The key to successful chronic peritoneal dialysis is a

Transcription

1 S 80 Indian Journal of Nephrology The key to successful chronic peritoneal dialysis is a permanent and safe access to the peritoneal cavity. Catheter related complications cause significant morbidity and often lead to removal of the catheter. The authors have given guidelines which are evidence based and certain recommendations based on experience. Although CAPD can be done in majority of patients with end stage renal disease the relative contraindications for this procedure are: Malnutrition, multiple abdominal adhesions, ostomies, hiatus hernia with reflux oesophagitis, severe diabetic gastroparesis and severe obesity. Perotial Catheters The ideal catheter should provide reliable, rapid dialysate flow rates without leaks and infections. The chronic peritoneal dialysis catheter comprises of a) Intra peritoneal portion b) Extra peritoneal portion which has a subcutaneous part and an external portion The Tenckhoff catheter was the one of the earliest PD catheter introduced and is still most widely used. However a number of variations are available such as i) Number of cuffs (one or two) i) Design of the subcutaneous pathway (permanently bent or straight) i) Intra peritoneal portion (straight or coiled) The catheters available in India are the Standard Tenckhoff straight or coiled catheters with one or two cuffs and the Swan neck (inverted U shaped with º bend between the two cuffs). The Swan neck catheter because of its design allows the catheter to exit the skin pointing downwards. A downward pointing exit site is associated with lower peritonitis rates. Network 9 study has demonstrated that catheter related peritonitis was reduced by 38 % if exit site was pointing downwards and increased by 50 % if it was pointing upwards. Single cuff is associated with earlier 1st peritonitis episodes, more exit site complications and shorter survival time of the catheter. Double cuff is preferable to single cuff. Catheter material: Silicone rubber (Silastic) is the most commonly used with 2 polyster cuffs. Polyurethane catheters (Cruz) increases the strength of the catheter and there by allowing the catheters to be thinner walled and the lumens to be bigger. However Silastic catheters are the most commonly used catheters. Guidelines for catheter choice: a) Catheter survival of more than 80% at 1 year b) Double cuff preferable to single cuff c) Downward directed exit site reduces risk of catheter related peritonitis d) No catheter appears to be superior to the original Tenckhoff although experience with Swan neck is promisisng. Consensus: Tenckhoff straight double cuff catheters are the most commonly used all over the world including India. They are the cheapest. However in view of the problems of upward migration of the catheter over a period of time in many patients Swan neck double cuffed straight catheters may be the choice if patients can afford and surgical expertise of inserting Swan neck is available. Recommendations for pre Catheter Insertion Protocol: 1 The patient and his/her family should be counseled about different modalities of RRT (pros and cons) and given full freedom to choose type of therapy. The patient should be explained about the catheter insertion procedure and informed about complications of the insertion procedure and of the therapy. 2 The patient should be evaluated for any evidence of hernias, eventration and any weakness of the abdominal wall. If any of these are evident it is advisable to repair these defects at the time of catheter insertion. In such situations the peritoneal dialysis should not be started for 4 weeks after repair to avoid leakage. 3 The exit site should be identified and marked prior to the catheter insertion. The exit site should be either above or below the belt line and should not lie on a scar or within the abdominal folds. The exit site should be marked with the patient in the upright position (seated or standing). The exit site should be placed laterally.

