Prospective controlled trial of a Y-connector and disinfectant to prevent peritonitis in continuous ambulatory peritoneal dialysis

Interferon-gamma levels in peritoneal dialysis effluents: relation to peritonitis

As peritoneal macrophages require Interferon-gamma (IFN-gamma) for bacterial lysis, IFN-gamma levels were measured in peritoneal dialysis effluents. (PDE) by a specific radioimmunoassay. High IFN-gamma levels were found in patients with peritonitis compared to low levels in patients without peritonitis (mean 9.73 +/- 2.63 SE U/ml, N = 39 vs. 0.25 +/- 0.04, N = 32). IFN-gamma levels varied among different bacteria: Staph. aureus (highest: 23.4 +/- 5.7, N = 14), Staph. epidermidis (lower: 3.2 +/- 0.8, N = 13), other gram-positive (1.06 +/- 0.32, N = 6), gram-negative bacteria (lowest: 0.57 +/- 0.30, N = 6). After treatment of peritonitis levels decreased. In corresponding blood and PDE samples, by comparing IFN-gamma levels in 10 peritoneal dialysis patients (5 with peritonitis, 5 without), levels were raised only in PDE of patients with peritonitis, implying local IFN-gamma production. Total lymphocytes, T, B and monocyte subsets in patients' plasma and PDE did not differ, except for a higher number of mononuclear cells in PDE of patients with peritonitis (P < 0.05). Further investigation of in vitro IFN-gamma production in PDE with peritoneal monocytes, syngeneic host lymphocytes, and bacteria showed that Staph. aureus induced the highest levels of IFN-gamma and E. coli the lowest, in experiments with T cell enriched host lymphocytic fractions. We conclude that Staph. aureus peritonitis induces high levels of IFN-gamma in PDE, possibly by a T cell dependent superantigen response.

The influence of continuous ambulatory peritoneal dialysis connection technique on peritonitis rate and technique survival

Peritonitis is still the most common complication of continuous ambulatory peritoneal dialysis (CAPD). Several measures have been used to prevent peritonitis, including prophylactic antibiotics and a variety of connection techniques. This study was designed to evaluate the effects of different connection techniques, age at the start of CAPD, sex, and diabetic status on peritonitis rate and technique survival. Three hundred twenty-seven patients treated with CAPD and followed for 8,804.4 patient-months at the Vancouver General Hospital between February 13, 1978, and August 31, 1992, were reviewed. The mean age of the patients was 57.1 +/- 16.3 years. The overall peritonitis rate was 16.6 patient-months per episode. The overall technique survival was 79.6%, 60.2%, and 41.8%, at 1, 2, and 3 years, respectively. Patients using "standard" spike technique (group A, n = 87), Luer lock connector (group B, n = 77), and Luer lock with iodine instillation at the dialysis bag connection site (group C, n = 120) had peritonitis rates of 10.4, 14.7, and 33.3 patient-months per episode, respectively. The relative risk (RR) of peritonitis was 3.5 for group A (95% confidence interval, 2.1 to 4.5) and 2.6 for group B (95% confidence interval, 1.7 to 3.9) compared with group C. Patient age at the start of CAPD, sex, and diabetic status had no effect on the RR of peritonitis. None of the variables studied, except patient age, affected technique survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Infecting organisms in continuous ambulatory peritoneal dialysis patients on the Y-set

