Masimo (Nasdaq MASI), the inventor of Pulse COOximetry(TM) and MeasureThrough Motion and LowPerfusion pulse oximetry, announced that three new independent studies demonstrating the clinical accuracy and utility of Masimo PVI as a noninvasive and continuous measure of patient fluid status and responsiveness were presented this week at the European Society of Anaesthesiology (ESA) Annual Congress in Milan, Italy.

Although fluid administration is critical to optimizing patient status and enabling end organ preservation, unnecessary fluid administration is associated with increased morbidity and mortality. Traditional invasive measurements such as central venous pressure are not reliable to predict whether a patient will benefit from fluid administration, and newer more reliable methods to predict fluid responsiveness are also invasive and costly. Multiple recent studies have shown that Masimo PVI provides a simple and costeffective method for accurate, noninvasive, and continuous monitoring of fluid responsiveness. The three studies presented at the ESA reinforce the accuracy of PVI compared to invasive measures and highlight its value for before, during, and after anesthesia.

Does the Pleth Variability Index correlate with stroke volume variation? Researchers in the Department of Anesthesiology at the Hamamatsu University School of Medicine in HamamatsuCity, Japan, compared the accuracy of Masimo PVI measurements with Stroke Volume Variation (SVV) obtained via an invasive catheter (Flo Trac(R)) in 13 patients. After analyzing data recorded at five pointsin the supine position, lateral position, start and end of onelung ventilation, and in the supine position againresearchers found a significant correlation between PVI and SVV (r = 0.75; p = 0.02). The study concluded that “Our results suggest that an accurate prediction of fluid responsiveness can be obtained noninvasively using the PVI.”(1)

The Change of Upper Limbs PVI in Spinal Block (Comparison in High Spinal Block and NonHigh Spinal Block)

At the Tokai University School of Medicine in Tokyo, Japan, researchers examined how PVI in the upper limbs of patients undergoing caesarean procedures for hernia surgery changed in response to the level of spinal block reached. PVI was recorded in all patients before and every two minutes after spinal block was performed. In patients reaching the anesthetic level Careaidentified as the high spinal block groupPVI decreased. In patients who did not reach the Careaidentified as the nonhigh spinal block groupPVI of the upper limbs did not change significantly. Researchers summarized that high spinal block dilates vessels and increases blood flow in the upper limbs, which in turn, is shown by decreased PVI.(2)

Perfusion Index and Pleth Variability Index After Administration of General Anesthetic Agents

In this study, anesthesiologists at the Teikyo University School of Medicine in Tokyo, Japan, analyzed changes in PVI and Masimo perfusion index (PI) in 21 surgical patients before and after administration of general anesthetic agents. After administration of general anesthetic agents and 10ml/kg/hr of fluid during induction, PVI significantly decreased from 22.9=/+8.1 to 17.1=/+7.2 (p