| Abstract|| |
The adequacy of peritoneal dialysis is generally dependant on the choice of peritoneal fluid, the intraperitoneal fill volume and the contact time. Moreover, the peritoneal surface area acts as a major factor in the exchange dynamics of a peritoneal membrane. We designed a mechanism to increase the membrane surface contact area by using an abdominal belt in order to exert enough pressure on the fill volume, to effectively recruit more area in contact for exchange. We studied 12 patients on regular continuous ambulatory peritoneal dialysis (CAPD) at our center from January to October 2008. The age of patients ranged from 44 to 75 years, with a median of 55 years. All the patients were maintained on the same prescription four months before and during the study. Dialysis solutions were 1.36% Deaneal® , two liters, three exchanges and the last fill volume was two liters 7.5% Extraneal® . The belt was applied to all the patients most of the day and all night. We then observed its effect on dialysis adequacy, reflected by various parameters over a period of eight months. The average Kt/V before wearing the belt was 1.89 and improved after applying the belt to 2.3 (P <0.05). Our study suggests that increasing the abdominal pressure by wearing an abdominal belt rendered the filling volume of the PD dialysate to have a better contact with the peritoneal membrane and improved the dialysis adequacy. Studies with larger sample size are required to confirm the results.
|How to cite this article:|
Alhwiesh A, Esam S, Saeed I, Ahmmed M, Almohana F. The influence of increased peritoneal membrane surface area on dialysis adequacy. Saudi J Kidney Dis Transpl 2011;22:717-22
|How to cite this URL:|
Alhwiesh A, Esam S, Saeed I, Ahmmed M, Almohana F. The influence of increased peritoneal membrane surface area on dialysis adequacy. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2021 Apr 20];22:717-22. Available from: https://www.sjkdt.org/text.asp?2011/22/4/717/82650
| Introduction|| |
Since the beginning of peritoneal dialysis (PD), there have been numerous trials on modifying the adequacy of PD by changing the number and duration of cycles, the volume of dialysis fluid applied, and the choice of dialysis solution. ,,,
Looking from another perspective, the adequacy can be altered by making use of peritoneal membrane anatomic dynamics. The membrane can be viewed as being composed of three exchange entities: the anatomic, the contact, and the vascular areas. First, the anatomic area appears to be constant for every individual when expressed as per square meter body surface area (BSA). The fluid volume can be selected based on this surface area. , However, 30-60% of this area, the contact area, is utilized for exchange. ,, The extent of its recruitment depends on factors such as posture, filling volume, and intra-abdominal pressure (IAP).  Finally, the vascular area is represented by the mesenteric blood flow and the number of perfusing capillaries. This area is also changeable and is affected by the composition of filling volume and the production of inflammatory agents as well as growth factors. ,
Out of the above-mentioned three exchange areas, the contact area can be worked upon easily and most efficiently to improve the adequacy of PD. Theoretically, the IAP, and hence the recruited contact area, can be increased externally by making the patient wear a special belt around his/her waist. This belt is to exert enough pressure, while not compromising patient's daily lifestyle and comfort.
The aim of our study was to evaluate the effect of increasing peritoneal surface area on the parameters that reflect dialysis adequacy and peritoneal membrane function by making the patient wear an abdominal belt that covers most of his/her abdomen.
| Patients and Methods|| |
We studied 12 patients on continuous ambulatory peritoneal dialysis (CAPD) from January to October 2008 at King Fahd Hospital of the University, Al-Khobar, Saudi Arabia. All the patients were stable on CAPD, six months prior to the study. Their age ranged from 44 to 75 years, with a median of 55 years. The patients' characteristics are shown in [Table 1].
Patients with one or more of the following conditions were excluded from the study: those who had peritonitis or exit-site infection during the last 6 months prior to the study, those with recent abdominal surgery, those with abdominal or inguinal hernias, and pregnant women.
