Schumacher Showing 'Slight Improvement' Michael Schumacher has shown "slight improvement" after a surgical procedure but is not out of danger, doctors treating him have said. The operation to remove the largest of a series of blood clots in the racing driver's brain took around two hours, and the coming hours are 'critical' according to medical staff in Grenoble, France. Schumacher continues to be kept in an artificial coma after he suffered a severe head injury while skiing off-piste in the resort of Meribel on Sunday. He was reportedly travelling at speeds of up to 60mph when the accident happened, and is thought to have been saved by his skiing helmet, which split on impact. Rescuers were on hand within minutes and he was initially conscious after the fall before deteriorating into a critical condition. Doctors have refused to give a prognosis for the 44-year-old Formula One champion. Schumacher's family are being kept fully informed about his treatment. Following the surgery, a new scan on Tuesday morning showed "a slight improvement" said the hospital's director general Jacqueline Hubert. But Professor Emmanuel Gay, one of the specialists treating Schumacher, told a news conference: "The dangers are still there. We cannot say that we have won because there are still some highs and some lows, but it's better than yesterday. He is still in a very critical condition, this has not changed. And we still cannot tell how he will be, which state he will be in when he does wake up. We cannot speculate on the future because once again it would be too early to do so. The seven-times F1 champion was admitted to hospital suffering from intracranial haematoma - blood clots - bruising and swelling of the brain. Professor Gay warned: "There are still many haematomas in the brain, with little bits everywhere. That is what makes the situation critical and it needs to be looked at hour by hour, day by day. The situation can still evolve, but we won't be able to evacuate the other haematomas at the moment because they are not accessible. They are not as big as the one we removed yesterday. Schumacher has received an outpouring of support from the racing world, with former and current stars urging him to pull through. German chancellor Angela Merkel said she was "extremely shocked along with millions of Germans" to learn of the accident. Schumacher retired from F1 for the final time in 2012 after a three-season comeback with Mercedes. Michael Schumacher: Hospital Press Conference As It Happened