| |
|
|
| Year : 1995 | Volume
: 6
| Issue : 1 | Page : 35-40 |
|
| Continuous Ambulatory Peritoneal Dialysis (CAPD) |
|
|
Nawaz AH Memon, Hassan Abu-Aisha
King Khalid University Hospital, Riyadh, Saudi Arabia
Click here for correspondence address and email
|
|
 |
|
How to cite this article:
Memon NA, Abu-Aisha H. Continuous Ambulatory Peritoneal Dialysis (CAPD). Saudi J Kidney Dis Transpl 1995;6:35-40 |
 Introduction | |  |
Continuous ambulatory peritoneal dialysis (CAPD) was first described in 1976 by Popovich et al. They called the procedure "equilibrium peritoneal dialysis technique" [1] . Two liters of dialysate were infused intraperitoneally and allowed to equilibrate for 5 hours while the patient continued his normal activities. The dialysate was then drained and fresh fluid was 'infused again. Five such exchanges were carried out every day. Subsequently, in 1978, further experience in a larger number of patients was reported by the same group, and the name of this method of dialysis was changed to continuous ambulatory peritoneal dialysis (CAPD) [2] . The procedure immediately gained acceptance among nephrologists due to its simplicity and the fact that it did not require expensive machines and materials.
Initially, the dialysate was available only in glass bottles. Oreopoulos' modification of CAPD using plastic bags made the technique easier to perform and decreased the rather high incidence of peritonitis [3] . Long-term access to the peritoneal cavity was made possible by the Tenckhof's design of indwelling silicon rubber catheter which had been widely accepted earlier [4] .
CAPD is more physiogical than hemodialysis since there is a constant removal of waste products thereby achieving steady chemistry. There is sufficient removal of fluid resulting in better salt and water balance. This makes control of hypertension easier. Improved erythropoiesis and better hematocrits are also observed in patients on CAPD. These advantages together with the relative absence of dietary restriction and the ease of training and management have made this modality of treatment well accepted by patients and physicians alike. However, peritonitis remains a major problem. With increasing improvement in the technique, the incidence of peritonitis has declined remarkably and technique survival has greatly improved. Today, CAPD is the commonest form of home dialysis throughout the world and perhaps the only form of home dialysis available in Saudi Arabia. The real long term success of CAPD is yet to be seen. However, it is increasingly evident that CAPD has become a first choice initial method of renal replacement therapy (RRT) for many patients.
The common indications and contraindications of CAPD are given in [Table - 1],[Table - 2] respectively.
| Procedure | | |
Peritoneal Access
Permanent peritoneal access is the lifeline for success of CAPD. There are several types of peritoneal catheters available. However, straight Tenckhoff's indwelling silicone rubber catheter with one or two Dacron cuffs and Tenckhoff's curled catheter with two cuffs are the ones most widely used [Figure - 1].
Patients should be prepared as per the routine followed for a surgical procedure. It is useful to follow a check list [Table - 3]. One should remember that it is imperative to explain the procedure to the patient in detail.
Method of Catheter Implantation
Complete aseptic technique during catheter insertion is crucial. Peritoneal catheter could either be implanted at the bedside or by a surgeon in the operating room. The latter method is preferred as it will allow direct vision and placement of catheter intraperito neally properly directed towards the pelvis. This method also makes the immediate, potentially serious complications like rupture of a viscous or injury to major blood vessels unlikely. The procedure can be done under local or general anesthesia. The catheter insertion is usually through a midline incision 3-4 cms below the umbilicus. Lately, catheters have been implanted under laparoscopic guidance.
There are three segments for the catheter [Figure - 1].
i) The first segment is from the tip to the first Dacron cuff. This part is with side holes and is implanted in the pelvis. The first Dacron cuff lies between the peritoneum and the rectus sheath,
ii) The second segment is from the first Dacron cuff to the second cuff. This segment is usually buried in a subcutaneous tunnel in one of the abdominal quadrants, usually the right quadrant. The second Dacron cuff is placed 2 cms deep to the skin exit-site,
iii) The third segment of the catheter is the part beyond the second Dacron cuff. This lies outside the body and is connected to the dialysate connection.
Catheter patency should be checked in the operating room itself by connecting the dialysate and administering two to three exchanges. Some surgeons infuse two to three liters of dialysate while the patient is still on the operation table to check the integrity of the catheter seal.
