"Basu's condition has turned very critical and he is heading for multi-organ failure with dysfunction in cardiac and renal system and stiffness in his lungs," Dr Maity, who is also a member of the medical board of AMRI hospital, where he is admitted, told mediapersons.

"The stiffness is usually reversible, but with his heart not working properly and renal dysfunction, it cannot be said if the stiffness will reverse," he said.

The leader's sensory apparatus was also not responding properly, he said.

His hemoglobin level, however, was near normal after the two blood transfusions given to him on Wednesday and the day before, Maity said.

The plan for tracheotomy, a surgical incision of the trachea through the neck to make an artificial opening for breathing will not be done, he said.

A medical bulletin issued by D N Agarwal, executive director of the hospital said, "He is on ventilatory support and his oxygen requirement has increased."