Non-invasive measurement of hemoglobin during cesarean delivery in patients with abnormal placentation: A case series
Abstract Number: 60
Abstract Type: Case Report/Case Series
Introduction: Obstetric patients diagnosed with abnormal placentation are at increased risk of major postpartum hemorrhage and cesarean hysterectomy. Transfusion management of these cases is often challenging. A new non-invasive monitor (Masimo Rainbow SET® 195 Radical 7 Pulse CO-Oximeter) provides real-time measurement of hemoglobin (assessed as SpHb) using multi-wavelength pulse oximetry (1, 2). This offers the potential to greatly assist transfusion decision making during the perioperative period. We present a review of five patients with suspected abnormal placentation who received SpHb monitoring during cesarean hysterectomy at our institution.
Methods: After obtaining written informed consent, we recorded perioperative SpHb and laboratory hemoglobin values (arterial and/or venous samples), transfusion and post-cesarean delivery outcomes data. SpHb and laboratory hemoglobin values were compared using Wilcoxon rank sum test, and Spearman correlation analysis was used to assess the association between SpHb and laboratory hemoglobin values; P <0.05 as statistically significant.
Results: Demographic, obstetric, anesthetic and outcome data are outlined in the Table. All patients required cesarean hysterectomies. SpHb values were higher than laboratory hemoglobin values in 15/16 (94%) blood samples in all patients. The median difference between SpHb and laboratory hemoglobin values was 2 g/dl [range = - 0.8 to 3.8 g/dl]. The median SpHb was significantly higher than the median laboratory hemoglobin value (10.4 g/dl vs 8.6 g/dl; P=0.001). The correlation between SpHb and laboratory hemoglobin values was R=0.89 (P<0.001).
Conclusion: This new co-oximeter shows potential clinical utility as a device to assess real-time hemoglobin values in patients at high risk for obstetric hemorrhage. Results suggest a bias towards higher values with SpHb compared to laboratory hemoglobin values in our case series. Further work is necessary to assess the accuracy and precision of SpHb in an obstetric setting.
References: 1. Anesth Analg, 2010:111;1424-26; 2. Richard KM et al. ASA Annual Meeting 2010, Abstract A187