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.

Can you guess the diagnosis using this radiology report?

Here are some excerpts from a radiology report I received. I left out some portions that were not pertinent and I highlighted in bold some of the better parts. My comments are in brackets.

This was in reference to a CT scan of the abdomen for abdominal pain.

Free peritoneal air is present. Proximal small bowel loops are dilated to about 4 cm in diameter. In the lower abdomen and upper pelvis there is a region of edema and a change in caliber of the diameter of the bowel consistent with bowel obstruction. This edema also surrounds the sigmoid colon. There are diverticula and diverticulitis is a consideration. Perforated diverticulitis is also another consideration for the free air. There are some collections of air along the right side of the sigmoid colon which may be extraluminal or perhaps some prominent diverticula. A small abscess in this region is a consideration. There is diffuse edema in the lower omentum.

No abnormal masses are seen in the pelvis. No significant amount of free pelvic fluid is present. {Is there an insignificant amount of fluid?]

No appendicitis. No diverticulitis. No free air.[!]

IMPRESSION: Proximal small bowel obstruction. Questionable diverticulitis with questionable small abscess adjacent to the sigmoid colon. Pneumoperitoneum [“Pneumoperitoneum” means free air in the abdominal cavity.]

Is there diverticulitis? Is there free air? What the hell is going on?

So if you were the surgeon, what would you do?

At least the radiologist used the correct plural form of the word “diverticulum.” See my previous post on this topic.

The Apocalypse Is Near: Part IV

A report from Egypt says that a medical center there is treating various maladies by having patients drink camel urine. It apparently is good for “the treatment of skin diseases such as ringworm, tinea and abscesses, sores that may appear on the body and hair, dry and wet ulcers, swelling of the liver, toothache, and for washing eyes.” Ah … no, thanks.

In Britain, 26% of the population has received a diagnosis of depression at some point in their lives. That is depressing. However, it doesn’t mean that they were all clinically depressed. I don’t know what goes on over there, but here in the US, it seems all you have to do is tell a doctor you feel depressed and you will likely receive a prescription for an anti-depressant.

How’s this for chutzpah? Francesco Schettino, the former captain of the ill-fated liner Costa Concordia, has sued the company that owned the ship for wrongful termination after he was fired. You may recall that he is facing charges of manslaughter and abandoning the ship. [LINK]

Here are five stories that make me pessimistic about the future of our country.

1. A boy removed the brakes from his bicycle, promptly ran through a stop sign and crashed into a car. [LINK]

2. An adult couple who were babysitting tied a 2-year-old girl to a coffee table because she wouldn’t stay away from the refrigerator. Yes, that’s bad, but it gets worse. They “began to wonder if it was a bad idea to tie up the girl, and discussed the situation with an upstairs neighbor” who then called the police. [LINK]

3. Two law students were arrested for killing a rare exotic bird at a hotel in Las Vegas. They were tossing it around and then decapitated it. Did I mention they were law students? The article describing this heinous crime says they attended “Berkeley University in northern California.” I think the reporter meant to say University of California, Berkeley, but how would he have any way to know this since Berkeley is at least 500 miles from Las Vegas? [LINK]

4. Another northern California story details a new diversion created by boys at a high school. They started a “fantasy slut league” in which “Male students earn points for documented engagement in sexual activities with female students." This is so bizarre that even I can’t think of anything to say about it. [LINK]

5. The University of North Carolina has banned the use of the word “freshman” to denote a student in the first year of college because the term is “non-gender inclusive.” From now on, they are to be called “first year students.” The story is amusing as it points out the problems with the words sophomore, junior and senior. [LINK]

Law school revamps final year curriculum. Will med schools ever do the same?

The New York Times reports that NYU Law School is planning to change its third-year curriculum to better prepare its graduates for the realities of legal practice today. In case you don’t know, law school graduates are having a tough time finding work and many require on-the-job training to make up for what they didn’t learn in school.

From the article: “There is a growing disconnect between what law schools are offering and what the marketplace is demanding in the 21st century,” said … the chairman of the panel of alumni recommending the changes.

A revelation from the article is that the third year of law school has been considered a waste of time by many observers.

“One of the well-known facts about law school is it never took three years to do what we are doing; it took maybe two years at most, maybe a year-and-a-half,” Larry Kramer, the former dean of Stanford Law School, said in a 2010 speech.

There has been much debate in the legal academy over the necessity of a third year. Many students take advantage of clinical course work, but the traditional third year of study is largely filled by elective courses. While classes like “Nietzsche and the Law” and “Voting, Game Theory and the Law” might be intellectually broadening, law schools and their students are beginning to question whether, at $51,150 a year, a hodgepodge of electives provides sufficient value.

