Few people want to be wide awake during their colonoscopy exams, but new research suggests too many are getting extra sedation treatment, costing as much as $1 billion yearly in potentially needless services.

Use of anesthesiologists to monitor sedation during colonoscopies and other digestive imaging tests has more than doubled in recent years, and they're used most often for low-risk patients who typically don't need the extra help, the study authors said.

"These services are not harming patients. They're basically giving them a luxury that is not strictly necessary," said the study's lead author, Dr. Soeren Mattke, a senior Rand Corp. scientist. That matters at a time when policymakers are trying to rein in rising medical costs, the authors said.

Patients usually are briefly sedated for a colonoscopy, and some kinds of sedation require monitoring by specialists. That includes use of propofol, a powerful intravenous drug that can cause deep sedation and was implicated in pop star Michael Jackson's death. Anesthesiologist-monitored sedation, with or without propofol, is recommended for high-risk patients, including those who are old or sick or previously had complications with anesthesia.

While propofol sedation is also sometimes given to low-risk colonoscopy patients, the study authors suggest that's often unnecessary. Drugs usually recommended for these patients typically cause lighter sedation, though most patients don't remember anything about the exams afterward. These drugs can be given by the doctor doing the exam, but the study suggests they're often also being given and monitored by anesthesiologists. --ASSOCIATED PRESS

Read the study in the Journal of the American Medical Association.