SHORT REPORTS. Construction and Use of Stencils in Planning for Peritoneal Dialysis Catheter Implantation

Peritoneal Dialysis International, Vol. 23, pp. 395 402 Printed in Canada. All rights reserved. 0896-8608/03 $3.00 +.00 Copyright 2003 International Society for Peritoneal Dialysis SHORT REPORTS Construction and Use of Stencils in Planning for Peritoneal Dialysis Catheter Implantation Peritoneal dialysis (PD) catheter function, catheterrelated complications, and patient satisfaction are greatly influenced by the catheter insertion site, shape of the subcutaneous tunnel tract, and exit-site location. Improper consideration of these procedural details can result in catheter-tip migration, omental wrap, pelvic pain, superficial cuff extrusion, exit-site irritation from the beltline, scar, or skin crease location, difficulty visualizing the exit site during daily care, and increased risk of catheter-related infections (1). Any of these factors may lead to loss of the catheter, patient dissatisfaction with the modality, and transfer to hemodialysis. Operative planning appropriately begins in the clinic in advance of the implantation procedure. Evaluating the patient for proper catheter selection, insertion site, and exit-wound location requires the input and cooperation of the PD nursing staff, nephrologist, and surgeon. The use of a marking stencil that embodies the principles used in making these decisions is a practical substitute for attempting the improbable gathering of the above individuals for each patient evaluation. A well-constructed marking stencil represents a quick, reliable, and reproducible method for selecting the best-suited catheter appliance for the patient. The stencil can serve as an accurate design tool for locating and marking the configuration of the dialysis catheter insertion site, tunnel tract, and exit wound. Presented here is an easy, economical do-it-yourself method that any PD unit can employ to create their own customized marking stencils. MATERIALS AND METHODS The stencils are conveniently constructed from plastic templates used in quilting and can be found in most hobby and craft stores. Extra-thick template plastic manufactured out of 100% polyvinyl chloride is available in 12 18-inch sheets (EZ Quilting; Wm. Wright Co., West Warren, Massachusetts, USA). The material is flexible, has a matte finish, and can be easily cut with scissors, hobby knife, and hand punch. A paper pattern of the stencil is prepared first and used as a guide for cutting the plastic template material. Other items that facilitate the construction of the pattern and stencil include a compass, protractor, and ruler. The design of the stencil should incorporate the best practices for optimal PD access as recommended by the International Society for Peritoneal Dialysis (1). These recommendations include the use of a twocuff catheter, paramedian insertion site, deep cuff within the rectus sheath, deep pelvic location of the catheter tip, downwardly or laterally directed exit site, and the superficial cuff at least 2 cm from the exit wound. The surgical incision through which the PD catheter will be inserted generally corresponds to the final location of the deep catheter cuff. This site is determined by noting the position of the deep catheter cuff when the upper border of the catheter coil (first side hole of straight-tip catheters) is aligned with the upper border of the symphysis pubis (Figure 1). This assures that the coil is located deep in the true pelvis in the retrovesical space but not so deep that redundant tubing produces pressure discomfort. A paramedian location of the incision is planned so that the catheter will traverse the rectus muscle toward the medial aspect of the rectus sheath to avoid the epigastric vessels. The center of the paramedian incision is 3-cm lateral of midline. To indicate the location of the deep cuff on the pattern, first measure the distance from the upper border of the catheter deep cuff to the upper border of the catheter coil (first side hole of straight-tip catheters). Make sure that the catheter is lying in an unstressed state during measurement of the cuff coil distance (Figure 1). The deep-cuff position on the pattern is the point of intersection of a vertical line 3 cm inside the medial border of the pattern and a horizontal line above the inferior border of the pattern equal to the cuff coil distance (Figure 2). The subcutaneous tunnel tract of a catheter with a swan-neck preformed bend must precisely follow the shape of the bend. The deep cuff of the catheter is superimposed over the deep-cuff position on the pattern. The shape of the preformed bend and the position of the superficial cuff are traced onto the pattern. 395

