Can a highly trained nurse deliver anesthetics as well as a physician who has specialized in anesthesiology, or does the nurse require close medical supervision? That issue emerges from two recent studies and from California’s decision last year to join 14 other states in freeing the nurses from a federal requirement that they be supervised by a physician. Colorado seems poised to join the group.

The issue is potentially important to patients and to health care reformers seeking to restrain costs and reduce reliance on high-priced medical specialists.

The two studies — hotly disputed by the American Society of Anesthesiologists — essentially concluded that there is no significant difference in the quality of care when the anesthetic is delivered by a certified registered nurse anesthetist or by an anesthesiologist. The studies were paid for by the professional association for the nurses, a potential conflict of interest, but were conducted by researchers at respected organizations.

Analysts at the Research Triangle Institute found that there was no evidence of increased deaths or complications in 14 states that had opted out of requiring that a physician (usually an anesthesiologist or the operating surgeon) supervise the nurse anesthetists. The analysts recommended that nurse anesthetists be allowed to work without supervision in all states. Researchers at the Lewin Group judged nurse anesthetists acting without supervision as the most cost-effective way to deliver anesthesia care.

Anesthesia has gotten remarkably safe in recent decades, with roughly one death occurring in every 200,000 to 300,000 cases in which anesthetics are administered during surgery, childbirth or other procedures.

There is not much difference between the two professions in the amount of training they get in administering and monitoring anesthetics. Where the anesthesiologists have a big advantage is in their much longer and broader medical training that, many doctors say, may better equip them to handle complex cases and the rare emergencies that can develop from anesthesia.

From a patient’s point of view, it would seem preferable to have a broadly trained anesthesiologist perform or supervise anesthesia services, but, in truth, the risk is minuscule either way.

Fifteen states have exempted the nurse anesthetists from a Medicare requirement that they be supervised by a physician. California’s move is being challenged in court by physician groups on procedural technicalities. The state’s reasoning, which appears sound, is that patients in areas short on anesthesiologists would lose access to surgery and childbirth services if no one else could deliver the anesthetic. The final decision ultimately rests with the hospitals on how best to serve their patients.

In the long run, there also could be savings to the health care system if nurses delivered more of the care. It costs more than six times as much to train an anesthesiologist as a nurse anesthetist, and anesthesiologists earn twice as much a year, on average, as the nurses do ($150,000 for nurse anesthetists and $337,000 for anesthesiologists, according to a Rand Corporation analysis). Those costs are absorbed by various institutions and public programs within the health care system. As health reformers seek ways to curb medical spending, they need to consider whether this is a safe place to do it.