Procedural Aspects and Physiologic Mechanisms of the Deep Inspiratory Maneuver

Sir, we have read the paper by S. Preau et al. “Hemodynamic changes during a deep inspiration maneuver predict fluid responsiveness in spontaneously breathing patients” with great interest. Based on the fundamental ideas of dynamic hemodynamic monitoring, inducing cardiac preload variations and monitoring corresponding pulse pressure variations [1], the paper presents a novel technique of varying cardiac preload in spontaneously breathing (SB) patients that does not necessitate specialised equipment apart from routine clinical monitoring. The paper is indeed relevant because it is, to our knowledge, the first to present the feasibility of a deep breathing method (deep inspiratory maneuver, DIM) for inducing preload changes. For the purpose of better understanding the presented technique, we wish to pose the following questions for the authors.