SHORT REPORTS JULY 2003 VOL. 23, NO. 4 PDI Figure 1 Schematic drawing showing the manner in which the proper catheter insertion site and deep-cuff location are selected in order to achieve proper pelvic position of the coiled-tip catheter. This process demonstrates the principle for determining the cuff coil distance. One or two exit-site options are indicated on the pattern in line with the external catheter limb at distances of 2 and 3 cm beyond the superficial cuff (Figure 2). We use an algorithm to plan the shape of the tunnel tract of a Tenckhoff-style catheter to reduce the risk of superficial cuff extrusion through the exit site, which results from the shape memory of a straight tube bent into an arcuate configuration. The algorithm described below was arbitrarily derived in our unit and has worked well for us. It is a simple matter for each PD unit to produce a stencil with the tunnel tract configuration that works best for them. Designing the subcutaneous tunnel tract for a Tenckhoff-style catheter begins with superimposing the deep catheter cuff over the deep-cuff position on the paper pattern (Figure 3). A point 2 cm proximal to the superficial cuff is marked on the pattern in the same paramedian line. Using the catheter as a compass, a 90-degree arc is scribed from the point 2 cm proximal to the superficial cuff to the lateral transverse plane of the pattern. Alternatively, a compass can be used to scribe this arc. The circumference of the 90-degree arc is divided into thirds. The planned exit site is the junction of the medial two thirds and the lateral one third on the arc. A protractor may be 396 Figure 2 Pictured is a completed paper pattern with its labeled components for a peritoneal dialysis catheter with a preformed swan-neck bend. Figure 3 Diagram representing the algorithm used to plan the tunnel tract and exit-site location for Tenckhoffstyle peritoneal dialysis catheters. used to indicate this location by drawing a line 30 degrees above the horizontal plane from the top center point of the deep cuff to where it intersects the arc. With the deep cuff maintained in the fixed position, a point 4 cm proximal to the superficial cuff on the tub-

PDI JULY 2003 VOL. 23, NO. 4 SHORT REPORTS ing is arched over with the convexity oriented upward until the 4-cm point intersects with the planned exit site. The shape of the arc and the position of the superficial cuff are traced on the pattern. This will correspond to the planned tunnel tract and superficial-cuff location. The shape of the arch will give the catheter a lateral and slightly downward direction as it exits the skin. At the time of implantation, the superficial cuff will be no closer than 4 cm to the skin exit site. The amount of tube straightening that occurs over time is a balance between the resilience forces of the tubing and the resistive forces of the tissues, and will be different from patient to patient. In the worse case scenario of tube straightening, the cuff will come no closer than 2 cm of the exit wound. The laparoscopic implantation technique performed in our institution makes use of a 4- to 6-cm rectus sheath tunnel to keep the dialysis catheter directed toward the pelvis. The technique for rectus sheath tunneling of the catheter has been described in detail elsewhere (2). The pattern and stencil provide measuring marks at 4, 5, and 6 cm below the upper border of the deep cuff, in line with the intramural catheter limb to assist in the tunneling process (Figure 2). The completed paper pattern is taped to the surface of the plastic template with care to align the medial and inferior borders exactly. Following the pattern, the stencil is constructed by cutting or punching out different shapes to represent the cuff positions, tunnel tract configuration, and exit-site locations (Figure 4). The stencil is used by aligning its medial border with the midline of the abdomen, and the lower border with the upper border of the pubis. In the event of diastasis recti abdominis (separation of the rectus muscle of the abdomen away from the midline), the medial border of the stencil is shifted laterally to compensate for the offset of the rectus muscle. The stencil cutouts for the catheter cuffs, tunnel tract, and exit sites are traced onto the skin surface with a suitable marking instrument. Planning the catheter exit site should include examining the patient dressed and in the sitting position to confirm that the exit site is easily visible to the patient and does not fall under the belt line, within a skin crease, or on the blindside of a skin fold. A catheter type is selected that produces the most optimal exit-site location without compromising deep pelvic position. The surgeon can use a sterilized version of the selected stencil to retrace the incision site, tunnel tract configuration, and exitwound location on the skin surface at the time of the implantation procedure. Standard sterilization techniques using ethylene oxide gas or STERRADs (Advanced Sterilization Products, Irvine, California, USA) Figure 4 Photograph of a completed plastic stencil for a Tenckhoff-style peritoneal dialysis catheter. (The semitransparent plastic was painted white for photographic purposes.) can be used to sterilize the previously referenced polyvinyl chloride