Evidence-Based Surgery: What Evidence?

Here is a study that illustrates everything that is wrong with the current status of evidence-based surgical practice.

Many of the standard procedures we perform in general surgery are based on observational studies, expert opinion or my favorite “That’s the way I was trained,” and not randomized controlled trials. Although some such research has been done, subjecting patients to sham operations raises ethical issues and would expose patients to anesthesia unnecessarily.

But some topics could be studied prospectively. A recent paper [Variation in the use of intraoperative cholangiography during cholecystectomy. Sheffield KM et al. J Am Coll Surg. 2012;214:668-79] highlights the problem of insufficient evidence in some areas of surgery.

A group from the University of Texas Medical Branch in Galveston looked at differences in the rates of operative cholangiography in their state. They analyzed data from 212 hospitals in which more than 160 cholecystectomies had been done including almost 177,000 such operations over the 8 years from 2001-2008. The surgeon was identifiable in 89% of cases.

Despite the known pitfalls of basing clinical research on administrative data, several interesting findings of this paper are worth discussing.

Operative cholangiograms were done on 44.6% of the total cohort. By hospital, the operative cholangiogram rates ranged from 6.0% to 98.2%. The breakdown by surgeon was limited to the 706 who had done at least 40 cases. The range of operative cholangiogram use by individual surgeons was 0% to 100% with a median of 39%. Medians were higher for patients with gallstone pancreatitis (69%) and lower for those with acute cholecystitis (25%).

Uninsured patients were only slightly less likely to have operative cholangiography than those who were insured. A puzzling finding was that of those patients who had both ERCP and operative cholangiography, 37% had undergone the ERCP before the cholecystectomy and operative cholangiogram. Why would an operative cholangiogram be necessary after an ERCP had already been done?

The authors found that the variation in rates of operative cholangiography was attributed much more strongly to the surgeon and the hospital rather than the indication for surgery. They concluded that the likelihood that a patient would undergo operative cholangiography depended on the hospital she arrived at and who the surgeons was.

The extent of the variation in the use of operative cholangiography could hardly be greater. It is difficult to believe that there is no agreement on the indications. I don’t think this is unique to Texas either.

The literature is conflicting. One can find multiple papers to support any position. Some claim that operative cholangiography helps prevent common bile duct injuries and reveals unsuspected stones. Others say false positive operative cholangiograms result in more procedures and that most asymptomatic stones discovered by cholangiography never cause symptoms. Surgeons who routinely perform operative cholangiography say it does not waste time while those who don’t do them say it does.

False negatives can occur. I have seen patients with negative operative cholangiograms readmitted within a few weeks because of symptomatic common bile duct stones.

I firmly reside on the low end of the operative cholangiography spectrum. I never perform one unless there is a specific indication as dictated by the liver function tests or a significant question involving the anatomy in the operating room.

A large, well-designed randomized controlled trial would help settle the issue, but it will probably never be done.

Who would sponsor such a study? The companies that manufacture the equipment for cholangiography certainly would have no incentive to fund it. Maybe the best we can hope for is a consensus statement from a group of expert surgeons.

Will it ever be forthcoming?

A version of this post appeared in General Surgery News in June of 2012.

What do interns do when they're on call?

You may be surprised and dismayed when you find out.

A study in the Journal of General Internal Medicine from a VA hospital affiliated with the University of Wisconsin reveals some startling facts.

During a 14-hour call period of 3 pm to 5 am, medical interns spent 40% of their time on computer work and 30% on “non-patient communication,” such as clinical conversations with team members, other physicians and nurses among other things. Direct patient care accounted for a whopping 12% of their time.

What about teaching and learning? Would you believe 2% of the time?

The study was conducted using observers trained in time-motion research. They followed the 25 interns who volunteered for the project, but did not interact with them or influence them in any way. The study was likely much more accurate than most previous research on this topic, which was based on self-reported surveys of house staff.

Other interesting tidbits from the paper were that the on-call intern cross-covered an average of 27 patients per night, which seems like a lot to me. The amount of time spent on “sign out” or “hand offs” was not stated. They averaged 4 admissions per night. Only 93 minutes [11% of the total time on call] were devoted to “downtime,” that is sleeping, eating and recreational computer time.

So it looks like internal medicine interns at the VA in Wisconsin do a lot of “scut work” and don’t have much time for learning or sleeping. With only 4 admissions per night, you would think there might be more opportunity for sleep, but since this was internal medicine, each admission probably took two hours.

The interns in the study worked every fourth night. Ironically, in the good old days when we worked every second or third night, we cross-covered far fewer patients because there were more of us on call each night. Therefore, we got more sleep and were less tired the next day.

