Biochemical effects of phosphate-containing replacement fluid for continuous venovenous hemofiltration

Aims: To examine biochemical effects of phosphate-containing replacement fluid (Phoxilium®) for continuous venovenous hemofiltration (CVVH). Methods: Retrospective comparison of respective serum biochemistry with sequential use of Accusol™ and Phoxilium, each over 48 h of CVVH. Results: We studied 15 critically ill patients. Accusol was switched to Phoxilium after 5 (4–8) days of CVVH. Respective serum biochemistry after 36–42 h of Accusol versus Phoxilium were: phosphate 1.02 (0.82–1.15) versus 1.44 (1.23–1.78) mmol/l, ionized calcium 1.28 (1.22–1.32) versus 1.12 (1.06–1.21) mmol/l, bicarbonate 24 (23–25) versus 20 (19–22) mmol/l, base excess 0 (–2 to 1) versus –4 (–6 to –3) mmol/l (p < 0.001). Cumulative phosphate intakes during respective periods were 69.6 (56.6–76.6) versus 67.2 (46.6–79.0) mmol (p = 0.45). Plasma strong ion differences were narrower with Phoxilium (p < 0.05), with similar strong ion gaps. No additional intravenous phosphate was given during Phoxilium use. Seven patients had serum phosphate >1.44 mmol/l. Conclusions: Phoxilium versus Accusol use during CVVH effectively prevented hypophosphatemia but contributed to mild hyperphosphatemia, and is associated with relative hypocalcemia and metabolic acidosis.