Disconnect systems for performing continuous ambulatory peritoneal dialysis (CAPD) use a flush-before-fill technique that should theoretically reduce the peritonitis caused by touch contamination. However, little information about the infecting organisms in CAPD-related infections using disconnect systems is available. We performed a retrospective matched-case controlled study to define the organisms responsible for the peritonitis and catheter infections seen in CAPD patients using the Y-set without disinfectant. One hundred nineteen patients who began CAPD on the Y-set were matched with 119 patients who began CAPD on the standard spike system. Patients were matched for age, sex, race, insulin dependence, and time on CAPD. Infection data were prospectively collected for all patients. Peritonitis, exit site, and tunnel infection rates (expressed as number of episodes per patient-year) were all significantly lower in the Y-set patients (0.56 v 0.94, 0.68 v 1.08, and 0.14 v 0.22, respectively). The lower peritonitis rate in the Y-set patients compared with that found in the standard spike system patients was due to a reduction in Staphylococcus epidermidis (0.17 v 0.26, P = 0.02), polymicrobial (0.014 v 0.06, P = 0.01), other gram-positive (0.007 v 0.09, P = 0.001), and sterile (0.10 v 0.19, P = 0.008) peritonitis. Rates of Staphylococcus aureus and gram-negative peritonitis were not different among the two groups. S epidermidis (0.12 v 0.23, P = 0.0014) and gram-negative (0.12 v 0.18, P = 0.04) exit site infection rates were also lower in the Y-set patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of ultrasound-assisted diagnosis of tunnel infections in continuous ambulatory peritoneal dialysis

The management of catheter-related infections has become a major challenge in continuous ambulatory peritoneal dialysis treatment. Early recognition and discrimination of mere exit site infections from more invasive and catheter menacing tunnel infections (TIs) are of therapeutic importance. As the diagnosis of TI is still based on clinical signs and only indicates advanced infections, we studied the usefulness of the ultrasound examination (UE) of the continuous ambulatory peritoneal dialysis catheter. Examinations were made by a mobile ultrasound unit using a 7.5 MHz transducer. Sixty-two continuous ambulatory peritoneal dialysis patients with an Oreopoulos Zellermann catheter (Oreopoulos-Zellerman Cathete-THWII, Baxter GmbH, Unterschleissheim, Germany) were studied repeatedly between February 1991 and July 1992. Pericatheter fluid collection (with typical sonographic localization) was consistent with surgical findings and histopathologic examination and proved to be a reliable criterion of TIs. The incidence of TIs was significantly higher when using UE (0.35/patient-year) compared with the usual clinical criteria (0.12/patient-year, P < 0.01). Staphylococcus aureus exit site infections were predominant and had the highest risk of concomitant TIs (83%). Eleven of 25 patients with a positive UE lost their catheter due to infectious complications, while no patient with a negative UE underwent operation for infectious reasons (P < 0.01). The peritonitis rate (0.64/patient-year) was markedly increased when UE indicated a TI (1.7/patient-year, P < 0.01). We conclude that sonography is a sensitive tool for the early diagnosis of unsuspected TIs. Sonography is a bedside method used for screening purposes and allows us to control the treatment regimen.

Controlled trial of a Y-set dialysis delivery system to prevent peritonitis in patients receiving continuous ambulatory peritoneal dialysis

Peritonitis rates were compared in patients receiving continuous ambulatory peritoneal dialysis (CAPD) via either a Y-set dialysate delivery system or a standard system. Forty patients in each arm of the trial were matched for age (range 20-67 years, mean 49 years), and remained in the study for similar periods (range 3-36 months, mean 14.1 months). The observation time was 564 patient-months for each arm of the trial. There were 22 episodes of peritonitis in nine out of 40 patients using the Y-set and 57 episodes in 21 out of 40 patients using the standard system (P = 0.005 Wilcoxon signed rank test for episodes, P = 0.02 McNemar's chi 2 test for patients). Peritonitis rates were one episode per 25 patient-months in the Y-set group, and one episode per 9.7 patient-months in the standard group. In the Y-set group there were significantly fewer episodes caused by coagulase-negative staphylococci and Acinetobacter spp. There was no difference in the rate of episodes caused by Staphylococcus aureus, streptococci, enterococci, corynebacteria, enterobacteria or pseudomonads. There was no difference in the incidence of catheter exit wound infections. The Y-set dialysis delivery system is effective in reducing peritonitis rates in CAPD patients caused by organisms derived from the commensal skin flora, principally coagulase-negative staphylococci, but does not reduce peritonitis caused by other organisms.

