Breathing in the warm summer breeze and exhaling a smoky breath into the icy winter air are all made possible by our lungs—without them, a person couldn’t survive. However, the lungs are vulnerable to various illnesses, such as the flu, pneumonia, and acute respiratory distress syndrome (ARDS).
Of these, ARDS, triggered by pneumonia or sepsis, is particularly life-threatening as it leads to severe oxygen deprivation. Treatment typically involves mechanical ventilation and/or oxygen therapy, and with time, the lung crisis may be resolved. However, one of the biggest challenges with ARDS is determining if the lung damage is reversible. If not, a lung transplant might be needed—but what if the patient is too ill to undergo the procedure?
This was the case for Ankit Bharat, a physician at Northwestern University, and his team. A patient had suffered from the flu followed by bacterial pneumonia, both of which triggered ARDS. Although in desperate need of a lung transplant, the patient was too sickly. In response, Bharat's team developed an artificial lung system that temporarily replaced the patient's failing lungs for 48 hours, allowing him to survive until he could receive a double lung transplant. Their findings, published in Med, revealed the patient’s extensive damage across the entire lung, similar to end-stage fibrotic lung disease—precisely the condition for which lung transplants are the standard treatment.1
“For the first time, biologically, we are giving molecular proof that some patients will need a double lung transplant, otherwise they will not survive,” emphasized Bharat in a statement.
The team first removed the patient’s infected lungs and used their artificial lung system to keep him alive. This system was designed to address shortcomings in conventional systems, which depend on the blood circulation between the heart and lungs and do not account for the effects of ongoing sepsis. This system oxygenated blood and maintained stable blood flow: The patient’s condition improved. After 48 hours, the patient received a double lung transplant.
Meanwhile, the team also assessed the explanted lung tissue. They performed single-cell RNA sequencing on seven lung regions and compared the data to samples from COVID-19 ARDS patients who either died or required transplantation. The results surprised the researchers.
“Conventionally, lung transplant is reserved for patients who have chronic conditions like interstitial lung disease or cystic fibrosis,” explained Bharat. “Currently, people think if you get severe ARDS, you keep supporting them, and ultimately the lungs will get better.” However, the patient tissue had a notable presence of increased T cell infiltration and cells associated with lung fibrosis, indicating severe—essentially irreversible—damage. The system kept the patient alive long enough to receive the life-saving lung transplant. More than two years later, the researchers reported that the patient has returned to daily life with good lung function.
“In my practice, young patients die almost every week because no one realized that transplantation was an option,” Bharat says. “For severe lung damage caused by respiratory viruses or infections, even in acute settings, a lung transplant can be lifesaving.”
