for people ages 18 years and up (full criteria)
study started
estimated completion:
Pekka Talke



Pleth Variability Index (PVI) is a variable that is derived from photoplethysmography (PPG) signal. It is used as a surrogate for intravascular volume status intraoperatively. PVI can have significant amount of baseline variability which appears to oscillate at a very low frequency (5-10 minute cycles). This study aims to investigate the origin of these baseline oscillations.


PVI is derived from the infrared photoplethysmography signal. Intraoperatively during mechanical ventilation it reflect fluid responsiveness which is a surrogate endpoint of intravascular volume.

PVI signal appears to have significant baseline variability which can not be explained by rapid changes in intravascular fluid volume. The baseline PVI changes also appear to oscillate at a very low frequency, much below any previously identified spontaneous vascular oscillations.

The aim of this study is to investigate weather the PVI variability originates from changes in the infrared photoplethysmography signal or if they are possibly due to the algorithm calculating PVI.


Intraoperative Monitoring


You can join if…

Open to people ages 18 years and up

  • Neurosurgical patients for tumor resection
  • neurointerventional patients
  • general anesthesia with mechanical ventilation
  • communicates in english (consent)
  • over 18 years of age

You CAN'T join if...

  • unable to sign consent
  • less than 18 years of age

Lead Scientist

  • Pekka Talke
    Professor, Anesthesia. Authored (or co-authored) 42 research publications


not yet accepting patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Last Updated