METHODS FOR ESTIMATION OF PERITONEAL DIALYSATE VOLUME AND REABSORPTION RATE USING MACROMOLECULAR MARKERS

Reabsorption of fluid and solutes from the peritoneal cavity poses sev eral problems for the correct estimation of peritoneal dialysate volum e and ultrafiltration rate with macromolecular volume markers. Althoug h physiological mechanisms of peritoneal reabsorption (direct lymphati c absorption vs reabsorption to the peritoneal tissue) are being curre ntly discussed, many experimental and clinical studies have demonstrat ed that peritoneal reabsorption of the marker is mainly a bulk ''backf low'' out of the peritoneal cavity. Theoretical bases for the estimati on of peritoneal dialysate volume and cumulative ultrafiltration of fl uid including the correction for peritoneal reabsorption are reviewed. A widely applied simplified method which, however, neglects the impac t of ultrafiltration on marker concentration is also discussed. The sy stematic errors involved in the application of the simplified method a re usually less than 10% in the standard conditions; however, in speci fic cases they may be much higher. Therefore, the correct method is su ggested for practical applications.