Kehm, Schumacher's long-time press aide, said there will be no official comment from his neurosurgery team on Wednesday as has been the case for the past two days.
"Michael's condition has been carefully supervised all the night and has remained stable also this morning," said Kehm.
"For the moment, the good news for today is that we will not hold a press conference because there are no significant changes.
"Still, the condition overall is critical."
Schumacher suffered cerebral contusion and edema plus lesions to his brain when he fell while skiing in Mirabel in the French alps on Sunday.
Doctors reported a slight improvement in his condition on Tuesday, having been able to perform a second operation to reduce pressure in his brain on Monday night.