Accuracy of Continuous and Noninvasive Hemoglobin Monitoring in the Presence of CO2 Insufflation: An Observational Pilot Study

Abstract

Background Laparoscopic surgery has several benefits, but it requires prolonged carbon dioxide (CO 2 ) insufflation. Several factors affect the accuracy of continuous and noninvasive hemoglobin (SpHb) monitoring, but the effects of CO 2 insufflation are undetermined. This study investigated the effect of CO 2 insufflation on SpHb monitoring in laparoscopic surgery. Material/Methods Twenty patients undergoing laparoscopic gastrectomy were enrolled. Anesthesia was maintained using sevoflurane and remifentanil within an end-tidal CO 2 of 30–45 mmHg. The CO 2 insufflation was maintained at 12 mmHg using CO 2 . SpHb was monitored with a Radical-7 Pulse CO-Oximeter, and laboratory hemoglobin (tHb) was analyzed using a satellite blood analyzer. Results Forty paired measurements were analyzed. The mean perfusion index, SpHb, and tHb were 3.10±1.77%, 10.92±1.48 g/dL, and 11.51±0.88 g/dL, respectively. SpHb underestimated tHb with a bias (precision) of −0.59 (1.28 g/dL), and the 95% limit of agreement was wide (−3.11 to 1.92 g/dL). SpHb was moderately correlated with tHb ( r =0.50, 95% CI: 0.23 to 0.70). The concordance rate was 67%. ΔSpHb was not correlated with ΔtHb ( r =0.29, 95% CI: −0.18 to −0.65). A similar bias, wider limits of agreement, a higher |SpHb-tHb|, but more significant correlation between SpHb and tHb were observed for the “PaCO 2 <40 mmHg” range compared with the “40 mmHg ≤PaCO 2 ” range. Conclusions SpHb may have an acceptable accuracy but has a weak trending ability in the presence of CO 2 insufflation, and it can be affected by PaCO 2 . Further research on the effects of CO 2 insufflation on SpHb is needed.

Impact of Increased End-Tidal Carbon Dioxide on Continuous Noninvasive Hemoglobin Monitoring during Laparoscopic Gastrectomy: A Randomized Controlled Study

“…Pulse oximetry and pulse CO-Oximetry have technological similarity based on light absorption through a finger sensor. Recently, an observational pilot study suggested that the values of SpHb may be affected by the presence of CO 2 insufflation [14]. Therefore, we hypothesized that increased end-tidal CO 2 (EtCO 2 ) would affect sensing of SpHb and reduce the accuracy and trending ability of SpHb during laparoscopic surgery.…”