Peritonitis in continuous ambulatory peritoneal dialysis: impact of a compulsory switch from a standard to a Y-connector system in a single North American Center

One hundred one continuous ambulatory peritoneal dialysis (CAPD) patients from a single North American center were analyzed in a retrospective and cross-over study for peritonitis rates using a standard system (Travenol System II) or a Y-shaped disconnect-disinfectant system (Travenol O-set). Twenty-one of 34 patients using the standard set (group I) had 53 episodes of peritonitis in 508 patient-months or one episode per 9.6 patient-months. Nine of 17 patients switching from the standard to the disconnect-disinfectant system (group II) experienced 22 episodes of peritonitis in 275 patient-months or one episode per 12.5 patient-months on the standard set, while six patients had 10 episodes of peritonitis in 275 patient-months or one episode per 27.5 patient-months on the disconnect-disinfectant system (P less than 0.04). Twenty-eight of 67 new CAPD patients starting on the disconnect-disinfectant system (group III) had 37 episodes of peritonitis in 1,086 patient-months or one episode per 29.4 patient-months (P less than 0.01 v group I). Exit-site infections (ESI) occurred in 35.3% of patients using the standard set versus 34.3% of those using the O-set. The presence of an ESI was not associated with a higher risk of peritonitis, but modified the bacteriological profile of subsequent peritonitis episodes in patients using the O-set, favoring the organisms isolated from the exit site. Decreases in peritonitis rates with the O-set were due to a reduction of peritonitis episodes secondary to most bacterial agents and not only to skin organisms. Diabetics using intraperitoneal insulin had similar peritonitis and ESI rates as nondiabetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Infectious consequences of continuous ambulatory peritoneal dialysis

The peritoneal cavity of patients undergoing CAPD is critically immunocompromised and infectious peritonitis is the most important complication of the technique. Nevertheless, recent research into the epidemiology and pathogenesis of infections caused by the most important microorganisms has enabled significant reductions in peritonitis rates to be made. Peritonitis caused by Staphylococcus aureus and Pseudomonas aeruginosa can be prevented by eliminating their principal source, an infected Tenckhoff catheter wound. The source of infection for coagulase-negative staphylococci and other pseudomonads cannot be eliminated, but peritonitis caused by these organisms may be prevented by interrupting their routes of entry into the peritoneal cavity. The identification of host factors predictive of enhanced susceptibility to infectious peritonitis offers the further possibility of prevention by immunological approaches. Although the main difficulties surrounding the diagnosis of infective peritonitis have been clarified, approximately 20% of episodes remain culture-negative, with multifactorial aetiology. Initial (empirical) combination antibiotic therapy can be both appropriate and effective in approximately 85% of cases. Intraperitoneal monotherapy with fluoroquinolones has been equally successful, and these agents may prove effective by the oral route, offering considerable advantages in cost and convenience. Approximately 5% of episodes of bacterial peritonitis are unresponsive to antibiotic therapy. These cases may be conveniently managed by the technique of Tenckhoff catheter removal and replacement at a single operation.

Recurrent CAPD peritonitis caused by coagulase-negative staphylococci: re-infection or relapse determined by clinical criteria and typing methods

Four hundred consecutive episodes of continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis in 105 patients were analysed. Of these episodes 161 (40.25%) were caused by coagulase-negative staphylococci (CNS). Thirty-seven patients developed recurrent attacks (3-10) of peritonitis and CNS accounted for 72 (60%) of these episodes. Classification of reinfection or relapse in 67 of these recurrent episodes of peritonitis was based on clinical criteria alone. This was compared with the results of three typing methods of CNS strains: biotyping plus antibiograms, immunoblotting and 35S-methionine-labelled protein patterns (radio-PAGE). Radio-PAGE was the most discriminatory method followed by biotyping with antibiograms and then immunoblotting. There was total agreement between clinical diagnosis and the three typing methods in 67.2% of episodes but there was total disagreement between the clinical diagnosis and the three typing methods in 11.9%, suggesting inaccurate clinical diagnosis, and in 20.8% typing by at least one method differed from the clinical criteria. Thus, clinical criteria alone are inadequate for the accurate distinction of reinfection from relapse in recurrent CNS peritonitis. This distinction is desirable for optimal management and accurate assessment of different therapies. We suggest that CNS strains from peritoneal dialysate are stored for future typing should the patient develop repeated episodes of peritonitis, to aid in the diagnosis and management of such patients.

