A New Graduated Dosing Regimen for Phosphorus Replacement in Patients Receiving Nutrition Support

Abstract

This weight-based phosphorus-dosing algorithm is safe for use in critically ill patients receiving nutrition support. The moderate and severe-dose regimens effectively increase serum phosphorus concentrations.

Phosphorus and Calcium

“…A few different regimens based on patient weight and serum [P] have now been published, but these have been primarily in critically ill trauma patients and surgical ICU patients with normal renal function. [61][62][63] There are several other published reports of fixed-dose phosphate supplementation in patients with normal renal function. [64][65][66][67][68][69][70] Based on these published reports, Table 2 provides one approach to IV P dosing for treating hypophosphatemia in patients with normal renal function.…”

“…In addition, oral P absorption may be decreased in patients with vitamin D deficiency. 5,72 Some have added P supplements directly to EN formulas (either oral or IV dosage formulations), 56,62 and this approach may be efficacious when treating asymptomatic hypophosphatemia, 56 although recent guidelines do not recommend this practice. 71 One report of 2 malnourished patients demonstrated enteral P contained in EN formulations was not adequate to prevent hypophosphatemia and ultimately required IV supplementation to correct serum [P], although there may have also been other contributing factors in these cases.…”

“…Several published studies on the treatment of hypophosphatemia describe monitoring serum [P] within approximately 12-24 hours after supplementation or on a daily basis. [61][62][63]65,69 Despite this, it may be prudent to monitor serum [P] more frequently in some patients with severe hypophosphatemia until serum concentrations normalize. Administer additional P supplements until the patient is asymptomatic and the serum [P] is at least >2.0 mg/dL; the goal is to return the serum [P] to the normal range (ie, 2.7-4.5 mg/dL) and avoid symptoms.…”

“…Some patients will require multiple doses over several days to completely correct hypophosphatemia, especially those with severe malnutrition/refeeding syndrome, those with P depletion, and critically ill patients. 57,61,62,65,70,74 Finally, when using weight-based dosing, there are no definitive data or recommendations for "adjusting" weight in obese patients or what threshold should be used to adjust weight (eg, using a percentage above ideal body weight [IBW] or based on body mass index). Total body water is slightly higher in males than in females, and adipose tissue is composed of approximately 10%-30% water.…”

Treatment of hypophosphatemia in the intensive care unit: a review

“…Intravenous therapy is generally recommended in symptomatic hypophosphatemia and phosphate levels <0.32 mmol/L. Multiple studies have evaluated the efficacy and safety of intravenous phosphate repletion regimens (Table 4) [61-67]. These studies generally agree that aggressive phosphate supplementation is safe with phosphate doses up to 45 mmol with infusion rates up to 20 mmol per hour.…”