Post-catheter Insertion Care
i) Immediately after the patient is received in the ward, give six quick exchanges without dwell time till color of the fluid clears. Add heparin 5001000 I.U./liter of dialysate to prevent formation of fibrin clots. Initially, infuse only 250-500 ml of dialysate at a time.
ii) This is to be followed by hourly exchanges. Thereafter, the form of exchanges is decided by the team on individual basis. In order to prevent leakage of dialysate and to allow healing, ideally the catheter should be capped and the exchanges should be resumed only after 7-10 days.
iii) A surgical dressing is placed at the catheter entry site and is changed after one week. The subsequent dressings are done daily
iv) The exit-site of the catheter and the skin surrounding the catheter is cleansed and covered with povidone iodine and several layers of dry gauze. Such a dressing is to be done daily.
v) Sutures are removed after two weeks.
| Dialysate Solution | | |
There are several dialysate solutions available commercially in various concentrations and in plastic bags. The most commonly used formula is given in [Table - 4]. Concentrated dialysate with 2.5% or 4.25% Dextrose and resultant higher osmolality (488 mosm/kg) is more suitable if excess fluid removal is desired. The standard solutions do not contain potassium. In patients with hypokalemia, potassium can be added to the dialysate.
| Technique of CAPD | | |
In most adult patients, four exchanges of two liters of dialysate are carried out in 24 hours, seven days a week, while the patient continues with his/her usual activities. The exchanges are performed roughly six hours apart but can be tailored according to the needs of the patient.
Observing sterile technique, two liters of dialysate are infused. The transfer set and the plastic bag, upon becoming empty, are folded and carried under the clothes. At the end of the pre-determined dwell time (around 6 hours) the empty bag is put on a clean drape placed on the floor and the control of the transfer set is released while the patient sits or reclines on the bed. The peritoneal dialysate effluent flows into the plastic bag by gravity. Complete drainage is ensured. The control is closed and again, while observing strict aseptic technique, the dialysate effluent bag is disconnected, a fresh bag is connected and fluid infused. It may be noticed that the connection site is the most vulnerable site for entry of microorganisms. Therefore, strict aseptic technique is mandatory and povidone iodine or other antiseptic solutions should be used during the connection and disconnection procedures.
The administration set is changed every month. This is yet another vulnerable point of entry for microbes and again povidone iodine or other antiseptic solutions should be used.
| Patients Training | | |
Commitment of the nephrologist and nursing team to meticulous sterile technique, regular catheter management and patient training is absolutely essential for a successful CAPD program. CAPD training can be imparted either in the hospital or on outpatient basis. Although good hospital backup and expert management is ideal, many centers have found that specialized nurses can handle both the outpatient as well as in-patient management. On an average, a patient can be trained in one week after the peritoneal access is successfully achieved.
| Modifications of Continuous PD | | |
There are several modifications of continuous PD. These modifications have given a chance for the patients to select one that suits them on individual basis.
Continuous Cycling Peritoneal Dialysis
This technique requires a special machine and the procedure is carried out every night. Upon retiring at night the PD catheter is connected to the cycler. The machine is programmed to deliver three exchanges of two liters of dialysate as three hour cycles. After the last exchange, two liters of dialysate are infused and the patient is disconnected and catheters capped. The dialysate remains in the peritoneal cavity during the day time.
| Semi-continuous Semi-ambulatory PD | | |
This procedure can be performed in two ways.
a) Eight rapid exchanges of one liter of dialysate are carried out at night followed by a two liter exchange. One two liter exchange is carried out during the day time.
b) Four rapid exchanges of one liter are carried out during day time ending in a two liter long cycle exchange. Another two liter long cycle exchange is done at night.
| Intermittent Peritoneal Dialysis (IPD) | | |
Dialysis sessions are done periodically several times per week in various ways as per the choice of the physician. There are three main types:
a) Series of two liter exchanges with an average inflow time of 10 minutes and dwell time of 30 minutes. The fluid is then drained which takes about 20 minutes.
b) Rapid IPD i.e., 2 liter exchanges with no dwell time.
c) Rapid IPD i.e., 2 liter exchanges with short dwell time.
d) Rapid IPD i.e., 2 liter exchanges with restricted drain time.