Ten years' experience with continuous ambulatory peritoneal dialysis

Up to January 1989, 171 patients were trained at our center on continuous ambulatory peritoneal dialysis (CAPD), and 17 on continuous cyclic peritoneal dialysis (CCPD). Over 10 years, we have gained 5,068 patient-months experience. Patient survival was 60% and 31% at 5 and 10 years, respectively. In contrast, diabetics had a survival of 32% at 5 years. Major complications included 499 new episodes of peritonitis, 304 exit-site infections, 22 hernias, five bowel perforations, one hydrothorax, and three episodes of sclerosing encapsulating peritonitis. Our technique survival has been 62% and 40% at 5 and 10 years, respectively. We believe that CAPD is a viable dialysis technique for long-term treatment of chronic renal failure and it should be offered as an option to intermittent hemodialysis.

The role of continuous ambulatory peritoneal dialysis in end-stage renal failure due to multiple myeloma

A study in 10 patients (eight male, two female; mean age 61.9 +/- 10.7 years) suffering from multiple myeloma (MM) and end-stage renal failure (ESRF) is detailed. Continuous ambulatory peritoneal dialysis (CAPD) was the preferred mode of chronic dialysis in all the patients. Survival after diagnosis was 32.2 +/- 23.9 months. Survival after starting dialysis was 24.6 +/- 20.6 months. All patients on CAPD were adequately dialyzed and in good fluid control. Peritonitis was the main problem on CAPD (one episode per 5.6 patient-months). The majority of peritonitis episodes responded to intraperitoneal antibiotic therapy. One patient with Staphylococcus aureus peritonitis, septicemia, and neutropenia secondary to chemotherapy, died. Recommendations for prophylaxis and treatment of peritonitis are given. Three patients were transferred to hemodialysis. The use of subclavian vein catheters during hemodialysis was associated with a high incidence of gram-positive septicemia. Alkylating agent-based chemotherapy resulted in hematological responses in five patients. Survival after diagnosis in those responders was 47.4 +/- 25.6 months, compared with 17.0 +/- 7.2 months in the nonresponders (P less than 0.05). All responders subsequently relapsed. Four patients died with progressive myeloma. Bone marrow suppression resulted in a high blood transfusion requirement, neutropenia, and thrombocytopenia associated with bleeding into the gastrointestinal tract and central nervous system. Uremic myeloma patients can be adequately dialyzed using CAPD. Those patients who do not have an initial hematological response have a poor prognosis.

CAPD peritonitis. Incidence, pathogens, diagnosis, and management

Peritonitis is a frequent complication of CAPD. Sixty percent of all patients on CAPD will have at least one episode of peritonitis during the first year of this mode of dialysis. Most of the episodes of peritonitis are caused by touch contamination of the dialysis tubing or by extension of the catheter exit site or tunnel infection. Coagulase-negative and coagulase-positive Staphylococcus are the two most common organisms, accounting for 50% or more of all CAPD peritonitis. Other gram-positive and gram-negative bacteria and fungi account for the rest. Intraperitoneal antibiotic treatments are usually effective in eradicating the infection. The choice of antibiotics depends on organisms isolated from cultured dialysate. Fungal peritonitis and, occasionally, Pseudomonas peritonitis require removal of the catheter to eradicate the infection. Prompt identification and treatment of peritonitis are essential to ensure success of a CAPD program. Although with newer techniques, like Y-connector or ultraviolet light system, the rate of peritonitis has declined; however, it has still remained the major complication of the CAPD program.

Long-term Increase in Peritoneal Membrane Transport Rates following Incidental Intraperitoneal Sodium Hypochlorite Infusion

A patient on continuous ambulatory peritoneal dialysis using an “O” set connection system with sodium hypochlorite as a disinfectant incidentally infused the disinfectant intraperitoneally on two occasions. The product of peritoneal membrane permeability and peritoneal membrane surface area increased after both infusions as judged by peritoneal equilibration test results and/or serum chemistries. Elevated peritoneal solute transport rates and reduced ultrafiltration gradually subsided but did not return to preinfusion values. This observation suggests that intraperitoneal sodium hypochlorite infusion may cause significant long-term alteration in peritoneal membrane transport characteristics.

