Reliability of a spot check non-invasive hemoglobin monitoring (SpHb) of the Masimo RAD-67™ and the HemoCue® for anemia screening

Abstract

Background : To test the reliability of the spot check Masimo Rad-67 (Masimo Corp., Irvine, CA, USA) as part of a preoperative anemia screening, hemoglobin measurements were compared to those of the HemoCue® Hb 201+ System (HemoCue AB, Ängelholm, Sweden) and the standard laboratory measurement.

Methods : During preoperative evaluation of patients scheduled for elective orthopedic surgery hemoglobin concentration was simultaneously determined by standard laboratory analysis (HbLab), the HemoCue® Hb 201+ System (Hb_Hemocue) and by Pulse Co-Oximetry using the Masimo Rad-67 (SpHb) with the rainbow® DCI®-mini Sensor (Masimo Corp., Irvine, CA, USA). Linear correlation, agreement (Bland-Altman analysis), sensitivity/specificity and positive/negative prediction values (PPV/NPV) for anemic hemoglobin values were determined. P-values less than 0.05 were considered statistically significant.

Results : 303 patients were analyzed. Twenty-one patients (12 male and 9 female) had mild or moderate anemia, detected by Hb_Lab. In 20 patients, the Hb_Hemocue, and in 34 patients, the SpHb detected anemia. Linear correlation and mean bias (limits of agreement, LOA) for Hb_Hemocue and Hb_Lab were r = 0.969 and -1.08 (+6.44/-8.60) g/L, and for SpHb and Hb_Lab r = 0.61 and +1.76 (+26.92/-23.4) g/L. Sensitivity/specificity of the Hb_Hemocue to detect anemia in all, male and female patients were 85.0/99.3%, 75.0/100/% and 88.9/98.9/% with a PPV/NPV of 89.5/98.9%, 100/98.0% and 80.0/99.3%, respectively. Sensitivity/specificity of SpHb to detect anemia for all, male and female patients were 71.4%, 93.3%, 75.0/95.2/% and 66.7/91.1%, with a PPV/NPV for all, male and female patients of 44.1/97.8%, 56.3/97.9% and 33.3/97.7%, respectively.

Conclusions : Hb_Hemocue and Hb_Lab show a strong linear correlation and a good agreement, while linear correlation of SpHb and Hb_Lab is moderate and agreement poor. For both devices, anemia detection is moderate, but the positive prediction value for anemia is much better with the Hb_Hemocue. Both devices reliably detected non-anemic patients.

Glossary : CO = carbon monoxide ; PPV = positive predicted value ; NPV = negative predicted value ; Hb_Lab = hemoglobin determined by the laboratory ; Hb_Hemocue = hemoglobin determined by the HemoCue device ; SpHb = hemoglobin determined by the Masimo-RAD67 device ; LOA = limits of agreement ; LOS = length of stay ; POC = point of care ; SpO₂ = arterial hemoglobin ; PR = pulse rate ; PI = perfusion index ; PVI = plethysmography variability index ; SpCO = carboxyhemoglobin ; SpMet = methemoglobin ; LED = Light Emitting Diodes ; HiCN = hemiglobincyanide ; SLS = Sodium Lauryl Sulphate ; BMI = body mass index ; BT = body temperature ; WHO = World Health Organization ; IQR = interquartile range ; MAP = mean arterial pressure ; HF = heart frequency ; SD = standard deviation

Key point Summary :
– Question : Is Hb measurement of the Masimo Rad-67 and of the HemoCue reliable?
– Findings : Non-anemic patients are reliably detected with the Masimo Rad-67. Of the 303 patients examined, HbLab detected twenty-one patients (12 male and 9 female) with mild or moderate anemia. The Hb_hemocue showed anemia in 20 patients, while the SpHb identified 34 patients as anemic. Hb_Hemocue and Hb_Lab showed a strong linear correlation and a good agreement, while linear correlation of SpHb and Hb_Lab was moderate and agreement poor. For both devices, anemia detection is moderate, but the positive prediction value for anemia is much better with the Hb_Hemocue. Both devices reliably detected non-anemic patients.
– Meaning : With both devices, non-anemic patients are reliably recognized, while anemia detection is moderate. However, the prediction for the presence of anemia is much better with the Hb_hemocue.