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PD IN THE DEVELOPING WORLD |
Renal Department,1 Centro Hospitalar Conde de São Januário, Macao SAR; Department of Nephrology,2 Beijing Chaoyang Hospital, Capital University of Medical Science; Renal Division,3 Peking University First Hospital & Institute of Nephrology, Peking University, Beijing, China
Correspondence to: U.I. Kuok, Renal Department, Centro Hospitalar Conde de São Januário, Macao SAR, China. kuokuni{at}ssm.gov.mo
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ABSTRACT |
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 TOP ABSTRACT PERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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Objective: To evaluate the safety and efficacy of
inserting a straight-tip Tenckhoff catheter configured with a subcutaneous
artificial swan neck. Design: Clinical outcomes of conventional swan-neck
straight-tip catheters and Tenckhoff straight-tip catheters implanted with an
artificial subcutaneous swan neck were compared in a prospective randomized
controlled trial in a single-center setting. Patients and Methods: Patients undergoing peritoneal
dialysis catheter insertion were randomized to receive either a double-cuff
straight-tip Tenckhoff catheter with an artificial subcutaneous swan-neck (TC)
or a conventional double-cuff straight-tip swan-neck catheter (SN). The
primary outcome was catheter exit-site infection rate; the secondary outcomes
were catheter-related mechanical events and surgery-related bleeding. Results: A total of 39 consecutive patients were
enrolled: 20 into the TC group and 19 into the SN group. More exit-site
infections were observed in the SN group than in the TC group, although the
difference was not statistically significant (0.97 vs 0.51 episodes per
patient-year, p = 0.0657). However, there were more peritonitis
episodes in the TC group than in the SN group (0.35 vs 0.15 episodes per
patient-year, p = 0.0256). Exit-site and main wound bleeding post
surgery were generally mild and similar in the 2 groups. No events of
dialysate leakage, catheter tip migration, or subcutaneous cuff protrusion
were observed in patients of either group. Outflow failure due to mechanical
causes occurred in 2 patients in the TC group and in 1 patient in the SN group
during the intermittent peritoneal dialysis period; all were corrected
successfully by laparoscopic omentectomy. Conclusions: Placement of the double-cuff straight-tip
Tenckhoff catheter configured with an artificial subcutaneous swan neck
appears to be an effective and safe procedure. It may be a good alternative to
the conventional swan-neck catheter.
KEY WORDS: Peritoneal catheter; artificial swan neck; insertion; migration; exit-site infection.
The Macao Special Administrative Region (handed over to the People's Republic of China by Portugal on 20 December 1999) is located at the Pearl River Delta on the southeastern coast of Mainland China and is approximately 60 km southwest of Hong Kong (Figure 1). The territory, 29.2 km2 in area, consists of the Macao Peninsula, Taipa Island, and Coloane Island. The Macao Peninsula is connected to Taipa Island by three bridges and the two islands are connected by land reclamation. By the end of 2007, the population of Macao was 543 000. Macao has experienced a fast-growing economy over the past decade. The GDP per capita increased from US$14 649 in 1998 to US$36 357 in 2007. The weather in Macao is, in general, subtropical to temperate, with an average temperature of 23.1°C in 2006. It is humid and rainy in the spring and summer whereas, in the autumn and winter, relative humidity and rain-fall decrease.
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The Centro Hospitalar Conde de São Januário is the only hospital in the territory providing peritoneal dialysis (PD) service. This hospital is also responsible for more than 99% of the hemodialysis (HD) patients in the region. By the end of 2007, there were 398 patients on chronic dialysis treatment in Macao; 75 patients were alive with a functioning kidney transplant. The total prevalence rate in 2007 was therefore about 871 patients per million population. The approximate incidence of end-stage renal disease in Macao is 138 patients per million population. Of the 398 chronic dialysis patients, 158 are on PD. This number includes 22 on automated PD and 7 on combined HD and PD. The PD penetration rate in Macao is therefore about 40%.