material. RESULTS All dialysis catheter implantation procedures reported here were performed in consecutive patients by the author, using a laparoscopic approach described elsewhere (2). Stencils were used in catheter selection and performance of the procedure in the most recent 86 patients (mean ± SD follow-up 15 ± 8.4 months). There have been no superficial cuff extrusions in these patients. The incidence of superficial cuff extrusion was 2.7% in the preceding 145 consecutive implant patients (mean follow-up 25.7 ± 18.4 months). Omental wrap and catheter-tip migration complicated 7.6% of the previous 145 implantation procedures. There have been no such occurrences in the last 86 patients. The results, however, should be interpreted with caution in view of the significant difference in follow-up between the two groups. The use of stencils emphasizes that one catheter style does not fit all patients. Preliminary results of a separate ongoing anthropometric investigation in a general patient population (n = 62, 55% male) using 397

SHORT REPORTS JULY 2003 VOL. 23, NO. 4 PDI the described stencils revealed that 24% of cases were best served with a swan-neck catheter, and 42% required a Tenckhoff-type catheter. Either catheter style was satisfactory in 29% of patients and neither in 5% of cases. Conflicts of exit site with skin creases or folds (41%), belt line (23%), or both (36%) were the most important determinants of required catheter type. DISCUSSION Catheter stencils should be used in the preoperative planning stage where the patient can be examined fully dressed in the erect, sitting, and recumbent positions. Because patients exist in all sizes and shapes, it should not come as any surprise that more than one type of PD catheter is needed in the armamentarium to establish successful peritoneal access. The catheter style that results in the best exit-site location without compromising correct pelvic position is the device that should be used. Stencils are an important adjunct to the PD catheter implantation process. They can be designed to incorporate the principles of best practices for optimal peritoneal access and assure accuracy and reproducibility in their application. They are inexpensive, easy to construct, and simple to use. Stencils facilitate the work of health care providers and possess the potential of significant impact on patient outcome. 398 John H. Crabtree Department of Surgery Kaiser Permanente Bellflower Medical Center Bellflower, California, USA REFERENCES email: John.H.Crabtree@kp.org 1. Gokal R, Alexander S, Ash S, Chen TW, Danielson A, Holmes C, et al. Peritoneal catheters and exit-site practices toward optimum peritoneal access: 1998 update. Perit Dial Int 1998; 18:11 33. 2. Crabtree JH, Fishman A. A laparoscopic approach under local anesthesia for peritoneal dialysis access. Perit Dial Int 2000; 20:757 65. Rapid Decline of Residual Renal Function in Patients with Late Renal Transplant Failure Who Are Re-Treated with CAPD Patients with late renal transplant failure (TxF) returning to a second chronic peritoneal dialysis (CAPD) therapy represent a special subgroup of end- stage renal disease (ESRD) patients in the integrated care model of renal replacement therapy (1). They are under nephrology care long before CAPD is required and they are familiar with the choices of mode of dialysis. However, neither the course of a second CAPD therapy nor the outcome of patients with failed renal allografts restarting CAPD has been characterized by prospective studies. Residual renal function (RRF) contributes significantly to adequacy of dialysis dose and determines morbidity in and mortality of CAPD patients (2 4). Although RRF is better preserved in CAPD patients than in hemodialysis patients, it declines in virtually all CAPD patients (5). We performed a prospective comparison of the decline of RRF in a small group of incident CAPD patients with failed transplants or native kidneys to characterize the time course of RRF in CAPD patients with failed renal allograft. MATERIALS AND METHODS Eight patients with late TxF chose a second CAPD therapy. End-stage renal failure of the patients native kidneys was caused by various kidney diseases (Table 1) and had been pretreated with CAPD (mean duration 26 months, range 8 60 months) prior to kidney transplantation. Mean graft survival was 56 months (range 8 78 months). Graft loss was due to biopsy-proven chronic transplant rejection in all TABLE 1 Baseline Characteristics of Incident CAPD Patients (Mean ± SD) Late TxF Never Tx Patients (n) 8 16 Age (years) 40±9 42±11 Sex (M/F) 3/5 8/8 Body mass index (kg/m 2 ) 25±4 25±5 Davies Risk Score No comorbidity 6 14 Intermediate comorbidity 2 2 Primary kidney disease (n) Glomerulonephritis 5 8 Interstitial nephritis 2 4 Diabetes mellitus 1 2 Polycystic kidney disease 0 2 Blood pressure (mmhg) Systolic 150±24 146±26 Diastolic 82±13 86±10 Medication Antihypertensives 6 13 Erythropoietin 6 12 TxF = renal transplant failure; Never Tx = no previous transplantation.

