By Dan Simonson, CRNA, MHPA (WANA
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I'd like to inform everyone about a new article that
just came out (July 14, 2014) from the
Cochrane Collaboration. I am very
excited about it, but in order to understand its significance, you
have to understand the role of the
Cochrane Collaboration. Based in Great Britain, the
Collaboration has become the "gold standard" of evidence based
The Collaboration does not do original research.
Instead, they assemble panels of experts to systemically (meaning
following a very specific algorithm and method) evaluate the
research available to answer important clinical questions. These
"Cochrane Reviews" as they are called, are tremendously important in
that they review the state of the science available, and then the
panel renders a judgment about the quality of the evidence and
whether or not they feel the question has been answered sufficiently
to guide medical care.
The question they asked in this particular Review
To assess the safety and effectiveness of
different anaesthetic providers for patients undergoing surgical
procedures under general, regional or epidural anaesthesia.
The fact that they even asked this question is of
tremendous importance to CRNAs. And their conclusion?
As none of the data were of sufficiently high
quality and the studies presented inconsistent findings, we
concluded that it was not possible to say whether there were any
differences in care between medically qualified anaesthetists
and nurse anaesthetists from the available evidence.
I can hear you all out there groaning. "What is this,
Dan? Why is this important? They didn't find any difference, in fact
they said that the studies done so far were not of 'sufficiently
high quality' to even show any difference!"
let me put it to you in a different fashion, and I think you will
see why I am so excited: The
Cochrane Collaboration has examined the existing studies (and
that would include the Silber study and any other study the mdas can
come up with) and found that there is no evidence sufficient to
show any difference between the two types of providers. In
addition, they state in their final "Implications for Research":
A definitive answer to this question is unlikely. A
randomized controlled trial is unlikely to be performed as it
poses logistic difficulties in terms of allocation concealment
and blinding of participants and personnel. Further,
randomization may be unacceptable to health service providers,
research ethics committees and patients, particularly for
high-risk patients and procedures. In the meantime, hospital
data could be collected or processed to better enable individual
other words, any time an MDA asserts, as was done recently in an
article that Jay referenced ". . . there is a significant
difference, in education and training, between a physician
anesthesiologist and an advanced practice nurse such as a nurse
anesthetist," we can reply that despite any difference in training,
the Cochrane Collaboration has found that there is no study out
there that demonstrates any difference in outcomes between CRNAs and
MDAs. Done. End of story.
this isn't the type of answer, due to the subtleties involved, that
we can put on billboards, it is of supreme importance in the halls
of academia and amongst the health policy wonks of CMS and Congress.
Cochrane Collaboration says it, then it is so.
also excited about the Review for a more personal reason: one of the
six articles chosen, amongst the thousands considered by the panel
to address the question, was mine!
Simonson DC, Ahern MM, Hendryx MS. Anesthesia staffing and
anesthetic complications during cesarean delivery: A
retrospective analysis. Nursing Research 2007; Vol. 56,
can't tell you how much importance is assigned to articles cited for
review by a Collaboration panel. In Health Care policy circles (I
teach in the Master's program in Health Policy and Administration at
Washington State University), it is equivalent to winning an Oscar.
My Nursing and HPA colleagues are all very excited for me - and this
despite the fact that the Review states that my paper was not "of
sufficiently high quality." They understand the very high bar the
Cochrane Collaboration sets for their reviews - to them,
anything less than a Randomized Controlled Clinical Trial cannot be
Cochrane Collaboration has found that there is no available
study demonstrating any difference between the quality of care
provided by CRNAs vs. anesthesiologists, and in addition, they find
that the question is unlikely ever to be answered. After fourteen
years, our battle over Silber is done. Let no anesthesiologist ever
try to state that the Silber study, or any other existing study,
supports their claim that they have better outcomes than CRNAs.
is the citation:
Lewis SR,Nicholson A, SmithAF, Alderson P. Physician
anaesthetists versus non-physician providers of anaesthesia for
surgical patients. Cochrane Database of Systematic
Reviews 2014, Issue 7.
the "plain language summary":
Physician anaesthetists versus nurse anaesthetists for
There is an increasing demand for surgery, pressure on
healthcare providers to reduce costs, and a predicted shortfall
in the number of medically qualified anaesthetists. This review
aimed to consider whether anaesthesia can be provided equally
effectively and safely by nurse anaesthetists (without medical
qualifications) as by medically qualified anaesthetists with
The evidence was current up to 13 February 2013. We found six
relevant studies, five of which were large observational studies
from the US with a comparison group and with study durations
from two to 11 years, and one was a much smaller twelve-week
study from Haiti. There were over 1.5 million participants in
the studies. Information for these studies was taken from
American insurance databases (Medicare) and from hospital
records. The small study was based on emergency medical care
after the 2008 hurricanes in Haiti.
Most studies stated that there was no difference in the number
of people who died when given anaesthetic by either a nurse
anesthetist or a medically qualified anaesthetist. One study
stated that there was a lower rate of death for nurse
anaesthetists compared to medically qualified anaesthetists. One
study stated that the risk of death was lower for nurse
anaesthetists compared to those being supervised by an
anaesthetist or working within an anaesthetic team, whilst
another stated the risk of death was higher compared to a
supervised or team approach. Other studies gave varied results.
Similarly, there were variations between studies for the rates
of complications for patients depending on their anaesthetic
Quality of the evidence
Much of the data came from large databases, which may have
contained inaccuracies in reporting. There may also be important
differences between patients that might account for variation in
study results, for example, whether patients who were more ill
were treated by a medically qualified anaesthetist, or whether
nurse anaesthetists worked in hospitals that had fewer
resources. Several of the studies had allowed for these
potential differences in their analysis, however it was unclear
to us whether this had been done sufficiently well to allow us
to be confident about the results. There was also potential
confounding from the funding sources for some of these studies.
none of the data were of sufficiently high quality and the
studies presented inconsistent findings, we concluded that it
was not possible to say whether there were any differences in
care between medically qualified anaesthetists and nurse
anaesthetists from the available evidence.
Further Reading (Article Links):