Study Investigates the Ability of Masimo PVi to Predict Preload Responsiveness in Patients On Nasal High-Flow Therapy

Masimo (NASDAQ: MASI) announced today the findings of a study published in the Journal of Applied Physiology in which Dr. Marina García-de-Acilu and colleagues at the Vall d’Hebron University Hospital in Barcelona evaluated the utility of Masimo PVi as a noninvasive method of predicting preload responsiveness in patients treated with nasal high-flow (NHF) therapy. They found that PVi may identify preload responders and noted that PVi may therefore be used in the “day-to-day clinical decision-making process in critically ill patients treated with NHF, helping to provide adequate resuscitation volume.”¹ More than 100 independent studies have demonstrated the utility of PVi as an indicator of fluid responsiveness.² This is the first time PVi has been evaluated in patients treated with NHF therapy.

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Masimo Radical-7 with PVi (Photo: Business Wire)

Noting the potential convenience of a noninvasive method of predicting fluid responsiveness in NHF patients, the researchers sought to evaluate whether PVi, which is noninvasive and easy to use, could play such a role. To do so, they compared PVi to reference measurements—stroke volume (SV) and cardiac output (CO)—in 20 adult ICU patients with acute respiratory failure (ARF) supported by NHF (flow ≥ 30 L/min). SV and CO were measured using transthoracic echocardiography (TTE) using a portable echocardiogram. PVi was measured using a Masimo Radical-7 Pulse CO-Oximeter with a pulse oximetry sensor attached to the finger. Within the first 24 hours of NHF support, the patients’ SV/CO and PVi were assessed. Passive leg raising (PLR) was performed and SV/CO and PVi were then reassessed. Preload responsiveness was defined as a ≥ 10% increase in SV after PLR. A fluid challenge was then conducted by administering a 250-mL saline solution to patients who were found to be preload responders (12 of the 20 patients). SV/CO and PVi were measured again after the fluid challenge in these patients.

The researchers found that preload responders showed higher baseline PVi values and ΔPVi after PLR. PVi and ΔPVi after PLR showed “excellent diagnostic accuracy for predicting preload responsiveness.” At a baseline cut-off value of 16%, PVi had sensitivity of 91.7% and specificity of 87.8% for discriminating between preload responders and non-responders; a change of 2% or more in PVi allowed for discrimination between the two groups with 100% sensitivity and specificity. Additionally, the researchers found that ΔPVi after PLR and after fluid challenge were strongly correlated (r = 0.84, p < 0.001).