The Body May Be Best

A lifesaving alternative to the kidney machine

For Ron Morgan, 36, of Macon, Mo., the future looked bleak. A victim of diabetes since childhood, he developed a common complication two years ago, permanent kidney failure. Ordinarily, that would have meant drastic changes in Morgan's lifestyle. To ensure his survival, it would have been necessary for him to drive the 65 miles from his parents' farm to the medical center in Columbia several times a week. There he would be hooked up for hours at a stretch to a kidney machine that would purge his body of poisonous wastes. Yet, in spite of his life-threatening ailment, Morgan continues to lead an active life, helping his father run the farm. Sometimes he even does such strenuous chores as chopping wood, herding cattle and baling hay.

Morgan is one of the several hundred beneficiaries of a promising new form of dialysis, or blood purification for kidney patients. Its name is awesome: continuous ambulatory peritoneal dialysis, CAPD for short. But its effect is simplicity itself. It totally frees patients from long, wearying sessions on the kidney machine. They can walk about, work and perform daily tasks while their blood is being cleansed. Dr. Karl Nolph, Morgan's nephrologist, or kidney specialist, calls CAPD the closest thing yet to a completely portable internal artificial kidney: "It functions continuously, maintains steady conditions in body chemistry, and requires no machinery, electricity, blood-thinning drugs or any of the other paraphernalia of conventional hemodialysis."

CAPD's secret? The wastes are filtered out not by the kidneys or a man-made substitute, but by another part of the body: the thin membrane lining the abdominal, or peritoneal, cavity and covering the organs that jut into it, including the stomach, liver, spleen and intestines, as well as the kidneys. To make this area accessible, doctors cut a small permanent opening just below the navel, then implant a tube that leads through the peritoneal membrane and into the cavity itself.

From there on, after about a week's training the patient can take over himself by attaching to the tube a small plastic bag containing two liters (about two quarts) of a special solution similar to the dialysate, or blood-cleansing fluid, used in kidney machines. The patient raises the bag to shoulder level or above, and the fluid flows down into the abdomen, bathing the peritoneal membrane, which contains many small blood vessels. The tube is then clamped off, and the patient folds up the empty bag into a neat package that he wears beneath the clothing at the waist.

Inside the abdominal cavity, a complex chemical movement, as in conventional hemodialysis, slowly begins. Toxic wastes and water from the bloodstream pass through the peritoneal membrane into the fluid. The process is allowed to continue for about five hours. Then the patient unwraps the empty plastic bag, lowers it to the floor, releases the clamp and lets the waste-laden fluid drain out of the abdominal cavity. Subsequently, a new bag of fluid is attached, and the procedure is repeated three times more at four-to eight-hour intervals every day. While the blood is being cleansed, patients can do just about anything. Morgan has even gone deer hunting.

Peritoneal dialysis is not for everyone who suffers kidney failure. Some object to the prospect of a permanent hole in the abdomen. Others are not fastidious enough; the dialysate bags must be handled with extreme care to avoid dangerous abdominal infections. Still, peritoneal dialysis has important advantages. CAPD's developers, Chemical Engineer Robert Popovich and Nephrologist Jack Moncrief, both of Austin, Texas, point out that it is simpler and, except for infections, less risky than using a kidney machine at home. A patient, for instance, can safely sleep through the procedure without the risk of bleeding to death if a tube is disconnected. Also, CAPD puts less strain on the heart, since no blood ever leaves the body, and thus is preferable for some people with cardiovascular problems.

So far fewer than a hundred of the nation's almost 45,000 dialysis patients use CAPD. But that is likely to change. A year's dialysis at a kidney center now costs some $25,000 a patient; the dialysis bill for the nation as a whole, which is footed by the U.S. Government, totals $1 billion a year. By contrast, the tab for a CAPD patient is only about $8,000 a year, and is likely to drop as the technique becomes more popular. Says Nolph: "We have here one of those rare circumstances in modern times where something is not only potentially better, but cheaper. That combination doesn't happen very often."

Even while this new method is being developed to treat kidney disease, thousands of Americans may be unwittingly bringing it upon themselves. Writing in the New England Journal of Medicine, Drs. Thomas Murray and Martin Goldberg of Philadelphia's University of Pennsylvania Hospital report that as many as 5% of all instances of kidney failure in the U.S.--some 8,000 new cases a year--may be caused by common over-the-counter and prescription analgesics. The usual culprit: a mixture of aspirin and either phenacetin or acetaminophen, ingredients found in many well-known painkillers as well as the APC (aspirin-phenacetin-caffeine) tablets handed out wholesale by some military and industrial dispensaries.

In their study, Murray and Goldberg found that 20% of patients with interstitial nephritis (a major form of kidney disease) had histories of excessive long-term analgesic use. Most were women 35 or older who took analgesics for recurrent headaches or backaches. Concludes Murray: "Pain relievers work. But people who take too many may only be relieving one kind of discomfort to cause another."

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