The Value of Continuous Noninvasive Hemoglobin Monitoring Using Masimo Radical Pulse Co-oximeter in Intraoperative Blood Transfusion Practice During Obestatric Procedure

Photoplethysmography of peripheral perfusion can be displayed by pulse oximeters. While the pulse oximeterplethysmogram represents a volume change and the arterial line blood pressure tracing represents a pressure change, it has been demonstrated that cyclical shifts in the plethysmogram reflect similar cyclic changes in the blood pressure tracing and that these changes reflect changes in the intravascular volume status of patients.Plethysmography Variability Index (PVI) is a measure of the dynamic changes in the perfusion index (PI) that occur during the respiratory cycle . PVI = ﴾PI Max - PI Min﴿ ÷ PI Maxx 100 %.

PVI has the potential to provide useful information concerning changes in the balance between intrathoracic airway pressure and intravascular fluid volume. Trending of PVI may be useful in monitoring surgical patients, both intraoperatively and postoperatively, for appropriate hydration states. For example, a rising PVI may indicate developing hypovolemia and gives an alarm for the need of appropriate fluid and or blood products transfusion supported by the patient hemoglobin level.

Continuous Hb monitoring may allow a more rapid detection of clinically significant blood loss, and has the potential to significantly improve perioperative transfusion practices, may enable a more rapid assessment of a patient's condition and more appropriate blood management and even perhaps reduce needless transfusions.