ARE WE UNDERESTIMATING THE PROBLEM OF ULTRAFILTRATION IN PERITONEAL DIALYSIS PATIENTS?

• Published in: Peritoneal dialysis international 2006-05, Vol.26 (3), p.349-352
• Main Authors: McCafferty, Kieran, Fan, Stanley L.-S
• Format: Article
• Language: English
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Emergency and intensive care: renal failure. Dialysis management; Glomerulonephritis; Hemofiltration - adverse effects; Hemofiltration - methods; Humans; Intensive care medicine; Interviews as Topic; Medical sciences; Nephrology. Urinary tract diseases; Nephropathies. Renovascular diseases. Renal failure; Patient Education as Topic; Peritoneal Cavity - physiology; Peritoneal Dialysis - methods; Peritoneal Dialysis, Continuous Ambulatory; Reproducibility of Results; Software; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the urinary system; Telephone; United Kingdom
• ISSN: 0896-8608; 1718-4304
• DOI: 10.1177/089686080602600312

Department of Renal Medicine and Transplantation, Barts and The London Hospital NHS Trust, London, United Kingdom Correspondence to: S. Fan, Department of Renal Medicine and Transplantation, Barts and The London Hospital NHS Trust, Whitechapel, London E1 1BB, United Kingdom. s.fan{at}qmul.ac.uk Background: Accurate measurement of ultrafiltration (UF) is important to improve the morbidity and mortality of peritoneal dialysis (PD) patients. The introduction of "flush-before-fill" PD systems has led to improved peritonitis rates. Partly to compensate for dialysate lost during flush-before-fill, extra dialysate was added to each PD bag. A 2-L PD bag now contains a mean volume of 2.225 L. That overfill volume might be erroneously measured as UF. We previously studied how this confounding factor might be affecting the diagnosis of UF failure and found that almost all units were overestimating daily UF by 900 mL. We now repeat the study to determine if the accuracy of UF estimation has improved. Methods: We conducted a telephone survey of PD units in the UK to determine how drain bags are weighed and how UF is calculated during formal assessment of adequacy and the peritoneal equilibrium test (PET). We also retrospectively analyzed our last 100, 24-hour dialysate collections and PET results to determine the potential clinical impact of overestimating UF. Results: There has been an improvement since our last study, but 70% of PD units in the UK are still overestimating daily UF in patients on continuous ambulatory PD (CAPD). Half the surveyed units also inaccurately calculate UF during the PET, and 85% were reporting results of PET and 24-hour dialysate collections through the software provided by Baxter Healthcare. By including the overfill volume, 73% of patients with daily UF