Intermittent Peritoneal Dialysis Research Articles

Effects of dialysate volume and flow on solute and water removal with different peritoneal dialysis schedules.

There exist both a strong rationale and convincing surface area rather than to total body water. Also, the evidence that the minimum weekly Kt/V urea should renal contributions of creatinine clearance are usually be 2.0 in continuous ambulatory peritoneal dialysis estimated as creatinine clearance solely by glomerular (CAPD) patients [1‐12]. In this same issue, I have filtration rate. This is calculated as the mean of renal presented arguments for initiating dialysis and main- urea and creatinine clearances. Also, if creatinine cleartaining a peritoneal dialysis prescription so that the ances are to be used for prescription modelling, then weekly Kt/V urea with continuous peritoneal dialysis attention must be paid to the corrections for glucose does not fall below 2.0. The weekly Kt/V urea for interference on creatinine concentrations in the nightly intermittent peritoneal dialysis (NIPD) should dialysate. be slightly higher than that for CAPD since NIPD is If the numerator of the Kt/V urea remains constant, intermittent and there are fluctuations in serum urea than Kt/V urea decreases as V increases [12‐15]. We nitrogen concentrations. Such recommendations are previously have published the Kt/V urea expected in based on the assumption that the control of peak anephric patients using various peritoneal dialysis cycle serum urea nitrogen concentration is important for times and exchange volumes, and have also shown control of uraemic symptoms and that at the same those standard body weights at which the clearances urea nitrogen generation rate, an intermittent therapy with each plan fall below recommended targets [14,15]. requires greater clearance than a continuous therapy The rate at which small solutes approach equilibrium to maintain the serum urea nitrogen concentration at across the peritoneal membrane markedly influences or below the steady-state value of the continuous the clearance achieved with given cycle times [16‐18]. treatment [13]. Here I will summarize approaches The peritoneal dialysis equilibration test is very helpful to maintaining target levels for peritoneal dialysis in defining the type of membrane transport that a treatment. patient has and in predicting various clearances at given cycle times [16 ].

Peritoneal mononuclear cell differentiation and cytokine production in intermittent and continuous automated peritoneal dialysis

The long period without dialysate exchanges in nightly intermittent peritoneal dialysis (NIPD; no peritoneal filling during the day) and continuous cyclic peritoneal dialysis (CCPD; peritoneal filling during the day) might lead to an improved repopulation and functional regeneration of peritoneal macrophages (PMOs). We investigated this issue in seven stable, noninfected CCPD patients and seven stable, noninfected NIPD patients. PMO differentiation and cytokine production were measured after automated peritoneal dialysis and after a 12- to 14- hour period without dialysate exchanges. PMO maturation was evaluated by antibody staining. The proportion of “young” monocytes (positive for 27E10 and RM3/1) was decreased, whereas the proportion of mature macrophages (positive for 25F9) was significantly increased after the exchange-free interval. No differences between NIPD and CCPD were observed. The cytokine response to lipopolysaccharide was significantly increased after the exchange-free interval in both NIPD and CCPD. The interleukin-1 receptor antagonist (IL-1Ra) content of PMO lysates significantly increased after the exchange-free interval in both groups, but no changes were found in dialysate and serum IL-1Ra. We conclude that the long daytime interval without dialysate exchanges allows for additional PMO differentiation. Furthermore, the potential for cytokine release, which is inhibited (possibly by dialysate effects) after automated peritoneal dialysis, is restored after a 12- to 14-hour interval without peritoneal dialysis exchanges. The “dry” day in NIPD seems to have no important additional positive effect compared with CCPD. (Am J Kidney Dis 1998 Feb;31(2):234-41)

A comparison of solute clearance and ultrafiltration volume in peritoneal dialysis with total or fractional (50%) intraperitoneal volume exchange with the same dialysate flow rate.