2 4. The preparation of the skin should be done properly prior to insertion of the catheter. The patient should if possible have a bath with an chlorhexidine soap on the morning of the surgery. The part should be prepared by shaving the skin hair from xiphisternum to mid thigh. The abdomen should be cleaned with betadine 12 hours before and on the morning of the surgery. 5. It is preferable to give an enema 12 hours before and on the morning of surgery. Also make sure that the bladder is empty before the surgery. 6. Prophylactic antibiotics (1st generation cephalosporin such as Cefazolin and an aminoglycoside) are given 1 hour before and for 12 hours post operative. Vancomycin is generally avoided. Catheter implantation techniques The implantation technique of the CAPD catheter is extremely important since it has a significant bearing on the complications and long term outcome of the catheter. The catheter implantation should always be done by a competent and experienced catheter insertion team. Inexperienced personnel should not be permitted to perform the implantation except under direct supervision of an experienced physician or surgeon. It is recommended that the person doing the implantation should have assisted in 5 patients and independently inserted under supervision in 5 patients. If a nephrologist is inserting the catheter by the percutaneous route he/ she should have assisted in open surgical insertion in 5 patients and do the percutaneous technique under supervision of a trained nephrologist (who has been routinely doing the procedure) in 5 patients. Orientation of the catheter means the doctor has to be sensitive and aware of the individuality of each catheter and also be sensitive to the location of the exit site. All catheters have a natural or relaxed state. This is the condition that the catheter assumes when it is free to assume whatever position it wishes to take. If the catheter is implanted in any other position other than that is to invite post implant complications such as migration, leaks, tunnel infections, exit site infections, exit cuff erosion and catheter failure. To determine a catheter s specific orientation, it is important to lay the catheter on the abdomen in the area that the doctor wants the catheter to assume. Then the doctor has to look at the area between the cuffs. Specifically he/she has to note the location or orientation of the radio opaque stripe between (in the middle) the cuffs. That stripe will be facing a certain direction. It is important that the catheter (i.e. the stripe between the cuffs) be positioned post implant the exact same way so that the catheter will be positioned correctly within the abdomen. The orientation of the exit site is also important to the success of the catheter. Many doctors think that S 81 tunneling and the location of the exit site is simple. Unfortunately that is not true. The wrong exit site can cause exit site infection, exit cuff erosion, sinus tract infection, and even catheter failure. The way the exact location of the exit site is determined is to lay the catheter flat on the abdomen with no excess catheter curvature at the original site. Once the catheter is laying flat on the abdomen in the desired position, relative to the implantation site, the doctor puts his thumb knuckle next to the distal cuff. A female doctor should use the length of the first thumb digit instead of the thumb knuckle. The doctor then anesthetizes a location on the opposite side of his knuckle and makes a stab incision the width of a #11 blade. It is important that the exit site incision not be too large or too small. If it is too large then the catheter will be too loose as it exits the skin. That in turn will require a suturing and suturing at the exit site greatly increases the probability of infection at the exit site. It is better to make a new exit site than to use a loose incision. If the exit site is too small, the skin will be pulled into the sinus tract by the Tunnelor increasing the probability of exit site infection. In addition the pulling sensation will be uncomfortable for the patient. Various catheter insertion techniques 1. Surgical insertion (placement by dissection) 2. Blind insertion using the Tenckhoff trocar 3. Blind placement using Seldinger technique 4. Moncrief Popovich technique Recommendations 1. Implantation must be done by a competent and experienced operator in a planned manner. The procedure must be regarded as an important surgical intervention demanding care and attention to detail equal to any other surgical procedure. 2 Peritoneal entry should be lateral (deep cuff in or below the rectus musculature), or paramedian (deep cuff at the medial edge of the rectus muscle), to give good deep cuff fixation and minimize herniation and fluid leaks. Other entry sites (midline through linea alba) are used for trocar insertions. 3. The deep cuff should be placed in the musculature of the anterior abdominal wall or in the pre peritoneal space. The deep cuff should never be placed in the peritoneal cavity. After proper positioning of the catheter tip the peritoneum is closed tightly around the catheter below the level of the deep cuff using a purse string suture. 4. The subcutaneous cuff should be located near the skin surface and at a distance of at least 2 cm from the exit site. Care should be taken to avoid mechanically stressing the cuff material.

