Friday, November 2, 2012

We order too many preop tests

As predictable as the leaves falling this time of year, another paper on the subject of unnecessary preoperative laboratory testing has appeared.

A group from the University of Texas Medical Branch looked at more than 73,000 elective hernia repairs in the National Surgical Quality Improvement Project (NSQIP) database. Almost 2/3 of the patients had preoperative laboratory tests. Of that group, 58.6% had a CBC, 53.5% had electrolytes, 23.7% had liver function studies, 18.7% had coagulation studies and 9.9% had all of the above. Even 54% of patients with no co-morbidities had at least one test.

An abnormal test was found in more than 60% of those tested, of the 7200 patients who had lab tests done on the day of surgery, 61.6% had at least one abnormal test including 23% with a coagulation abnormality, 41% with a chemical abnormality and 33% with an LFT abnormality. Despite these results, the scheduled surgery was done.

Tests did not predict complications in patients without co-morbidities. Obtaining a test (not necessarily an abnormal result) was associated with a higher risk of major complications (0.4% versus 0.2% p < 0.0001) but not wound complications. However, abnormal results did not predict complications.

The authors of the paper recommended that surgical societies establish guidelines for preop testing.

Hernia patients, particularly those without comorbidities, are similar to normal people. Obtaining lab studies on these patients is analogous to obtaining labs on the next 100 people who walk past the hospital. Few abnormal results will be found, and most of them will be false positives.

This fact has been known for at least 30 years, yet surgeons, who as shown by previous studies order 80% of preop tests, still continue to order them. Some question whether anesthesiologists insist on having the tests done. Is it defensive medicine? Force of habit?

When I was a department chairman and this subject came up for discussion, at least one person always said, "But if you miss one patient with (you fill in the blank), you will get sued." That type of comment is very difficult to refute because there is a grain of truth to it.

As far as I can tell, "I was following evidence-based guidelines" is not a foolproof defense against a malpractice suit. While there have been some attempts to legislate that following evidence-based guidelines should "immunize" doctors against malpractice suits, to my knowledge, no such laws exist. In 2004, an article in the AMA’s Virtual Mentor journal discusses this point very well as does a paper from the Journal of Law, Medicine & Ethics.

What then is a practicing physician to do? That unnecessary pre-op testing occurs has been understood for many years. The paper points out that the estimated cost of preoperative testing is anywhere from $3 billion to $18 billion. Several esteemed associations and societies have established guidelines which are not followed.

Meanwhile, extensive preoperative testing of ambulatory patients continues at the discretion of the surgeon, anesthesiologist and probably the patient’s primary care doctor too. And the tab mounts.


Hollywood Anesthesia said...

It drives me insane when surgeons I work with order labs for healthy patients undergoing minor procedures.
It drives me more insane when these tests hold up a patient from making it to the operating room on time because of difficult IV sticks or hold ups in the lab.
I think it is also a byproduct of laziness. Its alot easier to check off boxes than talk to your patients. If your patient is able to exercise, not diabetic, and not in renal failure, that would eliminate almost all of the preop lab tests for ambulatory surgery.
Thanks for tweeting this. Hopefully we can get people to stop wasting money on this.

Skeptical Scalpel said...

Thanks for commenting. Of course, I agree. There is a lot of misunderstanding about this subject.

artiger said...

I wonder if ordering all the tests is something that is learned in residency. Perhaps that would be the place to start discouraging such behavior. Or maybe newly minted surgeons learn this from more senior colleagues.

In a small area like mine, we use CRNA's, and some of the older ones insisted on a battery of irrelevant tests (forget trying to use science and literature on them). The newer ones seem to want less, if anything, so perhaps it's generational?

Skeptical Scalpel said...

Artiger, I agree that this is learned in residency. The chief resident wants numbers, so labs are ordered to placate her.

In my experience, it depends on which anesthesiologist/CRNA you get. Some can live without a lot of tests; others demand all kinds of tests and will hold up a case if they aren't done.

Anonymous said...

I am a very busy general surgeon, and agree with Skeptical Scalpel and the the other commentors here. The reason that I order all these unnecessary tests is that the preadmission testing center at my hospital insists on it. If you are over 50, you will have a CXR, EKG, CBC, Chem 7 and coags ordered., regardless of your health status. If those results are not in the preadmission testing center 3 days before the day of surgery, the case is cancelled. This is what happens when we "empower" nurses who blindly follow AORN guidelines

Skeptical Scalpel said...

Anonymous, thanks for commenting. I suspect the anesthesiologists have a lot to do with this too. It's easier to look at lab results than talk to the patients.

You might be interest in this blog I wrote back in May. [] It's on a similar topic.

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