Abstract BACKGROUND: The most efficient way to perform automated peritoneal dialysis (APD) has not yet been defined. Tidal peritoneal dialysis (TPD) has been claimed to be more efficient than traditional intermittent peritoneal dialysis (IPD), but few comparative studies have been done keeping dialysate flow the same in the two treatment techniques. METHODS: Six patients were treated with 10, 14 and 24 litres total dialysis fluid volume during 9 h (flow rate 18.5, 25.9 and 44.4 ml/min), receiving the treatments both as IPD and TPD. Glucose concentration in the fluid was held constant during all treatments. Transperitoneal clearances (ml/min) for urea, creatinine and uric acid and ultrafiltration volume was calculated, and comparisons made between TPD and IPD. The total intraperitoneal dwell time was calculated for each treatment session. A peritoneal equilibration test was also done for each patient. RESULTS: The ratio of the creatinine concentration in dialysate to the concentration in plasma at 4 h obtained with the peritoneal equilibration test (PET) averaged 0.77 (range 0.69-0.82). Urea clearance was higher for IPD than for TPD with 10 litres: 14.3 +/- 2.4 and 13.3 +/- 2.7 (P = 0.0092). For 14 and 24 litres urea clearance for IPD and TPD was 16.9 +/- 2.3 and 15.9 +/- 3.5 (n.s.) and 20.9 +/- 3.6 and 19.9 +/- 5.6 (n.s.) respectively. Creatinine clearance was higher for IPD than for TPD with 10 litres: 9.6 +/- 1.3 and 8.9 +/- 1.3 (P = 0.0002). For 14 and 24 litres creatinine clearance for IPD and TPD was 11.0 +/- 0.7 and 9.9 +/- 2.0 (n.s.) and 12.3 +/- 1.2 and 12.4 +/- 2.2 (n.s.) respectively. Uric acid clearance was higher for IPD than for TPD with 10 litres: 8.4 +/- 1.3 and 7.7 +/- 1.0 (P = 0.0054). For 14 and 24 litres uric acid clearance for IPD and TPD was 9.3 +/- 1.7 and 8.9 +/- 2.2 (n.s.) and 11.3 +/- 2.9 and 10.6 +/- 2.6 (n.s.) respectively. IPD gave significantly higher ultrafiltration volume (ml) than IPD for both 10 and 14 litres: 944 +/- 278 and 783 +/- 200 (P = 0.0313) and 1147 +/- 202 and 937 +/- 211 (P = 0.0478). For 24 litres there was no significant difference between IPD and TPD: 1220 +/- 224 and 1253 +/- 256. CONCLUSION: With the lowest dialysate flow rate (18.5 ml/min), solute clearance and ultrafiltration volume was higher on IPD than on TPD. With the intermediate flow rate (25.9 ml/min) the ultrafiltration volume was higher on IPD, but no difference was found for solute clearance. With the highest flow rate (44.4 ml/min) there was no difference neither for ultrafiltration nor for solute clearances.

Effect of Dialysis Modality and Membrane Transport Characteristics on Dialysate Protein Losses of Patients on Peritoneal Dialysis

To determine if peritoneal dialysis modality has an impact on protein losses in dialysate. Retrospective, cross-sectional study. 190 patients who had selected peritoneal dialysis were classified into one of four transport categories (high, high-average, low-average, or low) based on standard peritoneal equilibration test results. Patients were then assigned to continuous ambulatory peritoneal dialysis (CAPD) or nightly intermittent peritoneal dialysis (NIPD) based on membrane transport characteristics and individual preferences. Patients with similar membrane transport characteristics had essentially no differences in dialysate protein and albumin losses whether treated with CAPD or NIPD. Although high transporters may be better managed with short-dwell therapies such as nocturnal intermittent peritoneal dialysis or daily ambulatory peritoneal dialysis, consistent marked decreases in protein losses cannot be cited as a benefit of NIPD over CAPD.

Increase of the Bioavailabllity of Intraperitoneal Erythropoietin in Children on Peritoneal Dialysis by Administration in Small Dialysis Bags

To establish the effectivity of administration of erythropoietin intraperitoneally in a small amount of fluid in children with renal anemia on continuous ambulatory peritoneal dialysis (CAPD). Prospective study in which children with renal anemia on CAPD were treated with erythropoietin intraperitoneally, administered in a specially designed bag containing 50 mL NaCl 0.9%. University hospital. The patient population consisted of 9 children treated with CAPD and 1 treated with nightly intermittent peritoneal dialysis. The median age was 7.8 years (range 4.1-15.2). Four of these children had not been treated with erythropoietin before (group A), and 6 had been treated with erythropoietin administered intraperitoneally in 250 mL of dialysis fluid (group B). Patients in group A started on a dose of approximately 300 units/kg per week (group A). Patients in group B received their previous dose. Dosage was adjusted to achieve a target hemoglobin level of 6.5-7.0 mmol/L (104-112 g/L). Serum ferritin levels and transferrin saturation were monitored and iron supplementation was prescribed in the case of iron deficiency. Weekly erythropoietin dose in relation to hemoglobin level. In group A, median hemoglobin level rose from 5.3 mmol/L (85 g/L) to 6.6 mmol/L (106 g/L) after 6 months of therapy, whereas the median erythropoietin dose decreased from 266 to 234 U/kg/week. In group B, hemoglobin levels remained stable and median erythropoietin dose decreased from 262 to 194 U/kg/week. One patient in this group, for unknown reasons, never responded to erythropoietin treatment. He was excluded from further analysis. In the remaining 5 patients the median cumulative erythropoietin dose was 3250 U/kg in the 3-month period prior to the start of the study and 2713 in the 3-month period starting 6 months after the beginning of the study. This difference of 17% was statistically significant using a Wilcoxon test (p < 0.05). Intraperitoneal administration of erythropoietin in a small amount of dialysis fluid leads to a decrease in the required dose.

