Long-term incidence of peritonitis in CAPD patients treated by the Y set technique: experience in a single center

The impact of the superficial cuff position on the exit site and tunnel infections in CAPD patients

BACKGROUND

Peritoneal dialysis (PD) related infections continue to be a major cause of morbidity and mortality in patients on PD. In the last ten years, in order to reduce cuff and exit-site infections, in continuous ambulatory peritoneal dialysis (CAPD) patients, we have positioned the superficial cuff subcutaneously 4 cm instead of 2 cm internal to the exit-site.

METHODS

We analysed the infective episodes occurred in 123 CAPD patients (88 men and 35 women, mean age 62.4 ± 16.8) treated for 3337 months between 1st January 2011 and 31th December 2018 at Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico.

RESULTS

31 of the 123 patients (25.2%) developed 52 episodes of exit site infection, with an incidence of 1 episode every 64.1 patient-months. The cumulative probability of remaining infection free was 80.7% at 12 months and 61.8% at 36 months. Gram-positive organism accounted for 78.7% of exit site infections. Forty-one episodes (87%) were successfully treated with medical therapy. Peritonitis incidence was 1 episode every 51.7 and 1 episode every 49.2 patient-months, in patients with or without a history of exit site infection respectively. The overall incidence of tunnel infection was 1 episode every 278.1 patient-months.

CONCLUSIONS

Positioning the superficial cuff subcutaneously at least 4 cm internal to the exit-site might prevent the bacterial cuff colonization and reduce ESIs, tunnel infections and peritonitis.

Continuous Ambulatory Peritoneal Dialysis Connection Systems

The history of the various connection systems proposed and tried during the first 15 years of clinlcal application of continuous ambulatory peritoneal dialysis (CAPD) is reviewed.

In order to understand the reasons for their success or lack of success, the main technical and operating characteristics regarding their efficacy In preventing peritonitis are examined in detail, together with a range of other pros and cons (I.e., reliability, simplicity, ease of use, cost, aesthetlcal aspects).

The result Is an updated state-of-the-art review In the field of CAPD connectology, with a look at future trends.

A Comparison of Peritoneal Dialysis-Related Infections in Short and Long Term Peritoneal Dialysis Patients

Objective

We hypothesized that the infection rates and organisms would differ in long-term peritoneal dialysis (PD) patients versus those who died or transferred to hemodialysis during the first 4 years on PD.

Design

Data on PD-related infections and outcome were collected from 1979 to 1991 (prospectively since 1982).

Setting

The patients were followed at University and Veterans Administration dialysis centers.

Patients

All patients on continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD) for 4 years or more (n=43) were compared to those patients who died or transferred to hemodialysis prior to 4 years on PD (n=213).

Main Outcome Measures

Infection rates due to various microorganisms and reasons for transfer to hemodialysis were examined.

Results

Peritonitis rates were 1.2/year versus 0.8/year (p<0.001) in patients on peritoneal dialysis less than 4 years compared to those on 4 years or more, respectively, a difference due to S. epidermidis (0.32/year vs 0.20/year, p=0.0001) and gram-negative rods other than P. aeruginosa (0.15/year versus 0.06/year, p<0.001). Exitsite infection rates were 1.2/year versuss 0.7 /y (p<0.0001) in the patients on less than 4 years compared to those on 4 years or more, respectively, a difference in part due to S. aureus (0.45/year vs 0.3/year, p<0.001) and other gram positive organisms (0.28/year vs 0.1 0/year, p<0.001). The rates of infections that were similar in the two groups were tunnel infections (0.2/year), P. aeruginosa infections, and S. aureus peritonitis (0.18/year vs 0.14/year, p=0.09). S. aureus was the most common cause of exit-site and tunnel infections in both groups. Forty-two percent of the patients on PD 4 years or more subsequently transferred to hemodialysis, most often due to infections, especially S. aureus.

Conclusions

Although infection rates are lower in patients on peritoneal dialysis 4 years or more, S. aureus and P. aeruginosa continue to account for a high proportion of the infections. Improvement in technique survival will require prevention of these infections.

A Prospective Randomized Study of the Effect of a Subcutaneously “Buried” Peritoneal Dialysis Catheter Technique versus Standard Technique on the Incidence of Peritonitis and Exit-Site Infection

♦ Objective

A new method for implantation of peritoneal dialysis (PD) catheters was described in 1991. The distal part of the catheter is buried subcutaneously and exteriorized at the start of PD. This study was designed to evaluate the effect of such a subcutaneous rest period on the incidence of peritonitis and exit-site infections (ESI).