The funding system for end-stage renal disease in Macao is a bit different from Hong Kong, where dialysis (mainly PD) is free for all patients although they need to pay a small amount for accessories and the extra cost of some medications. In Macao, dialysis (both PD and HD) is free for patients in the following categories: pregnant women receiving pre- and postnatal care, children under 10 years of age, students, teachers, individuals with or suspected of having infectious diseases, drug addicts, patients with psychiatric diseases, patients with malignant tumors, prisoners, government service and missionary employees, individuals in danger of or living in poverty, and individuals over 65 year of age. The Macao SAR government pays all expenses, including the costs of dialysis and medication. Those patients that do not belong to the above categories are evaluated for their financial status by the Social Department. Almost all these patients can get free dialysis treatment eventually, while a few might be required to pay for their medications by themselves. Very few patients (<1%) need to pay all expenses. Medical insurance is not popular in Macao. There is no PD-first policy in Macao but patients are advised to start with PD if there are no contraindications.
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PERITONEAL CATHETER STUDY |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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In recent years, a new approach has been explored in certain PD centers: an arcuate subcutaneous bend in the Tenckhoff catheter is created with either a tunneler or surgically (4,5,7). We have been using a similar method with certain modifications for peritoneal catheter implantation in Macao since 2002. It has been justified to be a good method to reduce ESI and catheter migration over the years, but no controlled study has been done. The current study was carried out to evaluate the method by comparing it to surgical implantation of swan-neck catheters.
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PATIENTS AND METHODS |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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Cefazolin 1 g was given intravenously for prophylaxis just before the operation. A nasal swab was taken before the antibiotic was administered. All patients showered and applied chlorhexidine to the proposed incision site on the evening prior to their surgery. All patients had repeat blood analysis before implantation. For those patients with low hemoglobin levels, blood transfusions were given to increase hemoglobin levels to 10 g/dL before the operation.
All catheter implantations were performed by the same group of 3 well-trained nephrologists using mini-laparotomy with a paramedian approach. Under local anesthesia, a primary 3 – 4 cm incision was made 1 – 2 cm from or just below umbilical level by dissecting the skin, subcutaneous tissue, rectus sheath, and muscle to expose the peritoneal membrane. A small opening was made in the peritoneum and the catheter was introduced into the opposite side of the pelvis using a semirigid blunt stylet. The peritoneum was then closed just below the level of the deep cuff using purse-string sutures; one more stitch was made on the deep cuff at 12 o'clock to allow tight fixation to the posterior rectus fascia/peritoneum. The deep cuff was buried in the rectus muscle and the anterior rectus fascia was closed using interrupted sutures in such a way to maintain cranial direction of the catheter. A second skin incision was made on the same side as the primary incision, approximately 1 – 2 cm laterally and 3 – 4 cm above the deep cuff. The catheter was brought out via the secondary incision with the assistance of a tunneler, then placed back via the same incision and directed caudally and parallel to the linea alba. A cutaneous exit was created by perforating the skin with a pointed tunneler. The exit site should be predetermined to allow approximately a 2-cm distance from the subcutaneous cuff. The intraperitoneal and subcutaneous/external segments of the TC were parallel and about 2 – 3 cm apart. The subcutaneous cuff was located on the same side of the cutaneous exit (Figure 2).
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The position of the catheter tip was checked by x-ray monitor during the operation and by abdominal x-ray immediately after implantation to ensure that it was in the pelvic cavity. Catheter function was tested for fill and drain with 20 mL normal saline immediately after closure of the peritoneum, and 500 – 1000 mL PD fluid after the catheter was pulled out via the exit site. Peritoneal membrane leakage was also checked and dealt with either by immediate surgical approach or by delayed commencement of intermittent peritoneal dialysis (IPD) after implantation.
Twice-weekly IPD (more frequent at the beginning for a patient who stating dialysis late with severe uremia syndrome) usually started immediately after implantation, except in those patients that were found to have peritoneal membrane leakage during the operation (usual delay was 1 – 2 weeks). Continuous ambulatory peritoneal dialysis (CAPD) training was conducted at about 6 weeks after catheter implantation.
During the IPD period, a nephrologist and/or a renal nurse inspected the catheter whenever the patient arrived for IPD. Exit-site swab for culture was taken every week. We treated methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas nasal carriers, even without symptoms or signs of infection. All acute infections and equivocal exit sites with positive cultures were treated. Pseudomonas infection was treated with two sensitive antibiotics for at least 21 days. All patients used chlorhexidine solution for exit-site care (8). Neither mupirocin nor gentamicin cream was applied to the nares or exit site as prophylactic treatment.