Continuous Flow through Peritoneal Dialysis (Cfpd): Comparison of Efficiency to Ipd, Tpd, and Capd in An Animal Model

To determine whether continuous flow-through peritoneal dialysis (CFPD), a treatment schedule in which peritoneal dialysate is infused continuously into one part of the abdomen (over the liver) and is drained from a distant part of the abdomen (the pelvis), can provide greater clearance than continuous ambulatory peritoneal dialysis (CAPD), tidal peritoneal dialysis (TPD), or intermittent peritoneal dialysis (IPD). A prospective study comparing four schedules of peritoneal dialysis in the awake, normal dog, using glucose clearance as a substitute for urea clearance. We placed two chronic dialysis catheters into the abdomen of anesthetized dogs (with intraperitoneal portions of fluted or miniature column-disc design). On successive days, with the dogs awake and prone, we performed peritoneal dialysis for 4 hours with 1.5% dialysate according to one of four schedules, each with 2 L maximum intraperitoneal volume: CFPD (unidirectional flow at an average of 3.6 L/hr), IPD (2 L/hr), TPD (average of 3.6 L/hr, 1 L residual volume), and CAPD (2 L/4 hr). Glucose and urea clearances were calculated from blood and peritoneal concentrations and dialysate flow rates. Stabilized glucose clearances (from 60 to 240 minutes) averaged 11 +/- 5 mL/min for IPD, TPD, and CFPD, and 5 +/- 2 mL/min for CAPD. However, glucose clearances of CFPD were 13 +/- 6 mL/min when the intraperitoneal volume was maintained at 800-100 mL, and 16.5 +/- 6 mL/min when flow rate was 6 L/hr. Urea clearances were twice the measured glucose clearances. When CFPD is performed with an appropriate intraperitoneal volume and flow, it is the most chemically effective method of peritoneal dialysis in removing small molecules like urea.

Cibenzoline-induced respiratory muscular paralysis in a hemodialysis patient

A 69-year-old man was admitted to our kidney center with endstage renal failure. We started intermittent peritoneal dialysis immediately because of severe azotemia, hyperkalemia, and metabolic acidosis. Two weeks after admission, he developed uremic pericarditis with frequent ventricular premature contractions and supraventricular premature contractions. The intermittent peritoneal dialysis was then replaced by intensive hemodialysis, and oral administration of 300 mg/d of cibenzoline was started. Four days later, he developed thirst, weakness, and dyspnea due to respiratory muscular paralysis. We initiated respiratory support with a respirator because analysis of his blood gases revealed marked hypercapnia and hypoxia. He also developed hypoglycemia and prolonged PQ and QRS intervals on the electrocardiogram, which we believed were due to cibenzoline intoxication; we discontinued the cibenzoline immediately. All symptoms improved, and he was extubated 5 days later. After 2 months, his pericardial effusion disappeared. He now continues maintenance hemodialysis as an outpatient. We suspect that the cibenzoline induced the respiratory muscular paralysis for 2 reasons: 1) the patient experienced the respiratory muscular paralysis, at the same time he also experienced thirst, weakness, hypoglycemia, and prolonged PQ and QRS intervals on electrocardiogram, and all of these symptoms improved after the discontinuation of cibenzoline, and 2) his plasma concentration of cibenzoline became remarkably elevated, to 20 times above the standard therapeutic level. This patient's clinical course indicates that hemodialysis might be superior to intermittent peritoneal dialysis for treatment of cibenzoline intoxication.

