Abstract
Background and aim: Correction of metabolic acidosis is one of the main objectives of dialysis treatment. In peritoneal dialysis (PD), correction of metabolic acidosis is obtained by the addition of alkali (lactate, bicarbonate or mixture of both) into the PD fl uid (PDF).
Instead commonly used glucose, another osmotic agent is icodextrin (glucose polymer with molecular weight of 12-20 kDa). It was observed, that the permeability of peritoneal membrane for creatinine and phosphates is increased, during the peritone al equilibration test (PET) performed after the nighttime dwell with icodextrin.
The effect of icodextrin PD fluid on alkali gain has not been studied yet. The aim of our study is to describe, if the preceeding nighttime exchange with icodextrin can affect the alkali inlfux during the next exchange with the PD fluid containing mixture of lactate and bicarbonate.
Methods: A total of 21 patients with chronic renal failure (14 men), aged 58.8 (22-84) years, treated by PD for 22.6 (1-147) months were examined. Eleven of them used, during the nighttime dwell, a solution with icodextrin (Extraneal (R) , Baxter, Castelbar, Ireland, lactate base 40 mmol/L).
The control group consists of ten patients, they used during the nighttime dwell, a glucose- based solution (Phy sioneal (R) , Baxter, Castelbar, Ireland, bicarbonate 25 mmol/L and lactate 15 mmol/L). Samples of PDF and blood for lactate and bicarbonate determination were obtained at 0, 2 and 4 hours of standard 4-hour periton eal equilibration tests (PET).
Base influx was calculated as follows: [(PDF instilled volume x base concentration) - (PDF drained volume x base concentration)] Results: In the icodextrin group the bicarbonate influx during 4 hours dwell was -3.25 +- 4.03 mmol, lactate influx 18.42 +- 5.50 mmol and total alkali influx 15.17 +- 5.53 mmol. In the control group -3.66 +- 6.66 mmol, 19.33 +- 5.73 mmol resp. 15.67 +- 8.96 mmol.
There were no statisticaly significant differences between both groups. Conclusions: It is evident, from our results, that the previous nighttime exchange with icodextrin had no effect alkali gains.
The reason can be the significant bidirectional transport of bicarbonate which is in this way different from the creatinine an d phosphate transport. The next reason is the absence of relation between peritoneal transport charakteristics and alkali transpo rt, when using PD fluid with mixture of bicarbonate and lactate Our results does not rule out an effect of this PDF on 24-hour alkali gain.