Patients were regularly seen by a renal nurse and/or nephrologists for inspection of their exit site and catheter function (every 4 – 8 weeks) thereafter during CAPD or continuous cycling PD. Acute ESI was defined as purulent or serous-like discharge with local pericatheter erythema and/or tenderness. A culture swab was taken from any exit-site discharge at each clinic follow-up. Outflow failure was defined as very poor drain and/or fill of PD fluid that made PD impossible to be carried out. Catheter tip migration was defined as x-ray documented change in catheter tip position from the pelvis to the abdominal cavity. It was usually accompanied by outflow failure that could not be resolved after rigorous catharsis using lactulose enemas and oral sorbitol over a 48-hour period. Peritonitis was defined as the presence of at least two of the following three conditions: symptoms and signs of peritoneal inflammation, cloudy peritoneal fluid with an elevated peritoneal fluid cell count, and demonstration of bacteria in the peritoneal effluent by Gram stain or culture.
The primary outcome was catheter ESI rate; secondary outcomes included peritonitis rate, catheter-related mechanical events, including catheter migration and outflow failure, and surgery-related bleeding. This study was not designed to detect a difference in these outcomes between the two groups. Patients were regularly followed for as long as possible after catheter implantation unless they withdrew from the PD program.
STATISTICAL ANALYSIS
Data are expressed as mean ± standard deviation unless otherwise
specified. Unpaired t-tests were used for between-group comparisons;
categorical variables were compared by chi-square analyses or Fisher's exact
test in the intent-to-treat population, as appropriate. The incidences of
infectious complications were compared using Poisson analysis. All statistical
tests were two sided and significance was defined as p < 0.05.
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RESULTS |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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The study was carried on until September 2007. Six patients in the TC group and 10 patients in the SN group withdrew from the study during the follow-up period (Figure 3). Total follow-up period was 31.8 patient-years for the TC group and 20.7 patient-years for the SN group.
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Exit-site infections occurred in 10 patients in the TC group and in 10 patients in the SN group (50% vs 52.6%, p = 0.869) (Table 2). More ESI episodes were observed in the SN group than in the TC group but this did not reach statistical significance (0.97 vs 0.51 episodes/patient-year, p = 0.0657). The two MRSA nasal carriers did not develop ESI later during the IPD and CAPD periods. One of them had 1 episode of peritonitis later during CAPD with good recovery, but PD fluid culture showed negative results. No tunnel infection was observed in either group.
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Six patients in the TC group developed peritonitis, compared with 3 patients in the SN group (incidence rate 30% vs 15.8%, p = 0.451). The number of peritonitis episodes was also higher in the TC group than in the SN group (0.35 vs 0.15 episodes/patient-year, p = 0.0256) (Table 2); however, this was due mainly to the fact that 1 female patient in the TC group had 5 episodes of peritonitis. She was later confirmed to have multiple colon diverticula and was switched to HD.
As for surgery-related bleeding, 9 patients in the SN group experienced wound bleeding, compared with only 5 patients in the TC group (p = 0.146); 13 patients in the SN group and 9 patients in the TC group experienced exitsite bleeding (p = 0.140). Most of the bleeding was mild. None of the patients in either group had severe bleeding (Table 3). Three patients developed outflow failure due to catheter problems (2 in the TC group and 1 in the SN group) during the IPD period (Table 3); all were successfully corrected by laparoscopic omentectomy.
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No catheter tip migration was observed in either group and no subcutaneous cuff protrusion was found in either group during the study period.
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DISCUSSION |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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The advantage of a downward exit site was realized long ago. In 1968, an arcuate tunnel that made both external segments and internal segments sit in a downward direction was proposed by Tenckhoff (7). However, there were concerns that the resilience force between the two cuffs of the straight Tenckhoff catheter might cause problems, such as catheter tip migration and outer cuff protrusion if a sharply arcuate subcutaneous bend was created. These concerns might be justifiable, as some studies did point out that catheter migration has occurred with Tenckhoff catheters with upward directed exit sites (1) and that, compared with SN, there have been more migrations of Tenckhoff catheters with even an obliquely downward exit site (4,5). Favazza et al. (7) used a semicircular tunneler to create a 180-degree subcutaneous arc bend in a straight Tenckhoff catheter, with the exit site directed vertically downwards. They reported similar ESI rates with this 180-degree bent Tenckhoff catheter and the conventional swan-neck catheter, but a higher migration rate than the swan-neck catheter. Moreover, in three cases from the above study, the arcuate tunnel straightened.