Sotalol-Lnduced Torsade De Pointes in a Capd Patient -Successful Treatment with Intermittent Peritoneal Dialysis

Sotalol-Lnduced Torsade De Pointes in a Capd Patient -Successful Treatment with Intermittent Peritoneal Dialysis

Adequate Dialysis? Measurement of Ktn in a Pediatric Peritoneal Dialysis Population

To measure the urea and creatinine kinetics in a pediatric population. In 19 children treated with peritoneal dialysis (PD) KT/V, urea and creatinine clearances (Ccr) were measured. Thirteen children were on continuous ambulatory peritoneal dialysis (CAPD) and 6 on highly intermittent peritoneal dialysis (NIPD). Mean KT/V per week was 2.31 +/- 0.78 and mean creatinine clearance 74 +/- 47 L/week/1.73 m2. There was no difference in dialytic KT/V between patients treated with CAPD and NIPD (1.75 +/- 0.21 vs 1.76 +/- 0.50). The correlation between KT/V urea and creatinine clearance was 0.9 (p < 0.001). There was a clear relationship of these parameters with residual renal function, but not with age or blood urea level. A weak positive correlation was found with serum albumin and protein intake. Mean KT/V in this patient group was higher than the values reported for most adult patient groups. Residual renal function considerably contributes to this high KT/V. It is not clearly defined which KT/V should be aimed for, since criteria for adequate dialysis are multifactorially determined and therefore difficult to interpret.

Early increase in blood nitric oxide, detected by electron paramagnetic resonance as nitrosylhaemoglobin, in haemodialysis.

The objective of this study was to determine intradialytic blood levels of nitric oxide (NO), in patients undergoing chronic haemodialysis. This was done by detection of nitrosylhaemoglobin by a sensitive technique of spin trap electron paramagnetic resonance at 0, 5, 15, 60, 180 and 240 min of a 4-h standard bicarbonate dialysis, using the same dose (6000 U) of heparin and different dialysis membranes. The study group included 12 patients treated with cellulose-derived dialysis membranes (nine with cuprophan and three with cellulose triacetate) and 10 patients treated with synthetic membranes (five with polysulfone and five with polymethylmethacrylate). Control groups included 11 normal subjects and six patients with end-stage renal failure who were receiving intermittent peritoneal dialysis. Basal blood levels of nitrosylhaemoglobin in haemodialysis patients were significantly higher than normals, but similar to peritoneal dialysis patients. A significant increase (P < 0.01) in nitrosylhaemoglobin level was detected at 15 min of haemodialysis irrespective of the membrane used. A decrease to basal levels at 180 min was observed in all but two cuprophan-treated patients who, in contrast to the others, had a symptomatic hypotension at the end of the session and a further increase in blood nitric oxide. Patients undergoing peritoneal dialysis did not show any change in blood levels of nitrosylhaemoglobin during the first 180 min of the procedure. Thus, a constant increase in nitrosylhaemoglobin levels was observed early in haemodialysis, but not in peritoneal dialysis patients. Very preliminary evidence was obtained for a role of nitric oxide in the vascular instability at the end of haemodialysis in a few patients who had hypotensive episodes.

Peritoneal Dialysis for Acute Renal Failure in Infants: A Comparison of Three Types of Peritoneal Access

Peritoneal access for peritoneal dialysis (PD) poses a significant problem in infants due to their small size and can result in considerable morbidity and occasional mortality. This study was carried out to compare the complications associated with three different types of PD catheters for intermittent PD. A total of 79 sessions of PD were given to 51 infants with acute renal failure. Twenty-nine infants received 1, 18 received 2 and 2 infants received 3 and 4 sessions of PD, respectively. For PD access an intravenous cannula was used in 36, stylet catheter in 18, and guide wire inserted femoral vein catheter in 25 procedures. Percentage reduction of serum creatinine per PD session was comparable in infants being dialysed with different types of PD access. Local puncture site and intraperitoneal bleed were associated with the use of a stylet catheter during 4 procedures each (22.2%). Catheter blockade was commonest with the intravenous cannula (22.2%), followed by guide wire inserted femoral vein catheter (16%), and was least with the stylet catheter (5.5%). Total mechanical complications were lower with guide wire inserted femoral vein catheter (16%) as compared to intravenous cannula (25%) and stylet catheter (66%) (p < 0.05). There were 4 episodes of peritonitis (5.0%), 3 bacterial and 1 fungal. Although peritonitis was more common with intravenous cannula (8.3%) than guide wire inserted catheter (4%) and stylet catheter (nil), the difference was not statistically significant. Total complications including mechanical and infective were least with guide wire inserted femoral vein catheter (20%), followed by intravenous cannula (33%) and stylet catheter (66%) (p < 0.05). Of 51 infants, 20 died (39.0%). The PD procedure per se resulted in mortality in 2 cases, 1 because of massive intraperitoneal bleed due to stylet induced injury of an intra abdominal blood vessel and the other due to fungal peritonitis. To conclude, of the three types of access for intermittent PD, complications related to the PD procedure are the least with guide wire inserted femoral vein catheter.

