Influence of Urine Output on Magnesium Level in Aneurysmal Subarachnoid Hemorrhage (P02.210)

Abstract

Objective: To investigate whether high urine output after aneurysmal subarachnoid hemorrhage (aSAH) is associated with a decrease in serum magnesium level. Background Hypomagnesemia frequently occurs in critically ill patients and may be correlated with worse outcome in the subset of aneurysmal subarachnoid hemorrhage (aSAH) patients. These patients are at risk of developing cardiac arrhythmias and cerebral vasospasm, and maintaining normal serum magnesium levels may help to prevent these complications. However, the mainstay of prevention and treatment of cerebral vasospasm includes “Triple-H Therapy” (hypertension, hypervolemia and hemodilution), which may artificially increase patients9 urine outputs and subsequently lower magnesium levels. Design/Methods: A retrospective chart review at an Academic Hospital from July 1 st 2010 to December 31 st 2010 yielded 16 patients with the diagnosis of aSAH. Serum magnesium level, magnesium repletion, total fluid intake and total urine output were recorded daily. Statistical correlation was used for statistical analysis. Results: Of the 16 patients, one patient was excluded from the study due to short hospital stay. Three patients showed strong correlation (r= -0.8831; -0.7039 and -0.5840 respectively) between high daily urine output and low serum magnesium level. All three patients needed multiple magnesium replacements to maintain a stable magnesium level. Six patients showed moderate correlation (r= -0.4021; -0.3976; -0.3657; -0.3557; -0.3285 and -0.3120 respectively), and 6 showed weak and very weak correlation. Daily serum magnesium level tended to fluctuate around the admission magnesium level. Conclusions: There is no significant correlation between daily urine output and daily serum magnesium level. However, there is a tendency that more hypomagnesemia occurs when daily urine output is higher than 5 liters (L). Serum magnesium level tends to fluctuate around the admission level. Admission serum magnesium may indicate the relative magnesium level throughout the acute aSAH period. Disclosure: Dr. Gu has nothing to disclose. Dr. Klinger has nothing to disclose. Dr. Boudreaux has nothing to disclose. Dr. Botros has nothing to disclose. Dr. Griffith has nothing to disclose. Dr. Rickert has nothing to disclose. Dr. White has nothing to disclose. Dr. Samson has nothing to disclose.