Impact of intravenous magnesium infusion rate during ambulatory replacements on serum magnesium concentrations after allogeneic stem cell transplant.

Abstract

For an outpatient cancer center to operate efficiently, optimizing the use of chair time is essential. Allogeneic hematopoietic cell transplant (allo-HCT) recipients are seen frequently in this setting after hospital discharge and regularly for several months thereafter. Aggressive electrolyte replacement is commonly required in these patients, primarily due to renal wasting with calcineurin inhibitor use. Frequent intravenous (IV) magnesium repletion, requiring several hours of infusion time, is often needed in these patients to adequately manage their magnesium deficiencies. The purpose of this study is to explore the impact of extending the infusion rate of intravenous magnesium sulfate on the frequency and degree of IV magnesium replacements required in allo-HCT recipients. We conducted a retrospective study to compare two cohorts of patients administered IV magnesium sulfate at a rate of 4g/1h versus 4g/2h. A total of 103 continuous patients were assessed in two groups as cohort 1 at the 4g/1h rate and cohort 2 at the 4g/2h rate. Cohort 1 required less IV magnesium per outpatient visit (median 2.2 vs. 2.9g/visit, P = 0.0211) and less total IV magnesium replacement through day +100 (median 68 vs. 85g, P = 0.0479) than cohort 2. These data suggest that there is no apparent benefit of prolonging magnesium infusion from 1 to 2h in our outpatient allo-HCT population.