Key result
During laparoscopic surgery with CO2 insufflation, continuous noninvasive hemoglobin monitoring underestimated laboratory hemoglobin with a mean bias of -0.59 g/dL and wide 95% limits of agreement (-3.11 to 1.92 g/dL).
Why the study?
Several factors affect the accuracy of continuous noninvasive hemoglobin monitoring, but the effects of prolonged CO2 insufflation during laparoscopic surgery remain undetermined.
Does continuous and noninvasive hemoglobin monitoring accurately reflect laboratory hemoglobin in patients undergoing laparoscopic surgery with CO2 insufflation?
Observational (n=20)
No
Does continuous and noninvasive hemoglobin monitoring accurately reflect laboratory hemoglobin in patients undergoing laparoscopic surgery with CO2 insufflation?
Mean Difference: -0.59 (95% CI -3.11–1.92)
Continuous noninvasive hemoglobin monitoring has acceptable accuracy but weak trending ability during laparoscopic surgery with CO2 insufflation, and is affected by PaCO2 levels.
Clinicians should interpret noninvasive hemoglobin readings cautiously in laparoscopic CO2 insufflation; Level 3 data leaves open its reliability and clinical utility.
BACKGROUND Laparoscopic surgery has several benefits, but it requires prolonged carbon dioxide (CO₂) insufflation. Several factors affect the accuracy of continuous and noninvasive hemoglobin (SpHb) monitoring, but the effects of CO₂ insufflation are undetermined. This study investigated the effect of CO₂ insufflation on SpHb monitoring in laparoscopic surgery. MATERIAL AND METHODS Twenty patients undergoing laparoscopic gastrectomy were enrolled. Anesthesia was maintained using sevoflurane and remifentanil within an end-tidal CO₂ of 30-45 mmHg. The CO₂ insufflation was maintained at 12 mmHg using CO₂. 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 "PaCO2 <40 mmHg" range compared with the "40 mmHg ≤PaCO₂" range. CONCLUSIONS SpHb may have an acceptable accuracy but has a weak trending ability in the presence of CO₂ insufflation, and it can be affected by PaCO₂. Further research on the effects of CO₂ insufflation on SpHb is needed.
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Lee et al. (2021) conducted an observational in Patients undergoing laparoscopic gastrectomy (n=20). Continuous and noninvasive hemoglobin (SpHb) monitoring during CO2 insufflation vs. Laboratory hemoglobin (tHb) was evaluated on Agreement between SpHb and tHb (bias and limits of agreement) (Bias -0.59 g/dL, 95% CI -3.11 to 1.92). During laparoscopic surgery with CO2 insufflation, continuous noninvasive hemoglobin monitoring underestimated laboratory hemoglobin with a mean bias of -0.59 g/dL and wide 95% limits of agreement (-3.11 to 1.92 g/dL).
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