Operator's Manual

Rad-97 Chapter 1: Technology Overview
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General Description for Pulse Rate (PR)
Pulse rate (PR), measured in beats per minute (BPM) is based on the optical detection of
peripheral flow pulse.
General Description for Perfusion Index (Pi)
The Perfusion Index (Pi) is the ratio of the pulsatile blood flow to the non-pulsatile or static
blood in peripheral tissue. Pi thus represents a noninvasive measure of peripheral perfusion
that can be continuously and noninvasively obtained from a pulse oximeter.
General Description for Pleth Variability Index (PVi)
The Pleth Variability Index (PVi) is a measure of the dynamic changes in the Perfusion Index
(Pi) that occur during the respiratory cycle. The calculation is accomplished by measuring
changes in Pi over a time interval where one or more complete respiratory cycles have
occurred. PVi is displayed as a percentage (0-100%).
PVi may show changes that reflect physiological factors such as vascular tone, circulating
blood volume, and intrathoracic pressure excursions.
The utility of PVi has been evaluated in clinical studies [1-11]. Technical and clinical factors
that may affect PVi include probe malposition, probe site, patient motion, skin incision,
spontaneous breathing activity, lung compliance, open pericardium, use of vasopressors or
vasodilators, low perfusion index, subject age, arrhythmias, left or right heart failure, and tidal
volume [12-14].
Citations for Pleth Variability Index (PVi)
1. Cannesson M., Desebbe O., Rosamel P., Delannoy B., Robin J., Bastien O., Lehot J.J.
Pleth Variability Index to Monitor the Respiratory Variations in the Pulse Oximeter
Plethysmographic Waveform Amplitude and Predict Fluid Responsiveness in the
Operating Theatre. Br J Anaesth. 2008 Aug;101(2):200-6.
2. Forget P, Lois F, de Kock M. Goal-Directed Fluid Management Based on the Pulse
Oximeter-Derived Pleth Variability Index Reduces Lactate Levels and Improves Fluid
Management. Anesth Analg. 2010 Oct;111(4):910-4.
3. Zimmermann M., Feibicke T., Keyl C., Prasser C., Moritz S., Graf B.M., Wiesenack C.
Accuracy of Stroke Volume Variation Compared with Pleth Variability Index to
Predict Fluid Responsiveness in Mechanically Ventilated Patients Undergoing Major
Surgery. Eur J Anaesthesiol. 2010 Jun;27(6):555-61.
4. Desebbe O, Boucau C, Farhat F, Bastien O, Lehot JJ, Cannesson M. Anesth Analg. The
Ability of Pleth Variability Index to Predict the Hemodynamic Effects of Positive
End-Expiratory Pressure in Mechanically Ventilated Patients under General
Anesthesia. 2010 Mar 1;110(3):792-8.
5. Tsuchiya M., Yamada T., Asada A. Pleth Variability Index Predicts Hypotension
During Anesthesia Induction. Acta Anesthesiol Scand. 2010 May;54(5):596-602.