Timing and characteristics of multiple peritonitis episodes: a report of the National CAPD Registry

Patterns of recurrent peritonitis episodes were examined in 6,335 new continuous ambulatory peritoneal dialysis (CAPD) patients entered into the National CAPD Registry. Forty-six percent of all peritonitis episodes were initial occurrences, with 8% of the patients reporting four or more episodes. The proportion of gram-positive and gram-negative infections was constant across episodes. In patients with multiple infections, negative organisms were found to have increased risk of recurring as gram-negative infection. A similar observation was made for fungal infections. Of patients with multiple peritonitis episodes, more than 40% of those who transferred to other maintenance renal replacement therapy identified peritonitis as the reason for transfer. A discrete time logistic model was used to estimate peritonitis risk in 4-month follow-up periods. Patients like those on the registry are estimated to have a 22% risk of developing peritonitis during any 4-month period. This risk was increased 4% for patients aged less than 21 years, 7% for nonwhite patients, and 19% in the period following a peritoneal infection.

A six-year comparison of patient and technique survivals in CAPD and HD

Comparisons of patient and technique survival were made for 120 CAPD and 139 HD patients undergoing dialysis between January 1981 and December 1986. Cox's proportional hazard regression model was used to compare patient and technique survival, with an adjustment for pre-treatment prognostic differences. Only the patients' first treatments were considered. The CAPD patients were 10 years older, on the average, than the HD patients and had more complicated conditions (58% with 3 or more co-existing risk factors vs. 35%). Overall patient survival between CAPD and HD did not differ (P = 0.2694). However, when adjusted for patient age, sex and other comorbid complicating conditions, CAPD patients over the age of 66 had a significantly lower risk of death than their HD counterparts (P less than 0.05). There were no differences in the adjusted patient survival for patients aged 30 to 66. Four pre-treatment prognostic factors had statistically significant adverse effects on patient survival: age, diabetes, malignancy and peripheral vascular disease. Survival of the HD technique, when unadjusted, was better than survival of CAPD (P = 0.0457). Even after adjustment for sex and age, this difference was still very nearly significant (P = 0.0656). No risk factors were found to be significantly associated with technique survival. Based on patient and technique survival, CAPD would appear to be an excellent alternative to HD and may be the preferred treatment for high risk patients over the age of 66.

Current concepts. Continuous ambulatory peritoneal dialysis

As a long-term dialysis therapy, CAPD has attractive features for use in children (in whom access to the circulation and immobility are often problems), adults in whom blood access is difficult, patients with diabetes, patients prone to hypotension, and patients seeking independence from a machine or medical facility. CAPD and related procedures are still evolving and improving. Efforts to reduce the rates of peritonitis are ongoing and should decrease the rates of treatment dropout and increase the use of this alternative method of dialysis. Continued research toward improvements in catheter configuration and connection devices and the tailoring of technique to meet the particular needs of patients have made peritoneal dialysis an acceptable replacement therapy in patients with end-stage renal disease. Neither peritoneal dialysis nor hemodialysis is the superior long-term dialysis therapy for all patients; the choice depends on numerous medical, social, geographic, and life-style considerations.

Dialysis fluids and local host resistance in patients on continuous ambulatory peritoneal dialysis

The ability of polymorphonuclear leukocytes, monocytes and peritoneal macrophages to mount a respiratory burst in continuous ambulatory peritoneal dialysis (CAPD) fluids was tested in a phorbol-myristate acetate stimulated chemiluminescence assay. Fresh CAPD fluids depressed the chemiluminescence response of all three types of phagocytes tested to less than 18% of their chemiluminescence response in control buffer. When tested in spent CAPD fluids the suppression of chemiluminescence was 30-32%. Oxygen consumption of polymorphonuclear leukocytes was depressed in fresh CAPD fluids to below 40%. Both phagocytosis of Escherichia coli by and bactericidal capacity of polymorphonuclear leukocytes and monocytes were suppressed in fresh CAPD fluids but not in spent effluents. The influence of acidic pH and hyperosmolality on phagocytic functions were studied separately by modifying the acidity or the glucose content of the control buffer. pH values below 6.0 significantly inhibited chemiluminescence but not phagocytosis. Under hypertonic conditions, both phagocytosis and chemiluminescence were inhibited. We conclude that the currently available CAPD solutions are beyond the limits of acid and osmotic tolerance of human phagocytic cells, and may thus compromise the peritoneal defenses of CAPD patients.