All the patients were maintained on the same dialysis prescription for six months before and during the study period in the form of 1.36% Dianeal® (Baxter Company, Deerfield, USA), filling volume of two liters, three exchanges per day, and the last filling volume was two liters 7.5% Extraneal® (Baxter Company-USA). Complete blood count, renal function tests, liver function tests, calcium, phosphorus, uric acid, serum albumin, bicarbonate level, KT/V and peritoneal creatinine clearance were measured monthly. The patients were routinely evaluated by PD nurses and nephrologists.
The abdominal belt [Figure 1], [Figure 2] and [Figure 3] designed at our hospital was worn by all the study patients most of the day and all night. The belt is made of a combination of elastic and soft nylon pile bonded to 1/4 foam for comfort with special elastic panel construction that provides even support and prevents roll over. In addition, there is a special hole in the center through which the external part of the catheter passes with the transfer set. There is also a special rubber hook at the side of the belt to fix the transfer set. The belt's width is fixed (23 cm), but its length varies according to the patient's size.
|Figure 2: Diagrammatic illustration of the peritoneal dialysate before applying the belt.|
Click here to view
|Figure 3: Diagrammatic illustration of the peritoneal dialysate after applying the belt.|
Click here to view
Urea Kt/V and peritoneal creatinine clearance were calculated weekly based on 24-hour urine and dialysate collections prior to the scheduled visit to the PD unit. Serum, urine, and dialysate urea and creatinine levels were analyzed using Hitachi 917 equipment (Roche Diagnostics, Division of Hoffmann-La Roche, Basel, Switzerland). Calculations of Kt/V and creatinine clearance were performed using original Polish software, Nephron 97 for Windows (DDPS, Kraków, Poland).
The above protocol was reviewed and approved by our local ethics committee.
| Statistical Analysis|| |
Analysis of the data was performed using statistical 5.1 software (StatSoft, Tulsa, Oklahoma, USA). All normally distributed variables were presented as mean ± SD and those with nonnormal distribution were presented as median and range. Pearson test was used for correlation between variables. We considered P values less than 0.05 as statistically significant.
| Results|| |
Of the total 8 months of follow-up, the study patients were kept off the abdominal belt for four months, followed by its application for the rest of the study period. There were no exit site infections or peritonitis. Eight patients were slow and four were fast average transporters. The 24-hour urine output ranged from 155 to 1,837 mL, with a mean of 664 mL. The body mass index ranged from 18.8 to 42.5 with a mean of 31.3 Kg/M 2 . The average Kt/V before applying the belt was 1.89 and after applying the belt was 2.3; the difference was statistically significant with a P value <0.05 [Table 2]. The difference was more significant in patients with low body mass index as compared with patients having high body mass index (3.1 vs. 2.2, P <0.01). The average peritoneal creatinine clearance before wearing the belt was 71 mL/min compared with 68.6 mL/ min after wearing the belt. The difference was not statistically significant. The average peritoneal creatinine clearance in patients with low body mass index (patients 5, 7 and 9) after applying the belt was 83.9 mL/min compared with 67.7 mL/ min in those with high body mass index (P <0.05) [Table 3]. The rest of biochemical markers including serum blood urea nitrogen (BUN), creatinine, phosphorus, albumin, bicarbonate and uric acid did not show significant differences before and after wearing the belt.
|Table 3: Creatinine clearance (peritoneal) before and after applying the belt.|
Click here to view
IAP was measured with and without the belt as described by Durand et al.  The mean values during inspiration and expiration were used, and the IAP was expressed in mmHg by multiplying the result of IAP in cm H 2 O by conversion factor 0.74.
The mean IAP in supine position without and with the belt was 12.6 ± 4.7 and 12.8 ± 4.8 mmHg, respectively, (P = 088), while in the erect position without and with the belt, the values were 21.4 ± 7 and 21.6 ± 6.9 mmHg, respectively, (P = 0.9).