PDI JULY 2003 VOL. 23, NO. 4 SHORT REPORTS cases. The immunosuppressive regimen prior to commencement of CAPD consisted of prednisone (mean daily dose 4 ± 3 mg) and cyclosporine (mean daily dose 200 ± 43 mg). Residual renal function (creatinine clearance was measured by 24-hour urine collection and a blood sample drawn in the morning) and peritoneal solute transport (4-hour peritoneal dialysateto-serum creatinine ratio, adjusted for glucose content) were prospectively measured at 6-month intervals during the 2-year study period in all 8 patients with failed kidney transplant and in 16 matched new CAPD patients. Matching criteria were RRF at start, age, and comorbidity. None of these patients had severe coexisting diseases. They all had residual creatinine clearance above 5 ml/minute/1.73 m 2 at the start of the study. Consent was obtained from all patients before inclusion. Postinitiation RRF data were plotted on a semilogarithmic scale, and half-life of RRF was calculated for both patient groups. Comparison analysis between the two patient groups was done using two-sided unpaired t-tests (for continuous variables) or Fisher s exact test (for discrete variables). A p value less than 0.05 was considered statistically significant. RESULTS All CAPD patients completed the 2-year observation period. One control patient suffered an episode of bacterial peritonitis. Two patients (one in each group) underwent radiological studies with contrast media. None of the patients received nephrotoxic drugs or had signs of clinically evident dehydration during the study. Cyclosporine and prednisone (after exclusion of secondary adrenal insufficiency by appropriate tests) were tapered off over the first 3 months after commencement of CAPD in patients with a late TxF. None of these patients experienced an episode of acute rejection necessitating transplant nephrectomy. Baseline characteristics did not differ between the groups (Table 1). The two groups were comparable in age, sex, cause of primary renal disease, body mass index, severity of hypertension, and percentage of patients taking antihypertensive drugs or receiving erythropoietin. Baseline RRF was not different between the two patient groups. Over the 2-year period, RRF dropped significantly in all patients but there was a more rapid rate of loss in the TxF patients. The majority of the TxF patients developed anuria during the observation period (Table 2). Furthermore, 6 of 8 patients that were treated with CAPD after TxF, but only 2 of 16 never-transplanted patients, demonstrated high peritoneal transport rates (> 0.81), as assessed by the standard peritoneal equilibration test. TABLE 2 Residual Renal Function (RRF) of Incident CAPD Patients (mean ± SD) DISCUSSION The most striking clinical difference between CAPD patients with a failed renal transplant and CAPD patients with failed native kidneys was the more rapid loss of RRF in previously transplanted CAPD patients. The earlier cessation of RRF in our patients with a failing renal allograft cannot be explained by differences in patient characteristics, nonpharmacological renal risk factors (hypertension, proteinuria, dehydration), or antihypertensive drugs. However, the cause of definite renal failure and exposure to immunosuppressive medications differentiate these patients from the general, incident ESRD population. Reinstitution of dialysis after TxF presents the clinician with the dilemma of whether to withdraw immunosuppressive medication and, if withdrawal is initiated, which method for tapering immunosuppression following TxF is best. Most transplant centers have center-specific empirical protocols. The use of immunosuppression in peritoneal dialysis patients is known to increase the frequency and severity of infection (6 8) and is believed to increase malignancy. By contrast, maintaining predialysis levels of immunosuppressive therapy after commencement of dialysis may result in better-preserved RRF and in a survival advantage (9). There is a need for randomized controlled clinical trials to test the hypothesis that benefits of preserved RRF outweigh the risks associated with continued immunosuppression. Our experience and other observations (10) indicate that early anuria after stopping immunosuppression in combination with peritoneal transport failure (11) contributes to poor technique survival in this subgroup of CAPD patients. CONCLUSIONS Late TxF Never Tx Patients (n) 8 16 Creatinine clearance Baseline (ml/min/1.73 m 2 ) 8.5±2.1 8.0±1.4 Half-life of RRF (months) 8±4 28±4 a Anuria at 2 years (n) 6 0 a TxF = renal transplant failure; Never Tx = no previous transplantation. a p < 0.05 versus corresponding value in the late TxF group. The commencement of CAPD would appear to be a good option for patients with failing kidney transplants. However, the earlier loss of RRF in these patients might 399

SHORT REPORTS JULY 2003 VOL. 23, NO. 4 PDI necessitate strategies of continued immunosuppression, although risk of infection is an important issue. 400 Helmut Schiffl 1, * Claudia Mücke 1 Susanne M. Lang 2 Dialysezentrum des Kuratorium für Dialyse und Nierentransplantation 1 Zentrum München-Laim Medizinische Klinik Innenstadt 2 Ludwig Maximilians University Munich Munich, Germany REFERENCES *email: hschiffl@hotmail.com 1. Van Biesen W, Davies S, Lameire N. An integrated approach to end-stage renal disease. Nephrol Dial Transplant 2001; 16(Suppl 6):7 9. 2. Szeto CC, Lai KN, Wong TY, Law MC, Leung CB, Yu AW, et al. Independent effects of residual renal function and dialysis adequacy on nutritional status and patient outcome in continuous ambulatory peritoneal dialysis. Am J Kidney Dis 1999; 34:1056 64. 3. Shemin D, Bostom AG, Lambert C, Hill C, Kitsen J, Kliger AS. Residual renal function in a large cohort of peritoneal dialysis patients: change over time, impact on mortality and nutrition. Perit Dial Int 2000; 20: 439 44. 4. Bargman JM, Thorpe KE, Churchill D. Relative contribution of residual and peritoneal clearance to adequacy of dialysis. A reanalysis of the CANUSA Study. J Am Soc Nephrol 2001; 12:2158 62. 5. Jansen MA, Hart AA, Korevaar JC, Dekker FW, Boeschoten EW, Krediet RT. Predictors of the rate of decline of residual renal function in incident dialysis patients. Kidney Int 2002; 62:1046 53. 6. Andrews PA, Warr KJ, Hicks JA, Cameron JS. Impaired outcome of continuous ambulatory peritoneal dialysis in immunosuppressed patients. Nephrol Dial Transplant 1996; 11:1104 8. 7. Smak Gregoor PJH, Zietse R, Van Saase JLCM, op de Hoek CT, Ijzermans JNM, Lavarijssen ATJ, et al. Immunosuppression should be stopped in patients with renal allograft failure. Clin Transplant 2001; 15: 397 401. 8. Sasal J, Naimark D, Klassen J, Shea J, Bargman JM. Late renal transplant failure: an adverse prognostic factor at initiation of peritoneal dialysis. Perit Dial Int 2001; 21:405 10. 9. Jassal SV, Lok CE, Walele A, Bargman JM. Continued transplant immunosuppression may prolong survival after return to peritoneal dialysis: results of a decision analysis. Am J Kidney Dis 2002; 40:178 83. 10. Davies SJ. Peritoneal dialysis in the patient with a failing renal allograft. Perit Dial Int 2001; 21(Suppl 3): S280 4. 11. Wilmer WA, Pesavento TE, Bay WH, Middendorf DF, Donelan SE, Frabott SM, et al. Peritoneal dialysis following failed kidney transplantation is associated with high peritoneal transport rates. Perit Dial Int 2001; 21:411 13. The Spectrum of Bacterial Peritonitis in CAPD Patients in a Developing Country: Is It Different? Peritonitis is still the leading cause of morbidity and technique failure in continuous ambulatory peritoneal dialysis (CAPD) patients. While the incidence of peritonitis depends on factors such as age, race, educational background, environment, and type of system used (1), the outcome depends on the organism isolated (2 4). Recently, several studies have shown that there is a decreasing trend in the incidence of grampositive peritonitis while there is