Two New Clinical Studies Show Masimo Noninvasive Hemoglobin Demonstrated Similar Precision As Hemoglobin From Point Of Care Devices

Masimo

announced two new studies today that showed that noninvasive hemoglobin (SpHb®) demonstrated similar accuracy as hemoglobin measured by invasive hemoglobin analyzers when both SpHb and the invasive hemoglobin analyzer were compared to laboratory hematology analyzer. The first study was presented at the American Society of Anesthesiologists (ASA) Annual Meeting in New Orleans, the largest gathering of anesthesiologists in the world, in patients undergoing potential high blood-loss surgery. Masimo SpHb showed similar absolute and trending accuracy as hemoglobin values determined by a laboratory blood gas analyzer, when both the SpHb and the hemoglobin from the blood gas analyzer were compared to hemoglobin from a laboratory hematology analyzer. At the University of West Paulista (UNOESTE), Presidente Prudente, Brazil, Dr. Edmundo P. Souza Neto and colleagues compared absolute and trending accuracy of hemoglobin values from SpHb (Masimo Radical-7® Pulse CO-Oximeter and SpHb adhesive sensor, Revision K) and an invasive laboratory blood gas analyzer (Cobas B221, Roche Diagnostics, Indianapolis, USA) to hemoglobin values from a hematology analyzer (XE-2100, Sysmex, Kobe, Japan).(1) While blood gas analyzers (also referred to as CO-Oximeters) and hematology analyzers are both laboratory devices that analyze blood samples to determine quantitative hemoglobin values, their methodologies are different and according to prior studies, their values are not interchangeable.(2) In 33 patients, arterial blood gas samples were obtained 15 minutes after the incision, after each bleeding event (loss of at least 400 ml of blood in 40 minutes), and at the end of the surgery. A total of 69 arterial blood gas analyzer-determined hemoglobin values and 69 hematology analyzer-determined hemoglobin values were recorded. SpHb values were available continuously throughout the case and were recorded each time that arterial blood gas samples were obtained. Absolute accuracy was evaluated by comparing the SpHb and arterial blood gas hemoglobin values to the hematology analyzer hemoglobin values. The bias, or average difference, when compared to the hematology analyzer was -0.8 g/dL for SpHb and -1.4 g/dL for the invasive blood gas analyzer. The standard deviation, or maximum difference in approximately 68% of comparisons, was 1.3 g/dL for SpHb and 1.2 g/dL for the invasive blood gas analyzer. Outliers were defined as values >1 g/dL from hematology analyzer. There were fewer SpHb outliers (43%) than blood gas analyzer outliers (69%). Trend accuracy was evaluated by calculating the change in SpHb and change in hemoglobin from the blood gas analyzer and comparing the values to changes in hemoglobin from the hematology analyzer. The trend accuracy sensitivity of SpHb and the blood gas analyzer was determined by analyzing the percentage of time each method had the same directional trend as the hematology analyzer. There were no statistically significant differences between the two test methods for absolute accuracy (p=0.08) or for trending accuracy (p=0.6). The researchers concluded: "Analysis of absolute accuracy showed a smaller bias but slightly larger standard deviation for SpHb than the blood gas analyzer when compared to the hematology analyzer reference. SpHb measurements had less outliers than blood gas analyzer and similar sensitivity to follow the correct directional sample to sample trend as determined by the reference. Further studies to increase sample size will be required to confirm these results and show potential differences between the test methods." Separately, in a study published in the journal Anaesthesia and Intensive Care, Dr. R. Hiscock and colleagues at Mercy Hospital for Women in Heidelberg, Australia, studied the accuracy and repeatability of SpHb from a Masimo Pronto-7® spot-check device and a HemoCue Hb 201+ point of care invasive hemoglobin measurement device, compared to hemoglobin measured by a laboratory hematology analyzer (Sysmex XE-5000).(3) For both devices, manufacturer instructions were followed to minimize recording variability and all readings were performed by a single operator, who collected an invasive venous sample and three SpHb measurements on 141 pregnant women aged 19 to 46 years. Venous samples were used to obtain three replicate hemoglobin measurements on the HemoCue Hb 201+ and a single hemoglobin measurement from a hematology analyzer. Compared to the hematology analyzer, researchers found a bias and standard deviation of 1.18 g/dL, +/-1.19 g/dL for the Pronto-7 and 0.01 g/dL, +/-1.34 g/dL for the HemoCue Hb201+. The Pronto-7 demonstrated higher repeatability than the Hemocue Hb 201+, as evidenced by a lower coefficient of variation % of (2.3% vs. 5.2%). Researchers, who noted that neither device can replace laboratory-based hemoglobin analysis, concluded: "We found that the Pronto-7® device showed substantially better repeatability compared to the HemoCue® Hb 201+ device. Under stable conditions, we would be 95% certain that a repeat haemoglobin measurement using the Pronto-7® co-oximeter would lie within 0.82 g/dl of the previous reading, compared to 1.7 g/dl for the HemoCue® 201+." Radical-7 and Pronto-7 are monitoring devices. They are not intended to be used as standalone diagnostic devices. 1 Neto E, Cursino de Moura Junior J, Laish J, Lalier Junior O, Mortatti P. Agreement of Noninvasive Hemoglobin Monitoring by Pulse CO-Oximetry (SpHb) with Invasive Laboratory Measurements. Proceedings of the American Society of Anesthesiologists, Oct.13, 2014, New Orleans, A3093, Room Hall B-1, Area C 2 Carabini LM, Navarre WJ, Ault ML, Bebawy JF, Gupta DK. "A Comparison of Hemoglobin Measured by Co-Oximetry and Central Laboratory During Major Spine Fusion Surgery." Anesth Analg. 2014 Sep 3. 3 Hiscock R, Simmons S, Carstensen B, Gurrin L. "Comparison of Massimo Pronto-7 and HemoCue Hb 201+ with laboratory haemoglobin estimation: a clinical study." Anaesthesia and Intensive Care, Vol. 42, No. 5, September 2014