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Our objective is to investigate transperitoneal buffer fluxes with solution containing lactate and bicarbonate, and to compare the final effect on body base balance of the two solutions.One hundred and four exchanges, using different dwell times, were performed in 52 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Dialysate effluent lactate and bicarbonate and volumes were measured. Net dialytic base gain was calculated. Patients’ acid-base status and plasma lactate were determined.In lactate-buffered CAPD solution, lactate concentration in dialysate effluent inversely correlated with length of dwell time, but did not correlate with plasma lactate concentration and net ultrafiltration. Bicarbonate concentration in dialysate effluent correlated with plasma bicarbonate and dwell time but not with ultrafiltration.The arithmetic sum of the lactate gain and bicarbonate loss yielded the net dialytic base gain. Ultrafiltration was the most important factor affecting net dialytic base gain.A previous study demonstrated that in patients using a bicarbonate-buffered solution the net bicarbonate gain is a function of dwell time, ultrafiltration, and plasma bicarbonate.By combining the predicted data of the dialytic base gain with the calculated metabolic acid production, an approximate body base balance could be obtained with both lactate and bicarbonate-buffered CAPD solutions.The body base balance in CAPD patients is self-regulated by the feedback between plasma bicarbonate concentration and dialytic base gain. The level of plasma bicarbonate is determined by the dialytic base gain and the metabolic acid production. This can explain the large interpatient variability in acid-base correction. Bicarbonate-buffered CAPD solution is equal to lactate solution in correcting acid-base disorders of CAPD patients.

The aim of renal replacement therapy is to obtain blood purification from metabolic waste products sufficient to achieve patient rehabilitation, the control of dry body weight, and the correction of acid base and electrolyte imbalances (1–3).Among these, the correction of the hormonal imbalances as a result of renal disease would also be required (4). However, this is difficult to achieve, and the majority of substitute therapies such as hemodialysis and peritoneal dialysis focus on blood purification and fluid and electrolyte homeostasis.For this reason the search for the optimal dialytic therapy has been limited to the possibility of achieving a treatment that could at least be adequate in terms of blood purification and patient rehabilitation. Therefore, dialysis adequacy has been selected as a term to indicate successful renal replacement therapy, one that could overcome most of the uremic symptoms and allow the patient to reach a sufficient degree of rehabilitation, even though the treatment is far from the complete and optimal substitution of the lost kidney function in its whole.In recent years the concept of dialysis adequacy has been studied by several authors, and a continuous evolution of this concept has been observed. From the original description of the square-meter-hour hypothesis of Babb and Scribner in 1971 (5), a series of new studies led to the clinical application of various indices devoted to describing the level of efficiency achieved by dialysis treatment (6,7). Finally, after the American National Cooperative Dialysis Study was analyzed, and the KTNindex was selected as a marker for dialysis adequacy, the majority of authors now rely on this index and are proposing various formulas for its calculation (8–11).

Objective To evaluate bicarbonate fluxes across the peritoneal membrane and bicarbonate gain in patients treated with continuous ambulatory peritoneal dialysis (CAPD) using dialysis solutions with different bicarbonate concentrations.Patients and Design Ninety-seven exchanges, using different dwell times and glucose and bicarbonate concentrations were performed in 43 stable CAPD patients. Dialysate effluent bicarbonate concentration and volumes were measured at different dwell times. Net dialytic bicarbonate gain was calculated. Patients’ acid-base status was determined at the middle of the dwell.Results In prolonged dwells (6 –12 hours)thedialysate effluent bicarbonate concentration correlated with arterial plasma bicarbonate concentration (F = 129, p < 0.0001), but not with ultrafiltration rate or dialysis solution bicarbonate concentration. In 4-hour dwells, effluent bicarbonate concentration correlated with both plasma bicarbonate concentration and ultrafiltration rate (F = 32.52, p < 0.0001 and F = 4.4, p < 0.05, respectively). The effluent bicarbonate concentration may be predicted from the patient's plasma bicarbonate concentration and net ultrafiltration rate for either a 4-hour or prolonged (6 –12 hours) dwell time. Net bicarbonate gain by the patient correlated with ultrafiltration rate, plasma bicarbonate, and dialysis solution bicarbonate concentration (F = 100.56, p < 0.0001 at 4 hours and F = 108.08, p < 0.0001 at 6 12 hours), with the ultrafiltration rate being the predominant parameter.Conclusions The effluent bicarbonate concentration is related to plasma bicarbonate concentration, with ultrafiltration playing a marginal role only during short dwells. However, the ultrafiltration rate has a profound effect on net patient bicarbonate gain. Multiple linear regression analysis allows the prediction of the effect of acid-base status, ultrafiltration, dwell time, and dialysis solution bicarbonate content on net patient bicarbonate gain. It seems that bicarbonate content in the CAPD dialysis solution should be progressively increased with increasing solution osmolality.

This study has evaluated the influence of peritoneal blood flow and plasma protein concentration on the peritoneal ultrafiltration rate. In vitroand in vivoexperiments were done to assess the effective peritoneal capillary blood flow.Based on the assumption that one can compare the behavior of an hollow fiber hemofilter with the peritoneal dialysis system, we have compared the opera tional characteristics of the two systems. After demonstrating that there was filtration pressure equilibrium in the filter, the plasma protein concentration was measured in the venous site of the filter at different applied transmembrane pressures. The nomogram, so obtained, was used to calculate the plasma-protein concentration in the blood leaving the peritoneal capillary during exchanges with an established glucose concentration (and therefore at a given transmembrane pressure), and to calculate the filtration fraction.Once that fraction had been calculated, based on the value of the ultrafiltration rate, one can calculate the importance of the plasma flow and then the blood flow. In this study the filtration fraction ranged between 45 and 55% and the blood flow ranged between 21 and 27 ml/min. It was concluded that the blood flow may be very low and hence may limit ultrafiltration.

Objective To investigate the effect on the patient's acidbase status of a 39 mmol/L bicarbonate-buffered continuous ambulatory peritoneal dialysis (CAPD) solution.Design This was an open, controlled, cross-over, two-center study in 9 patients. After three months of treatment with a 34 mmol/L bicarbonate-buffered solution (to) patients were switched to a 39 mmol/L bicarbonate-containing solution for four weeks. At the end of the study period (t4) patients were again treated with a 34 mmol/L bicarbonate-buffered CAPD solution for one month (t8).Results Mean venous plasma bicarbonate level significantly increased during the study and decreased at the baseline level during the control period (to = 22.94±2.54, t1 = 26.74±3.07, t2=28.47±2.68, t3=28.11±3.56, t4=28.71±3.27, t8=24.94±2.56). Arterial blood pH and plasma bicarbonate significantly increased during the study and significantly decreased attheend of the control period (pH: to= 7.37±0.04, t4= 7.42±0.04, t8= 7.37±0.06. Bicarbonate: t0= 21.97±2.57, t4= 25.85±2.02, t8= 21.87±2.89). The changes in plasma bicarbonate during the study period were inversely correlated with the metabolic acid production calculated from the protein catabolic rate and with the apparent distribution space for bicarbonate (ABS) of patients.Conclusions The 39 mmol/L bicarbonate-buffered CAPD solution improved the patient's acid-base status. Potential undesirable metabolic alkalosis could be prevented by analyzing the ABS and the metabolic acid production of patients.

Our objective is to investigate transperitoneal buffer fluxes with solution containing lactate and bicarbonate, and to compare the final effect on body base balance of the two solutions.One hundred and four exchanges, using different dwell times, were performed in 52 stable continuous ambulatory peritoneal dialysis (CAPD) patients. Dialysate effluent lactate and bicarbonate and volumes were measured. Net dialytic base gain was calculated. Patients’ acid-base status and plasma lactate were determined.In lactate-buffered CAPD solution, lactate concentration in dialysate effluent inversely correlated with length of dwell time, but did not correlate with plasma lactate concentration and net ultrafiltration. Bicarbonate concentration in dialysate effluent correlated with plasma bicarbonate and dwell time but not with ultrafiltration.The arithmetic sum of the lactate gain and bicarbonate loss yielded the net dialytic base gain. Ultrafiltration was the most important factor affecting net dialytic base gain.A previous study demonstrated that in patients using a bicarbonate-buffered solution the net bicarbonate gain is a function of dwell time, ultrafiltration, and plasma bicarbonate.By combining the predicted data of the dialytic base gain with the calculated metabolic acid production, an approximate body base balance could be obtained with both lactate and bicarbonate-buffered CAPD solutions.The body base balance in CAPD patients is self-regulated by the feedback between plasma bicarbonate concentration and dialytic base gain. The level of plasma bicarbonate is determined by the dialytic base gain and the metabolic acid production. This can explain the large interpatient variability in acid-base correction. Bicarbonate-buffered CAPD solution is equal to lactate solution in correcting acid-base disorders of CAPD patients.

