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July 31, 2007
Pulmonary Artery Catheters
The Swan-Ganz catheter is the paragon of useless medical testing. It has taken forty years to see the beginning of the end of a technique which seemed to make good sense. Here was a way to measure central venous pressure and pulmonary artery pressure. Measurement is the heart of Cartesian/Baconian medicine. And so beautifully ironic that it measured parameters most critical to the book that first demonstrated the new Medicine, Harvey's Circulation. The Swan-Ganz (PA catheter) was the very definition of critical care when I was training.
The JAMA article in 1990 revealed that many of us did not understand even some of the basic concepts involved. Other studies demonstrated increased mortality, or no benefit.
This week's JAMA has a study of the declining use, as well as two editorials on the S-G. One summarizes, "The 40-year story of the PA catheter is nearing its end. It is a cautionary tale of rapid adoption and slow evaluation of a monitoring device that, when used correctly, provides exquisitely detailed physiological data that, regrettably, does not appear to benefit patients. Older clinicians will look back wistfully on the hours spent placing, troubleshooting, and debating the data from the PA catheters. Younger colleagues will just wonder what all the fuss was about."
Excellent summary. And how many other procedures in medicine will fall on the same sword? Many, I would guess.
Posted by Robert Maddox at 11:35 PM | Comments (0)
mammogram fight
ACS and ACP have taken opposing positions on mammograms for women 40-49. The ACP position is that women need to be told the risks and benefits of screening. The ACS position is that such a position will cause some women to skip mammograms. They are convinced that many cancers are found in women who have none of the risk factors.
What remains unproven is that finding those cancers is a net benefit to the women.
Posted by Robert Maddox at 06:48 PM | Comments (0)
triangulation
I have returned from the year's best conference. I am still processing (meditating on/ murmuring about) some of the lessons. One in particular was helpful to me as I work through these medical issues.
Bowen applied the term "triangulation" to dysfunctional family systems. Having trained in family practice during the height of systems thinking, I was forced to read some of this. So when my favorite Barfieldian used this concept, it brought back many bad memories.
But at the base of it, it explains much of the behavior I see every day. When two people relate (dysfunctionally), they cannot talk about each other very long before the conversation turns to a third person or object. That third stabilizes their relationship, but when a child (in Bowen's analysis), this attention is usually negative, and leads generationally to greater dysfunction, even schizophrenia.
When a doctor and patient relate, the suffering patient does not want to be suffering. Ever since Sydenham, we have attempted to isolate the disease as a separate entity, to reify it, to give it its own existence. This has been an apparently effective approach. Much of this blog has been an attempt to demonstrate the limitations of this approach by revealing the limits of the effects. But this approach ultimately fails because it is flawed in its understanding of humans and history.
A disease is not a separate entity. There is no such thing as cancer or diabetes or hypertension. There are people who suffer. Many times their suffering falls into patterns that we construct into logical systems and name cancer or diabetes or hypertension. When it is named as a self-existent entity, it makes the patient and the doctor feel better. They triangulate on the disease. If the disease is given too much emphasis, too much weight, too much glory, that is idolatry. But to eliminate the disease as the object of triangulation is to destabilize the relationship between doctor and patient, and to cause the patient to feel his suffering once again.
The only solution to this problem is one outside the relationship who agrees to take the burden. Ultimately, this is done as the sufferer gives thanks and rejoices. The Holy Spirit, the ultimate paraclete, comes alongside and bears this burden. We are called in the body of Christ to bear one another's burdens, and so fulfill the law of Christ.
Posted by Robert Maddox at 06:34 PM | Comments (0)
July 12, 2007
CABG
On the face of it, it makes sense to bypass a blocked artery. This is a common surgery in the US. 1998 figures indicate over a half million CABG's were performed annually, at a cost of $30 Billion. In the United States in 2004, the NCHS estimates that 427 000 of these procedures were performed on 249 000 patients.
Are they accomplishing what they purport? Almost definitely not. Part of the problem is that from the beginning, everyone knew they were only effective (statistically) for a limited subset of high-risk patients. But it makes so much sense that everyone thought they needed one.
A good review of the data is available several places. I am tempted to quote the 12 pages of an article by David K. Cundiff. But I won't. The gist is this. Even for the particular subset most benefited, the NNT is 20 for 5 and 10 year survival. That is a cost of $1 million for one patient more surviving at 5 and 10 years. And [uncertain-Cundiff claims 3%] operative mortality, and other harms (infection, heart attacks, disabilities).