When one looks at the small amount of time allotted to patient care and teaching and learning, one is not shocked that many graduates of residency these days are not confident about starting independent practice.

I suspect the results would be similar if surgical residents were observed.

What do you think about this?

A version of this appeared on Sermo yesterday and most agreed that interns are not being properly trained.

Cancer fears raised by newspaper stories

It’s bad enough that every week there’s another study finding germs everywhere. Now it’s chemicals. Here are two recent alarms sounded by reputable newspapers about the problem of toxic substances found on commonly used items.

The LA Times says that Samsonite is recalling 250,000 suitcases because a Hong Kong consumer group found a sample from a side handle “had levels of polycyclic aromatic hydrocarbons higher than recommended in voluntary guidelines.” The substance is apparently a carcinogen.

Deeper in the story is the finding that the consumer group found levels of the chemical that were 1000 times higher than tests run by Samsonite. The company recalled the items “to allay consumer concerns.”

The model in question, called “Tokyo Chic,” [shown above] has a pull-out end handle that is much more likely to be used than the side handle. Also, the story says the high levels of polycyclic aromatic hydrocarbons were found in “a sample.” Really? Was it just one sample? 

Closer to home, the Washington Post headline reads “Don’t Drink The Water: Study Warns Drinking From Garden Hose.” Researchers from an outfit called “Healthy Stuff” studied 90 garden hoses and found high levels of lead and phthalates as well as “PVC plastic additives, which can cause birth defects, liver toxicity, and cancer.” 

The article closes with the suggestion that you shouldn’t drink water from a hose, but if you do, you should let the water run for a few seconds first.

Now, people, with everything we have to worry about in today’s world, are these real problems? Unless you are a member of an airline flight crew, how often do you travel and come in intimate contact with the side handle of a suitcase?

And how often do you feel the need to drink from a garden hose? If you have ever tried drinking from a hose, you know you always let the water run for a few seconds because water that is standing in the hose is usually warm. By the way, that headline “Don’t Drink The Water: Study Warns Drinking From Garden Hose” doesn’t make any sense to me.

Let’s just say that I was able to get to sleep without much worry about these two cancer threats.

Institute of Medicine: Obesity is not caused by lack of willpower

In a 48-page report, the Institute of Medicine “refutes the idea that obesity is largely the result of a lack of willpower on the part of individuals.” [You know the IOM, the same folks who brought you the “98,000 people are killed each year by medical errors” report, the accuracy of which has been challenged.]

According to a spokesman for the IOM, “"When you see the increase in obesity you ask, what changed? And the answer is, the environment. The average person cannot maintain a healthy weight in this obesity-promoting environment."

The report goes on to say, “People cannot truly exercise ‘personal choice’ because their options are severely limited, and biased toward the unhealthy end of the continuum."

Quoting further from an article about this revelation from the IOM, “The panel recommended tax incentives for developers to build sidewalks and trails in new housing developments, zoning changes to require pedestrian access and policies to promote bicycle commuting.”

"We've taken fat and sugar, put it in everything everywhere, and made it socially acceptable to eat all the time. We're living in a food carnival, constantly bombarded by food cues, almost all of them unhealthy," said David Kessler, former head of the U.S. Food and Drug Administration. Maybe Kessler should have done something about this when he was in charge of the FDA.

Are they serious?

Things like this really aggravate me. [Lots of things aggravate me.]

Everyone who drinks alcohol doesn’t become an alcoholic. The IOM says it's not willpower. How is it then that some who are exposed to the same environmental factors and food cues as obese people manage to maintain a normal weight?

How much did the IOM’s 48-page report cost and who paid for it?

Do you think building sidewalks and promoting bicycle commuting will really decrease obesity?

What do you think of the IOM report?

A version of this post appeared on Sermo yesterday. Most of those who commented felt that the IOM was out of touch with reality or al least, mistaken.

Overused Words

While reading the iconic New York Times the other day, I happened to notice that the word “iconic” was used in a few different articles.

The world-wide resources of the Skeptical Scalpel Institute for Evidence-Based Outcomes and Advanced Research were mobilized. Fact checkers swarmed over the Times and discovered that in the last 30 days, the word iconic has appeared 87 times in the paper for an average of 2.9 times per day.

The range of occurrences was 0 (on July 20, July 30 and August 6) to 8 (on August 1, a truly iconic day). The mode, or most frequent number of occurrences per day, was 1, which happened on 10 separate days.

By comparison, the previously unchallenged overused word of the century “artisanal” has only appeared 52 times in the Times during the last 30 days or about 1.7 times per day.

Now I am a mere blogger and am admitted somewhat (artis)anal retentive, but it seems to me that iconic just may have achieved cliché status.

