Related Experiment Video
Updated: Jun 5, 2026
Monitoring Lung Function with Electrical Impedance Tomography in the Intensive Care Unit
Published on: September 6, 2024
[The ability of pleth variability index to predict fluid responsiveness in mechanically ventilated patients under
Qin-fang Cai1, Wei-dong Mi, Wei-xiu Yuan
1Department of Anesthesiology, General Hospital of People's Libration Army, Beijing 100853, China.
Objective:
To evaluate the ability of pleth variability index (PVI) in predicting fluid responsiveness in mechanically ventilated patients under general anesthesia.
Methods:
From August to November 2009, 25 patients were enclosed in this study following anesthesia induction. PVI was continuously displayed by the Masimo Radical 7. All patients were also monitored with Vigileo/FloTrac system. Haemodynamic data such as cardiac index (CI), stroke volume variability (SVV), mean arterial pressure, heart rate, central venous pressure, PVI, perfusion index were recorded before and after volume expansion (hetastar 6%, 7 ml/kg). Fluid responsiveness was defined as an increase in CI ≥ 15% (ΔCI ≥ 15).
Results:
SVV and PVI were significantly higher in the responders (16.0% ± 2.6% and 20.5% ± 3.7%) than those in non-responders (11.6% ± 1.4% and 13.8% ± 2.6%) respectively (P < 0.05). The SVV threshold of 13.5% before volume expansion was able to discriminate the responders from the non-responders with a sensitivity of 88.2% and a specificity of 87.5%. The threshold for PVI was 15.5%, the same sensitivity of 88.2% and specificity of 87.5% were obtained. There was a significant relationship between PVI before volume expansion and change in CI after volume expansion (r = 0.683, P < 0.01), the same as the changes of SVV (r = 0.600, P < 0.01).
Conclusion:
PVI as a new dynamic indices can predict fluid responsiveness non-invasively in mechanically ventilated patients during general anesthesia.
Related Concept Videos
01:29Mechanical Ventilation I: Indication and Settings
01:14Ventilatory Modes
There are three ventilatory modes: full support, partial support, and spontaneous. These are described below.
Full Support Modes
Full support modes include controlled mechanical ventilation, continuous mandatory...
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
01:23Mechanical Ventilation II: Invasive Ventilation
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
01:23Mechanical Ventilation III: Noninvasive Ventilation
Noninvasive Positive-Pressure Ventilation (NIPPV)
01:29Assessment of Ventilation II: Respiratory Depth and Rhythm
Respiratory depth measures the volume of air inhaled or exhaled during a breath. It can vary from shallow to deep and typically remains consistent when a person is at rest or asleep. Occasionally, individuals will automatically inhale deeply, known as sighing, which inflates the lungs with more air than normal breathing.
To assess respiratory depth, observe the degree of chest excursion or movement: