The Israeli prime minister remains unconscious although pressure on his brain had been relieved.
Doctors at Hadassah Hospital also inserted a new intravenous line into Mr Sharon's arm in order to prevent infection.
In the coming days, however, surgeons may have to cut a hole in Mr Sharon's neck to assist breathing, while still waiting for the clearest sign of improvement: the moment he opens his eyes.
With Mr Sharon, 77, still incapacitated, US President George W Bush called acting prime minister Ehud Olmert for the first time since the Israeli leader's stroke.
Mr Bush sent his regards to Sharon and his family, and pledged to work to implement the vision for Mideast peace that he shared with
Mr Sharon.
Mr Olmert could visit Washington in the coming weeks, Israeli and US officials said.
Treatment debate
Meanwhile, a debate rages over Mr Sharon's medical care.
After he suffered an initial, minor stroke December 18, doctors put him on Cloxane, an anticoagulant injected twice a day.
A few days later, doctors acknowledged that blood-thinners increased the risk of brain haemorrhage, but said the fear of a clot leading to another stroke was greater in this case.
The debate gained momentum after the Haaretz daily revealed that Mr Sharon also suffered from cerebral amyloid angiopathy, known as CAA, a disease that weakens the blood vessels in the brain and increases the risk of haemorrhaging.
CAA, which is linked to dementia and Alzheimer's Disease, is common in the elderly.
Doctors were prescribing the Cloxane until they could seal a small hole in Sharon's heart that they said caused Mr Sharon's first stroke.
Doctors confirmed that they knew about the disease after the first stroke, but prescribed the blood thinners anyway, a move criticised by outside experts.
"If someone has a disease that caused bleeding, that causes bleeding, that could cause bleeding in the future, giving anticoagulants ... is certainly an undesirable situation," said Amos Korczyn, head of the Tel Aviv University Medical School's neurology department.
Mr Sharon suffered a massive stroke January 4, a day before he was to undergo the procedure to seal the hole in his heart.
"The likelihood is that the hole in the heart was of no relevance," said Dr Anthony Rudd, a stroke specialist at London's St Thomas' Hospital, adding that CAA could have caused the first stroke.
Dr Rudd said he would not have prescribed Cloxane if he suspected CAA, and might have gone for a weaker drug, such as aspirin, or a lower dose of blood-thinners.
No definite answer
Other doctors disagreed, saying there are no clear-cut answers, and each physician must weigh the risks based on their knowledge of the drug and the patient's condition.
"This is a very difficult situation because you are between the devil and the deep blue sea," said Dr John Martin, a professor of cardiovascular medicine at University College in London.
"The decision is always different and it's never black and white, and it's very easy in hindsight to say that was the wrong decision."
Mr Sharon's medical team said the criticism was inappropriate.
"Let's say they would have given him less or wouldn't have given him anything and then suddenly he would have developed a clot in the brain instead of bleeding in the brain," Dr Jose Cohen, one of
Mr Sharon's neurosurgeons, told Israel TV.
"Then everybody would have asked why didn't you give him a higher dosage of blood thinners?"