May I suggest that the Times consider removing Iconic from its style book? In my opinion, doing so would increase its iconicity and help to maintain the artisanality of its writers.

Reduced Rate of Infections in Colorectal Surgery: Real or Hawthorne Effect?

There was some buzz last week on medical news sites like MedPage Today, Fierce Healthcare and Science Codex, about a paper from Johns Hopkins describing how the institution reduced its surgical site infection (SSI) rate for colorectal surgery. A multidisciplinary project called the Comprehensive Unit-Based Safety Program (CUSP), involving 36 people including a “team coach” and a hospital executive, began when the SSI rate was 27.3%. After meetings and suggestions for change, they came up with six interventions that they felt would make a difference. They were

• Standardization of skin preparation with chlorhexidine
• Administration of preoperative chlorhexidine showers
• Selective elimination of mechanical bowel preparation
• Warming of patients in the preanesthesia area
• Adoption of enhanced sterile techniques for skin and fascial closure
• Addressing previously unrecognized lapses in antibiotic prophylaxis

In the year following the implementation of the changes, the SSI rate dropped to 18.2%.

Sounds great, doesn’t it? Let’s take a closer look at a few of the interventions.

The issue of chlorhexidine for skin preparation is not quite settled. One of this paper’s own references cites a study which says that povidone iodine use leads to significantly fewer SSIs than did chlorhexidine.

The bowel prep intervention is very confusing. To quote the paper, “In December 2011, the CUSP group reviewed the literature again and decided to change from no mechanical bowel preparation to mechanical bowel preparation with oral antibiotics beginning in February 2012.” This is interesting since the paper was submitted to the journal in January of 2012.

Regarding enhanced sterile techniques for skin and fascial closure (which means they changed gloves and some instruments after the intestinal anastomosis was completed), there is no evidence that doing so prevents wound infections. The only reference they provided was to a book of standards from the Association of periOperative Registered Nurses (AORN), a notoriously non-evidence-based document. [See my previous blog on rules without foundations.]

The lapses in antibiotic prophylaxis involved patients who were allergic to penicillin, a condition that affects only about 10% of the population. There were 602 patients in the study of whom about 60 would probably have been allergic to penicillin. That’s hardly enough to make a big difference in the infection rate.

These policy changes reduced the infection rate of colon surgery from 27.3% to 18.2%. A quick search reveals that in 2010, the colon surgery SSI rate for all hospitals in the state of New York was 5.3%. That’s all hospitals, not just university medical centers. The respected medical resource UpToDate also says the expected SSI rate for colon surgery is 5%.

Despite the well-known effectiveness of 36-person committees (and wouldn’t you have liked to have attended those meetings?), I think there is another explanation for these results. It’s called the Hawthorne effect, which is the name given to the fact that the behavior of experimental subjects changes if they know they are being watched. For example, if you tell the staff of an ICU that there will be changes to the hand washing protocol and compliance will be monitored, whatever the changes are, the rate of compliance with hand washing will increase.

In summary, the authors have turned an abysmal colon surgery SSI rate into a merely bad one by observing it. Medical news sites reported the findings without questioning any of the conclusions. One wonders why the paper is receiving any attention at all or even why it was published.

Vague radiology reports: Can anything be done?

Possible mild peri-appendiceal inflammation. So states a CT scan reading I received the other night.

Here’s another. The findings are concerning for appendicitis.

And another. The appendix is dilated and mildly thick walled with suggestion of mild surrounding inflammatory change, although there is air within the lumen. There is an appendicolith at the base of the cecum. The findings are suspicious for mild acute appendicitis. Clinical and laboratory correlation are recommended. [Digression: You can't diagnose appendicitis with lab tests.]

Even radiologists are questioning the way their colleagues dictate reports. From an editorial in the journal Applied Radiology: The report might say “there appears to be a nodule in the right lower lobe.” If you’re wrong, and there isn’t a nodule in the right lower lobe, you’re covered because you never actually said there was a nodule, only that there appeared to be a nodule, and we all know that nothing is ever as it appears.

Some Stanford researchers looked at radiology reports and found that the most frequent terms used to modify conclusions were probable, consistent with, consider, likely, suggestive, no definite evidence, suspicious, cannot exclude, not likely, maybe and possible. They surveyed radiologists and clinicians and found wide variations in what these words meant to each physician regarding the specifics of whether a hypothetical lesion should be biopsied.

An editorial in the journal Radiology scorned the use of the often-seen phrase if clinically indicated.

I could go on.

Do you know of similar examples of radiologic ambiguity?

Is there a solution to this problem?

A version of this post appeared on Sermo yesterday with interesting comments. About 2/3 of those who voted said there is no solution to the problem. Some commenters said the radiologists are just describing what they see.