CHICAGO (CBS) — Chicago’s own Northwestern Medicine performs a double-lung transplant on a second COVID-19 patient.

The recipient, a man in his 60s spent 100 days on ECMO, a life support machine that does the work of the heart and lungs. He contracted the virus in late March. His surgery was performed over the Fourth of July weekend.

Before he could be added to the transplant wait list, he had to test negative for COVID-19. The ECMO machine helped clear the coronavirus from his body.

Typically, a double-lung transplant takes six to seven hours, but this surgery took about 10 hours because the virus had so badly damaged the patient’s lungs.

Doctors said he’s recovering at an optimal pace.