a relative increase in the incidence of gram-negative peritonitis (5). The spectrum of bacterial peritonitis in patients from a developing country, such as India, may be different from that observed in patients from developed countries due to the different social, environmental, educational, and financial backgrounds of the patients. We therefore analyzed our data on the incidence of peritonitis caused by either gram-positive or gramnegative bacteria in our CAPD patients and their eventual outcome. MATERIAL AND METHODS This was a retrospective study of 225 patients (mean age 56 ± 13 years) with end-stage renal disease that started on CAPD at our center between October 1993 and May 2001. All patients were on a disconnect system. The diagnosis of peritonitis was made based on the following criteria: (1) the presence of a cloudy effluent with total leukocyte count 100 cells/mm 3 or greater, and with more than 50% polymorphonuclear cells in the differential count; (2) isolation of an organism from the effluent smear and subsequently by culture; and (3) clinical features of peritonitis. Peritonitis was diagnosed if at least 2 of the 3 criteria were fulfilled. A total of 50 ml dialysate was centrifuged at 10 000 rpm for 10 minutes. The pellet was routinely examined microscopically and cultured on blood agar, MacConkey agar, biphasic brain heart infusion medium (Difco, Sparks, Maryland, USA), and Sabouraud s dextrose agar (Difco). All media were incubated at 37 C and Sabouraud s dextrose agar was also incubated at 28 C. Blood agar and MacConkey agar plates were examined every 24 hours for 48 hours, biphasic brain heart infusion medium was

PDI JULY 2003 VOL. 23, NO. 4 SHORT REPORTS observed for 1 week, and Sabouraud s dextrose agar was examined every day for 1 week, then twice weekly for 3 weeks for evidence of growth. Culture technique was consistent over the study period. Relapse of peritonitis was defined as repeat culture positive within 2 weeks of completion of therapy for a gram-positive organism or within 4 weeks for a gram-negative organism, and was considered a single episode. Excluded from outcome analysis were polymicrobial peritonitis and fungal peritonitis, due to their different outcomes; culture-negative peritonitis, due to uncertainty of the organism; and patients that were treated for both gram-positive and gram-negative organisms. The outcome of gram-positive and gramnegative peritonitis was analyzed in terms of catheter loss, hospitalization, death within 4 weeks of peritonitis, shifting the patient to permanent maintenance hemodialysis, and reimplantation of the Tenckhoff catheter. Patients were hospitalized only if they did not respond to antibiotic therapy for 5 7 days; catheter removal was considered only if peritonitis did not resolve with 2 courses of antibiotics. This policy was consistent over the study period. Statistical analysis was performed using Fisher s exact test with Yates correction and chi-square test for difference in proportions. Data are expressed as mean ± standard deviation. Statistical significance was defined as p value less than 0.05. RESULTS The duration of CAPD was 264.16 patient-years in 225 patients; 168 episodes of peritonitis (range 1 6 episodes per patient) were identified in 82 patients; 47 (57.3%) of the diabetic patients developed peritonitis, compared to 35 (42.7%) of the nondiabetic patients (p = 0.06). The mean duration of peritonitis after CAPD catheter insertion was 16.5 ± 6.5 months. Sixtytwo (36.9%) episodes were culture negative and 106 (63.1%) episodes were culture positive. Gram-negative, gram-positive, polymicrobial, and fungal organisms were isolated in 45 (42.5%), 30 (28.3%), 11 (10.4%), and 20 (18.9%) episodes of culture-positive peritonitis, respectively. The peritonitis rate was 0.63 episodes per patientyear. The gram-positive and gram-negative peritonitis rates were 0.11 and 0.17 episodes per patient-year respectively; the polymicrobial and fungal peritonitis