O3, available on Masimo’s Root® patient monitoring and connectivity platform, uses near-infrared spectroscopy (NIRS) to monitor and display continuous regional oxygen saturation values (rSO2) in the tissue of interest. rSO2 reflects the balance between oxygen delivery and metabolic demands in the organ being monitored. However, rSO2 alone may not always indicate the reason for any imbalance. With the addition of delta hemoglobin parameters, clinicians can gain the insight needed to better understand why a patient’s rSO2 is changing by monitoring relative changes in the underlying components used to determine it: total hemoglobin (cHb), deoxygenated hemoglobin (HHb), and oxygenated hemoglobin (O2Hb). These additional data support more informed clinical assessment of the appropriate intervention, ultimately helping drive improvements in the patient’s care.
Each of these parameters can provide valuable additional context for helping clinicians assess a variety of physiological conditions. For example, venous congestion, a slowing or pooling of blood that has been associated with negative outcomes in a variety of scenarios, such as the failure of reconstructive flaps, has been found to increase total hemoglobin (cHb) in tissue.1
The use of the O3 delta hemoglobin parameters has also been successfully incorporated into clinical practice. In a randomized controlled trial published in 2024, researchers in Korea explored how the use of the three parameters in their clinical practice could improve the maintenance of cerebral physiology, including cerebral blood flow and cerebral metabolic rate, in elderly patients undergoing surgery with general anesthesia.2 Comparing the additional monitoring data and insight provided with O3 to traditional regional oximetry (i.e. relying on rSO2 data alone), they found that adopting the more comprehensive approach, which included the delta hemoglobin parameters, “may be crucial for ensuring optimal management of cerebral physiology” in anesthetized elderly patients, “enhancing patient care and safety in this vulnerable population.”
These findings are in agreement with numerous publications, most notably, a 2022 article published in Anesthesia & Analgesia that highlighted the benefits of using these parameters in patients undergoing cardiac surgery.3 As Dr. Alexander Calderone and his colleagues noted, “[Traditional] [c]erebral oximeters are limited by their inability to reveal the exact cause of cerebral desaturation. … Anesthesiologists must, therefore, rely on complementary modalities to identify the etiology of desaturation.” In contrast, the researchers found that the provision of the delta hemoglobin parameters with Masimo O3 helped to overcome these limitations. They determined that “[v]ariations in ΔHHb, ΔO2Hb, and ΔcHb can be used clinically to further characterize cerebral desaturation based on changes in cerebral metabolism and oxygen blood content, arterial cerebral blood flow, and venous congestion.”
O3 Regional Oximetry uses Masimo’s proprietary technology to provide both trending and absolute accuracy,* giving clinicians confidence that the numbers they see reflect actual current tissue oxygenation. With delta hemoglobin parameters now available for all applications and populations, O3 prioritizes insight into the physiology of each individual patient. And with the combination of O3 and SedLine® Brain Function Monitoring on Root, Masimo is proud to offer the only brain health solution on the market to provide comprehensive data about the bilateral brain on a single platform.
Basil Matta, M.D., SVP of Global Clinical Affairs & Solutions for Masimo, said, “Ensuring vital organs and tissues are receiving enough oxygen to meet their metabolic needs is the cornerstone of optimal anesthesia and critical care. Masimo SedLine provides a measure of brain activity and thus indirectly oxygen demand. O3 provides an indication of the balance between vital organ oxygen delivery, by tracking relative changes in oxygenated hemoglobin (O2Hb), and demand, by tracking the changes in deoxygenated hemoglobin (HHb). By using SedLine and O3 together, the clinician can investigate why this balance may have changed, as indicated by concomitant changes in delta hemoglobin parameters – and take advantage of this complementary information, as part of their overall clinical assessment, in initiating the appropriate intervention to restore the balance of oxygen delivery to demand baseline. Masimo Root with O3 and SedLine is a true Brain Health Platform and provides a truly multimodal view of the brain.”
*O3 Regional Oximetry provides regional or tissue hemoglobin oxygen saturation with a trending specification of 3% ARMS (cerebral and somatic, all ages) and absolute accuracy specifications of 4% ARMS (cerebral, adults) and 5% ARMS (cerebral, pediatric patients and non-cerebral, adults). ARMS accuracy is a statistical calculation of the difference between device measurements and reference measurements. Approximately two-thirds of the device measurements fell within +/- ARMS of the reference measurements in a controlled study.