Although I wasn’t aware of this issue in law schools, it sounds familiar in a way. Copy the above paragraphs, take your word processing program and replace “law school” with “medical school” and “third year’ with “fourth year” and you will have an accurate story about medical education.

The fourth year of medical school has been known to be a waste of time for at least 40 years. Most schools allow some or all of it to be electives of the students’ choosing. This results in anesthesia rotations in Paris and dermatology rotations in New York City. In a previous blog, I have pointed out some of the problems of both the third and fourth years of med school.

A 2011 piece in the New York Times Magazine pointed out that some law firms are providing new associates with intensive training in the nuts and bolts of lawyering that they apparently don’t get in school. For example, although they had studied mergers in law school, graduates had no idea how to make a merger happen.

As an interesting parallel, some surgical residency programs have begun to offer “boot camps” (See links here and here.) as a way to teach incoming first-year trainees some of the material they should have learned in medical school. Apparently, this is necessary in Scotland too, where the boot camp lists such topics as communication skills for surgeons, polytrauma, how to lead a ward round and handling and writing the evidence. These all seem like subjects appropriate for a med school curriculum, but lacking.

I hope that someday medical schools will recognize the problem as NYU Law School has done. Meanwhile, I will keep cranking out the blogs.

Is normal saline bad for the kidneys?

Answer: Yes.

This week, the two heavyweight medical journals, JAMA and the New England Journal of Medicine, featured papers describing the effect of certain intravenous fluids on the incidence of renal failure in critically ill ICU patients.

The JAMA paper compared normal saline (relative to human plasma, a high chloride-containing solution) administration to more physiologic, low chloride-containing IV fluids such as Hartmann’s solution (very similar to Ringer’s lactate) or Plasma-Lyte 148. It showed that using the low chloride intravenous infusions led to a statistically significant decrease in the incidence of acute kidney injury and the need for renal replacement therapy.

The NEJM paper compared the use of intravenous hydroxyethyl starch (HES) fluid resuscitation to normal saline and found that patients given HES had significantly more acute kidney injury and needed more renal replacement therapy. Bear in mind that HES is actually a solution of 6% HES in normal saline.

Neither study found a significant difference in mortality rates related to the various solutions used.

Both studies were performed in Australia during different time periods. The JAMA paper was based on research from a single hospital in Melbourne in 2008-2009 and was a before-and-after trial while the NEJM study was multi-institutional, randomized and prospective and took place from December 2009 to January 2012.

Is normal saline bad for the kidneys? Yes. If you compare high chloride normal saline to lower chloride solutions, normal saline causes more renal dysfunction and need for renal replacement therapy. Normal saline vs. HES really compared normal saline alone to 6% starch in normal saline, and showed that the starch is probably the factor causing renal injury.

So what is a clinician to do? Normal saline is not really “normal.” Solutions containing amounts of chloride closer to that of human plasma are the correct ones to use. As we surgeons have maintained all along, Ringer’s lactate should be the resuscitation fluid of choice in the U.S.

See the table below for the amounts of sodium, chloride and buffer in standard IV solutions.

Medical School Grading and T-Ball: Everyone Gets A Trophy

"Variation and Imprecision of Clerkship Grading in US Medical Schools” is the understated title of the paper (full text here) in the August 2012 issue of the journal Academic Medicine. The authors, from the department of medicine at Brigham and Women’s Hospital, analyzed 2009-2010 third-year clerkship grades from 119 (97%) of the 123 US medical schools. They found many different grading systems ranging from two levels (pass/fail) to 11 levels of grades.

The terminology used by the schools to describe the different grades is positively comical. To borrow an analogy I’ve used in a previous post about dean’s letters, the citizens of Lake Wobegon would be proud because no student is “average.”

Here are some examples:

High honors, honors, pass, fail (In some schools “honors” is not the highest possible grade).
Honors, satisfactory plus, satisfactory, fail.
Honors, satisfactory, low satisfactory, fail.
Honors, high satisfactory, satisfactory, low satisfactory, unsatisfactory. (Does “unsatisfactory” mean, dare I say it, “fail”?)
Honors, near honors, pass, fail.
Excellent, good, fail.
Honors, advanced, proficient, fail.
Honors, letter of commendation, fail.

The highest grade attainable was awarded to 23% of those students in schools with three-tiered systems (range 5-51%), to 34% (range 2-84%) in four-tiered systems and to 33% (7-93%) in schools with five grade levels.