Pathophysiology of peritoneal ultrafiltration is analyzed in the present study. Peritoneal equilibration test is the easiest procedure to study in detail the possible causes of failure to control the ultrafiltration rate in patients undergoing peritoneal dialysis. Membrane failure, reduction in peritoneal blood flow, excessive lymphatic reabsorption catheter malposition, and fluid sequestration are the most common causes of ultrafiltration loss. Pharmacologic manipulation of peritoneal membrane, correction of mechanical inconvenients, reduction in peritonitis rate and in the level of immunostimulation of the mesotelial macrophages, together with a careful policy in terms of glucose concentration in the dialysate and dwell times may contribute not only to treat different forms of ultrafiltration loss but also to prevent their incidence.

Four hundred and eighty CAPD and 373 HD patients started regular dialysis treatment between 1981 and 1987 in 6 dialysis centers. The CAPD patients were 6 years older, on average, than the HD patients and had more complicating conditions (43.3% with 3 or more coexisting risk factors versus 28.9% with coexisting complications). The 7-year patient survival rate was not significantly different. Cox's proportional hazards regression showed that age, cardiovascular disease, cerebrovasculardisease, peripheral vasculardisease, diabetes, malignancy and multisystem disease had significant adverse effects on patient survival. After correcting for the influence of these factors, no significant differences in patient survival were seen. However, after 53.5 years of age, the increase in the risk of death was significantly higher in HD than in CAPD patients. Technique survival was significantly different in the 6 centers and was better for HD than for CAPD. There was no statistically significant difference between CAPD and HD technique survival when peritonitis was eliminated as a cause of failure. Based on this 7 year analysis, CAPD would appear to be an excellent alternative to HD.

Objective The evaluation of the efficacy, adequacy, clinical tolerance, and safety of a new bicarbonate continuous ambulatory peritoneal dialysis (CAPD) solution.Design and Patients A 6–week cross-over clinical study in 6 stable CAPD patients was performed. After a control period (2 weeks) with a standard CAPD solution (lactate, 35 mmol/L), a two-chamber bag containing 34 mmol/L of bicarbonate was used for 4 weeks. A breakable valve divided the two chambers, one containing bicarbonate and the other calcium. The two solutions were mixed just before use, thus avoiding the calcium and magnesium carbonate precipitation.Results No differences between control and study periods were found for blood urea nitrogen, creatinine, total proteins, albumin, total and ionized calcium, phosphate, sodium, potassium, chlorine, and hemoglobin. Blood bicarbonate significantly increased from 21.25±2.02 to 23.36±1.15 (p<0.05) during the study. The peritoneal equilibration tests for urea nitrogen, creatinine, proteins, sodium, potassium, and glucose were slightly reduced during bicarbonate dialysate, but this effect was compensated for by a slight increase of ultrafiltration, thus keeping peritoneal clearances constant. Residual renal function did not change during the study. No side effects occurred during the bicarbonate period.Conclusion A CAPD bicarbonate solution is effective in uremic acidosis correction, does not affect dialysis adequacy, is safe, and well tolerated.

From January 1975 to April 1982, 10 of our patients undergoing chronic peritoneal dialysis developed fungal peritonitis. Of six treated without removing the catheter two survived after intraperitoneal (IP) administration of imidazole derivatives, and four died despite combined IP and intravenous (IV) therapy. Of four patients treated by catheter removal, all survived, two without any additional therapy and two after IV antifungal treatment. Three of the deaths followed cardiac or cerebral accidents, while one was related to Candida sepsis.Bacterial peritonitis is a frequent complication of peritoneal dialysis (FD). In addition fungal peritonitis has been reported with increasing frequency with the growing diffusion of FD, the subsequent increase in infectious episodes, the antibiotic treatment, which such complications require and the improvement in technique for mycological diagnosis.This paper describes our experience with the clinical manifestations of fungal peritonitis and its treatment in 10 patients undergoing intennittent peritoneal dialysis (IFD) or continuous ambulatory peritoneal dialysis (CAFD).