[The Carboclip, a new, atraumatic vascular access for hemodialysis].

The Carboclip is a no-needle vascular access device made of an inverted Titanium body. The horizontal bar of 6 mm inner diameter is connected with artery and vein via a vascular graft. The vertical body houses an elastic plug in which is inserted a double canula diving in the blood stream for extracorporeal blood circulation (EBC).

Renal biofiltration.

Biofiltration is a hemodiafiltration technique performed with a base-free dialysate and simultaneous infusion in postdilution mode of isotonic bicarbonate solution. This technique has the advantages without the inconveniences of bicarbonate dialysis that result from complicated hardware and the need of frequent trouble shooting. In biofiltration, 1) the sodium dialysate concentration should be monitored according to the patient's body weight gain and to the sodium concentration of infusion fluid to obtain adequate sodium mass balance and 2) plasma bicarbonate is easily controlled because the final plasma bicarbonate concentration depends upon the bicarbonate infusion flow rate.

Characterization and identification of substances isolated from dialyzer extracts.

The organic phase of dialyzer dried extracts obtained from Cuprophan hollow fiber and polyacrylonitrile AN 69 parallel-plate dialyzers, all sterilized by ethylene oxide, were submitted to light and polarized light microscopy, infrared (IR) spectrophotometry, and gas chromatography coupled with mass spectrometry. Colorless polygonal (approximately 5 X 20 micron) and needle-like (approximately 3 X 50 micron) crystals were found in great quantity on microscopy examination. IR spectrophotometry of the crystals embedded in potassium bromide disc showed specific spectra in the 1400-800 cm-1 wave number range and typical peaks on wave number assigned for hydroxy or amine (3420 cm-1), aromatic hydrogen (3060 cm-1), methyl, methylenic, or methenyl (2960-2860 cm-1), and carbonyl (1715 cm-1) groups can be demonstrated.

Clinical validation of a predictive modeling equation for sodium.

Changes in plasma sodium (Na) concentration during hemodialysis were predicted by changes in Na concentration of the dialysate at equilibrium with the plasma, according to the formula C't = CD - (CD - C'0) [(V0 - QFt)/V0]A/QF, where C'0 and C't are the Na concentration of the dialysate at equilibrium with the plasma at times 0 and t, respectively; QF is the ultrafiltration flow rate; V0 is the initial total body water; and CD is the Na dialysate concentration. This modeling involves only one parameter, A, which is the effective sodium dialysance and depends on the dialyzer, the QF, the plasma water flow rate, and the actual Donnan coefficient. Parameter A was evaluated after 1 h of dialysis.

[Bicarbonate-containing dialysate: a critical study].

Renewed interest in bicarbonate as the dialysate base replacement during hemodialysis has introduced new settings on acetate-dialysate delivery systems commercially available. Numerous technical problems are associated with unstable bicarbonate solutions. Therefore, several precautions must be observed: 1) Bicarbonate dialysis requires two concentrates: one containing the base replacement bicarbonate and the other containing basically calcium and magnesium chlorides, 2) A two-stream proportioning system afforded by an appropriate dialysate delivery machine should be used to mix the bicarbonate and acid concentrates, in order to ensure on-line production of the final dialysate, 3) Additional monitors, such as pH monitor, are required to prevent misuse of concentrates.