The changes of non-invasive hemoglobin and perfusion index of Pulse CO-Oximetry during induction of general anesthesia / 대한마취과학회지

BACKGROUND: We hypothesized that induction of general anesthesia using sevoflurane improves the accuracy of non-invasive hemoglobin (SpHb) measurement of Masimo Radical-7(R) Pulse CO-Oximetry by inducing peripheral vasodilation and increasing the perfusion index (PI). The aim of this study is to investigate the change in the SpHb and the PI measured by Rad7 during induction of general anesthesia using sevoflurane. METHODS: The laboratory hemoglobin (Hb(lab)) was measured before surgery by venous blood sampling. The SpHb and the PI was measured twice; before and after the induction of general anesthesia using sevoflurane. The changes of SpHb, Hb(bias) (Hb(bias) = SpHb - Hb(lab)), and PI before and after the induction of general anesthesia were analyzed using a paired t-test. Also, a Pearson correlation coefficient analysis was used to analyze the correlation between the Hb(bias) and the PI. RESULTS: The SpHb and the PI were increased after the induction of general anesthesia using sevoflurane. There was a statistically significant change in the Hb(bias) from -2.8 to -0.7 after the induction of general anesthesia. However, the limit of agreement (2 SD) of the Hb(bias) did not change after the induction of general anesthesia. The Pearson correlation coefficient between the Hb(bias) and the PI was not statistically significant. CONCLUSIONS: During induction of general anesthesia using sevoflurane, the accuracy of SpHb measurement was improved and precision was not changed. The correlation between Hb(bias) and PI was not significant.

Efficacy of noninvasive pulse co-oximetry as compared to invasive laboratory-based hemoglobin measurement during spinal anesthesia

BACKGROUND: The Masimo Radical 7 (Masimo Corp., Irvine, CA, USA) pulse co-oximeter(R) noninvasively determines the hemoglobin concentration using the principle of transcutaneous spectrophotometry. We compared hemoglobin levels determined using this device (SpHb) with those determined using an invasive laboratory-based technique (tHb) during spinal anesthesia. METHODS: Thirty patients received spinal anesthesia with 0.5% hyperbaric bupivacaine. The pulse co-oximeter probe was mounted on the second toe, and arterial blood samples were obtained from a radial artery catheter. SpHb, tHb, and perfusion index (PI) values were recorded before and 20 and 40 min after intrathecal injection of bupivacaine. RESULTS: Before spinal anesthesia, the SpHb and tHb showed a significant difference of -2.86 +/- 1.56 g/dl (P < 0.005), but no significant differences were found between tHb and SpHb at 20 and 40 min after spinal anesthesia (-0.16 +/- 2.45 g/dl and 0.29 +/- 2.68 g/dl). Additionally, PI was significantly increased at 20 and 40 min after spinal anesthesia compared to the pre-anesthetic value (P < 0.001). CONCLUSIONS: The toe is not the monitoring site for pulse co-oximetry in adult patients, but the pulse co-oximetry on the toe appears to be appropriate as a noninvasive hemoglobin monitoring device after spinal anesthesia.