as it might be with exercise or an infection, a person often develops a sensation of a strong urge to breathe or a feeling of severe breathlessness, known as air hunger, as well as an increase in the number of breaths per minute and the size of the breaths taken. Under these conditions, restricting the breath size can make the sensation of breathing discomfort worse.
Ventilation and medication strategies can help avoid psychological trauma for survivors of severe COVID-19 treated for acute respiratory distress syndrome (ARDS) with mechanical ventilation. But some outdated treatment practices are still in use and may lead to trauma in patients who suffer from air hunger due to ventilation strategies that protect the lungs but may cause other problems.
Now, researchers at Harvard Medical School and Beth Israel Deaconess Medical Center report online in the Annals of the American Thoracic Society their examination of the medical literature and compare evidence-based practices with outdated or misguided practices still in use.
Richard Schwartzstein, the Ellen and Melvin Gordon Professor of Medical Education at HMS and chief of the Division of Pulmonary, Critical Care and Sleep Medicine at Beth Israel Deaconess, is senior author on the study.
“Numerous studies have demonstrated that lungs injured by infection leading to ARDS and respiratory failure can be further injured if the size of the breath provided by the ventilator is too large or the pressure used to inflate the lung is too great,” said Schwartzstein. “So, we manage these patients with low breath sizes to try to protect their lungs from additional damage. This makes the sensation of air hunger much worse, however.”
In looking at recent reports of patients with severe COVID-19 infections admitted to intensive care units in Seattle, as well the authors’ own ICUs at Beth Israel Deaconess and Massachusetts General Hospital, 88 to 91 percent of patients had shortness of breath prior to intubation and mechanical ventilation.
“With the likelihood that hundreds of thousands of short-of-breath patients around the world during this pandemic will require low tidal volume mechanical ventilation, we are concerned about the potential for mass psychological trauma among the survivors, induced by untreated air hunger,” the authors stated in the article. Research has shown that among ICU survivors, the experience of air hunger is often associated with post-traumatic stress disorder.
Schwartzstein and colleagues believe that the problem is solvable, however. “Physicians who are treating ARDS due to COVID-19, some of whom may not be accustomed to treating patients with respiratory failure, must first be aware of the problem and then consider means by which air hunger can be ameliorated,” said Schwartzstein.
Schwartzstein points to a mistaken belief that paralysis reduces breathlessness. As a result, patients are often treated with neuromuscular blocking drugs, which serve as muscle relaxants, to minimize lung injury. “This does not diminish air hunger,” he said. Paralysis may make the situation worse and prevents the patient from communicating or demonstrating their discomfort. While patients are often sedated as well, most sedatives that have been studied do not relieve shortness of breath.
In the article, the researchers refer to studies of the use of opiates for these patients. “Opiates are the most reliable agent for symptomatic relief of air hunger—they seem to act both through depression of ventilatory drive and ascending perceptual pathways, as they do with pain.”
“There has been a tendency to equate ‘sedation’ with an ‘anti-dyspnea’ effect, and the push has been to use sedation primarily because patients are often anxious and agitated when being treated with mechanical ventilation,” said Schwartzstein. “We now know that many sedatives do not relieve dyspnea, and we urge doctors to use opiates for dyspnea and sedatives, when needed, for anxiety and agitation.”
Co-authors include Robert Banzett, HMS associate professor of medicine at Beth Israel Deaconess, and Christopher Worsham, HMS research fellow in medicine at Mass General.
Adapted from a Beth Israel Deaconess news release.