Follow-Up: Anesthesiologists, Nurse Anesthetists and Evidence

A post we did on Tuesday about a study on anesthesia outcomes published in Health Affairs has attracted a lot of comments and debate, to put it mildly. (This wasn’t a big surprise — the last time we covered the discussion of whether nurse anesthetists need to be supervised by a physician, there was a similar reaction.)

We wanted to address some of the questions raised by commenters. So here’s a summary of the more common themes:

What do the anesthesiologists think of the research?

Not much. Here’s the official reaction from the American Society of Anesthesiologists. Billing data is a poor way to judge quality and outcomes, and can’t distinguish between complications stemming from a surgical procedure and from anesthesia, ASA president Alexander Hannenberg tells the Health Blog. He says the study didn’t include enough cases to capture any significant differences in mortality rates, given that mortality is exceedingly rare — one estimate is one death per 240,000 anesthetics. He also cites an ASA-funded survey that found that the public wants physicians to supervise their anesthesia.

What are the requirements for CRNAs?

We wrote: “Prerequisites for becoming a CRNA include a bachelor of science degree in nursing or science-related field, one year of critical care experience before a two- or three-year masters program in anesthesia, a certification exam and a year of residency.” But an AANA spokesperson referred us to this page listing the education and experience necessary to becoming a CRNA. The year of residency we mentioned is not on it, and so we will correct the original post.

Since the AANA sponsored the study, shouldn’t we dismiss its conclusions?

If we dismiss the research on this topic that’s funded by the AANA or the ASA, there’s not much left. The ASA, for example, was the primary sponsor of a 2000 study published in Anesthesiology that concluded that mortality rate and so-called “failure to rescue,” or mortality rate after complications, “were lower when anesthesiologists directed care.” (That study actually also involved billing data.) Most groups funding this research have skin in the game.

So what kind of study would settle this question?

One that isn’t likely to be done. To satisfy everyone, it would have to be large enough to capture any statistically significant differences in mortality rates, be based on clinical rather than billing data and be independently funded. The CDC considered doing a study in 1980, Hannenberg says, but concluded that “mortality rates were so low that it was near impossible.” And mortality rates are lower now, which would make the project even harder.

How can CRNAs be found more cost effective than anesthesiologists?

We asked Paul Hogan, an economist and vice president with the Lewin Group (an independent consulting unit of UnitedHealth) and an author of a recent cost-effectiveness study of anesthesia delivery (and yes, it was funded by AANA). That study ran simulations of different delivery models and concluded that in most (but not all) cases, CRNAs acting independently provide anesthesia services at the lowest economic cost.

This will hinge on demand, the characteristics of the anesthesia procedures and the mix of payers — Medicare doesn’t make a distinction, but private payers will, on average, reimburse (or “allow” in insurance-speak) at lower rates for care delivered by a solo CRNA than by other provider mixes. If CRNAs were allowed to provide more services, eventually, Hogan says, “you’d expect the price for those services to go down.” (In addition, more physicians, including anesthesiologists, are being employed directly by hospitals and surgical centers, in some cases guaranteeing a certain salary.)

Here’s what the ASA had to say about Hogan’s study, in case you were wondering.


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This entry was posted on Wednesday, August 4th, 2010 at 6:36 am and is filed under Health Care. You can leave a response, or trackback from your own site.

One Response to “Follow-Up: Anesthesiologists, Nurse Anesthetists and Evidence”

  1. Carroll B. Merriman Says:

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