PUNE: The condition of yoga guru BKS Iyengar became more critical on Tuesday.Doctors treating the the 96-year-old yoga guru had to insert a nasogastric tube to provide him with liquid sustenance.Iyengar was put on dialysis on Sunday due to renal (kidney) insufficiency. Renal insufficiency is a medical condition in which the kidneys fail to adequately filter waste products from the blood."Compared to Monday when he had become little drowsy for the first time after hospitalisation, Iyengar's condition has become more critical on Tuesday (August 19). He has become more drowsy, hence we had to put a tube to ensure he remains hydrated and nourished," said a doctor treating him.Iyengar was ill for three weeks prior to hospitalisation. "He was ill for three weeks and had steadfastly refused to get himself admitted and was treated at home by his family physician. He was even put on intravenous fluid at home. His family members could finally pursuade him to get admitted after his condition worsened. He was admitted to the hospital on August 12. He was put on non-invasive ventilator for a day but he refused to undergo aggressive treatment and hence, he was put off the artificial respiration," the doctor said.BKS Iyengar interacting with students of Krishnamacharya Yoga Mandiram, Institute of Yoga and Yoga Studies at Mandaveli in Chennai. (TOI Photo)Iyengar' s heart muscles have become very week following which less blood was being pumped by the heart. "His heart's current ejection fraction (capability of the heart to pump blood) is 20% now. It was 25 per cent when he was admitted. He has been put on medication to improve the heart function, but it has not shown much results," the doctor said."The ejection rate of human heart should be in the range of 45 to 55% for proper blood circulation in the body. But low ejection rate of his heart has led to decreased blood supply to all the vital organs including brain, kidney and intestines. This has also led to kidney failure," the doctor said.After the kidney failure on Sunday, the Yoga guru has been advised continuos renal replacement therapy (CRRT) by nephrologists from Mumbai-based Jaslok Hospital who visited him on Sunday so that fluid as well as toxins accumulated in blood are removed slowly with the help of CRRT machine."We have put him on intermittent dialysis from Sunday. He has undergone three cycles of dialysis so far but his kidneys didn't respond to the treatment," the doctor said.