CATHETER CHOICE AND CATHETER OUTCOMES
A Network 9 study (Golper et al., 1996) reported the outcome of 1930 catheters used between 1991 and 1993. Overall, 1- and 2-year catheter survivals were 82% and 70%, respectively. Peritoneal dialysis-related infections, including peritonitis, catheter-related peritonitis, and catheter infection, account for 75% or more of the catheters lost (Golper et al., 1996; Eklund, 1995; Weber et al., 1993). In the Network 9 study, mechanical problems such as dialysate leaks (3%) and drainage failure (4%) were less common causes of catheter loss than reasons involving infections.
These are summarized as follows:
Randomized Studies: Table 1 summarizes outcomes in randomized trials with various catheter designs and placement techniques.
Other Outcome Analyses: An extensive overview of outcomes in terms of complication rates (infection, obstruction, and leaks) by type of catheter and placement technique has been published and shows variable results (Ash and Nichols, 1994).
1. Catheter survival of >80% at 1 year is a reasonable goal.
2. Convincing data exist to indicate that the double-cuff catheter is preferable to the single-cuff catheter, therefore a double-cuff configuration is advocated.
3. A downward-directed exit may decrease the risk of catheter-related peritonitis. Properly implanted, preformed arcuate or pail-handle catheters, will always have a downward-directed exit and are, therefore, advantageous in this respect.
4. Overall, no catheter appears to be superior to the original 2-cuff, standard Tenckhoff catheter, although experience with Swan neck catheters is promising; there is a need for large, randomized prospective studies and long-term experience.
|Randomized Controlled Studies on Catheter Outcome|
|Akyol, 1990||Tenkhoff straight vs coiled, 20 pts||1-yr Survival:||90% Straight|
|Nielson, 1995||Tenckhoff straight vs coiled, 72 pts||3-yr Survival:||78% Straight|
|p < 0.01|
|Scott, 1994||Straight vs coiled vs|
Toronto-Western, 90 pts
|No differences in complications||NS|
|Eklund, 1994||Straight vs Swan neck, 40 pts||2-yr Survival:||78%||NS|
|Eklund, 1995||Straight vs Swan neck, 40 pts||3-yr Survival:||90% Swan neck|
|Lye, 1996||Straight vs Swan neck coiled, 40 pts||1-yr Survival:||95% Swan neck|
|Swan neck:||less exit-site infection|
Ideally, catheter insertion should be undertaken under operating room, sterile conditions. This can be done on either an inpatient or an outpatient basis. Several placement techniques are described and practiced:
1. Surgical placement by dissection.
2. Blind placement using Tenckhoff trocar.
3. Blind placement using guidewire (Seldinger technique).
4. Minitrocar placement using peritoneoscopy.
5. Other modifications (Moncrief and Popovich, presternal).
The procedure, including the incidence and nature of complications, should be described to the patient and all questions answered in a reassuring way, allowing a change to HD if not satisfactory.
Presurgical Assessment: Presurgical assessment of the patient is essential, searching for herniation, eventration, and weakness of the abdominal wall. If present, it may be possible to correct these at the time of catheter insertion. Peritoneal dialysis should then not start during the first 4 weeks, due to increased risk of leakage.
Determination of the Exit Site: Prior to insertion, the exit site should be identified and marked on the skin. This can be done by the operating surgeon, the nephrologist, or an experienced PD nurse. It is advisable to avoid locations where there may be pressure during daily activities.
The exit site should be:
1. either above or below the belt line, should not lie on a scar, and should not be in abdominal folds. The umbilicus should not be used as a reference mark;
2. determined with the patient in an upright (seated or standing) position;
3. placed laterally. A stencil can be applied to demarcate the tunnel and exit site clearly (as is the case for the Swan neck catheter insertion).
Skin Preparation: On the morning of the operation, the patient should bathe or have a shower with chlorhexidine soap. If necessary, abdominal hair should be clipped. Patient’s nares may be swabbed to determine nasal carriage of Staphylococcus aureus. Eradication of nasal carriage has shown significant improvement in exit-site infections but has a cost implications (Dryden et al., 1991; Mupirocin Study Group, 1996).
Bowel Preparation: Bowel preparation and the avoidance of constipation are of paramount importance. Similarly, emptying the bladder before the procedure is mandatory.
Prophylactic Antibiotics Before Implantation: There is some recent evidence that prophylactic antibiotics prevent subsequent catheter infections, peritonitis, and wound sepsis (Golper and Tranćus, 1996). In a recent controlled study using cefuroxime (1.5 g, IV 1 – 2 hours preoperatively, and 250 mg intraperitoneally perioperatively), the prophylactic group had fewer peritonitis episodes than controls (Wikdahl et al., 1997). However, other reports differ (Lye et al., 1992). USRDS 1992 data in 3366 patients showed no difference between patients having had antibiotic prophylaxis compared to those who did not (using the Cox proportional hazards method).
Nevertheless, the use of antibiotic prophylaxis during surgical interventions has a large and convincing literature. It usually consists of using an antistaphylococcal antibiotic, given 1 hour pre- and 6 – 12 hours postoperation.
