Introduction: The passive leg raising test (PLR) allows physicians to determine which patients require treatment with intravenous fluids. Objectives: It is important to be aware of tools that help us to determine the response to the passive leg raising test, as well as understanding in which clinical situations it can be performed. Materials and methods: Non-systematic review. Medline and PubMed databases were consulted in search of relevant articles. Results: Through echocardiography, pulse pressure and capnography can be determined as a response to leg raising. Conclusions: This article explores the tools that are useful in determining the response to this maneuver, and the clinical conditions in which it is indicated.