Continuous And Noninvasive Hemoglobin Monitoring Reduces Red Blood Cell Transfusion During Neurosurgery: A Prospective Cohort Study

Abstract

Context: Continuous, noninvasive hemoglobin (SpHb) monitoring provides clinicians with real-time trending of changes or lack of changes in hemoglobin, which has the potential to alter red blood cell transfusion decision making. Objective: The objective was to evaluate the impact of SpHb monitoring on blood transfusions in high blood loss surgery. Design: Prospective cohort study. Setting: Tertiary academic hospital in Cairo, Egypt from February to August, 2012 Patients: Convenience sample of adult neurosurgical patients were enrolled (n=111) with 106 completing the study. Exclusion criteria included significant liver or renal disease, coagulopathy, pregnancy, anemia, and patients scheduled for procedures with excepted low blood loss. Interventions: Patients were enrolled into either a Control Group or a SpHb Group. The Control Group received standard anesthesia care including intraoperative blood sampling when estimated blood loss was ≥15% of total blood volume and transfusion when hemoglobin was ≤10 g/dL. In the SpHb Group, the anesthesiologist was guided by the addition of SpHb monitoring. Main Outcome Measures: The effect of SpHb on transfusion practice and absolute and trend accuracy of SpHb compared to laboratory hemoglobin were evaluated. Potential cost savings from reduced red blood cell utilization were estimated. Results: Compared to the Control Group, the SpHb Group had fewer of units of blood transfused (1.0 vs 1.9 units for all patients; p≤0.001, and 2.3 vs 3.9 units in patients receiving transfusions; p≤0.01), fewer patients receiving >3 units (32 vs 73%; p≤0.01) and a shorter time to transfusion after the need was established (9.2±1.7 vs 50.2±7.9 min; p≤0.001). The absolute accuracy of SpHb was 0.0±0.8 g/dL and trend accuracy yielded a coefficient of determination of 0.93. SpHb monitoring could save $470,000 to $1,065,000 per 1,000 surgeries performed. Conclusions: SpHb monitoring resulted in decreased blood utilization and decreased transfusion costs in high blood loss neurosurgery, while facilitating earlier transfusions.