3 S 82 Indian Journal of Nephrology 5. Check for catheter patency to ensure adequate inflow and outflow without leakage by infusing 1 litre of peritoneal dialysis fluid over 5 minutes and allowing it to drain out in an equal time. 6. The exit site should be facing downwards or be directed laterally. Upward directed exit sites should be avoided. No sutures should be placed at the exit site. 7. The intra peritoneal portion of the catheter should be placed between the visceral and parietal peritoneum towards the pouch of Douglas and should not be placed within the loops of the bowel or directly in omental tissue. Surgical insertion of PD catheters: Surgical implantation is the most common method for insertion of chronic peritoneal catheters. It is done under either extensive local anesthesia or light general anesthesia. It can be done by either the lateral approach or paramedian approach. The Missouri (Swan neck) is usually placed by the paramedian route. Blind insertion: This procedure should not be done in patients who are extremely obese or where intra abdominal adhesions are expected since there is risk of bowel perforation is increased in these patients. It is also not recommended in patients for whom PD is to be started immediately since there is an increased incidence of early leakages (2%-43%), outflow failures (5%-50%) and infectious complications. Surgical back up should be available for complications such as bowel perforation or excessive hemorrhage. Blind placement using Seldinger technique: This technique is similar to split sheath technique used for subclavian or internal jugular catheters. The technique involves passing a guide wire attached to a syringe with 2-3 ml of saline, through the linea alba or the dissected recurs muscle sheath into the peritoneal cavity with the syringe contents being injected after appreciating the give, indicating entry into the peritoneal cavity. A Seldinger guide wire is introduced through the needle, which is then removed. A tapered dilator with surrounding scored sheath is passed caudally over the wire which is in turn removed. The Tenckhoff catheter is then inserted through the guide and the sheath is split to allow the cuff to reach the outer surface of the fascia. With the catheter held in place, the catheter guide is stripped away. Peritoneoscopic technique: This is a well accepted technique and is gaining popularity since this can be done by the nephrologists. This technique would require specialized equipment (Y-Tec) and the operator needs to experienced and comfortable using the peritoneoscope. This technique has the advantage that the insertion of the catheter is done under direct vision and can be used in patients who are likely to have intra abdominal adhesions. Like the blind insertion it is performed through a single abdominal puncture. No fluid is instilled before insertion of the cannula and the trocar into the abdomen. After the trocar is introduced through the medial or lateral border of the rectus, it is removed and the peritoneoscope is inserted through the cannula. After assuring the intra peritoneal location by observing motion of the glistening surfaces, the scope is removed and 600cm² of air is placed in the peritoneal cavity in the Trendelenburg position. The scope is reinserted and during continuous observation, scope, Quill and the canula are advanced into the clearest space and the most open direction between the visceral and parietal peritoneum. Following this, the scope and the cannula are removed and the Quill catheter guide is left in place. After this the next procedure is the dilatation of the Quill and musculature to 0.5 cm. After this the catheter is inserted through the rectus muscle and the cuff is advanced into the muscle. The catheter follows the path as directed by the Quill guide and is on astylet. After the catheter has reached the desired position and the deep cuff is in place the Quill guide is removed. Subsequently a subcutaneous tunnel is made as in the surgical insertion technique. Moncrief-Popovich technique: This technique incorporates 2 modifications of the conventional technique. The external portion of the catheter that would be ordinarily be brought out through the skin in the standard implantation technique is completely buried under the skin in a subcutaneous tunnel. The entire wound is then closed with no exit site. Healing and tissue in growth occurs into the cuffs in a sterile environment. At a subsequent date of convenience about 4 to 6 weeks later a small incision is made 2 cm distal to the subcutaneous cuff and the distal segment of the catheter is exteriorized and brought out through the skin. This technique theoretically prevents early bacterial invasion of the tunnel and cuff material immediately post operatively. Peritoneal dialysis can be started immediately following exteriorization without break in or waiting period. Complications of catheter insertion: Major complications include bleeding from the wound and exit site, malfunction of the catheter, injury to abdominal organ, paralytic ileus. Bleeding from the main wound or exit site may occur if hemostasis is not maintained. Surgeons inserting the catheter should be told that patients with renal failure tend to have excessive bleeding tendencies because of uremia and good care should be taken to prevent post operative bleeding. The main reasons for immediate catheter malfunction are blockage of the catheter by blood clots, omental wrap (specially in children), twist of the catheter in the subcutaneous tunnel and catheter malposition. Catheter position can be checked by getting a X-ray of the abdomen. If the catheter tip is in the true pelvis and flushing of the catheter does not improve the catheter function repositioning of the catheter is the only option.

