Dennis Quaid's newborn twins in medical emergency

Dennis Quaid's newborn twins are in stable condition after being given an accidental drug overdose at Cedars Sinai Medical Center in LA. "This was a preventable error, involving a failure to follow our standard policies and procedures," said Dr. Michael L. Langberg, the chief medical officer of Cedars Sinai in a statement. "I want to extend my deepest apologies to the families who were affected by this situation." Quaid's rep also issued a statement, saying, "Dennis and [his wife] Kimberly appreciate everyone's thoughts and prayers and hope they can maintain their privacy at this difficult time." Thomas Boone and Zoe Grace - whom Quaid and his wife welcomed via a surrogate on November 8 - were given 10,000 units of Heparin, an anti-coagulant used to flush out IV lines and prevent blood clots this past Sunday and began to "bleed out." Babies typically get 10 units. "They are doing well, much better," the twins' grandmother told the New York Daily News. "I certainly am thankful for that." The newborns, who are in the hospital's neo-natal intensive care unit, are being given protamine sulfate, which reverses the effects of Heparin. Doctors are continuing to closely monitor the seven patients who were affected by the drug mix up. "We are conducting a comprehensive investigation, cooperating fully with the LA County Department of Health Services and will take all necessary steps to ensure that this never happens again," Langberg said.