| Discussion|| |
Optimal treatment of ESRD involves consideration of several interrelated aspects: fluid removal, blood pressure control, nutrition, acid-base balance, mineral metabolism (calcium and phosphate), anemia and lipid control, and small-solute removal. Adequate small-solute removal is frequently, though perhaps not correctly, taken as the single parameter of dialysis adequacy.  Theoretically, patient survival and morbidity have a dose-dependent relationship with small-solute clearance.  Several prospective cohort studies found that a higher dialysis dose, in terms of total Kt/V or creatinine clearance, was associated with a better patient survival and a fewer hospitalizations. ,, Based on the results of these studies, the Dialysis Outcomes Quality Initiative (DOQI) workgroup recommended a total weekly Kt/V of 2.0 or weekly creatinine clearance of 60 L as targets for adequate PD.  The prescription of PD is based mainly on the choice of the PD fluid, the intraperitoneal filling volume based on the BSA, and the contact time. The working mode of the peritoneal membrane as a dialysis membrane is more related to a dynamic complex structure. ,,,,, Both posture and filling volume may affect the extent of recruitment of the contact area with the dialysate. ,,,, The contact area is an expandable surface and a new contact area may be recruited by different factors. , In support of this hypothesis, the PD membrane has been proven in animal studies to be impacted by mechanical factors, such as agitation, or pharmacological factors, such as surfactant. , Using computed tomography in humans, Chagnac et al  have shown that only 25-30% of the anatomic area comes into contact with the filling volume under basal conditions. In other studies, authors have clearly demonstrated that an increase in the filling volume from 2 to 3 L resulted in an increase in the contact area from 0.57 to 0.67 m 2 (18% ± 2.3%), which in turn resulted in a significant increase in the mass transfer area coffeciance (MTAC) value for creatinine from 10.6 to 13.6 mL/min (28% ± 2.4%). , When the dose of dialysis is increased to achieve higher target values, there is always a potential for an introduction of adverse effects associated with efforts to enhance the dose. This may include hernias from the increased IAP, patient dissatisfaction because of the increased time needed to perform exchanges, weight gain from glucose absorption, possible systemic toxicity from components of the dialysate that may be absorbed (glucose degradation products), and increased cost because of the additional dialysis solutions.  Discrepancy between KT/V and creatinine clearance is multifactorial and includes low transporter membrane status and a decrease of residual renal function. In our patients 2 and 12 and in patient 11, the creatinine clearance was better than the KT/V. However, up to 20% of patients may reveal a significant discrepancy between the two measurements.
We found a positive effect of wearing an abdominal belt that exerts enough abdominal pressure on the filling volume in our PD patients. The dialysis adequacy in terms of Kt/V and peritoneal creatinine clearance increases, especially in patients with low and normal body mass index. This may be explained by an increase of the contact area with pressure support obtained from wearing the belt. The limitations of our study include the small number of the study patients and short duration of follow-up. Additional studies with a large sample size are needed to confirm this conclusion.
| References|| |
|1.||Blake P, Burkart JM, Churchill DN, et al. Recommended clinical practices for maximizing peritoneal dialysis clearances. Perit Dial Int 1996;16:448-56. |
|2.||Krediet RT, Douma CE, van Olden RW, et al. Augmenting solute clearance in peritoneal dialysis. Kidney Int 1998;54:2218-25. |
|3.||Krediet RT, Boeschoten EW, Struijk DG, et al. Differences in the peritoneal transport of water, solutes and proteins between dialysis with two-and with three-liter exchanges. Nephrol Dial Transplant 1988;2:198-204. |