Outcome in patients on continuous ambulatory peritoneal dialysis and haemodialysis: 4-year analysis of a prospective multicentre study

In a study in seven large renal units in England, the morbidity and mortality of all patients starting continuous ambulatory peritoneal dialysis (CAPD) and haemodialysis during 1983-85 were monitored prospectively over a 4-year period and related to reasons for choice of therapy and potential risk factors. 610 new patients (median age 52 years, range 3-80 years) started CAPD; 16% had diabetes mellitus and 21% cerebrovascular or cardiovascular disease. 329 patients (median age 48 years, range 5-77 years) started haemodialysis; 7% had diabetes mellitus and 17% cerebrovascular or cardiovascular disease. The Kaplan-Meier patient survival estimates at 4 years were 74% for haemodialysis and 62% for CAPD; technique survival figures for the same period were 91% for haemodialysis and 61% for CAPD. Cox's proportional hazards regression analysis showed that cerebrovascular/cardiovascular disease, age over 60 years, and diabetes mellitus were important predictors for survival in CAPD patients; there were no risk factors associated with permanent change to haemodialysis. In the haemodialysis group early change to CAPD was associated with presence of cerebrovascular or cardiovascular disease. The major cause of drop-out in both groups was transplantation. The mean length of hospital admission was 14.8 days per patient-year for CAPD and 12.4 days per patient-year for haemodialysis.

In vitro antibacterial activities of antibiotics against Pseudomonas aeruginosa in peritoneal dialysis fluid

Intraperitoneal antibiotics are used to treat Pseudomonas aeruginosa peritonitis, a serious complication of continuous ambulatory peritoneal dialysis. However, P. aeruginosa killing is often inefficient despite low MBCs. Broth dilution MIC/MBC and time kill curves of tobramycin, amikacin, netilmicin, azlocillin, piperacillin, ceftazidime, cefsulodin, and ciprofloxacin were determined in peritoneal dialysis fluid (PDF), buffered PDF, fluid recovered from patients on continuous ambulatory peritoneal dialysis (RPF), and cation-supplemented Mueller-Hinton broth. MBCs of all antibiotics were 8 to 16 times greater in PDF and RPF than in Mueller-Hinton broth or buffered PDF. Use of the time kill curve technique and Mueller-Hinton broth showed that aminoglycosides killed greater than or equal to 99.9% of P. aeruginosa at 1 h, ciprofloxacin killed greater than or equal to 99.9% at 2 h, and beta-lactams killed greater than or equal to 99.9% at 6 h. In contrast, killing was not demonstrated in PDF by any drug at 6 h and by aminoglycosides only at 24 h. Bactericidal activity was optimal in RPF for ciprofloxacin at 1 h and for aminoglycosides at 2 h; bactericidal activity was not demonstrated in RPF with any beta-lactam (no kill by penicillins; less than 99% kill by cephalosporins). Slow bacterial growth, increased protein binding, and glucose concentrations and other inhibitors may interfere with beta-lactam activity in RPF. These considerations and reported clinical failures and toxicity of aminoglycoside therapy warrant further study of quinolones and drug combinations in P. aeruginosa peritonitis.

Problems of CAPD: Progress of the 4 years’ experience

Results of four years’ experience of CAPD in our Centre are reported. The incidence of peritonitis in 13 patients dropped with the use of Y-set from 1/4 patient-months to 1/26 p-m).

As experience was gained we reduced the use of hypertonic bags and improved diet suggestions. By these interventions during the past year, we obtained a good control of triglycerides and cholesterol concentration and a reduction in weight gain.