Correlation of Blood Hemoglobin Values with Non-Invasive Co-Oximetry Measurement of SpHb in Dogs Undergoing Elective Ovariohysterectomy

Simple Summary The addition of pulse co-oximetry in anesthesia monitoring to continuously determine blood hemoglobin concentration (SpHb) represents a biomarker correlating with the oxygen saturation of patients undergoing surgery. This study aimed to correlate and determine the measurement bias between blood Hb levels with SpHb and arterial oxygen content (SpOC), both derived from pulse co-oximetry in dogs undergoing elective ovariohysterectomy (OVH). Eighty-five bitches were admitted to elective surgery where SpHb was measured during surgery. Five minutes before the end of the procedure, blood sampling was performed to determine the blood Hb concentration (HbLAB). The Bland-Altman analysis showed 95% limits of agreement from -4.22 to 4.99 g/dL, and a positive correlation was found between SpHb and HbLAB (r = 0.401). In conclusion, SpHb presents a moderate positive correlation with direct Hb blood concentration. This possibly shows that continuous measurement of SpHb by noninvasive co-oximetry is a reliable and advanced alternative for monitoring Hb concentration in dogs under anesthesia.Abstract Cardiovascular function monitoring has been suggested as a key parameter to determine patient stability during the anesthetic process. However, the use of pulse co-oximetry has been suggested as a technology to complement the monitoring of this system as a direct way to assess hemoglobin (Hb) blood concentration. Therefore, this study aimed to correlate and determine the measurement bias between Hb blood levels with continuously determined blood hemoglobin concentration (SpHb) and arterial oxygen content values (SpOC), both obtained by noninvasive co-oximetry in dogs undergoing elective ovariohysterectomy (OVH). A total of 85 clinically healthy bitches of different breeds that were admitted for elective OVH surgery were evaluated. These animals underwent SpHb and SpOC capture after the in vivo setting for the duration of the surgical procedure. Likewise, five minutes before the end of the surgical procedure, a blood sample was obtained directly from the jugular vein to determine the blood concentration of Hb (HbLAB). The Bland-Altman analysis showed 95% limits of agreement from -4.22 to 4.99 g/dL with a BIAS (mean difference) of 0.384 +/- 2.35 g/dL (r = 0.401). SpHb recordings were correlated with oxygen saturation (SpO2) (r = 0.995), SpOC (r = 0.992) and with perfusion index (PI) (r = 0.418). Therefore, SpHb presents a moderate positive correlation with direct blood concentration of Hb. This possibly shows that continuous measurement of SpHb by noninvasive co-oximetry is a reliable and advanced alternative for monitoring Hb concentration in dogs under anesthesia.