4 Outflow/Inflow Obstruction: Outflow and inflow obstruction are the most frequently observed early events within 2 weeks after the catheter implantation. It is important to differentiate between various causes: 1. Mechanical obstruction (tip migration, kink in the external tubing, clamp); 2. Constipatio, 3. Catheter blockage Outflow Obstruction: Outflow obstruction (one way obstruction) is the most frequent problem characterized by poor flow and failure to drain the peritoneal cavity. The pathogenesis includes intra luminal catheter factors such as debris (blood clot or fibrin), or extra luminal factors such as stool filled bowel enwrapping the catheter (constipation); occlusion of the catheter holes from pressure exerted by the adjacent organs; omental wrapping; catheter dislocation out of true pelvis; tip entrapment in peritoneal pockets because of adhesions; incorrect catheter placement at implantation. Although one way obstruction is the most common form, two way obstructions can also occur. Also a reversed one way obstruction is known wherin the fluid can be drained but the next infusion cannot be performed due to clot within the catheter lumen. Inflow obstruction: Inflow obstruction is related to either kinking of the catheter either in the subcutaneous tunnel or because of intra luminal debris. Recommendations for treatment of inflow and outflow problems: 1. Before treating catheter obstruction the cause and type of obstruction should be established. 2. Conservative or noninvasive approaches such as body position change, laxatives, flushing with heparinised saline (push and suck manouvre) should be undertaken. If these fail, then instillation of fibrinolytic agents (urokinase or streptokinase can be left in the catheter for 2 hours) may be tried though it is very often not beneficial. In the case of recurrent fibrin clots, heparin in the doses of units/ litre dialysis fluid may prevent obstruction. 3. Aggressive therapies include (a) blind techniques using fluoroscopically guided stiff wires or stylet manipulation (rotating manouvre) combining with a whiplash technique, cleaning out with a Fogarty catheter, or use an intra luminal brush; (b) direct or visualized techniques of peritoneoscopy, open surgical catheter revision or catheter replacement. The sequence of steps should be as follows: 1.Examination and evaluation, 2. Laxatives, Urokinase, 4. Fluoroscopy and manipulation, 5. Revision, 6. Replacement. Catheter migration: The most common reason for early migration is internal rotational stress on the catheter itself. S 83 The most common cause for delayed migration is omental entrapment of the catheter. There is no cure for omental entrapment. The catheter needs to be reinserted. If the catheter migration is because of rotational stress and it still works, leave it alone. If it does not work, remove the catheter and reinsert. Peritoneoscopic / laparoscopic repositioning of the catheter can be attempted but the technique is difficult and at best has a 60% success ratio. Leaks: Early leaks (first 4-6 weeks) are almost due to the fact that the hole through the rectus muscle and the peritoneum was too big for the catheter. This can be caused by several factors. The surgeon cut the muscle and the peritoneum and did not suture the muscle and peritoneum well enough. If the suturing had been good but the PD had been started too soon or too much PD volume was used too soon, it can lead to leaks. Another common cause is that the catheter was not immobilized well enough. Surgically implanted catheters that leak moderately require a period of zero volume (PD) exchanges to enable the muscle to heal and grow into the deep cuff. Normally it take 2-4 weeks to seal off after the leak has been noticed. For all heavy flow leaks, surgical intervention may be needed to close the rectus muscle followed by a dry abdomen for 2-4 weeks. Peritoneoscopic implanted catheters that leak usually require a dry abdomen for hours followed by a gradual break in period starting with litre exchanges. Exit site cuff erosion: If the exit site cuff comes out, it usually is due to the fact that it was not placed properly relative to the exit site itself. That is, it was implanted too close to the exit site instead of cm from the exit. Sometimes the cuff will protrude due to a oatient s weight loss. If the cuff is protruding, sometimes it can be successfully shaved or removed and the catheter salvaged. However it is important to be extremely cautious while shaving the cuff since one can accidentally puncture or cut the catheter itself. Exit Sinus Tract (exit tunnel) infection: The exit sinus tract infection is usually caused BT 2 problems. The first problem is that the deep cuff is not properly seated in the rectus sheath. That in turn allows the catheter to piston in and out which in turn results in an improperly seated exit cuff. Improperly seated exit cuffs always result in infections due to fluid leaks. The second cause is that the exit cuff is implanted too far from the exit site itself. As a result the epithelial cells lining the sinus tract are too thin and will break with normal patient activities. Sinus tract infections are often difficult to cure with medication.

