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CHRONIC CARE OF THE HEALED EXIT SITE

The primary goal of chronic exit-site care is to prevent exit-site infections. In a broad sense, exit-site care includes assessment of the exit, cleansing the exit, anchoring or immobilizing the catheter, and protecting the exit site and tunnel from trauma (Prowant and Twardowski, 1996).

As with postimplantation care, optimal chronic exit-site procedures for peritoneal catheters are undetermined. The few controlled studies have focused primarily on the cleansing agent used for exit care or on the use of dressings.

The optimal frequency of exit-site care has not been established; however, frequent cleansing is essential to reduce resident bacteria, and daily care is recommended by the vast majority of units. Exit-site care should also be repeated when the exit becomes grossly dirty or wet. 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 a routine part of exit-site care for both health care professionals and patients. Initial patient education should include how to assess the exit site, signs and symptoms of exit-site infection, and when to notify the PD unit of exit-site problems.

Cleansing Agents

Several studies have compared cleansing agents used in exit-site care. A large, multicenter study found significantly fewer infections when povidone iodine was used in comparison with pure soap (Luzar et al., 1990); another study found similar rates between povidone iodine and soap (Warady et al., 1987), and one study (Prowant et al., 1988) and a quality improvement report (Hasbargen et al., 1993) found higher rates with povidone iodine compared to an antibacterial soap. It is likely that pure soap does not effectively reduce the number of organisms at the exit site, and that use of a cleansing agent with antimicrobial properties is essential. An antibacterial soap may be appropriate. Liquid soap is preferred to avoid the risk of cross contamination from bar soap. Povidone iodine solutions contaminated with Pseudomonas spp have been implicated as the source of both peritonitis and exit-site infection in CAPD patients. To avoid contamination of liquid soaps and disinfectants, they should not be transferred from one container to another.

RECOMMENDATIONS

1. Catheter exit sites should be washed daily or every other day with antibacterial soap or a medical antiseptic to keep the exit clean and to diminish resident bacteria.
2. The choice of a soap or cleansing agent may need to be individualized because of skin sensitivities or allergies.
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. The exit should be patted dry after cleansing. The use of sterile gauze or cotton-tipped applicators is not necessary for care of the healed exit; a clean wash cloth and towel suffice.
5. Liquid soap and disinfectants should not be transferred to other containers because of the risk of cross-contamination.

Dressings

Studies in chronic exit-site care in adults showed a similar incidence of exit infection in groups with and without dressings (Starzomski, 1984; Khanna and Oreopoulos, 1983). Because there are no data to document lower infection rates in adults, the use of dressings for chronic care is based on anecdotal experience or individual preference. Theoretically, the use of dressings may help keep the exit clean, protect it from trauma, and help to stabilize the catheter. Furthermore, dressings are indicated for all patients when the exit is infected or likely to become grossly contaminated.

Gauze dressings are used most frequently but semipermeable dressings and occlusive dressings are also used. The few studies comparing different types of dressings have found either no differences in infection rates or have conflicting findings.

A retrospective analysis in pediatric patients showed significantly fewer infections in exit sites covered with an occlusive sterile dressing. It may be that this difference is due to the increased risk of gross contamination and trauma to the exit site of infants and children.

DIAGNOSIS AND TREATMENT OF EXIT-SITE AND TUNNEL INFECTIONS

A detailed description of the peritoneal catheter tunnel morphology has been published (Twardowski et al., 1991). In addition, a supplement of Peritoneal Dialysis International has been dedicated to this topic (Perit Dial Int, 1996).

Exit-site and tunnel infections are important because they may lead to refractory or relapsing peritonitis and subsequent catheter loss. In the majority of these patients, the catheter must be removed to resolve the infection (Gupta et al., 1996). The risk of peritonitis from a catheter infection varies with the infecting organism. Staphylococcus epidermidis exit-site infections seldom result in tunnel infections, peritonitis, or catheter loss, while exit-site infections due to Staph. aureus and Pseudo. aeruginosa frequently lead to peritonitis and catheter loss.

Definition and Occurrence

The site of the infection can be the sinus (exit-site infection) or the subcutaneous or external cuff and tunnel (tunnel infection). The preperitoneal cuff can also be infected but this is difficult to diagnose. Infections can be acute or chronic. Acute infections last for less than 4 weeks while chronic infections are of greater duration.

Acute Exit-Site Infection: An acute exit-site infection is defined as purulent and/or bloody drainage from the exit site which may be associated with erythema, tenderness, exuberant granulation tissue, and edema (Twardowski and Prowant, 1996b). The erythema needs to be more than twice the catheter diameter; there is regression of the epithelium in the sinus. An acute catheter infection may be accompanied by pain and the presence of a scab, but crusting alone is not indicative of infection.

Appearance of the infected exit site correlates with catheter outcome (Flanigan et al., 1994). Catheter loss is rare with isolated erythema or serous drainage. Purulent drainage, should always be cultured. Positive cultures of normal appearing exit sites indicate the presence of colonization, not infection.

Chronic Exit-Site Infection: This may be the result of an untreated or inadequately treated acute infection. It may also be a sequela of a resolved acute infection which recurs after withdrawal of antibiotic therapy. Symptoms of chronic infection are similar to those of acute infections; however, exuberant granulation tissue is more common both externally and in the sinus. Granulation tissue at the external exit is sometimes covered by a large stubborn crust or scab. Pain, erythema, and swelling are frequently absent in chronic infection.

An Equivocal Exit Site: This is defined as purulent and/or bloody drainage only in the sinus that cannot be expressed outside, accompanied by regression of the epithelium and the occurrence of slightly exuberant granulation tissue in the sinus. Erythema may be present but with a diameter less than twice the width of the catheter. Pain, swelling, and external drainage are absent (Twardowski and Prowant, 1996b). The equivocal infected exit site represents low grade infection. Although some equivocal exits improve spontaneously, most progress to overt infection if untreated.

Tunnel Infection: Tunnel infection is defined as erythema, edema, and/or tenderness over the subcutaneous pathway, and may be characterized by intermittent or chronic, purulent, bloody, or gooey drainage which discharges spontaneously or after pressure on the cuff. Tunnel infections are often occult (Plum et al., 1994) and can sometimes be detected by ultrasonography of the subcutaneous pathway (Plum et al., 1994; Holley et al., 1989). Most, but not all, tunnel infections occur in association with exit-site infections. Here the risk for subsequent peritonitis is increased.

Traumatized Exit Site: Traumatized exit-site appearances depend on the intensity of the trauma and the time interval until examination. Common features are pain, bleeding, scab, and deterioration of exit appearance.

Pathogens: Staph. aureus is responsible for the majority of exit-site and tunnel infections. Pseudo. aeruginosa is much less common, but like Staph. aureus, is difficult to eradicate and frequently leads to peritonitis if catheter removal is delayed. Staph. epidermidis is a relatively infrequent cause of tunnel infection in contrast to peritonitis. Other gram-positive organisms, other gram-negative bacilli, and, rarely, fungi account for the remaining infections.

Exit-Site Cultures: Within 2 – 4 weeks after catheter implantation, almost all exit sites are colonized by bacteria. Positive cultures from normal-appearing exit sites indicate colonization, not infection. Whenever possible, the cultures should be taken from the exudate (Twardowski and Prowant 1996a, 1996c). Cultures should only be taken from abnormal-looking exit sites.