Use of the Masimo Rainbow Noninvasive Hemoglobin Measurement Technology for Children with Sickle Cell Disease




Farris, Landon

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PURPOSE OF STUDY: Until recently, pulse oximeters have been limited by the fact that they use two wavelengths of light to measure oxygen saturation. The use of only two wavelengths often resulted in serious errors, especially in patients with hemoglobinopathies. Although multiwavelength pulse oximeters have been the subject of research in the past, the first multiwavelength instruments did not reach the commercial medical market until 2005. More recently, the new ‘Rainbow Technology’ pulse oximeters developed by Masimo Corp., which also use multiple wavelengths, have permitted the noninvasive measurement of total hemoglobin. To further evaluate the accuracy of this new technology, we intended to test the hypothesis that the total hemoglobin as measured by the Masimo Rainbow Radical correlates with laboratory data in children with sickle cell anemia as measured by the Sysmex Automated Hematology Analyzer. METHODS USED: Hemoglobin measurements were taken at Children’s Medical Center in Dallas from patients under the age of 18 with a diagnosis of sickle cell anemia. In addition, the study limits enrollment to patients which are scheduled for routine hemoglobin measurements as part of their clinical course. A single use, flexible probe is applied on the middle finger of the hand from which blood is drawn, and the monitor is allowed to run for 3-5 minutes until the readings are stabilized. Only the readings taken at the time of the blood draw are recorded as SpHb values and used for subsequent analysis. SUMMARY OF RESULTS: 150 patients were enrolled, and the device completed measurements on 133 of the patients. The Masimo Rainbow Radical recorded a total hemoglobin measurement an average of 17 minutes from when blood was taken for laboratory analysis. The hemoglobin values as measured by the Radical (SpHb) and the Sysmex Automated Hematology Analyzer (Hb) differed by an average absolute value of 1.26 g/dL. Additionally, when the SpHb measurements are plotted against the Hb values, the Pearson Correlation Coefficient is 0.69. The mean bias was 0.8 g/dL with a standard deviation of 1.3 g/dL and limits of agreement of -1.8 to 3.4 g/dL. SpHb. CONCLUSIONS: The bias and precision of SpHb to Hb in our patients was higher than that found in healthy volunteers. This might be due to the different sensors used in adults and children, or may be due to the presence of sickle hemoglobin in our patients. Further studies are needed to clarify this issue. However, at this preliminary stage, the correlation between the Rainbow Radical and Hematology Analyzer suggests that the multiwavelength technology could be used as a substitute for routine screening hemoglobin measurement by blood draw.

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