Histological and Functional Characteristics of the Peritoneal Membrane of a Diabetic Patient after 34 Months of CAPD

This report describes the course of a 37-year-old man with diabetic nephropathy over 34 months of CAPD. These data suggest that the functional characteristics and the histology of the peritoneum were not altered by CAPD or repeate4 episodes of peritonitis up to the time of his death from an acute myocardial infarction.

Effect of the Peritoneal Dialysate Buffer on UL TRafil Tration: Studies in Normal Rabbits

We studied an animal model to test the ultrafiltration capability of three different peritoneal dialysis solutions: Brand A, containing lactate and manufactured in Canada, Brand B, containing acetate and manufactured in U.S.A. and Brand C also containing acetate and manufactured in France. Solutions with 1.5 g0/o and 4.25 g0/o glucose concentrations were tested. We found no significant difference in the amount of ultrafiltration produced with the three brands when glucose concentration was 1.5 g0/o. However with glucose concentration of 4.25 g 0/o ultrafiltration was significantly lower with the Brand C-French acetate solution comparing to Brand A-Iactate solution. Brand B (acetate U.S.A.) solution produced ultrafiltration volumes that were between the other two and were not statistically significantly different from either Brand A (acetate) nor from Brand C (acetate).

We concluded that the lower ultra-filtration produced by Brand C is not due to the presence of acetate buffer but to other factors operating alone or in combination with acetate.

Adequate peritoneal ultrafiltration for fluid balance is one of the main factors in the success of continuous ambulatory peritoneal dialysis (CAPD). Ultrafiltration failure associated with the use of acetate buffered dialysis solution has been described frequently in France (I, 2, 3), but only occasionally in North American centres (4,5,6).

It is still controversial whether acetate or some other element(s) is the factor responsible for the ultrafiltration failure observed in French patients. The first report of an international co-operative study revealed that ultrafiltration is significantly lower in patients using acetate, compared to those using lactate dialysis solutions (7). However, the second report of this study, which contained results from patients using a larger number of brands, showed that acetate may not be a responsible factor because there were patients using acetate-solutions manufactured outside France who had an ultrafiltration similar to that produced with lactate brands (8). Because of this, we chose to study in an animal model the ultrafiltration produced with solutions containing different buffers during acute experiments. This paper reports our findings.

Effects of dipyridamole on peritoneal clearances

To see if oral dipyridamole increases peritoneal clearances in humans undergoing peritoneal dialysis, two types of double-blind clinical studies were undertaken. In a single-dose study, 7 patients were randomized to take dipyridamole or placebo early in a peritoneal dialysis with 2 L, hourly cycles; later in the same dialysis a crossover administration was studied. In a multidose study, 17 patients were randomized to take dipyridamole or placebo three times daily and clearance studies were performed on days 1, 4, and 8 during 2 L, hourly peritoneal dialysis cycles. Neither the single dose of dipyridamole or placebo significantly altered drainage volumes, clearances, or dialysate protein from control periods. In the multidose study, mean values on dipyridamole or placebo were not significantly changed from respective baseline predrug values. Mean values with dipyridamole and placebo usually were not significantly different. Dipyridamole did not appear to improve peritoneal clearances even with repeated ingestion.

The quantitative transperitoneal absorption of a fat emulsion: implications for intraperitoneal nutrition

Intraperitoneal (IP) administration of nutrients would be an attractive alternative to intravenous nutrition since it eliminates intravascular complications. If glucose alone were used as the nonprotein calorie source, associated fluid shifts might not be well tolerated by the patient. A fat emulsion does not have osmotic properties and thus might be incorporated into a program of IP nutrition as a calorie source. Transperitoneal absorption of a commercial fat emulsion (Liposyn 10%, Abbott Laboratories, N Chicago, IL) was studied in 12 beagle puppies divided into two groups. One group received 2.5 gm/kg of fat and the other group received a similar volume of 3.5% crystalline amino acids and 5% glucose in one IP dose. In the first group, the serum triglyceride (TG) increased three fold from 61 +/- 25 mg% to 185 +/- 61 mg% at 15 minutes and then decreased slowly while remaining significantly elevated (p less than 0.05) at 4 hours. 1.94 +/- 0.20 gm/kg of TG were absorbed from the peritoneal cavity over 4 hours. Concommitant IP administration of amino acids and glucose did not affect that absorption. Radiolabeled amino acids and glucose instilled IP were demonstrated in the blood immediately after administration and their absorption was not affected by the presence of a fat emulsion. Plasma free fatty acids showed a small increase at 4 hours (from 0.32 +/- 0.09 mEq/L to 0.59 +/- 0.22 mEq/L). Animals receiving no IP fat showed no change in serum TG. Serum glucose rose in both groups and serum cholesterol showed no changes in either group. Peritoneal fluid accumulation 4 hours after IP fat administration was minimal at 12.7 +/- 6.4 mL/kg. This study shows that a fat emulsion can be quantitatively absorbed from the peritoneal cavity over four hours and that IP nutrition may be feasible.

Hyperosmolality, acetate, and lactate: dilatory factors during peritoneal dialysis

Factors that alter peritoneal blood flow may influence the clearance of solutes during peritoneal dialysis. Arteriolar vasodilation, for instance, could increase the delivery of solutes to the capillaries and venules leading to an increase in solute transport into the peritoneal cavity. This study was designed to identify the vasoactive effects of several major components of McGaw and Dianeal peritoneal dialysis solutions to understand how the composition of these solutions may alter in vivo blood flow in the peritoneum. Because the major differences between these solutions and Krebs solution are a high osmolality, a high dextrose concentrations, and an acetate or lactate buffer system, we investigated the effects of these components. Rats were anesthetized with the combination of urethane and chloralose. The cremaster muscles, with the nerve and blood supplies from the rat still intact, was placed in a specially designed tissue chamber that was filled with Krebs solutions. A port permitted microscopic observations of the blood vessels. In vivo television microscopy observations was used to quantitate changes in small arteriole diameters induced by changes in the composition of the solution bathing the cremaster or by the addition of nitroprusside. Hyperosmolality produced by the addition of dextrose, sucrose, or sodium chloride to the Krebs solution induced a submaximal dilation of the small arterioles of the cremaster. The rate of dilation differed depending on the substance used to increase osmolality. A normal osmolality acetate (74 mM) or lactate (45 mM) solution produced a slow, submaximal dilation of the cremaster arterioles. Hyperosmolar acetate (37 or 74 mM) or lactate (45 mM) solutions produced a rapid, maximal dilation of these vessels. Because the rate of dilation and maximal effect produced by the commercial dialysis solutions were similar to these same parameters produced by the high-osmolality acetate or lactate solutions, the dilatory effects of McGaw and Dianeal solutions appear to be due to the combinations of high osmolality and the buffer anion acetate or lactate.