Liver disease in dialysis patients with antibodies to hepatitis C virus

Eighty-three patients with chronic end-stage renal failure, including 65 on haemodialysis and 18 on intermittent peritoneal dialysis, were evaluated for hepatitis B virus profile and antibodies to hepatitis C virus (HCV). All those positive for HBsAg were excluded from the study. Nineteen patients were found to be positive for antibodies to HCV by the ELISA II test. Eight cases were already positive for HCV antibody when they started dialysis in our unit, the other 11 became positive during dialysis in our unit. Only one of the patients on peritoneal dialysis was positive for HCV. A liver biopsy was obtained from 17 patients, who consented to the procedure. All the cases were evaluated for the number of blood transfusions received, HIV infection and the approximate time of contracting the HCV infection. Liver enzymes were determined every month. Only three patients had abnormally raised serum aminotransferase at the time of biopsy. The various histopathological lesions detected were chronic active hepatitis ( n =3, including one with changes consistent with cirrhosis), chronic persistent hepatitis ( n = 4), non-specific hepatitis ( n = 3) and haemosiderosis ( n =3); four biopsy samples were normal. There was no correlation between the biochemical and histopathological changes. Moreover, patients with normal serum aminotransferase levels had abnormal histopathological changes. All were negative for HIV and none of the patients had received a renal graft. Twelve patients had received blood transfusions varying from 2 to 12 units, four had not received any blood, and in one the history of blood transfusion could not be confirmed. The four patients with anti-HCV antibodies who had not received blood transfusion had relatively mild disease-non-specific hepatitis ( n =2) or normal biopsy ( n =2). One patient with cirrhosis died 30 months after liver biopsy from hepatic insufficiency and three received renal transplants. Others are continuing on dialysis and their biochemical tests are within normal limits 12−45 (30± 14) months after biopsy. In conclusion, biochemical tests are poor indicators of liver disease, and liver biopsy is a definitive way of evaluating the patients of dialysis with positive HCV antibodies for prognosis.

Liver disease in dialysis patients with antibodies to hepatitis C virus.

Eighty-three patients with chronic end-stage renal failure, including 65 on haemodialysis and 18 on intermittent peritoneal dialysis, were evaluated for hepatitis B virus profile and antibodies to hepatitis C virus (HCV). All those positive for HBsAg were excluded from the study. Nineteen patients were found to be positive for antibodies to HCV by the ELISA II test. Eight cases were already positive for HCV antibody when they started dialysis in our unit, the other 11 became positive during dialysis in our unit. Only one of the patients on peritoneal dialysis was positive for HCV. A liver biopsy was obtained from 17 patients, who consented to the procedure. All the cases were evaluated for the number of blood transfusions received, HIV infection and the approximate time of contracting the HCV infection. Liver enzymes were determined every month. Only three patients had abnormally raised serum aminotransferase at the time of biopsy. The various histopathological lesions detected were chronic active hepatitis (n = 3, including one with changes consistent with cirrhosis), chronic persistent hepatitis (n = 4), non-specific hepatitis (n = 3) and haemosiderosis (n = 3); four biopsy samples were normal. There was no correlation between the biochemical and histopathological changes. Moreover, patients with normal serum aminotransferase levels had abnormal histopathological changes. All were negative for HIV and none of the patients had received a renal graft. Twelve patients had received blood transfusions varying from 2 to 12 units, four had not received any blood, and in one the history of blood transfusion could not be confirmed. The four patients with anti-HCV antibodies who had not received blood transfusion had relatively mild disease--non-specific hepatitis (n = 2) or normal biopsy (n = 2). One patient with cirrhosis died 30 months after liver biopsy from hepatic insufficiency and three received renal transplants. Others are continuing on dialysis and their biochemical tests are within normal limits 12-45 (30 +/- 14) months after biopsy. In conclusion, biochemical tests are poor indicators of liver disease, and liver biopsy is a definitive way of evaluating the patients of dialysis with positive HCV antibodies for prognosis.