All these modalities are inferior methods to CAPD and are not encouraged.
| Complications of CAPD | | |
There are many potential complications of CAPD due either to the procedure itself or those that occur soon after peritoneal access is achieved or later in the course of treatment. In well trained hands, the complications related to implantation of catheter are rare. Bleeding due to injury to vessels, bowel perforation or urinary bladder perforation have all been described but if the procedure is done by surgeons in the operating room under direct vision, these complications are rare. The early complications that occur following initiation of CAPD and the action to be taken in each case are given in [Table - 5]. The late complications that could occur are listed in [Table - 6].
With improvements in the technique, the incidence of peritonitis has declined remarkably. As technique survival of CAPD has improved, rarer irreversible complications, which may limit the real long term success like sclerosing peritonitis and progressive calcific peritonitis are being recognized.
| Recent Advances in CAPD | | |
New technical developments that have been made include use of bacterial filters in dialysate infusion lines [5] , use of the heat sterilization or ultraviolet light for connections [6] and the discontinuation of carrying empty bags during dwell time [7] . In order to decrease catheter migration and malpositioning, and to decrease the incidence of exit-site and tunnel infections, -various modified catheters are available. Examples are Tenckhoffs straight and curled catheters type I and II, Toronto-Western catheters type I and II, Swan neck catheters, Swan neck 2 Missouri, Toronto and Tenckhoff catheters and column disc catheters. However, the Tenckhoff straight or curled catheter with two Dacron cuffs is the most commonly used one [8] . Mesothelial cell transplantation, low calcium solutions and urea kinetic modeling are also important new areas of interest with potential to improve therapy [9].
| Conclusion | | |
CAPD is a simple and effective method of RRT and is the commonest form of home dialysis. It allows freedom to the patient, imposes no dietary restrictions, achieves effective control of blood pressure and good biochemical, water and electrolyte as well as acid base control.
| Acknowledgment | | |
We would like to thank Ms. Bennie Campos for her most valuable secretarial assistance.
| References | | |
| 1. | Popovich RP, Moncrief JW, Nolph KD, et al. The definition of a noval portablewearable equilibrium technique. Abstract. Am Soc Artif Intern Organs 1976;64.  |
| 2. | Popovich RP, Monrief JW, Nolph KD, Ghods AJ, Twardowski ZJ, Pyle WK. Continuous ambulatory peritoneal dialysis. Ann Intern Med 1978;88:449-56. |
| 3. | Oreopoulos DG, Robson M, Izatt S, Clayton S, de Veber GA. A simple and safe technique for continuous ambulatory peritoneal dialysis (CAPD). Trans Am Soc Artif Intern Organs 1978;24:484-9. |
| 4. | Tenckhoff H, Schechter H. A bacteriologically safe peritoneal access device. Trans Am Soc Artif Intern Organs 1968;14:181-7. [PUBMED] |
| 5. | Slingeneyer A, Mion C. Peritonitis prevention in continuous ambulatory peritoneal dialysis: long-term efficacy of a bacteriological filter. Proc Eur Dial Transplant Assoc 1983;19:388-96. [PUBMED] |
| 6. | Moncrief JW, Mullein-Blackson C, Le Bourglois J, Popovich RP, Pyle K. Development and testing of an ultraviolet light resterilizing procedure for CAPD. Abstract. 4th I SAO Official Satellite Symposium on CAPD. Kyoto, Japan. November 1983. |
| 7. | Bazzato G, Coli U, Landini S, Lucatello S, Fracasso A, Moracehiello M. Continuous ambulatory peritoneal dialysis without wearing a bag complete freedom of patient and significant reduction of peritonitis. Proc Eur Dial Transplant Assoc 1980;17:266-75. |
| 8. | Rottembourg J, De Groc F. Peritoneal access using the curled Tenckhoff catheter. Perspectives in peritoneal dialysis 1983;l:7-8. |
| 9. | Nolph KD. What's new in peritoneal dialysis-an over view. Kidney Int 1992;38:S148-52. |
Correspondence Address:
Nawaz AH Memon
Department of Medicine, King Khalid University Hospital, P.O. Box 2925, Riyadh 11461
Saudi Arabia
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 18583842 
[Figure - 1]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6] |
|
|
|
|
|
|
|
|
|
|
|
|
|
| Article Access Statistics | | | Viewed | 2180 | | | Printed | 54 | | | Emailed | 0 | | | PDF Downloaded | 272 | | | Comments | [Add] | | |
|
|
