Blessing Osondu, MD, Nephrologist
Critical Care Medicine Clinical Fellow
Washington University in St Louis
Saint Louis, MO
Disclosure information not submitted.
Julianne Yeary, BCCCP, PharmD
Clinical Pharmacy Specialist - Emergency Medicine
Barnes Jewish Hospital
Saint Louis, MO
Disclosure information not submitted.
Bethany Pennington, PharmD
Clinical Pharmacy Supervisor, Critical Care
Washington University School of Medicine
Saint Louis, Missouri, United States
Disclosure information not submitted.
Anitha Vijayan, MD,
Professor of Medicine
Washington University of Saint Louis
Saint Louis, MO
Disclosure information not submitted.
Charbel Khoury, MD
Assistant Professor of Medicine, Division of Nephrology
Washington University School of Medicine
Saint Louis, Missouri, United States
Disclosure information not submitted.
Title: Oral Phosphorus Repletion for Hypophosphatemia in Continuous Renal Replacement Therapy (CRRT)
Introduction: Hypophosphatemia (serum phos < 2.5 mg/dL) is a frequent complication in CRRT and is associated with adverse outcomes including prolonged mechanical ventilation. Given the frequent shortages of IV phosphate (phos) solutions and the added cost of phos-containing CRRT solutions, we sought to determine whether per oral (PO) replacement of phos prevents hypophosphatemia and limits the need for IV phos in patients on CRRT.
Methods: This was a retrospective, observational study in medical and surgical ICUs at Barnes Jewish Hospital. A review of the electronic medical record was conducted to identify adults with AKI on CRRT for ≥ 48hrs in 2020, who received PO phos. ESRD patients were excluded. Clinical characteristics were examined over a 14-day period. Data was analyzed by SAS®.
Results: Our study included 135 patients of mean age 59.7y. 37.8% were male and 36% were black. Mean Apache II score was 19.3 ± 4.5 and 14-day mortality was 14.1%. On average, nadir serum phos was reached on day 5 from CRRT initiation (2.6 ±1.1 mg/dL). The total dose of PO phos received was 5764.8 ±4330mg. 46.7% of patients required IV phos.
A Spearman’s correlation test found a negative correlation between serum phos and daily PO phos dose (cc=-0.1646, p< 0.0001), suggesting that PO phos was unable to prevent hypophosphatemia. This also shows that the prescription pattern is in reaction to, rather than to prevent hypophosphatemia.
In further analysis, we stratified patients into tertiles of total PO phos prescribed (≤3, 3-7, ≥7 g PO phos). We found that 30% of patients in the lower tertile required IV phos compared to over 50% in the 2nd and 3rd tertile (p=0.0376 ANOVA with tukey’s multiple comparison). However the overall dose of IV phos was not statistically different among tertiles.
Conclusions: Hypophosphatemia is a significant complication in patients on prolonged CRRT. While our current PO phos repletion strategy is often not sufficient to prevent hypophosphatemia, we hypothesize that the initation of PO phos within the first 24hrs of CRRT may help maintain serum phos levels and prevent dependence on IV phos repletion.