Modifications in implantation technique were made to overcome the adverse effects resulting from resilience forces in our study. The ascending and descending segments of the catheter were brought closer to each other and the subcutaneous cuff was located on the same side of the exit site. Therefore, a U-shaped catheter was created with two arms only 2 – 3 cm apart and with two cuffs residing in different arms. The stitch made on the deep cuff at 12 o'clock was imperative for tighter fixation of the catheter onto the posterior rectus fascia and maintaining the cranial direction.
All effort was made to minimize the resilience forces, keep the desired U-shaped configuration, and ultimately reduce ESI rate and prevent the catheter tip from migrating. The results of the current study indeed demonstrate that the practice is effective in preventing catheter tip migration. Savader et al. (9) showed that the majority (>50%) of radiology-confirmed catheter migrations occurred within 60 days of surgical placement and that 75% of these failures occurred within 270 days. No migration was observed in the study group for an average period of 16.2 months post-implantation in the current study.
The secondary incision was essential in facilitating the construction of a U-shaped subcutaneous tunnel during surgical implantation. More significant bleeding was anticipated with Tenckhoff catheters due to the extra incision. However, both wound and exit-site bleeding were actually less with TC than SN, and most of the bleeding was mild and could be controlled with dressing changes. This might be attributed to the fact that blunt dissection of subcutaneous tissue with a hemostat is more often required for creating the long subcutaneous tunnel for swan-neck catheter implantation.
Our definition of ESI was derived from CARI (Caring for Australasians with Renal Impairment) guidelines 2004 (10). The current study was conducted in Macao, which has the same warm and humid weather as Hong Kong. Isolated serous discharge along with local erythema is an important sign of ESI in this environment. The definition was employed to avoid any chance of underdiagnosis of ESI. The incidence of ESI in the study group (with the artificial swan neck) was lower than in the control conventional swan-neck catheter group, although it was not statistically significant (0.51 vs 0.97 episodes/patient-year, p = 0.0657). This might be attributed to the more flexible choice of exit site in the study group, which could be achieved by adjusting the position of the secondary incision according to the body figure of the individual patient. However, the result must be interpreted with caution as the smaller sample size of the current study yielded less power. Nevertheless, the ESI rate of 0.51 episodes per patient-year in the study group was a satisfactory achievement and was comparable with the ESI rate of 0.77 episodes/patient-year for swan-neck catheters reported previously in one Hong Kong study (6). To our surprise, the peritonitis rate was significantly higher in the TC group. However, 5 of the total of 11 peritonitis episodes in the TC group were attributed to one female patient who was later confirmed to have multiple colon diverticula and was switched to HD.
Much as we believe the placement procedure to be as good a method as the insertion of the swan-neck catheter, no such conclusion could be drawn from the current study, even with the prolonged follow-up period. The biggest limitation of our study was the small sample size. The current analysis would be considered likely to detect a 50% relative difference only 20% – 40% of the time. In order to declare equivalence of the two catheters, some 200 patients would be required to enroll for a statistical power of 80%. It was impractical to conduct such a trial in the setting of a single-center study due to the high dropout rate of the long-term PD patient. A multicenter study is suggested.
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CONCLUSION |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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DISCLOSURE |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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Received 27 January 2007; accepted 17 July 2008.
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REFERENCES |
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TOPABSTRACTPERITONEAL CATHETER STUDYPATIENTS AND METHODSRESULTSDISCUSSIONCONCLUSIONDISCLOSUREREFERENCES |
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This article has been cited by other articles:
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  P. K.-t. Li and K. M. Chow Importance of peritoneal dialysis catheter insertion by nephrologists: practice makes perfect Nephrol. Dial. Transplant., November 1, 2009; 24(11): 3274 - 3276. [Full Text] [PDF]
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