Non-invasive Continuous Total Hemoglobin Measurement by Pulse CO-Oximetry

This study is a data collection/sampling project for transcutaneous continuous Pulse CO-Oximetry and accessories (SW-Version Radical-7® Pulse CO-Oximeter with the Masimo rainbow SETTM, V1.6.2.4i Masimo Corp., Irvine, CA, USA, and the RD rainbow SET-2, Rev-O Fingersensor). The device received the CE Mark in 2012 and is approved by the Swiss Medic for clinical use. The Radical-7 device isolates multiple (7+) wavelengths of light of arterial signals using adaptive filters. It provides continuous noninvasive monitoring of arterial oxygen saturation (RadSpO2), pulse rate (RadPR), carboxyhaemoglobin saturation (SpCO), methaemoglobin saturation (SpMET), total haemoglobin concentration in g/dl (SpHb) and/or respiration rate (RRa). Additionally, Low Signal IQ (Low SIQ), Perfusion Index (PI), Pleth Variability Index (PVI), total arterial oxygen content (SpOC), Haematocrit (SpHCT), Signal identification Quality (SIQa), Respiration Indicator (RI) are displayed.The purpose of this prospective study is to investigate the reliability of non-invasive continuously measured SpHb by the Masimo Radical-7® Pulse co-oximeter (Radical 7 device) under steady state conditions by comparison against simultaneously invasive measured arterial haemoglobin concentrations (CoOxHb) in major spine surgery patients, in which high blood loss was expected