Twenty years ago a diagnosis of kidney failure was a death sentence. Doctors could do little to combat the slow buildup of poisonous wastes in the blood. (Kidney transplants had become possible by 1954, but were rare.) In the early 1960s the artificial kidney was developed to perform dialysis, or the filtering out of those wastes.
Most Americans who suffer from kidney failure today still rely on dialysis, but the treatment is incapacitating and expensive. Patients must spend some 15 hours a week hooked up to a desk-sized machine. It costs about $28,000 a year, which limited the treatment to a few victims until the federal government began paying in 1973. Two years later another breakthrough in treatment occurred when two Texans, Robert Popovich, a chemical engineer, and Jack Moncrief, a physician, devised a portable, machine-free do-it-yourself dialysis system. But it was not until 1978 that all its components received FDA approval. Now 1,500 patients use the system, and the number grows by 200 each month.
Moncrief, 43, a nephrologist at Austin's Diagnostic Clinic and Bracken-ridge Hospital, and Robert Popovich, 41, an assistant professor at the University of Texas, call their system CAPD, for Continuous Ambulatory Peritoneal Dialysis. During the treatment two liters of fluid—sterile water, body salts and dextrose—pour into the abdominal cavity through a permanently grafted catheter in a patient's midriff. The fluid absorbs toxic wastes by osmosis via the peritoneal membrane, which encloses the intestines. The fluid stays in the abdomen for several hours before it is drained into a plastic bag through the catheter and replaced with fresh fluid. The process must be repeated at least four times a day.
Equipped with fluid and bags, a patient can go anywhere and indulge in any activity from sex to swimming, except for rough contact sports. The cost of the CAPD device, including surgical installation of the catheter, is $13,000, which Medicare covers. Supplies for one treatment cost $5.50. Unlike machine dialysis, which removes the blood and strips it of toxins while outside the body, CAPD does not result in hazardous variations in blood pressure. The only side effects are a slightly enlarged waist and a sloshing noise when patients jog, as some do.
The inventors were inspired to develop CAPD by an engineering student. On a 1975 visit to one of Popovich's classes, Dr. Moncrief glumly announced he had just seen a 40-year-old male patient who did not have long to live. The patient's kidneys had failed and his blood clotted too quickly to go through the dialysis machine. "You mean," asked a student, "you're just going to let him die?"
Popovich resolved to "put what knowledge I had to saving lives." Moncrief adds, "As a doctor, I knew a lot of questions but not many answers. Bob had the skills to find the answers if somebody would give him the questions." Prior attempts to use the body's membrane system to strain out poisons had failed because of contamination and rejection of foreign objects like the catheter in the abdominal wall. Antibiotics and Silastic, a blend of Teflon and silicon that the body will tolerate, solved those problems.
The two friends developed the first CAPD system within a few months and persuaded Moncrief's patient—who then had only a few days to live—to try it. The man is a rancher today; a transplant later made dialysis unnecessary.
CAPD will never replace the artificial kidney, Moncrief says; psychotic and elderly patients, for instance, often cannot treat themselves. But he adds, "CAPD will offer a better quality of life to many."
A student challenged Moncrief s creativity: 'You mean you're just going to let that man die?'