PVI Measurement Could Help Reduce Septic Shock Risk

A new study suggests that noninvasive plethysmographic variability index (PVI) can be used to assess fluid responsiveness in mechanically ventilated patients in the early phase of septic shock in the emergency room (ER).

Researchers at the Centre Hospitalier de Belfort-Montbeliard (CHBM; France) conducted a prospective, observational feasibility study that included 31 mechanically ventilated and sedated patients with septic shock in whom volume expansion was planned. The patients were wired to the Masimo (Irvine, CA, USA) Radical-7 Pulse CO-Oximeter, which automatically calculated and displayed PVI. The intervention consisted of an 8 mL/kg of hydroxylethyl starch infusion over a 20-minute period. Before and after intervention, aortic velocity-time integral (VTIao) was measured using transthoracic echocardiography; responders were defined as patients who increased their VTIao by 15% or higher after fluid infusion.


The results showed that 16 patients were classified as responders, and 15 as nonresponders. The researchers found that the mean PVI values before intervention were significantly higher in responders (30%) than in nonresponders (8%). When the researchers correlated PVI values before intervention with percent changes in VTIao induced by intervention, a PVI threshold value of 19% was found to discriminate responders from nonresponders with a sensitivity of 94% and a specificity of 87%. The study was published in the October 2013 issue of the Journal of Critical Care.

“Removing the need for central arterial catheter placement in the emergency department represents a considerable time gain and avoids an additional puncture site that could be a potential port of entry for bacteria,” concluded lead author Marc Feissel, MD, and colleagues. “Optimizing hemodynamic status as early as possible, that is, in the emergency department, could help avoid progression to multiorgan failure, thereby reducing morbidity and mortality in patients with severe sepsis or septic shock.”

“This study demonstrates the practical and cost-effective advantage of PVI, particularly for physicians for whom time and ease of use are of the essence,” said Steve Barker, MD, PhD, interim chief medical officer of Masimo. “The findings also add to the growing body of evidence that shows the efficacy of PVI across a wide range of patient populations.”

PVI is a new algorithm allowing for automated and continuous monitoring of pulse oximetry plethysmographic waveform amplitude (ΔPOP), which can predict fluid responsiveness in mechanically ventilated patients but that cannot be easily assessed at the bedside.

Related Links:
Centre Hospitalier de Belfort-Montbeliard
Masimo