LISA CLARK: I'm Lisa Clark. Welcome, and thank you for joining us for this webcast. As little as 40 years ago, a diagnosis of total kidney failure meant that death would soon follow, but thanks to major advances in medical technology, patients with kidney failure are living longer, healthier lives. One of the major jobs of the kidney is to remove waste and toxins from the blood. It's possible through several types of dialysis. In this segment, we're going to take a look at peritoneal dialysis.
Joining us for this discussion, Dr. Leonard Stern. Welcome. And also Dr. Jai Radhakrishnan. Thank you for being here. Both men are Assistant Professors of Clinical Medicine at the College of Physicians and Surgeons of Columbia University. They both practice at the Columbia Presbyterian Medical Center, and Dr. Stern is the medical director of the peritoneal center at the hospital and the director of the new Columbia University Dialysis Center, so you are eminently qualified for this discussion.
I want to begin with a clarification. When does dialysis become necessary for any kidney patient?
LEONARD STERN, MD: The body is remarkably resilient, and you could be largely asymptomatic with loss of as much as 85% to 90% of kidney function, but when you reach about 10% of kidney function, you begin to get symptoms. Those symptoms may be related to appetite reduction, nausea, fatigue, and a variety of progressive symptoms that produce a syndrome which we call renal failure.
In years past, we waited until patients were symptomatic, and then we initiated dialysis. Our approach today is a bit different. When patients reach that 10% approximate level, we try to get them to start dialysis sooner, when they're asymptomatic, because we think their survival is improved.
LISA CLARK: Jai, there are two major types of dialysis, hemodialysis, which is through the bloodstream, and then peritoneal dialysis. Will you just highlight the chief differences for our audience?
JAI RADHAKRISHNAN, MD: The basic principle of dialysis is that you need a membrane through which the exchange of fluid and toxins can occur. In hemo-, or blood, dialysis, there is a machine with an external membrane inside the machine that does this exchange. In peritoneal dialysis, we use the body's own membrane, and we use what's called the peritoneal membrane -- that is the lining of all the organs inside the abdominal cavity through which the exchange occurs.
LISA CLARK: If you wouldn't mind describing the basics of peritoneal dialysis for us, Len? I know this is complicated, but try to help us understand.
LEONARD STERN, MD: With any form of dialysis, we need an access. In hemodialysis there is a blood access. In peritoneal dialysis the access is a tube called a Tenckhoff catheter, Tenckhoff named after the surgeon called Henry Tenckhoff, who invented this in 1969, and the tubes are generally placed by surgeons in the abdominal cavity. The tube is in potential space, because ordinarily our abdominal cavity is only filled with intestines. But this catheter is left in place, and the outside part can be connected through a series of specialized connectors to bags of rinsing fluid, and a rinsing solution is connected and it flows into the abdominal cavity, where it stays for a period of time and acts as a collector for waste products. The membrane can act as a barrier, and the waste products travel across the membrane into this fluid compartment, where they're retained, and after a few hours of time, this fluid is drained out -- it essentially becomes urine equivalent -- and then fresh fluid is placed in.
Typically, the exchange of draining the fluid out and adding new fluid takes about 30 to 45 minutes, and an average schedule for a normal person might be four to five exchanges per day, generally spaced out at four- to six-hour intervals.
LISA CLARK: Now, you're talking about CAPD, right?
LEONARD STERN, MD: Correct. That's the manual form of treatment.
LISA CLARK: Let me get the exact right name of it. That is the continuous ambulatory peritoneal dialysis?
LEONARD STERN, MD: Right, nicknamed that because the concept is that after the patient does the exchange they're not confined to bed. They can be ambulatory. The original name for it, though, was continuous equilibration peritoneal dialysis, because the fluid in the cavity equilibrates with the body compartment. That means that all the waste products are removed at a very high concentration. So it's a very reasonable way to eliminate waste products and fluid.
LISA CLARK: Let me reiterate. Does the patient have to remain quiet or sitting still during this process, or not?
LEONARD STERN, MD: Well, it's a sterile procedure, so during the drainage of the fluid and the entry of the new fluid, it's a sterile technique that the patient is taught by trained nurses, so they don't necessarily have to sit still, but it's time-consuming, taking 30 to 45 minutes.
