DENVER — A long-running dispute over whether nurses should be allowed to administer anesthesia without doctor supervision has been playing out here and around the country in recent months, with some states insisting that such a move is needed to address the shortage of physicians in rural areas.

The debate pits nurse anesthetists, who specialize in administering anesthesia and maintain that they are well equipped to treat patients on their own, against anesthesiologists, who are physicians and say nurses lack the necessary training.

The dispute dates to a 2001 change in Medicare and Medicaid regulations, allowing states to opt out of a requirement that nurse anesthetists be supervised. And it is part of a broader turf war over how much power nurses should have in treating patients.

“With the removal of the requirement, it actually increases access to health care for citizens in rural Colorado,” said Scott K. Shaffer, president of the nurse anesthetists association in Colorado, one of 17 states that have chosen to allow nurses to deliver anesthesia without supervision.