♦ Design

Sixty patients were randomized to either the new method (B group; n = 30) or to not having the distal part buried subcutaneously (NB group; n = 30). Sixty-five patients (NS group) were not randomized as they had to start PD within 1 – 2 weeks after implantation. The Moncrief–Popovich catheter was used in the B and NB groups and a standard Tenckhoff catheter was used in the NS group.

♦ Patients

Patients scheduled for PD treatment, judged not in need of PD for at least 6 weeks after implantation.

♦ Results

There was no statistically significant difference in the cumulative probability of not developing peritonitis during the first 6, 12, and 24 months. The incidence of the first episode of peritonitis was 1/40, 1/26, and 1/33 treatment-months in the B, NB, and NS groups, respectively. The incidence of ESI was 1/103 and 1/95 treatment-months in the B and NS groups, respectively. The cumulative probability of not developing ESI was similar in both groups. There were no episodes of ESI in the NB group. The difference in the number of ESI between the NB and NS groups was significant ( p < 0.05).

♦ Conclusions

Subcutaneous burying of the distal catheter segment prior to starting PD does not reduce the risk of contracting peritonitis or exit-site infection.

Bacteria on catheters in patients undergoing peritoneal dialysis

BACKGROUND

Peritonitis is the leading cause of morbidity for peritoneal dialysis (PD) patients, and microbial biofilms have previously been identified on catheters from infected patients. However, few studies of catheters from patients without clinical signs of infection have been undertaken. The aim of the present study was to investigate the extent to which bacteria are present on catheters from PD patients with no symptoms of infection.

METHODS

Microbiologic culturing under aerobic and anaerobic conditions and confocal laser scanning microscopy were used to determine the distribution of bacteria on PD catheters from 15 patients without clinical signs of infection and on catheters from 2 infected patients. The 16S rRNA gene sequencing technique was used to identify cultured bacteria.

RESULTS

Bacteria were detected on 12 of the 15 catheters from patients without signs of infection and on the 2 catheters from infected patients. Single-species and mixed-microbial communities containing up to 5 species were present on both the inside and the outside along the whole length of the colonized catheters. The bacterial species most commonly found were the skin commensals Staphylococcus epidermidis and Propionibacterium acnes, followed by S. warneri and S. lugdunensis. The strains of these micro-organisms, particularly those of S. epidermidis, varied in phenotype with respect to their tolerance of the major classes of antibiotics.

CONCLUSIONS

Bacteria were common on catheters from patients without symptoms of infection. Up to 4 different bacterial species were found in close association and may represent a risk factor for the future development of peritonitis in patients hosting such micro-organisms.

Development and treatment of peritonitis in continuous ambulatory peritoneal dialysis

The main complication of continuous ambulatory peritoneal dialysis is peritonitis. This paper reviews its causes and treatment.

Comparison of double-bag and Y-set disconnect systems in continuous ambulatory peritoneal dialysis: a randomized prospective multicenter study

We performed a multicenter, single-blinded, prospective randomized study on the use of a double-bag disconnect system (B) versus a Y-set disconnect system (Y). The peritonitis rate, exit site infection, clinical outcome, and patients' acceptance to the procedure were assessed. A total of 120 new end-stage renal failure patients of three regional hospitals were randomized: 60 each to the B and the Y systems. The results of 60 patients on the B system and 51 on the Y system were analyzable. They were followed up for a median of 16 months. Peritonitis rates for the B and the Y systems were 33.5 and 29.4 patient-months per episode, respectively. Exit site infection rates for the B and Y systems were 17.4 and 16.0 patient-months per episode, respectively. Four catheters were removed in each group. Patients on the B system were hospitalized for 2.1 days per patient per year related to peritonitis and exit site infection, and those on the Y system were hospitalized for 1.2 days. There was no significant difference between the B and Y systems in the incidences of peritonitis (all causes and those due to coagulase-negative staphylococci), exit site infection, and in hospitalization days. However, there was a higher percentage of gram-positive infections in the Y system (52%) than in the B system (32%) and a lower percentage of gram-negative infections in the Y system (16%) than in the B system (32%). Patients on the B system had a better acceptance of the procedure than patients on the Y system, as assessed by a six-item, 10-point questionnaire (total score, 43.1 +/- 10.2 v 37.6 +/- 9.4; P < 0.005 at 1 month; 44.6 +/- 9.1 v 39.8 +/- 8.6; P < 0.01 at 6 months). From this study, it is concluded that the B and Y systems are similar in the incidences of peritonitis and exit site infection, although the B system is better accepted by patients. This is probably the first multicenter randomized study comparing the double-bag and Y-set disconnect system using only new patients who had never used other systems of continuous ambulatory peritoneal dialysis.