Further, Cundiff argues that even the improved survival seems to be from some mechanism other than revascularization, based on discrepancies between the groups in the BARI trial. Even "the reduction in angina and increased exercise tolerance with CABG compared with medical treatment in high-risk subgroups may well have occurred because of an effect other than revascularization -- the placebo effect (ie, the patient's belief in the efficacy of the therapy), surgically induced infarction of ischemic tissue, denervation of the myocardium, increased motivation to reduce cardiac risk factors, and/or other influences."
Could it be that we have misled and been misled concerning the efficacy of CABG? Is it because we are so desperate to believe that medicine/surgery can cure?
Posted by Robert Maddox at 07:43 PM | Comments (0)
Gardasil ad
I knew there was something odd about the ubiquitous (iniquitous) Gardasil ad besides the obvious HPV vaccine problems I have discussed.
"Gardasil--help protect a generation of girls and young women"
None of the featured females have eyes. Several have eyebrows, but I think they are all blind. Is that why we have to protect them? Or has Merck pulled the wool over our eyes?
Posted by Robert Maddox at 02:21 PM | Comments (0)
July 10, 2007
First Significant Figure in American Medicine
Cotton Mather, of course. Proven by Beall and Shryock in their great study. Fascinating discussion of the man, the medicine and the times. But OW Holmes didn't think so. He faulted Mather for bringing religion into medicine, for pretending that he could talk about medicine as a preacher (ignoring that Mather's training at Harvard at 14 was first in medicine), but most of all for the ignorant view of medicine. In this last, he ignores that Mather was far ahead of his contemporaries (even the best trained) in many of his cures. Holmes lived and wrote when the scientific mindset was just coming into its own, and before its fatal flaws were revealed.
Mather was responsible for the smallpox inoculation, the first proponent of the modern germ theory. Perhaps more importantly, he designed statistical analysis to test the usefulness of inoculation. But most importantly of all, he did not lose sight of the humanity of the sick, nor the providence of God in the affairs of men through it all.
Posted by Robert Maddox at 11:25 PM | Comments (0)
July 06, 2007
statins
There is much controversy over cholesterol. Most of the establishment is convinced that high cholesterol is a bad thing, for your heart, your brain, and your life. There is good evidence that they are right, found in an association between high cholesterol and increased incidence of cardiovascular and cerebrovascular disease. Of course, the association does not prove causation and there is some evidence that higher cholesterol is cardioprotective in older folks.
But even granting that high cholesterol is bad is far short of demonstrating that lowering cholesterol is life-saving. So there was great rejoicing when the Scandinavian Simvastatin Survival Study (4S) proved a significant decrease in all-cause mortality in 1995. This was tested in a population that were at high risk and had already had heart attacks. (This is called secondary prevention.) The year before, the West of Scotland study tested a primary prevention population, finding a decreased incidence of heart attacks and coronary deaths. There are dozens of other studies now that purport to prove the same thing.
But a meta-analysis of four primary prevention studies, though finding a lower incidence of cardiovascular events and a lowered cholesterol, found no reduction in overall or cardiovascular mortality. In plain English, these drugs might affect how you die, but you die just as certainly, though with a lower cholesterol. And to even prevent one coronary event requires treating 60 people for five years, with a drug that costs over $1000/year. That is $300,000 to prevent one heart attack and not even save a life.
There are even more damning aspects to these studies, but you will have to wait for the movie. oops. I am no MM.
What is the bottom line? Statins do help prevent heart attacks and strokes, especially in the high-risk population, who have already had one event and want to prevent another. But even that attempt to prevent is lost in the host of other problems that plague mankind. This is the context that EBM misses. Even a relatively decent NNT falls into meaningless when considered amidst the myriad of medical, physical and routine risks of living. More on that when someone challenges me.
Posted by Robert Maddox at 04:32 PM | Comments (3)
Positives
One of the two people who read this site posed a question in person to me that I thought I should address. Why am I still a doctor if medicine is all that useless?
I am documenting for myself, and those few, those happy few, that band of brothers, how the current approach to medicine has failed us. It does not follow that I have nothing to offer patients as their doctor. In fact, I hope I am working to the point that focuses on the greater benefit to the patient in both of us understanding the limitations of the current system. There is much to offer in terms of relief from suffering when those terms are properly understood.
Medical care has a commodity aspect. The commodity being purchased is a mix of goods (access to medications), advice, time, and availability. The relationship aspect includes the last three of these, but cannot be quantified, which makes it harder to subject to the free market, or even to market at all. That is the profession side of medicine. The tension between those two aspects is a driving force in health care change.
Posted by Robert Maddox at 02:54 PM | Comments (0)