Hemoperitoneum in Peritoneal Dialysis Secondary to Retroperitoneal Hematoma

Editor: Hemoperitoneum is an unusual complication in patients undergoing CAPD (1). In most cases it has a benign course. Two milliliters of blood can dye the peritoneal effluent an intense red. The most frequent cause is endometriosis. However, other gynecological, hematological, tumoral, and abdominal sources can cause hemoperitoneum. Polycystic kidney disease, peritonitis, pancreatitis, cholecystitis, and extracorporeal lithotripsy are other possibilities. Rarely, hemoperitoneum is associated with rupture of the spleen (2) or iliopsoas spontaneous hematoma (3). We present a case of hemoperitoneum consequent to retroperitoneal hematoma after manipulating a double-lumen femoral catheter for hemodialysis. This 44-year-old woman with systemic lupus erythematosus and end-stage renal disease has been on hemodialysis for the last three years. Because of thrombosis of every possible vascular access site, it was decided to change her to peritoneal dialysis. A left Swan neck Missouri peritoneal catheter was placed by surgical technique without complication. A peritoneal lavage at the seventh and fourteenth day was clear. The patient continued on hemodialysis through a doublelumen femoral catheter on the right side. We waited four weeks before standard CAPD was begun. Seventeen days after placement of the peritoneal catheter, during a hemodialysis session, her femoral catheter was changed through a guide wire because of poor flow. Suddenly, she developed severe pain in the right lumbar fossa, right hemiabdomen, and acute anemia and hypovolemic shock occurred. The femoral catheter was removed, and she received intravenous fluids and transfusion of six packed red blood cells, achieving hematologic and hemodynamic stabilization. No surgery was required. A computed tomography scan of the abdomen showed retroperitoneal hematoma involving the right anterior and posterior pararenal space and right iliopsoas muscle. Twenty-four hours later, nightly intermittent peritoneal dialysis was begun. The first peritoneal effluent was very bloody. After continuous peritoneal lavage with 1-L exchanges at room temperature over two hours, the dialysate became clear. One year later, the patient continues on continuous cycling peritoneal dialysis without any problems. To our knowledge, this cause of hemoperitoneum has not been reported before. Therefore, we believe that retroperitoneal hematoma secondary to hemodialysis with a femoral catheter may be listed in the causes of hemoperitoneum in peritoneal dialysis. F. Fernandez Giron F. Hermosilla Sanchez M. Paralle Alcalde J. Gonzalez Martinez

Peritonitis influences mortality in peritoneal dialysis patients.

Mortality remains high in peritoneal dialysis (PD) patients. Known risk factors for mortality include age, diabetes, race, initial albumin level, and cardiovascular disease. Peritonitis is reported to cause death in 1 to 6% of PD patients but has not been well studied as a risk factor for mortality. This study examined 516 adults with a total of 896 yr on PD at one center to determine if peritonitis influenced mortality. Time at risk began on Day 1 of training and ended at death, transplant, or 60 days after transfer to hemodialysis or intermittent peritoneal dialysis. The overall mortality rate was 17.4/100 patient yr. Survival was lower for whites, men, diabetic patients, and older patients. Independent risk factors for mortality (by Cox proportional hazards) were race, diabetes, increased age, and increased peritonitis rate. Use of the Y-set was not associated with decreased mortality. Peritonitis was a risk factor only in whites, nondiabetic patients, and those patients over the age of 60. For every 0.5/yr increase in the peritonitis rate, the risk of death increased 10% in whites, 11% in those patients who were over the age of 60, and 4% for nondiabetic patients. Mortality rates did not decrease over time (1979 to 1995), although peritonitis rates fell significantly (P < 0.001). Rates of Gram-negative and fungal peritonitis showed no trend over time. Peritonitis contributed to 25 of 158 (15.8%) of deaths. Gram-negative/fungal peritonitis accounted for 14 deaths (9.5% of all Gram-negative/fungal episodes) whereas Staphylococcus epidermidis accounted for only 1 death (0.5% of all S. epidermidis episodes) (P < 0.001). Cardiovascular disease was more common in those patients whose deaths were unrelated to peritonitis (P < 0.01), whereas an infectious cause was more common in those patients whose deaths were peritonitis-related (P < 0.001). In this study, peritonitis was a risk factor for death in whites, nondiabetic patients, and older patients. However, the Y-set did not improve survival, perhaps because it does not decrease Gram-negative/fungal peritonitis. To have an impact on survival, efforts are needed to reduce the peritonitis that results from these more serious pathogens.

