PURPOSE: New advances in pulse oximetry technology have led to the development of multi-wavelength Pulse CO-Oximeters designed to measure multiple physiologic parameters. The utilization of multiple wavelengths has led to the development of a prototype Pulse CO-Oximeter that allows for noninvasive and continuous measurement of hemoglobin concentration (SpHb). This study examines this device's ability to measure continuous SpHb and evaluates the accuracy compared with hemoglobin concentration measured by a laboratory CO-Oximeter (Hb).
METHODS: After IRB approval and informed consent, 49 patients scheduled to undergo surgery and 18 healthy volunteers undergoing a hemodilution protocol were enrolled in this ongoing study. Each subject was monitored with ASA standard monitors and a radial artery cannula. Three prototype SpHb sensors, optically isolated from each other, were attached to a prototype monitoring device (Masimo Inc., Irvine, CA). Routine anesthetic care of these patients was not altered. The hemodilution protocol consisted of withdrawal of 1 unit of blood and replacement with 30ml
kg of saline. Data was collected throughout the course of each surgery and during hemodilution. Arterial blood samples were analyzed by laboratory CO-oximeter (Radiometer ABL735), and the resulting Hb measurements were compared with the data collected from the corresponding SpHb readings. Regression analysis, bias, precision and ARMS were calculated.
RESULTS: 1207 data pairs were collected from a total of 67 subjects. The mean (SD) and range of Hb values were 10.4 (2.3) and 4.4 to 15.8 g/dl respectively. Bias, precision and ARMS were -0.11, 1.28, 1.28 respectively. Regression equation for Hb vs SpHb is y=2.66 + 0.734x with a correlation coefficient of 0.827.
CONCLUSION: This device is the first device developed that can continuously and non-invasively measure hemoglobin concentration in addition to the other common hemoglobin species, and therefore provides a significant expansion of existing physiologic monitoring technology.
CLINICAL IMPLICATIONS: Rapid and continuous measurement of hemoglobin would be an extremely useful tool in many clinical scenarios. This technology in combination with methemoglobin and carboxyhemoglobin measurements should allow for significant advances in patient care.
DISCLOSURE: Mark Macknet, Grant monies (from industry related sources) LLU Department of Anesthesiology has received industry support from Masimo, Irvine CA, covering expenses related to this ongoing clinical study; Consultant fee, speaker bureau, advisory committee, etc. I am a community member of the Scientific Advisory Board for Masimo, providing input into the development of the device discussed. As a member, I have received small amounts of money to cover expenses related to time and travel. Total received is less than $10,000; Product/procedure/technique that is considered research and is NOT yet approved for any purpose. The Masimo prototype pulse CO-oximeter that measures hemoglobin is not an FDA approved device for hemoglobin monitoring monitoring. The device as configured in this study is not currently approved for clinical use.