[Automatic and continuous monitoring of preload dependence in the perioperative period: Interests and limits].

OBJECTIVES: To describe preload dependence monitoring tools currently available as well as their limits and potential applications in the anaesthesiology setting. DATA SOURCE: References were obtained from PubMed data bank (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) using the following keywords: fluid responsiveness, cardiopulmonary interactions, preload dependence, hypovolemia, cardiac output. DATA SYNTHESIS: When measured in optimal conditions, dynamic parameters are the best predictors of fluid responsiveness as compared to static indicators in patients under general anaesthesia and mechanical ventilation. These dynamic parameters rely on cardiopulmonary interactions and allow evaluating preload dependence and the ability of the heart to transform an increase in preload into an increase in cardiac output. Recently, it is possible to monitor these dynamic parameters either invasively (from the arterial pressure waveform) or noninvasively (from the plethysmographic waveform). These tools have intrinsic limitations. However, they have potential to be used for fluid optimization during anaesthesia. 2010. Published by Elsevier SAS.