Epidemiologic and Demographic Aspects of Peritoneal Dialysis in Mexico

To assess some epidemiological and demographic aspects of peritoneal dialysis (PD) at the Instituto Mexicano del Seguro Social (IMSS), the major institution of social security in Mexico, that provides health care services for 57% of the Mexican population at the time of the study. A cross-sectional analysis of data about patients under peritoneal dialysis in 1992. A national survey containing demographic data, dialysis modality, type of catheter, peritonitis and death rates, and questions on costs, medical staff, and physical facilities for PD in all of the hospitals of the IMSS. All hospitals returned the information requested. Intermittent peritoneal dialysis (IPD) was performed in 19 hospitals, continuous ambulatory peritoneal dialysis (CAPD) in 11, and both modalities in 90. In 61 hospitals, a special area was designed for PD; in the rest of them, beds from general internal medicine departments were used. All hospitals had a head for the PD programs; overall, teams had 240 physicians and 765 nurses for IPD, and 182 physicians and 313 nurses for CAPD. CAPD prescription was four 2-L bags/day. For IPD, patients were hospitalized once a week and received 28 manually performed exchanges of 2-L bags; the mean time of hospitalization was 2.7 days, and 878 beds were used. The number of patients receiving PD was 7785, with a prevalence of 199.6 per million population. Of them, 4011 were on IPD and 3774 on CAPD; 54% of the patients were males. IPD patients' mean age was 49 +/- 17 yr, and that of CAPD patients' was 42 +/- 17 yr (NS). Diabetic nephropathy was the most frequent cause of ESRD (44%). Infection was the most important complication detected. Rates of peritonitis were 0.5/patient/yr on IPD and 0.8/patient/yr on CAPD. Annual mortality rates without stratification for specific causes were 34% in IPD and 17% in CAPD. Mortality rates may have been influenced by malnutrition and cardiovascular complications of diabetes, but specific causes of death were not investigated. All of the PD programs costs were covered by the institution. The cost per patient was not calculated, but IPD is known to be more expensive, due to its higher hospitalization rate. In spite of its higher cost and mortality, the institutions still use IPD, not so much on medical basis, but as the only alternative available for patients with adverse environmental, social, educational, and economic conditions for CAPD or HD.

Rapid Decline of Residual Renal Function in Patients on Automated Peritoneal Dialysis

To determine the effect of peritoneal dialysis modalities such as nightly intermittent peritoneal dialysis (NIPD), continuous cyclic peritoneal dialysis (CCPD), and continuous ambulatory peritoneal dialysis (CAPD) on residual renal function. A six-month prospective, nonrandomized comparison study. Outpatient CAPD unit of a university hospital. Eighteen end-stage renal disease patients treated by peritoneal dialysis (8 by NIPD, 5 by CCPD, and 5 by CAPD). Samples from the total dialysate, blood, and 24-hour urine collection were obtained monthly. Urea, creatinine, and beta2-microglobulin concentrations were measured. Renal and peritoneal clearances of each substance and KT/V urea were calculated. Residual renal function (RRF) was estimated by renal creatinine clearance (RCcr). No significant differences in age, sex, and primary renal disease among the three groups were noted. In all groups, anemic and hypertensive states were controlled identically, and mean weekly total (renal + peritoneal) KT/V urea (over 2.1/wk) and total creatinine clearance (over 60 L/wk/1.73 m2) were maintained during the whole experimental period. Starting mean RCcr was near 4.0 mL/min/1.73 m2 in all groups. Thereafter, a rapid and significant decline in RRF was demonstrated on NIPD and CCPD. The declining rates of RCcr values at 6 months after starting NIPD and CCPD were -0.29 and -0.34 mL/min/month, respectively, which were much greater than those of CAPD (+0.01 mL/min/month). Because of a possibly characteristic progressive loss of RRF in automated peritoneal dialysis (APD), strict regular assessment of RRF should be performed from the start of APD.

A Comparison of Bone Scans in Uremic Patients Treated with Intermittent Peritoneal Dialysis Or Hemodialysis

