Will having one lung limit Pope Francis?

"A person with two lungs has a lot of reserve function, so if one lung is removed, he or she can still function normally, without shortness of breath," said Loyola University Medical Center pulmonologist Dr. Daniel Dilling.

Today, physicians rarely remove lungs due to infections, Dilling said. But last century, it was more common to remove part of a lung (lobectomy) or an entire lung (pneumonectomy) to treat tuberculosis or another lung condition caused by infection, bronchiectasis.

Removing a lung leaves a cavity in the chest, which gradually fills up with sterile, watery fluid that does not cause problems, Dilling said.

Having just one lung might affect the performance of an elite athlete, Dilling said. But otherwise, people who have just one lung "can live normal, productive lives without shortness of breath or other symptoms," Dilling said.

However, if a person with one lung suffers a lung disease, he or she will not have any reserve capacity to compensate for loss of lung function caused by the disease, Dilling said.

Today, lungs are rarely removed to treat infections. Rather, prompt and aggressive treatment with antibiotics can treat tuberculosis or stop the development of bronchiectasis, Dilling said.

Dilling treats advanced and end-stage lung diseases and is a lung transplantation specialist. He is an associate professor in the Division of Pulmonary and Critical Care Medicine at Loyola University Chicago Stritch School of Medicine.