A mother of three wanted a change and went in for a common procedure -- a face-lift. She never came out of surgery.

Her family now says that a well-known, nationwide chain is responsible for her death and has filed a lawsuit against Lifestyle Lift in Middlesex Superior Court. The company insists the procedure is safe and the patient is to blame. In nationwide television ads and on its Web site, Lifestyle Lift promotes a youthful look through a safe cosmetic procedure.   The family of Donna Ames, 49, of Lowell, however, said Lifestyle Lift and two of its doctors are responsible for her death. Their lawsuit alleges carelessness and negligence. It says Ames' blood pressure and oxygen levels fell and she had a seizure.

Andrew Meyer said when Ames had a bad reaction to local anesthesia, the doctors waited nearly an hour to call for help.

"They delayed 45 minutes before they called anybody for help. Emergency medical services only took two minutes to get there, but they hadn't been called for 45 minutes. So by the time they got there, all was gone," said family attorney Andrew Meyer.

Ex-husband John Ames said the loss has been terrible for the former couple's three children, ages 18, 16, and 11.

"I think it's quite devastating. I think anyone would be devastated over the loss of their mom," said Ames.

Donna Ames went in for the procedure last July 10 at the Waltham offices of Lifestyle Lift, which has since moved to the New England Executive Park in Burlington.

Lifestyle Lift, which is based in Troy, Mich., maintains that the procedure in question was safe and that what happened to Ames is not the company's fault. A company statement said: "Ms. Ames did not disclose a history of either seizures or seizure-like symptoms nor did she indicate any allergies to anesthesia."

The Amees family lawyer responded: "She wasn't allergic to anything. This was about whether they responded to an appropriate emergency," Meyer said. Meyer said he has consulted with numerous medical experts who say Donna Ames would be alive and well if emergency services had been called for immediately.