Accuracy of the Masimo Pronto-7® system in patients with left ventricular assist device

Abstract

BackgroundThe Masimo Pronto-7® calculates hemoglobin (Hb) values using the pulsoximetry technique and a variety of mathematical algorithms analyzing the pulse waveform. Although this system has demonstrated a high level of accuracy in average patients, the performance might be altered in special patient populations. Regarding patients with left ventricular cardiac failure, a rotary blood pump generates a constant, continuous, non-pulsatile flow to improve effective cardiac output. Due to this alteration in both, blood flow and arterial blood pressure we hypothesized a reduced accuracy of the Masimo Pronto-7® to detect Hb in patients with left ventricular cardiac failure. To test our hypothesis, we evaluated the Pronto-7®SpHb system in outpatients after continuous-flow-left ventricular assist device (cf-LVAD) implantation (HeartMate II, Thoratec).Methods21 cf-LVAD outpatients from the Clinic for Cardiac, Thoracic and Vascular Surgery were investigated during routine follow up examinations. After venous blood samples were drawn, the Pronto-7® sensor was attached to one randomly selected finger of one hand. The collected SpHb data were compared with Hb values measured by our central laboratory. The difference between the methods was determined using Bland – Altman analysis. The study was registered in the DRKS (DRKS00004415).ResultsIn all cf-LVAD patients evaluated, the Pronto-7® successfully detected SpHb values. Using Bland – Altman analysis, a bias of 0.14 g/dl (95% upper and lower limits of agreement ± 2.76 g/dl) was calculated.ConclusionThe Pronto-7® overestimated the actual Hb value in cf-LVAD outpatients with the HeartMate II. Due to this, we conclude that the system is suitable for screening in routine examinations and further analysis can be performed if needed. However, its use as an emergency tool is questionable because of the increased inaccuracy when Hb values are critically low.

Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings

“…5A and C). Eleven studies included 13 comparisons between the reference and the Masimo Radical-7 with the reference among children aged 3 years and 12−17 years and adult males and females aged 18 years and older 41,43,107,116,[123][124][125][126][127][128] (Fig. 5A).…”

“…107 Ten studies with 11 comparisons analyzed venous blood with six comparisons finding a lower mean Hb concentration (1.4−10.0 g/L) and five comparisons having a higher mean Hb concentration (1.2−7.0 g/L) by Radical-7 compared with the reference. 43,53,104,123,124,[126][127][128] Von Schweinitz et al also analyzed venous blood by the Masimo Radical-57 compared with the reference finding a higher mean Hb concentration (12.0 g/L) by the Masimo Radical-57 (data not shown). 125 When applying the variation in mean difference threshold of ±7% to the studies comparing the Masimo Radical-7 with the reference, nine studies 41,43,53,104,116,124,125,127,128 were within the allowable range of variation and four studies exceeded the ±7% bias range 43,107,123,126 (Fig.…”

Assessing serum hemoglobin levels without venipuncture: accuracy and reliability of Pronto-7 noninvasive spot-check device

“…Bruells et al 15 reported a low bias of .14 g/dL between the invasive reading and noninvasive Hb readings but noted increased inaccuracy in patients with an Hb level less than 7.5 g/dL when evaluating patients with continuous flow left ventricular assist devices. In contrast, Joseph et al compared the Pronto-7 spot-check Hb device to standard laboratory Hb measurements in trauma patients arriving at the emergency department in a level 1 trauma center and found a strong correlation (r 5 .77), and on subanalysis of patients by anemia (Hb %8 g/dL and Hb .8 g/ dL), there was strong correlation between invasive and noninvasive Hb measurement in patients with Hb greater than 8 g/dL (r 5 .79; P 5 .03).…”

Research on improving the accuracy of near infrared non-invasive hemoglobin detection

“…Radical-7 and Pronto-7 produced by Masimo Corporation could accomplish non-invasive Hb real-time monitoring. [15][16] Though near infrared non-invasive Hb measurement technology has developed tremendously, and numerous researches and practices have been achieved, the not intensely excellent measurement precision and stability are the important obstacles hindering widespread application of this technology in clinic. 4 Now, weak valid spectra signal and strong background interference have become the primary problems which obstacle the development of near infrared non-invasive detection, leading to a difficulty for precision of near infrared non-invasive Hb measurement to meet the requirements of clinical applications.…”