Former President Pranab Mukherjee continues to be in deep coma and on ventilator support, but his renal parameters have improved, the hospital said on Saturday.

Doctors attending on the 84-year-old Mukherjee said he remains haemodynamically stable and is being treated for lung infection.

A patient is haemodynamically stable when his blood circulation parameters -- blood pressure, heart and pulse rate -- are stable and normal, doctors say.

Mukherjee was admitted to the Army's Research and Referral Hospital in Delhi on August 10 and was operated for removal of a clot in the brain the same day. He later developed a lung infection and had a renal dysfunction, the doctors said.

"Shri Pranab Mukherjee is being treated for lung infection. His renal parameters have improved. He continues to be in a deep coma and on ventilator support. He remains haemodynamically stable," a statement from the hospital said.

The former President had also tested positive for Covid-19 at the time of his admission.

Mukherjee was the 13th President of India from 2012-2017.