LISA CLARK: How many times a day?
LEONARD STERN, MD: An average schedule is four to five times a day for the manual mode, largely dependent on the size of the person. The bigger you are, unfortunately, the more exchanges. The smaller you are, the less exchanges. The volume also varies based on the size of the patient. The larger the patient, the larger the volume.
LISA CLARK: Right. Now, there's also something called CCPD, continuous cycling peritoneal dialysis. How does this option work?
LEONARD STERN, MD: The cycler is essentially a computer that you can program to replace the function of the person, so you could use the cycler machine to prepare 24 hours of treatment. It means that you can hang enough fluid to do multiple exchanges. You program the machine the way you would a VCR -- and many of these machines look just like VCRs -- and the machine does the exchanges at a defined interval. One schedule that works is patients do this at night, where they connect to the machine right before bedtime. They go to sleep. The machine does the exchanges, automates the process until early in the morning. The machine leaves them filled with fluid, and then a few hours later, they can return to the machine to do another exchange, and most patients require machine treatment at night, and perhaps one or two exchanges during the daytime, but the machine acts as a workstation, where it prepares the fluid for the 24 hours.
LISA CLARK: Now, the exchanges that take place during the daytime, how long are those? How long is that process?
LEONARD STERN, MD: Typically longer intervals. Once you connect to the machine, it's actually quick, so that the ones during the daytime are a bit faster, because there's no preparation time. The manual procedure is complicated by preparation time -- clearing the work space, sterilizing the gadget and things of that sort, whereas the machine is already prepared, so you save about 15 or 20 minutes doing the machine exchanges during the daytime.
LISA CLARK: Jai, it seems like the peritoneal dialysis, both methods, would require a patient a high level of motivation. Is that the sort of patient that you would recommend this treatment for?
JAI RADHAKRISHNAN, MD: Absolutely. One of our screening criteria is that the patient needs to be completely motivated. If there's any lapse in following a schedule, the patient could get very sick over a period of time. It also does require a little bit of dexterity. The biggest problem is infection, and it relates to how the connection is made between the external bag and the internal catheter.
LISA CLARK: When you do make a recommendation to a patient, Len, for one of these types of peritoneal dialysis, how do you recommend which method they should go for?
LEONARD STERN, MD: What I try to do is determine how the patient lives and the context of their life, what their support systems are. Do they have family? I try not to recommend this for patients that are isolated, that have not support systems. Patients need to be not only independent, but they need to be organized. They need to be able to deal with schedules. Peritoneal dialysis is less efficient than hemodialysis. That means we can't do it three times a week. It needs to be done seven days per week, so it requires a patient who has the persistence, the organizational skills and the ability to call the company for their delivery, call the nurse for questions about the machine or the bags or the solutions, so they require a person who is willing to take responsibility for their care, and many times the assistant is the family member that helps them in the organization for all of this.
LISA CLARK: Jai, what advantages do these methods have over hemodialysis, and what are the disadvantages that make it perhaps not as --
JAI RADHAKRISHNAN, MD: The biggest advantage lies in the word "continuous," because this is going on at least 12 hours a day, so it takes away a lot of the stress associated with hemodialysis, so the patient can eat better and there's less stress on the cardiovascular system.
So if you do quality of life scales, people with peritoneal dialysis score much higher, because they're more satisfied with their quality of life.
The disadvantage, as Len said, the efficiency, because the patient needs to be quickly dialyzed and gotten better soon.
LISA CLARK: And you mentioned the risk of infection, as well.
JAI RADHAKRISHNAN, MD: Exactly. So that's one big problem, and it directly relates to how meticulous a patient is with the procedure of connection and disconnection.
LISA CLARK: Right. Well, as always we want to stress to our viewers that all of these decisions must be made in conjunction with your own doctor, obviously, and we're not giving advice. We're trying to give information here.
I'd like to thank both of you for helping illuminate this very complex topic. Thank you both for being here, Dr. Leonard Stern and Dr. Jai Radhakrishnan. We'd also like to thank you for tuning in to our webcast. Thanks. I'm Lisa Clark.
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