The influence of peritoneal surface area on dialysis adequacy.

In children, the prescription of peritoneal dialysis is based mainly on the choice of the peritoneal dialysis fluid, the intraperitoneal fill volume (mL/m2 body surface area (BSA)], and the contact time. The working mode of the peritoneal membrane as a dialysis membrane is more related to a dynamic complex structure than to a static hemodialyzer. Thus, the peritoneal surface area impacts on dialysis adequacy. In fact, the peritoneal surface area may be viewed as composed of three exchange entities: the anatomic area, the contact area, and the vascular area. First, in infants, the anatomic area appears to be two-fold larger than in adults when expressed per kilogram body weight. On the other hand, the anatomic area becomes independent of age when expressed per square meter BSA. Therefore, scaling of the intraperitoneal fill volume by BSA (m2) is necessary to prevent a too low ratio of fill volume to exchange area, which would result in a functional "hyperpermeable" peritoneal exchange. Second, the contact area, also called the wetted membrane, is only a portion of the anatomic area, representing 30% to 60% of this area in humans, as measured by computed tomography. Both posture and fill volume may affect the extent of recruitment of contact area. Finally, the vascular area is influenced by the availability of both the anatomic area and the recruited contact area. This surface is governed essentially by both peritonealvascular perfusion, represented by the mesenteric vascular flow and, hence, by the number of perfused capillaries available for exchange. This vascular area is dynamically affected by different factors, such as composition of the peritoneal fluid, the fill volume, and the production of inflammatory agents. Peritoneal dialysis fluids that will be developed in the future for children should allow an optimization of the fill volume owing to a better tolerance in terms of lower achieved intraperitoneal pressure for a given fill volume. Moreover, future peritoneal dialysis fluids should protect the peritoneal membrane from hyperperfusion (lower glucose degradation products).

[Off label drug use in adult patients treated by anticancer chemotherapy]. / Evaluation des indications hors AMM chez des patients adultes traités par chimiothérapie anticancéreuse.

Off-label drug use is supposed to be widespread in chemotherapy but very few studies have determined its extent in clinical practice. This prospective study evaluates the proportion of off-label anticancer drug use in terms of indications in a French teaching hospital. Adult ambulatory patient prescriptions were analysed by pharmacists in the year 2002. Data concerning the type of cancer and the indication of the antitumor agent were collected and compared with the official Summary of Product Characteristics in France. In the year 2002, 6,168 chemotherapy cycles (prescriptions) were administered to 1,206 patients. Four hundred and fifteen (6.7%) prescriptions presented a drug used in an off-label manner. Off label prescriptions were common in patients with hormone-refractory prostate cancer (57.6% of the courses for this type of tumor) and in patients with bladder cancer (37.6%). No off-label use was observed in patients with colorectal cancer. The drugs most commonly used in an off-label indication were docetaxel (29.1% of the off label prescriptions) and oxaliplatin (23.6%). Overall, in our hospital, the proportion of off-label use of anticancer agents in terms of indications in adult patients appears low.

Long daytime exchange in children on continuous cycling peritoneal dialysis: preservation of drained volume because of icodextrin use.

Daytime exchanges with glucose osmotic agents often lead to dialysate reabsorption, poor ultrafiltration (UF), positive sodium balance, and restricted purification of uremic toxins. We studied 5 anuric children on continuous cycling peritoneal dialysis (mean age: 10 years, 10 months), comparing icodextrin to a conventional glucose-based dialysate. The same fill volume (980 +/- 290 mL/m2) and the same dwell duration (720 minutes) were used with both solutions for the daytime exchange. In a crossover design, we compared 7.5% icodextrin with 1.36% glucose, and then 1.36% glucose with 7.5% icodextrin. Tolerance, net UF, sodium balance, and solute extraction were analyzed. The Student t-test for paired data was used for statistical analysis. The drained volume was 44% +/- 18% higher during icodextrin exchanges, allowing a mean enhanced sodium extraction of 44 +/- 15 mmol per daytime exchange. The uremic toxin extraction capacity was enhanced under icodextrin: weekly Kt/V urea increased by 0.41 +/- 0.1, weekly creatinine clearance increased by 8.4 +/- 3.6 L/1.73 m2, and phosphate removal increased by 23%. Similarly, beta2-microglobulin extraction increased with icodextrin use. Dialysate protein loss under icodextrin increased from 1.3 +/- 0.6 g to 1.9 +/- 0.96 g per daytime exchange. Icodextrin improved ultrafiltration and purification capacities (urea, creatinine, phosphate, beta2-microglobulin), but the large drained volume directly affected dialysate protein loss.