Evaluation of Fluid Responsiveness: Is Photoplethysmography a Noninvasive Alternative?

Background. Goal-directed fluid therapy reduces morbidity and mortality in various clinical settings. Respiratory variations in
photoplethysmography are proposed as a noninvasive alternative to predict fluid responsiveness during mechanical ventilation.
This paper aims to critically evaluate current data on the ability of photoplethysmography to predict fluid responsiveness.
Method. Primary searches were performed in PubMed, Medline, and Embase on November 10, 2011. Results. 14 papers
evaluating photoplethysmography and fluid responsiveness were found. Nine studies calculated areas under the receiver operating
characteristic curves for ΔPOP (>0.85 in four, 0.75–0.85 in one, and <0.75 in four studies) and seven for PVI (values ranging
from 0.54 to 0.98). Correlations between ΔPOP/PVI and ΔPP/other dynamic variables vary substantially. Conclusion. Although
photoplethysmography is a promising technique, predictive values and correlations with other hemodynamic variables indicating
fluid responsiveness vary substantially. Presently, it is not documented that photoplethysmography is adequately valid and reliable
to be included in clinical practice for evaluation of fluid responsiveness