Examining Masimo PVi® as a Fluid Responsiveness Indicator for Guiding Goal-Directed Fluid Therapy in Elderly Patients During Gastrointestinal Surgery: A Recent Study

Monday, August 21, 2023

Masimo, a leader in medical technology, has revealed the outcomes of a groundbreaking study recently published in the esteemed journal Perioperative Medicine. Spearheaded by Dr. Yu Wang and a distinguished team of researchers hailing from institutions in Shenzhen, Shaoguan, and Guangzhou, China, this innovative research sought to evaluate the efficacy of Masimo's PVi® technology in guiding fluid administration during gastrointestinal (GI) surgeries for elderly patients. The study focused on comparing the utilization of Masimo PVi®, a noninvasive, continuous monitoring tool, within the framework of goal-directed fluid therapy (GDFT), against the conventional approach to fluid management.

The study's revelations unveiled significant advantages associated with patients subjected to the PVi approach. Notably, this group experienced a marked reduction in cardiopulmonary complications (8.4% vs. 19.2%) and were administered a considerably lower volume of fluids (median 2075 ml vs. 2500 ml)^1.

The research was prompted by the critical importance of optimizing fluid management during GI surgeries, particularly for the elderly who often grapple with postoperative complications and fluid imbalances triggered by factors like preoperative fasting, bowel preparation, and intraoperative fluid loss. The researchers' primary goal was to ascertain whether the application of Masimo PVi within GDFT could lead to better surgical outcomes. PVi, short for pleth variability index, gauges changes in the perfusion index over the breathing cycle. Unlike invasive methods such as stroke volume variation (SVV) and pulse pressure variation (PPV) that require arterial lines, PVi is acquired noninvasively through Masimo's rainbow SET® pulse oximetry and Pulse CO-Oximetry. Acknowledged as a noninvasive, dynamic indicator of fluid responsiveness specifically tailored for certain ventilated adult patient groups, prior studies have underscored PVi's comparability to invasive fluid assessment techniques like PPV and SVV across diverse surgical procedures^2.

The study enlisted patients aged 65 or older slated for elective GI surgery at two university hospitals spanning from November 2017 to December 2020. Participants were randomly assigned to either the GDFT group (n = 107) or the conventional fluid therapy (CFT) group (n = 104). In the GDFT group, PVi was utilized to guide fluid therapy, harnessing data from photoplethysmographic waveforms captured by rainbow® Pulse CO-Oximetry sensors affixed to the fingertip. Various outcomes were assessed across both groups, encompassing composite complications at 30 days post-surgery, cardiopulmonary complications at 30 days (such as pneumonia, atelectasis, pulmonary edema, arrhythmia), recovery markers like time to first flatus, incidence of postoperative nausea and vomiting, infection rates including anastomotic leaks, and duration of postoperative hospital stays.

The study outcomes unmistakably highlighted a statistically significant decrease in the occurrence of cardiopulmonary complications and the total volume of intraoperative fluids administered in the GDFT (PVi) group, as meticulously detailed in the provided data. Although a trend was discernible toward reduced hospital stays and diminished anastomotic leakage rates in the PVi group, these differences, alongside other findings, didn't attain statistical significance.

In their concluding remarks, the researchers noted that while PVi-guided GDFT didn't result in an overall reduction of composite postoperative complications in elderly GI surgery patients, it was associated with a lowered frequency of cardiopulmonary complications compared to standard fluid management.

Joe Kiani, the visionary Founder and CEO of Masimo, expressed, "In 2007, we introduced PVi, a pioneering method that remains the sole avenue for noninvasive fluid responsiveness assessment through pulse oximetry. This approach not only costs significantly less than invasive techniques but also eliminates the need for subjecting patients to invasive procedures. Over 100 distinct published studies have substantiated PVi's effectiveness as a fluid responsiveness indicator, underscoring its pivotal role in elevating patient care. This recent study further solidifies the potential of PVi to assist healthcare practitioners in adeptly managing patient fluid levels without resorting to invasive measures."

It's imperative to note that PVi holds FDA 510(k) clearance in the U.S. as a noninvasive dynamic fluid responsiveness indicator tailored for specific subsets of mechanically ventilated adult patients. However, the accuracy of PVi in predicting fluid responsiveness may vary and is influenced by a spectrum of patient-related, procedural, and device-related variables. Therefore, decisions regarding fluid management should be based on a comprehensive assessment of the patient's overall condition and should not rely solely on PVi measurements.

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