title: Hybrid dialysis: recirculation peritoneal dialysis revisited.
abstract: In a crossover trial, eight patients were studied during one treatment each of automated peritoneal dialysis (APD) and hybrid dialysis (HyD). During HyD, a fixed quantity of peritoneal dialysis fluid (PDF) was continuously removed at a flow rate of 141.3 +/- 23. 7 mL/min, dialyzed against the secondary dialysate (250 +/- 53.5 mL/min) generated by the hemodialysis delivery system with single-needle dialysis capability, and the regenerated PDF (PDF(HyD)) was reinfused into the peritoneal cavity. Despite using a smaller volume (6,195 +/- 737 versus 13,321 +/- 1,201 mL; P < 0. 0001) of PDF(HyD) with a lower glucose concentration (729 +/- 562 versus 1,659 +/- 373 mg/dL; P < 0.0001) and osmolality (331 +/- 79 versus 387 +/- 184 mOsm/kg; P < 0.001) during HyD compared with APD (PDF(APD)), weight loss was similar with both treatments (1.4 +/- 1. 0 versus 1.6 +/- 1.2 kg). Lactate levels were lower (3.2 +/- 2.5 versus 11.4 +/- 5.4 mEq/L), but pH (7.5 +/- 1.3 versus 5.6 +/- 0.9; P < 0.001) and bicarbonate concentration (22.6 +/- 8.0 versus 11.9 +/- 7.9 mEq/L; P < 0.0001) were greater in PDF(HyD) than PDF(APD). Although the mean dialysate calcium level was lower (6.0 +/- 0.5 versus 6.9 +/- 1.1 mg/dL; P < 0.001) in PDF(HyD), it was more stable throughout the dialysis compared with PDF(APD). A steeper concentration gradient between the blood and dialysate resulted in greater clearance of urea (26.5 +/- 9.1 versus 11.0 +/- 4.7 mL/min; P = 0.04), creatinine (24.1 +/- 11.4 versus 12.0 +/- 7.9 mL/min; P = 0.03), phosphate (19.2 +/- 4.3 versus 9.8 +/- 7.2 mL/min; P = 0.01), and uric acid (15.6 +/- 6.9 versus 9.1 +/- 2.7 mL/min; P = 0.04) and a greater percentage of reduction in values for blood urea nitrogen (20.7% +/- 7.7% versus 11.6% +/- 5.5%; P = 0.02), serum creatinine (16.1% +/- 5.3% versus 6.6% +/- 3.0%; P < 0.001), phosphate (22.7% +/- 8.9% versus 9.8% +/- 4.5%; P = 0.004), and uric acid (15.8% +/- 2.9% versus 6.3% +/- 3.4%; P < 0.001) during HyD than APD. To conclude, HyD is a novel dialytic technique that uses biocompatible bicarbonate-based dialysate to achieve excellent clearance of uremic toxins and ultrafiltration with minimal glucose load.
authors.affiliation: Division of Nephrology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-5271, USA. rajdominic@hotmail.com
authors.forename: D S
authors.initials: DS
authors.lastname: Raj
authors.forename: M
authors.initials: M
authors.lastname: Self
authors.forename: J
authors.initials: J
authors.lastname: Work
mesh_terms: D001639:Bicarbonates / Q000032:analysis; D003404:Creatinine / Q000378:metabolism; D015314:Dialysis Solutions / Q000737:chemistry; D005260:Female; D005947:Glucose / Q000032:analysis; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D019344:Lactic Acid / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000379:methods*; D014508:Urea / Q000032:analysis
chemical_list: D001639:Bicarbonates; D015314:Dialysis Solutions; D019344:Lactic Acid; D014508:Urea; D003404:Creatinine; D005947:Glucose