5 S 84 Indian Journal of Nephrology Tunnel Infections: This occurs because either one or both cuffs are improperly seated, that is tissue did not grow into the cuffs well. There are several reasons why tissue did not grow into the cuffs well. The most common reason, at least early on, is that the catheter is not properly immobilized. As a result the catheter keeps moving around, continuously breaking any fibroblasts that attempt to grow into the cuffs. Once the fibroblasts have not grown into the cuff, almost anything can and does make its way down the sinus tract and cause infection. Also if the deep cuff does not become properly anchored the catheter will move up and down or piston in and out. That in turn will allow the dialysate to leak into the tunnel track and there by lead to infection. If the infection does not respond to medication it is always advisable to remove the catheter. Hernia: Many people have hernias and never know it until 2 litre of dialysate is infused. It is always important to check for hernial orifices before inserting the catheter and repair it at the time of inserting a catheter. The most frequently occurring hernias during PD are incisional, umbilical and inguinal. Incisional hernia through the catheter placement site is most frequent if the implantation is made through the midline instead of the paramedian approach through the rectus muscle. If a patient develops hernia after CAPD has been started the only option is to surgically correct it. Bleeding: The obvious cause is cutting or puncturing blood vessels. It is convenient to grade the bleeding into 3 categories. Minimum, moderate or severe. Minor bleeding will stop with compression. Platelet and plasma infusion is sometimes helpful. For moderate and heavy bleeding the specific vessel needs to be located and cauterized or tied. Merits and shortcomings of different catheter insertion techniques: Surgical insertion technique: Merits: 1. Good hemostasis and low risk of bleeding 2. Tissue injury or viscus perforation is completely eliminated 3. Precise positioning of the inner segment is possible 4. All types of catheters can be inserted. 5. Low risk of dialysate solution leaks Shortcomings: 1. Larger incision may predispose to late hernias. 2. Immediate use is not recommended due to risk of dialysis solution leak. 3. High cost of surgical procedure (dependence on surgeon s availability, OR time) Trocar and Seldinger guidewire techniques: Merits: 1. Quick and convenient 2. Small incision 3. Low risk of late hernia 4. Low cost of procedure Shortcomings: 1. Blind procedure and higher risk of early solution leakage 2. High risk of viscus perforation or tissue laceration 3. Inadequate hemostasis results in minor hemorrhages 4. Higher incidence of catheter malfunction (poor flow) 5. Precise location of the inner segment may be difficult Peritoneoscopic insertion technique: Merits: 1. Quick and convenient 2. Small incision; low risk of late hernias 3. Immediate use possible 4. Adequate hemostasis; low risk of bleeding 5. Low risk of tissue injury 6. Precise positioning of inner segment possible Shortcomings: 1. Need for special equipment 2. Expertise in using the peritoneoscope Immediate post operative care: Goals of post operative care: 1. Minimize bacterial colonization of the exit site and tunnel during early healing period. 2. Prevent trauma to the exit site and traction on the cuffs by immobilization of the catheter 3. Minimize intra abdominal pressure to prevent leakage. Recommendations for post operative care: 1. Flush the catheter with small volumes until the effluent is clear. It is useful to flush the catheter with

6 500ml to 1000ml of heparinised ( u/l) PD solution to check patency of the catheter and to prevent fibrin or blood clot formation. Once the effluent is clear the catheter can be capped safely. Before capping the catheter instill units of undiluted heparin into the catheter. Flushing can be repeated after 7 days. 2. Commencement of CAPD is dependent upon the implantation technique but generally it is recommended to wait for 10 days to 14 days before starting regular CAPD. Longer the period of nonuse the better is the healing with a resultant reduction in complications. During this time the patient can be placed on HD or intermittent PD. 3. Peritoneal dialysis in the interim period if absolutely necessary should not be started before 3 days after catheter insertion. It should be done using small volumes ( ml) volumes with short dwell times (start with 30 minutes) with the patient in the supine position. The exchange volumes and dwell time can be increased gradually. It is preferable to use a cycler for initiating intermittent PD during the break in period. Early exit site care: There is no consensus regarding specific procedures, cleansing agents, dressings or methods of immobilization. The recommendations are based on broad general principles. Dressings: 1. After implantation the exit site should be covered with several layers of sterile gauze. Transparent, occlusive dressings should not be used. The surgical dressing should not be changed for 72 hours unless there is obvious bleedings or signs of infection. 