rates were 0.04 and 0.09 episodes per patient-year respectively. Seventy-five episodes of monomicrobial peritonitis were detected in 49 patients. Of these 75 episodes, 45 (60.0%) were gram-negative and 30 (40.0%) were gram-positive (p = 0.03). Among gramnegative peritonitis (45 episodes), Escherichia coli, Pseudomonas, Klebsiella, Enterobacter, Acinetobacter, and others were isolated in 14 (31.1%), 10 (22.2%), 8 (17.8%), 7 (15.5%), 4 (8.9%), and 2 (4.44%) episodes, respectively. Among gram-positive peritonitis (30 episodes), Staphylococcus aureus, S. epidermidis, Enterococcus sp, and others were isolated in 10 (33.3%), 7 (23.3%), 9 (30.0%), and 4 (13.3%) episodes, respectively. No peritonitis episode was associated with exit-site and/or tunnel infection. On analyzing the organisms according to source of origin, it was found that organisms of fecal origin (40/ 75 episodes) occurred significantly more frequently than those of skin origin (21/75 episodes) (p = 0.0016). Escherichia coli, Klebsiella, Enterobacter, and Enterococci were considered organisms of fecal origin; S. aureus, S. epidermidis, and diphtheroids were considered organisms of skin origin. Pseudomonas and Acinetobacter could be of either fecal or skin origin. On outcome analysis (Table 1), catheter loss in gram-negative peritonitis [17/45 (37.8%)] was significantly higher than in gram-positive peritonitis [5/30 (16.7%)] episodes (p = 0.049). The hospitalization rate required for resolution of peritonitis was also significantly higher for gram-negative [31/45 (68.9%)] than for gram-positive [13/30 (43.3%)] peritonitis episodes (p = 0.033). The death rate within 4 weeks of peritonitis was higher for gram-negative episodes (20%) than for gram-positive episodes (10.0%), although not statistically different. Of the 12 patients that died, 8 were diabetic and 4 were nondiabetic (p = 0.2). The rates of patients opting for permanent hemodialysis (8.9% vs 3.3%) or reimplantation of the Tenckhoff catheter (4.4% vs 3.3%) were also higher for gram-negative than for gram-positive infections. Only 2 patients underwent kidney transplantation following peritonitis. DISCUSSION The peritonitis rate in our patients was 0.63 episodes per patient-capd-year; this is comparable to other leading centers. Peritonitis rates have shown a decreasing trend and have been reported as approximately 0.5 episodes per patient-year (2,5). This de- TABLE 1 Comparison of Outcome in Gram-Positive Versus Gram-Negative Peritonitis Episodes Gram Gram positive negative (n=30) (n=45) p Value Catheter loss [n (%)] 5 (16.7) 17 (37.8) 0.049 Death (4 weeks) [n (%)] 3 (10.0) 9 (20.0) NS Hospitalization [n (%)] 13 (43.3) 31 (68.9) 0.033 Maintenance HD [n (%)] 1 (3.3) 4 (8.9) NS Reimplantation [n (%)] 1 (3.3) 2 (4.4) NS NS = not significant; HD = hemodialysis. 401

SHORT REPORTS JULY 2003 VOL. 23, NO. 4 PDI cline has been achieved in large part because of exceptional patient education and new connector and catheter technology. The rate of culture-negative peritonitis episodes reported in the literature is 20% 34% of peritonitis episodes. The higher incidence of culture-negative episodes (36.9%) in our CAPD patients was due to poor availability of culture facilities in rural areas; 30% of our patients live in rural areas. The incidence of gram-positive peritonitis is decreasing, while gram-negative peritonitis remains constant (5). It was a novel observation in our study that the incidence of gram-negative peritonitis (45/ 75) was higher than the incidence of gram-positive (30/75) peritonitis. The rate of decline of gram-positive peritonitis has been attributed to the introduction of the twin-bag system and to a reduction in skin contamination with the use of disconnect dialysis systems and flush-before-fill technique (2,6,7). Gram-negative peritonitis usually occurs due either to fecal contamination or transmural migration of the organism (8). Peritonitis episodes due to transmural migration of bacteria across the bowel