It gets worse. The authors noted that 97% of all medical students were given one of the top three grades regardless of whether the schools used 4, 5, or 6 levels of grading.

From the paper, “Less than 1% of all US medical students fail required clerkships, regardless of the grading system used.” This raises the question of whether the grade “fail” is even necessary.

Focusing on surgery, an average of about 30% of all students got the highest grade possible in their surgical clerkship, but the percentage of the class receiving the top grade ranged from 7% to 67%. This may account for the paradox found in a paper on surgical resident performance: A significant predictor of the need for remediation was that the resident had received honors in his surgical third-year clerkship. It appears that a grade of honors is virtually meaningless.

This is an excellent example of what I call the “T-ball culture”: No one keeps score. All games end in a tie. Everyone gets a trophy.

The authors of the paper recommended that schools consider creating a more consistent, transparent and reliable system of grading. As a former surgical residency program director who grappled with the difficulty in interpreting the meaning of applicant grades from different schools, this seems remarkably clear to me.

An editorial in the same issue of the journal agreed that grade terminology should be standardized but cautioned that normative grading (establishing a set distribution or “curve” of grades) may not be the answer. The editorialists offered some other possibilities such as criterion-based grading or emphasizing the mastery of a subject as a goal rather than the achieving of a specific grade.

I do not have the background in educational theory to say what is right or wrong. I do know that a grading system with so many variables and such a skewed distribution is of no help whatsoever in evaluating the desirability of an individual applicant to a residency program.

Appendicitis: Accurate diagnosis or no radiation. You make the call.

Amid the mounting concern about radiation exposure and future increases in cancer rates comes a report from Washington State describing the benefits of imaging, particularly CT scanning, for the diagnosis of appendicitis.

The authors collected data from some 55 hospitals of all types and sizes over a six-year period for more than 19,300 patients older than age 15; 91% of patients underwent one or more imaging studies. There were 16,852 (87.2%) CT scans, 1160 (6.0%) ultrasounds and 108 MRIs (0.6%) with 1677 (8.7%) patients having no imaging.

If a patient had an imaging study, the rate of normal appendix removal was only 4.5% compared to 15.4% for those who were not imaged, p < 0.001. Stated another way, on multivariate analysis a patient who had no imaging was over 3 times more likely to have a normal appendix at surgery. Only 4.1% of those undergoing CT scan had a normal appendix compared to 10.4% of those who had only an ultrasound, p < 0.001.

The difference in the rate of normal appendix removal was true regardless of gender—men 3% with imaging vs. 10% without and women 6.9% vs. 24.7%, both statistically significant differences. In other words, nearly 1/4 of all women who were not imaged had a normal appendix at surgery.

Perforated appendicitis occurred in 15% of all patients, a figure that has remained constant over many years and has not been influenced by imaging.

The Washington appendicitis experience is probably generalizable because in most hospitals, CT scan is the preferred imaging modality over ultrasound, which is more operator-dependent, less accurate and less available during off hours than CT scan.

My personal experience is similar to that of the authors of the study. My rate of removal of a normal appendix when operating for the presumed diagnosis of appendicitis is 4.3% for my last 200 cases. Only 18 (9%) of my patients, all young males, had no imaging and just 1 had a normal appendix. CT scans were the only studies performed in 99% of my patients who were imaged.

I have previously written that patients and their families seem to prefer an accurate diagnosis over a theoretical slightly higher cancer risk 20 or 30 years later. The paper from Washington also confirms that a high accuracy rate of CT scanning for appendicitis is achievable outside of academic centers.

For many reasons, I can’t imagine the rate of CT scans for the diagnosis of patients with right lower quadrant pain decreasing. The accuracy of CT is no longer an issue. Most ED MDs are scanning everyone with right lower abdominal pain. They may tell you it’s because surgeons insist upon it, but whatever the reason, a lot of CT scans are being done. Another advantage of CT scanning is if the diagnosis is something other than appendicitis, the CT will very often reveal what is wrong with the patient. In a previous blog, I have mentioned before that it would be impractical to ask surgeons to examine every patient with abdominal pain, one of the more frequent complaints of patients presenting to emergency departments.

Face it, CT scanning for the diagnosis of appendicitis is here to stay. Whether implementation of protocols to lower the radiation dose of the devices will calm all the doomsday prophets remains to be seen.

[Thanks to Dr. Frederick Thurston Drake, lead author of the paper from Washington, for providing me with information not published.]