The aim of the study was a comparative analysis of bone scans in uremic patients treated with intermittent peritoneal dialysis (IPD) or hemodialysis (HD). Bone scintigraphy was performed using technetium Tc 99m etidronate (EHDP) in 28 uremics (age 46.0 +/- 13.5 years, x +/- SD) on IPD for 3.1 +/- 3.0 months and 28 uremics (age 43.5 +/- 11.6 years) on HD for 47.3 +/- 33.9 months. Serum c terminal parathormone (cPTH) exceeded 5.3 +/- 3.3 and 6.8 +/- 3.5 times the upper normal limit of 1.4 ng/mL in IPD and HD patients, respectively. Despite significant differences in dialysis treatment duration in IPD and HD patients, an increased Tc 99m EHDP uptake in bones was shown with similar frequency, when all the groups were compared. However, in the group of patients with serum cPTH exceeding four times the upper normal limit (n = 30) or in the age group less than 45 years old (n = 26), a greater marker uptake was observed in HD patients. Significant differences (p < 0.05) were shown in the cranial vault: 33% of HD patients (n = 18) with higher cPTH and 47% of those less than 45 years old (n = 15) revealed an increased marker uptake, whereas it was not observed in any IPD patient. When scans of HD patients dialyzed less than (n = 11) and more than (n = 17) 30 months were compared, a significantly higher appearance of increased marker uptake was shown in cranial vault (41% vs 0%, p < 0.02) and in sacral bone (82% vs 36%, p < 0.02) in patients with longer dialysis. The latter group of HD patients also showed an increased marker uptake in cranial vault compared to the entire group of PD patients (41% vs 7%, p < 0.01). Our studies suggest that bone scan changes, indicating secondary hyperparathyroidism, progress significantly with prolongation of dialysis treatment, especially in patients with higher cPTH levels of younger age.

Intermittent peritoneal dialysis (IPD) in the elderly

Twenty-one elderly patients with end-stage renal disease (ESRD) secondary to various etiologies received IPD at our unit. It was done manually by trained staff nurses. Each patient received 20-24 one hour exchanges of 2 liters PD solution twice a week through a permanent Tenckhoff catheter. Mean age of patients was 63 years (range 60–96),12 were male and 9 female. Mean duration of stay on IPD was 23 months (range 18–41). The etiologies of ESRD were: diabetes mellitus (9 patients), unknown etiology (7), hypertension (3), glomerulonephritis and liver cirrhosis (hepatitis C) (2). The peritonitis rate was one episode per 16.3 patient/month. The causative organisms were staphylococcus, coliforms, acinobacter and pseudomonas. Six patients died due to each of the following: 2 septicemia not related to PD; 2 hepatic failure; 2 massive myocardial infarction. Two patients were changed to hemodialysis due to recurrent peritonitis. We observed 7 episodes of catheter exit-site infection; causative organisms were staphylococcus (4), and pseudomonas (3). Staphylococcus cases of exit-site infection responded to local fucidin ointment and oral antibiotic, while in the pseudomonas cases the catheter had to be removed. All patients received erythropoietin and have maintained good hemoglobin levels (10.1 ± 1.2 gm%). They also had adequate control of their serum creatinine and urea level. As the patients improved, they became less dependent on their relatives.

Bicarbonate: The Alternative Buffer for Peritoneal Dialysis

For a long time bicarbonate, the physiological buffer of the body, was suggested to be the best buffer for peritoneal dialysis. However, since the production of bicarbonate containing solutions is associated with technical problems, lactate was favored. To avoid the well-known disadvantages of lactate solution concerning biocompatibility and possible metabolic side effects, different attempts have been made to use bicarbonate as a buffer in peritoneal dialysis. One of the major approaches was the total replacement of lactate by bicarbonate combined with storage of the fluid in a specially designed double-chamber bag. Further solutions of the above-mentioned problem were the on-line preparation of bicarbonate fluids for intermittent peritoneal dialysis, the addition of bicarbonate just before use, the combination of bicarbonate with organic acids, or its combination with the dipeptide glycylglycine as a stabilizing agent. By now, the beneficial effect of the neutral bicarbonate fluid, for example, on cell viability and cell functions, has been demonstrated in many different in vitro and animal studies. However, only few reports on clinical experience have been published. These investigations demonstrated independently that bicarbonate fluids diminish inflow pain, are well tolerated by the patients, and may correct metabolic acidosis of uremic patients. A controlled randomized multicenter trial using 34 mmol/L bicarbonate for at least three months confirmed that bicarbonate is as efficacious as lactate in equimolar concentrations. Concomitant investigations on energy metabolism and redox state of red blood cells and phospholipid secretion of mesothelial cells additionally demonstrated the improvement of cell function with bicarbonate solutions. For some patients with severe metabolic acidosis the bicarbonate concentration used in the multicenter trial seemed to be too low. Thus, a fluid containing a higher bicarbonate concentration was tested in a pilot study resulting in the expected significant increase of arterial bicarbonate levels. In summary, bicarbonate-containing peritoneal dialysis solutions are a promising alternative to lactate, especially if bicarbonate concentrations are adjusted individually to the patient's need.