Association of Fluid Balance and Hemoglobin Decline With Neurological Outcome After Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVES

To explore the relationship between fluid balance and hemoglobin decline with secondary infarctions and neurologic outcome in aneurysmal subarachnoid hemorrhage (aSAH) patients.

DESIGN

Secondary analysis of the Earlydrain trial, a prospective randomized controlled study investigating prophylactic lumbar drain use in aSAH patients.

SETTING

Patients with aSAH treated in ICUs at 19 tertiary hospitals in Germany, Switzerland, and Canada.

PATIENTS: From January 2011 to January 2016, 287 patients were enrolled in the Earlydrain trial. Only files with complete information on both daily hemoglobin and balance values were used, leaving 237 patients for analysis.

INTERVENTIONS: Investigation of fluid balance management and hemoglobin levels during the initial 8 days post-aSAH to establish thresholds for unfavorable outcomes and assess their impact on secondary infarctions and 6-month neurologic outcome on the modified Rankin Scale (mRS).

MEASUREMENTS AND MAIN

RESULTS

Patients with unfavorable outcome after 6 months (mRS > 2) showed greater hemoglobin decline and increased cumulative fluid balance. A significant inverse relationship existed between fluid balance and hemoglobin decline. Thresholds for unfavorable outcome were 10.4 g/dL hemoglobin and 4894 mL cumulative fluid balance in the first 8 days. In multivariable analysis, fluid balance, but not fluid intake, remained significantly associated with unfavorable outcome, while the influence of hemoglobin lessened. Fluid balance but not hemoglobin related to secondary infarctions, with the effect being significant after inverse probability of treatment weighting. Transfusion was associated with unfavorable outcomes.

CONCLUSIONS

Increased fluid balance influences hemoglobin decline through hemodilution. Fluid overload, rather than a slight decrease in hemoglobin levels, appears to be the primary factor contributing to poor outcomes in aSAH patients. The results suggest aiming for euvolemia and that a modest hemoglobin decline may be tolerated. It may be advisable to adopt a restrictive approach to transfusions, as they can potentially have a negative effect on outcome.