Continuous Renal Replacement Therapy for Acute Kidney Injury Using Phosphate Containing Fluid is Associated With Greater Biochemical Derangement than Conventional Fluid

Abstract

Background: Continuous Renal Replacement Therapy (CRRT) is the preferred means of renal
replacement therapy (RRT) in many intensive care units. Most units use only one type of RRT
fluid or identify a standard ‘default’ fluid. Little data is available comparing the effects of using
different RRT fluids. We aimed to identify the biochemical consequences of receiving CRRT
with potassium and phosphate free fluid, Hemosol-B0, or potassium and phosphate containing
fluid, Phoxilium, as a default RRT fluid.
Methods: Retrospective observational study in a mixed Level III Intensive Care Unit (ICU). A
period of two-six months study were compared during which either Hemosol-B0 or Phoxilium
were used as the unit’s default fluid. Daily biochemistry results and K+
and PO4
3- supplementation were recorded in all patients over eighteen years requiring CRRT during the study period;
data was collected on 35 patients in the Hemosol-B0 group and 31 patients in the Phoxilium
group. Our primary outcome was the proportion of CRRT treatment during which [PO4
3-],
[Ca2+]pl and [HCO3
-
]
pl were in the normal range, and secondary outcome the need for non-RRT
fluid K+
and PO4
3- supplementation.
Results: Phoxilium was associated with a greater proportion of the CRRT delivery time spent
with [PO4
3-] above the normal range. Furthermore, Phoxilium was associated with more time
spent with ionised [Ca2+]pl and [HCO3
-
]pl below the normal range. Phoxilium significantly decreased the requirement for phosphate but not potassium supplementation.
Conclusions: Patients receiving Phoxilium should be monitored to avoid hyperphosphataemia,
hypocalcaemia and metabolic acidosis. Phoxilium use does not abrogate the need to handle
concentrated potassium solutions.