1. The experience in general surgical practice indicates that perioperative antibiotics, especially in the presence of a foreign body, diminish the incidence of wound infection. A first-generation cephalosporin has been most frequently used in this context and is advocated especially in centers with high postoperative wound or exit infections.
2. Vancomycin should not be routinely used for perioperative prophylaxis to avoid the development of resistant micro-organisms such as vancomycin-resistant enterococci (VRE) and vancomycin-resistant Staph. aureus.
Catheter Implantation Techniques
The implantation technique has a significant influence on the complications and outcome of the chronic peritoneal catheter. To achieve good long-term results, implantation must be performed by a competent and experienced catheter insertion team. Inexperienced personnel should not be permitted to perform the implantation except under the direct supervision of an experienced physician or surgeon. There are several areas of general agreement regarding the placement of peritoneal catheter devices.
1. The implantation must be performed 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 the linea alba) are used with trocar insertions.
3. The deep cuff should be placed in the musculature of the anterior abdominal wall or in the preperitoneal space. Good results have also been obtained with the cuff placed within the posterior rectus fascia. The deep cuff should never be placed within 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 also be taken to avoid mechanically stressing the cuff material.
5. Check for catheter patency. The catheter should be tested to ensure that there is adequate inflow and outflow without leakage. Techniques to accomplish this include infusing 1 L of peritoneal fluid over 5 minutes and allowing an equal time for drainage, or injecting 60 mL of 0.9% saline and observing if 30 – 40 mL is easily aspirated.
6. The exit site should be facing downwards or be directed laterally. Upward-directed exit sites should, in general, be avoided.
7. The intra-abdominal portion of the catheter should be placed between the visceral and parietal peritoneum toward the pouch of Douglas and should not be placed within loops of bowel or directly in omental tissue. This maneuver has been shown to be facilitated by the use of a bent stylet (Stegmayr et al., 1993) or any device that will add rigidity to the catheter.
Surgical Insertion of PD Catheters (Placement by Dissection): Surgical implantation is the most common method for placement of chronic peritoneal catheters. Surgical placement begins with either extensive local anesthesia or light general anesthesia. There are two general approaches: the lateral approach and the paramedian approach. Either can be used with any of the catheters, although TWH and Missouri catheters are usually placed using the paramedian technique. Detailed descriptions of the various techniques can be found elsewhere and are not reproduced here (Ash and Nichols, 1994; Ash and Daugirdas, 1994).
Blind Insertion Technique (Tenckhoff Trocar): This procedure should not be done in patients who are extremely obese or where intra-abdominal adhesions may be expected, since the risk of bowel perforations will be increased in such patients. It also is not optimal in patients for whom PD is to start acutely, since there is an increased incidence for early leakage (2% – 43%), outflow failures (5% – 50%), and infectious complications. Normally, the catheter for chronic use is inserted on one occasion and then not used until 2 – 4 weeks later, enabling ingrowth of the cuff and thereby reducing the risk of leakage. If an immediate start is necessary, and supine dialysis is not possible, then this technique is inappropriate. Surgical back-up should be available for complications such as bowel perforation or excessive hemorrhage. The detailed description of the insertion technique has been previously described (Gokal et al., 1993; Ash and Daugirdas, 1994). If the catheter is not used, there is no need for regular flushing to maintain patency or checking for it.
Blind Placement Using the Seldinger Technique: This technique is somewhat similar to the split-sheath technique used for subclavian or internal jugular catheters, and is described in detail elsewhere (Ash and Daugirdas, 1994; Ash and Nichols, 1994).
This technique involves passing a guide needle, attached to a syringe with 2 – 3 mL of saline, through the linea alba or the dissected rectus 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 passed 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.
Use of the Minitrocar and Peritoneoscopy: The use of the peritoneoscopy for peritoneal catheter placement is now well accepted and details of the insertion technique are described elsewhere (Ash and Nichols, 1994; Ash and Daugirdas, 1994).
Moncrief–Popovich Technique: This technique incorporates two modifications of the conventional implantation procedure. The segment that would 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 ingrowth occurs into the cuffs in a sterile environment. At a subsequent date of convenience, 4 – 6 weeks after insertion, a small incision is made 2 cm distal to the subcutaneous cuff and the distal segment of the catheter is brought out through the skin. The catheter may be left in place under the skin for many months. Peritoneal dialysis may be initiated immediately following exteriorization, without break-in or waiting time. This technique theoretically prevents early bacterial invasion of the tunnel and the cuff material immediately postoperatively, when the wound is fresh and most vulnerable to bacterial invasion into the deep tissues.
Presternal Catheter Insertion Technique: This catheter is a modified Swan neck, Missouri coil catheter. The major difference from the Swan neck Missouri catheter is in the length of the subcutaneous tunnel. The catheter is composed of two silicon rubber tubes which are to be connected end-to-end at the time of implantation. Insertion details are described elsewhere (Twardowski et al., 1996).
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