Serum glucose and phosphorus concentrations during continuous renal replacement therapy using commercial replacement solutions with or without phosphorus

Abstract

Introduction Continuous venovenous hemofiltration (CVVH) is a common practice in the intensive care unit often associated with electrolyte derangements. Recently, our institution added a phosphate dialysis solution, Phoxillum®, to our formulary as an option for CVVH fluid in addition to the bicarbonate‐based Prismasol® products available. We sought to evaluate the impact of Phoxillum in patients who required CVVH when compared to Prismasol with regard to phosphate and glucose management. Methods This was a single‐center, retrospective, observational cohort analysis approved by Partners Health Care System Institutional Review Board that included patients who received a minimum of 24 hours of either Prismasol 4/2.5 or Phoxillum for CVVH from February 2017 to November 2017. Phosphate and glucose levels were monitored daily while on CVVH. Prevalence of hypoglycemia (glucose <70 mg/dL), hyperglycemia (glucose >180 mg/dL), hypophosphatemia (phosphate <2.5 mg/dL), and hyperphosphatemia (phosphate >4.3 mg/dL) were collected in terms of days of occurrence while on CVVH. Oral and intravenous phosphate repletion requirements were collected for all patients. Findings Hypophosphatemia occurred more frequently while patients were receiving Prismasol as compared to Phoxillum (130 [24.9%] vs. 13 [6.2%], rate ratio [RR] 0.20 [95% confidence interval—CI = 0.10–0.42, P < 0.0001]), and consequently there was a numerically lower need for intravenous phosphorous repletion in the Phoxillum group (RR = 0.58, 95% CI [0.26, 1.30], P = 0.19]. There was a numerically higher incidence of hyperphosphatemia while patients were on Phoxillum therapy as compared to Prismasol (78 [37%] vs. 145 [27.7%], RR 1.25 [95% CI = 0.84, 1.86, P = 0.27]). There was no difference between the Phoxillum and Prismasol groups in terms of hypoglycemia or hyperglycemia. There was no notable difference in the cost found between the two therapies. Discussion The findings suggest that the use of Phoxillum for CVVH may be associated with decreased incidence of hypophosphatemia and a potentially decreased need for phosphate repletion in patients who require CVVH.

Association of Phosphate Containing Solutions with Incident Hypophosphatemia in Critically Ill Patients Requiring Continuous Renal Replacement Therapy

“…Glucose measurements resulting in (hyper- and hypoglycemia) were not different in the 2 groups. Our study results align with the findings of Crowley et al [22], with a significant reduction in incidence of hypophosphatemia during CRRT, and higher rates of hyperphosphatemia with the use of phosphate containing CRRT solutions. Importantly, in our study, maximum serum phosphate levels during CRRT were not different between the 2 CRRT solutions groups, which may represent that clinically significant hyperphosphatemia may have been related to other factors beyond the CRRT solution type.…”

“…Another study by Crowley and colleagues [22] assessed the impact of phosphate containing CRRT solutions on phosphate levels and glucose measurements. This was a single-center, retrospective observational cohort study including 60 adult patients who received CRRT for ≥24 h. The incidence of hypophosphatemia (per CRRT days) in this study was higher in the non-phosphate containing CRRT solution group versus the 1 mmol/L phosphate containing CRRT solution group: 24.9 versus 6.2% (RR 0.20; 95% CI 0.10–0.42, p < 0.0001), respectively.…”

Association of Phosphate-Containing versus Phosphate-Free Solutions on Ventilator Days in Patients Requiring Continuous Kidney Replacement Therapy

“…It is reasonable to hypothesize that hypophosphatemia-induced diaphragm weakness impairs respiratory function, possibly prolonging mechanical ventilation and increasing the need for tracheostomy and the risk of mortality as some studies have shown (32). Importantly, this is a modifiable risk factor in critically ill patients requiring CRRT (18,19). Differing trajectories of serum phosphate levels by patients in the two CRRT solutions groups, as depicted in Figure 2, further support this hypothesis.…”

“…The two primary strategies for managing phosphate during CRRT include: (1) utilizing phosphate-free CRRT solutions plus protocolized phosphate replacement or (2) a preemptive strategy with phosphate-containing CRRT solutions through compounding or the use of commercially available options (16,17). The use of preemptive phosphate replacement with phosphate-containing CRRT solutions has been associated in several studies with a reduction in the severity and duration of hypophosphatemia in patients in the ICU requiring CRRT; however, none of these studies have been large enough to observe an effect on clinical outcomes (4,15,(18)(19)(20)(21). The aim of this study was to examine the relationship between the receipt of phosphatecontaining (versus phosphate-free) CRRT solutions and clinical outcomes of ventilator dependence in a mixed adult patient population in the ICU receiving CRRT and mechanical ventilation.…”

Continuous KRT

“…Notably, the commercially available phosphate-containing CKRT solutions are formulated without dextrose. Although observational data suggest the risk of severe hypoglycemia is not significantly higher with these solutions compared with standard phosphate-free solutions with dextrose (71,72), additional glucose monitoring may be prudent. Additionally, the prolonged use of glucose-free CKRT solutions in patients not receiving nutrition can predispose to the development of euglycemic ketoacidosis, which manifests as unexplained anion gap metabolic acidosis, normal serum glucose, and ketonemia and corrects with the provision of insulin with glucose (73).…”