|4.||Wang T, Heimbu¨rger O, Cheng HH, et al. Effect of increased dialysate fill volume on peritoneal fluid and solute transport. Kidney Int 1997;52:1068-76. |
|5.||Krediet RT, Zemel D, Imholz AL, et al. Indices of peritoneal permeability and surface area. Perit Dial Int 1993;13[Suppl 2]:S31-4. |
|6.||Krediet RT, Zemel D, Imholz ALT, et al. Impact of surface area and permeability on solute clearances. Perit Dial Int 1994;14[Suppl 3]:S70-7. |
|7.||Fischbach M, Haraldsson B, Helms P, et al. The peritoneal membrane: a dynamic dialysis membrane in children. Adv Perit Dial 2003;19: 265-8. |
|8.||Oreopoulos DG. The optimization of continuous ambulatory peritoneal dialysis. Kidney Int 1999;55:1131-5. |
|9.||Flessner MF, Lofthouse J, Zakaria ER. Improving contact area between the peritoneum and intraperitoneal therapeutic solutions. J Am Soc Nephrol 2001;12:807-13. |
|10.||Stompor T, Zdzienicka A, Motyka M, et al. selected growth factors in peritoneal dialysis: their relationship to markers of inflammation, dialysis adequacy, residual renal function, and peritoneal membrane transport. Perit Dial Int 2002;22:670-6. |
|11.||Durand PY, Chanliau J, Gamberoni J, et al. Measurement of hydrostatic intraperitoneal pressure: a necessary routine test in peritoneal dialysis. Perit Dial Int 1996;16(Suppl 1):84-7. |
|12.||Kim DJ, Do JD, Huh W, et al. Dissociation between clearance of small and middle molecules in incremental peritoneal dialysis. Perit Dial Int 2001;21:462-6. |
|13.||Paniagua R, Amato D, Vonesh E, et al. Effects of increased peritoneal clearance on mortality rates in peritoneal dialysis: ADEMEX, a prospective, randomized, controlled trial. J Am Soc Nephrol 2002;13:1307-20. |
|14.||Mak SK, Wong PN, Lo KY, et al. Randomized prospective study of the effect of increased dialytic dose on nutritional and clinical outcome in continuous ambulatory peritoneal dialysis patients. Am J Kidney Dis 2000;36:105-14. |
|15.||Genestier S, Hedelin G, Schaffer P, et al. Prognostic factors in CAPD patients: a retrospecttive study of a 10 year period. Nephrol Dial Transplant 1995;10:1905-11. |
|16.||NKF-K/DOQI. Clinical practice recommendations for peritoneal dialysis adequacy. Am J Kidney Dis 2006;48(suppl):S131-8. |
|17.||Gotch F, Keen M. Kinetic modeling in peritoneal dialysis. In: Nissenson AR, Fine RN, Gentile DE, eds. Clinical dialysis. 3 rd ed. East Norwalk, CT: Appleton & Lange, 1995. |
|18.||Chagnac A, Herskovitz P, Weinstein T, et al. The peritoneal membrane in peritoneal dialysis patients: Estimation of its functional surface area by applying stereologic methods to computerized tomography scans. J Am Soc Nephrol 1999;10:342-6. |
|19.||Rubin J, Clawson M, Planch A, Jones Q. Measurements of peritoneal surface area in man and rat. Am J Med Sci 1988;295:453-8. |
|20.||Twardowski ZJ, Tully RJ, Ersoy FF, Dedhia NM. Computerized tomography with and without intraperitoneal contrast for determination of intra-abdominal fluid distribution and diagnosis of complications in peritoneal dialysis lysis patients. ASAIO Trans 1990;36:95-103. |
|21.||Lo WK. Dialysis adequacy targets in continuous ambulatory peritoneal dialysis-higher is not necessarily better. Perit Dial Int 2003;23 (S2):S69-71. |
|22.||Zweers MM, de Waart DR, Smit W, et al. Growth factors VEGF and TGFβ1 in peritoneal dialysis. J Lab Clin Med 1999;134:124-32. |
|23.||Chung SH, Heimbŭrger O, Stenvinkel P, et al. Association between inflammation and changes in residual renal function and peritoneal transport rate during the first year of dialysis. Nephrol Dial Transplant 2001;16:2240-5. |
|24.||Flessner MF. Small-solute transport across specific peritoneal tissue surfaces in the rat. J Am Soc Nephrol 1996;7:225-33. |
|25.||Changnac A, Herskovitz P, Ori Y, et al. Effect of increased dialysate volume on peritoneal surface area among peritoneal dialysis patients. J Am Soc Nephrol 2002;13:2554-9. |
|26.||Sarkar S, Bernardini J, Fried L, et al. Tolerance of large exchange volumes by peritoneal dialysis patients. Am J Kidney Dis 1999;33: 1136-40. |
Nephrology Department, King Fahd University Hospital, Al-Khobar
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]