2. Frequent dressing changes in the immediate post implantation period are not necessary. The fewer the dressing changes, the less is the risk of local trauma from manipulations and less risk of contaminating the exit site. The dressing should not be changed more than once a week unless there is evidence of collection at the wound site. In a tropical country like India, sweating may affect the frequency of early dressing changes which should be done when the exit site is wet or when the patient feels itchy under the taped skin or when the stickiness of the tape is lost. Once the exit site is colonized with bacteria, by week 2-3, more frequent dressing changes are indicated. 3. The dressing changes in the break in period should be done by specially trained staff. Aseptic techniques, using face masks and sterile gloves is recommended for post implantation exit site care. 4. Patients should avoid submerging the exit site during healing to avoid colonization with water borne S 85 organisms. Patients should avoid taking a bath until the exit site has fully healed (when exit site can be labeled as good or equivocal as per Twardowski s classification). Cleansing agents: Povidone iodine and hydrogen peroxide used previously for cleaning the exit site have been reported to be cytotoxic causing tissue damage and delaying clean wound healing. If Povidone iodine is to be used, care should be taken that it does not enter the exit sinus. The newer cleansing agents recommended in the early post operative period are normal saline, or a nonionic surfactant agent (20% polaxamer) and pure soap. Immobilization: The catheter should be immobilized using a dressing or tape. It is advisable to prevent torquing movement and to minimize handling the catheter until the exit site and tunnel are completely healed. This will reduce the incidence of trauma and promote tissue growth. Recommendations for early exit site care: 1. The care should be done by experienced PD nursing staff or trained patients or their relatives who are trained. 2. Aseptic technique to be used. 3. Avoid irritating or toxic solutions for cleansing. If povidone iodine or hydrogen peroxide are used, they should be kept out of the sinus or wound. 4. Absorbent dressings should be used and the exit site be kept dry as possible. 5. Sterile dressings should be used for exit site care. 6. Immobilize the catheter. 7. Infrequent dressings in the initial post operative period. Long term care of the exit site: The primary goal of long term exit site care is to prevent exit site infections. The optimal frequency of exit site care has not been established. However frequent cleansing is essential to reduce resistant bacteria and daily care is recommended in atropical country like India. Good hand washing prior to exit care is critical to avoid cross contamination. Assessment of the exit site by visual inspection and palpation of the tunnel should be routine part of exit site care for both health care professionals and patients and their helpers. Initial patient education should include how to assess exit site, signs and symptoms of exit site infection. Recommendations regarding long term exit site care: 1. Catheter exit sites should be washed daily with anti bacterial soap or medical anti septic to keep the exit site clean and to reduce the number of resident bacteria.

7 S 86 Indian Journal of Nephrology 2. The choice of soap or cleansing agent may need to be individualized because of skin sensitivities or allegies. It is advisable to use either normal saline or povidone iodine. 3. It is important not to forcibly remove crusts or scabs during cleansing because this may traumatize the exit, causing a break in the skin and thus increase the risk of exit infection. 4. Exit site should be patted dry after cleansing. 5. Apply mupirocin at the exit site. It is recommended to apply mupirocin in all patients. This has been found to reduce the incidence of S.aureus exit site infection and S.aureus peritonitis. 6. The exit site should be covered with sterile gauze and micropore paper tape used to keep it covered. Recommendations regarding PD catheter insertion in pediatric patients: The maximum experience is with straight and coiled Tenckhoff catheters. Coiled catheters are associated with fewer obstructive events. Use of 2 cuff catheters recommended at all ages. It may be useful to consider doing omentectomy in children to prevent omental entrapment of the catheters. The catheter insertion in children is done under general anesthesia. The peri operative catheter care is similar to adults. The exit site care is also similar to adults.