Race and the risk of peritonitis: an analysis of factors associated with the initial episode

To study how clinical characteristics influence the risk of peritonitis in African American patients with end-stage renal disease treated with continuous ambulatory peritoneal dialysis (CAPD), we examined the risk of developing a first episode of peritonitis among 1,595 new dialysis patients initially treated by CAPD over a two year period in North Carolina, South Carolina, and Georgia (Network 6). Characteristics examined were demographic and socioeconomic factors, functional status, serum albumin and comorbid conditions. There were 538 initial episodes of peritonitis during an average of 8.8 patient months of follow-up; the time to peritonitis for the entire cohort was 26 months. Factors found to be independently associated with a risk for peritonitis were student status (Odds Ratio and 95% Confidence Interval = 2.4; 1.4 to 4.3), rental housing (1.2; 1.0 to 1.5), and substance abuse (1.9; 1.1 to 3.2). African Americans were 60% more likely to have an initial episode of peritonitis during follow-up than whites (1.6; 1.3 to 1.8). The time to the initial episode was 21 months for African Americans versus 32 months for whites (P < 0.001). Even after adjusting for other factors, African Americans were significantly more likely to develop peritonitis (1.5; 1.2 to 1.8). Thus, the increased risk of peritonitis of African American patients treated by CAPD is independent of other demographic, socioeconomic and comorbid characteristics.

Peritonitis rates in CAPD patients using the UVXD and O-set systems

We report experience with O-set and UVXD systems. Sixty-nine O-set patients (34 male; mean age +/- SD = 45.7 +/- 13.2 years) were compared with 54 UVXD patients (27 male; 56.8 +/- 16.8 years). Total (mean +/- SD) experience were 974 (14.1 +/- 10.8) months on O-set and 1010.9 (18.7 +/- 15.7) months on UVXD. Thirty-two O-set patients avoided peritonitis; 37 had 91 episodes. Seventeen UVXD patients avoided peritonitis; 37 had 137 episodes. Peritonitis occurred each 10.7 months (O-set) versus 7.4 months (UVXD), which was significantly different (p = 0.032, Z test; 95% confidence interval = -0.142 to +0.226). There were 18 relapses in 9 O-set patients, 34 in 12 UVXD. Gram-positive organisms caused 58.2% and 66%; gram-negative, 13.2% and 8.8%; and culture negative, 24.2% and 23.4% of peritonitis in O-set and UVXD, respectively. The time to first peritonitis was not different, 7.4 +/- 6.6 months O-set and 7.2 +/- 7.9 months (UVXD). There was no difference in the peritonitis-free period, 13.0 +/- 10.0 months (O-set) and 16.5 +/- 14.3 months (UVXD). There were 1.12 (O-set) and 16.1 (UVXD) cases per patient year, and 10.7 (O-set) and 7.43 (UVXD) patient months per episode. The peritonitis rate odds ratio was 1:1.85 (O-set:UVXD).

Exit-site and tunnel infections in continuous ambulatory peritoneal dialysis patients

One hundred two exit-site infections (ESI) were diagnosed in 63 of 163 (38.6%) patients, with an incidence of one episode every 23.7 patient-months in patients with a history of ESI, whereas in the overall continuous ambulatory peritoneal dialysis (CAPD) population the incidence was one episode every 48.7 patient-months. In diminishing order of frequency, the bacteria isolated were Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. The probability of remaining free of ESI was 72% at 1 year and 45% at 5 years. The ESI that led to catheter removal were due to S aureus and gram-negative rods. In 13 (48%) of 27 S aureus ESI unresponsive to antibiotics and local care, deroofing and outer cuff shaving completely resolved the ESI. Despite this treatment, the catheters of the remaining 14 patients had to be removed because of peritonitis associated with the tunnel infection. In conclusion, ESI is a major cause of CAPD failure. In our series, shaving the cuff as a rescue treatment was effective for almost 50% of the patients with antibiotic-resistant S aureus ESI.