October 18, 2007 - Masimo reports a new independent clinical study presented Oct. 15 at the 2007 American Society of Anesthesiologists (ASA) Meeting in San Francisco, demonstrated the ability of Pleth Variability Index (PVI) to accurately and noninvasively detect changes in ventricular preload.
The newest addition to the Masimo Rainbow SET technology platform, PVI is a continuous and noninvasive quantified measurement of changes in the perfusion index, capturing volume changes that may compromise cardiac function and affect systemic circulation.
The study entitled “New Algorithm for Automatic Estimation of the Respiratory Variations in the Pulse Oximeter Waveform,” was conducted at the Louis Pradel Hospital in Lyon, France, by a research team headed by Dr. Maxime Cannesson. The research team indicated that while respiratory variations in the pulse oximeter plethysmography waveform amplitude are sensitive to changes in preload and can predict fluid responsiveness in mechanically ventilated patients, they previously were not easily measured noninvasively from a bedside monitor. However, a new algorithm, PVI, available in the Masimo Rainbow SET technology platform may provide a new method for noninvasively predicting fluid responsiveness.
In this study, Dr. Cannesson and the research team tested the ability of PVI to detect changes in ventricular preload in 20 vascular surgery patients under mechanical ventilation. Mean arterial pressure (MAP) and central venous pressure (CVP) via arterial catheter and central venous catheter were recorded along with PVI at baseline and while patients were in head-down and head-up positions.
Researchers stated, this study is the first to demonstrate the ability of PVI, an index automatically derived from the pulse oximeter waveform analysis, to detect changes in ventricular preload. They also said this new index has potential clinical applications for noninvasive hypovolemia detection and fluid responsiveness monitoring.
“Fluid management optimization in mechanically ventilated patients undergoing anesthesia is of major importance since it may have clinical and economical impact,” Dr. Cannesson said. “Indicators of response to volume expansion relying on cardio-pulmonary interactions are the best predictors of fluid responsiveness. Ideally, continuous noninvasive monitoring of these parameters would provide valuable information to clinicians in caring for mechanically ventilated patients. Masimo’s new derived index, PVI, appears to offer such a continuous, noninvasive monitor.”
Masimo PVI is a new measurement featured in the Masimo Rainbow SET technology platform that quantifies changes in perfusion index. PVI displays a numeric representation of the changes as a percentage on the Rainbow SET oximeter, allowing clinicians to track and trend these changes over time. A rising PVI may indicate developing hypovolemia (an abnormally low volume of blood circulating through the body) and a falling PVI post-fluid resuscitation is evidence of an appropriate fluid responsiveness.
Appropriate fluid levels are vital to reducing postoperative risks and improving patient outcomes as fluid volumes that are too low (under hydration) or too high (over hydration) have been shown to decrease wound healing, increase risk of infection and cardiac complications. In extreme cases, severe hypovolemia can lead to hypovolemic shock as peripheral circulation shuts down to preserve central circulation in an attempt to maintain the heart, brain and kidney functions.
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