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Abstracts and Programme: EUROANAESTHESIA 2011: The European Anaesthesiology Congress: Monitoring: Equipment and Computers

Continuous tracking of hemorrhage by non-invasive hemoglobin monitor


Weinstein, A.; Gabis, E.; Herzenstein, O.; Singer, P.

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European Journal of Anaesthesiology: June 2011 - Volume 28 - Issue - p 27-28
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Background and Goal of Study: Monitoring of Hemoglobin (Hb) is essential for the detection of anemia and hemorrhage, and is widely used in ICU, ER, operating and recovery rooms. The current measurement methods are invasive, off-line and discrete. Non-invasive measurement of Hb has many advantages including the freedom to take multiple measurements continuously, the reduced time spent by medical staff, and the prevention of pain and potential transmission of infectious diseases. The purpose of this study was to evaluate the performance of the recently introduced NBM-200MP device in continuous monitoring of Hemoglobin during hemodilution procedure in healthy volunteers. The NBM-200MP (OrSense Ltd.) is a non-invasive system for monitoring of Hemoglobin and Oxygen saturation, based on Occlusion Spectroscopy technology.

Materials and Methods: The clinical study was conducted on 12 healthy volunteers (6F 6M, ages 20-36) upon receipt of informed consent. Two units of blood were drawn from each subject using an indwelling arterial catheter. Subjects then received, through an intravenous line, 30 ml/kg of isolyte fluid (up to a maximum of 2000 ml). The isolyte fluid compensated for the missing blood volume and rapidly reduced the level of Hb. Finally the removed 2 units of blood were reinfused through the intravenous line and increased the Hb again.The NBM sensor was placed on the subject's thumb and recorded a non-invasive reading every 2 minutes. For reference Hb values, arterial blood samples were taken periodically from the arterial catheter and analyzed by OSM3 CO-Oximeter (Radiometer).

Results and Discussion: Reference Hb values ranged from 8.4 g/dl to 15 g/ dl and the reduction in Hb was between 2.6 g/dl and 3.8 g/dl. For a total of 258 paired data points, the mean bias between NBM readings and the arterial reference values was 0.3 g/dl.

The correlation was 0.9 and the standard deviation of error (SD) was 0.7 g/dl. The average personal SD was 0.5 g/dl. Use of the device did not cause any discomfort to subjects, was safe and well tolerated.

Conclusions: The readings obtained were in good agreement with the invasive reference values, and identified correctly the rapid variations in Hemoglobin. The study substantiates the potential of the non-invasive NBM-200MP for continual, safe, and easy-to-use monitoring of Hemoglobin.

© 2011 European Society of Anaesthesiology