wall are usually associated with multiple gram-negative organisms and anaerobic organisms. In our patients, transmural migration seems unlikely because anaerobic peritonitis was not seen in our CAPD patients. Among gram-negative organisms, E. coli was the commonest. Escherichia coli is a bowel flora and usually of fecal origin. In a separate analysis of fecal versus skin origin of organisms, the incidence of fecal organisms was higher than skin origin (p = 0.0016). This analysis also suggests a higher incidence of peritonitis due to organisms of fecal origin. Staphylococcus aureus has been isolated in a higher percentage of episodes than has S. epidermidis. This trend of a higher incidence of S. aureus has been attributed to the introduction of the flush-before-fill disconnect system, a decrease in peritonitis due to touch contamination (6), better skin care due to occlusive dressing, and decreased trauma of the exit site during the postoperative period. Occlusive dressing during the postoperative period and exit-site dressing with mupirocin ointment are practiced with all patients at our center. The rates of catheter removal (37.8% vs 16.7%, p = 0.049) and hospitalization (68.9% vs 43.3%, p = 0.033) required for resolution of gram-negative peritonitis were significantly higher than for gram-positive peritonitis episodes. In our study, the number of deaths within 4 weeks of a gram-negative peritonitis (20%) was also higher than with gram-positive peritonitis (10.0%), but was not statistically different. Poor outcome of gram-negative peritonitis has also been observed in other studies (3,4). We conclude that the gram-negative peritonitis rate is higher than the gram-positive rate in our CAPD patients. The higher incidence of gram-negative peritonitis may be attributed to the unique cultural habit of post-defecation perineal washing, with contamination of the hands with ablution water. This predisposes the patient to fecal contamination during spiking and disconnecting the system, further predisposing the patient to an increased incidence of gram-negative peritonitis. However, there is also a relative decrease in the incidence of gram-positive peritonitis compared to gram-negative due to increasing use of disconnect systems and improved skin care. REFERENCES Narayan Prasad 1 Amit Gupta 1, * Raj Kumar Sharma 1 Kashi Nath Prasad 2 Samjeev Gulati 1 Ajay Prakash Sharma 1 Department of Nephrology 1 Department of Microbiology 2 Sanjay Gandhi Post Graduate Institute of Medical Sciences Lucknow, India *email: amitgupt@sgpgi.ac.in 1. Fried LF, Bernardini J, Johnston JR, Piraino B. Peritonitis influences mortality in peritoneal dialysis patients. J Am Soc Nephrol 1996; 7:2176 82. 2. Korbet SM, Vonesh EF, Firanek CA. Peritonitis in an urban peritoneal dialysis program: an analysis of infecting pathogens. Am J Kidney Dis 1995; 26:47 53. 3. Bunke CM, Brier ME, Golper TA. Outcomes of single organism peritonitis in peritoneal dialysis: gram negatives versus gram positives in the Network 9 Peritonitis Study. Kidney Int 1997; 52:524 9. 4. Troidle L, Gorban Brennan N, Kliger LPN, Finkelstein F. Differing outcomes of gram-positive and gram-negative peritonitis. Am J Kidney Dis 1998; 32:623 8. 5. Zelenitsky S, Barns L, Findlay I, Alfa M, Ariano R, Fine A, et al. Analysis of microbiological trends in peritoneal dialysis-related peritonitis from 1991 to 1998. Am J Kidney Dis 2000; 36:1009 13. 6. Canadian CAPD Clinical Trials Group. Peritonitis in continuous peritoneal dialysis (CAPD): a multi-centre randomized clinical trial comparing the Y connector disinfectant system to standard systems. Perit Dial Int 1989; 9:159 63. 7. Holley JL, Bernardini J, Piraino B. Infecting organisms in continuous ambulatory peritoneal dialysis patients on the Y-set. Am J Kidney Dis 1994; 23:569 73. 8. Scheinburg FB, Seligman AM, Fine J. Transmural migration of intestinal bacteria: study based on the use of radioactive Escherichia coli. N Engl J Med 1950; 242:747 51. 402