Assessment of Fluid Responsiveness in Spontaneously Breathing Patients
The first scenario refers to patients admitted to the emergency room for evident acute blood losses or body fluid losses. The diagnosis of hypovolemia is almost certain and the presence of clinical signs of hemodynamic instability (hypotension, tachycardia, oliguria, mottled skin, altered mental status, etc) strongly suggests that a positive hemodynamic response to volume resuscitation will occur, although these signs lack sensitivity. The degree of hypotension, of tachycardia, and of oliguria is important for estimating the degree of hypovolemia and hence the degree of urgency for initiating volume resuscitation.
The second scenario refers to patients admitted to the emergency room with a high degree of suspicion of septic shock. In this situation, cardiac preload is always inadequate since relative as well as absolute hypovolemia are always present in the early phase of septic shock. The study by Rivers et al.  emphasized the importance of volume resuscitation in the first hours of management in this category of patients. There is no need to search for sophisticated parameters to predict volume responsiveness since a positive hemodynamic response is always present at this stage. Rather, there is a need to define parameters that can indicate whether volume infusion should be either continued or stopped because of no further expected efficacy (see the third scenario). There is also a need to define indicators of lung intolerance; however, this is not the subject of the present chapter.
The third scenario refers to patients hospitalized in the intensive care unit (ICU) who experience hemodynamic instability that requires urgent therapy. In these patients, volume responsiveness is not guaranteed since they have already been volume resuscitated and continuation of volume infusion carries risks of pulmonary edema. In spontaneously breathing patients either without an endo-tracheal tube or making inspiratory efforts while receiving mechanical ventilation, prediction of volume responsiveness can be a difficult challenge. In these conditions, indices of volume responsiveness that use heart-lung interaction, such as respiratory variations in arterial pressure or in stroke volume and derived indices, are no longer reliable.
KeywordsRight Ventricular Fluid Responsiveness Pulse Pressure Variation Pulmonary Artery Occlusion Pressure Right Atrial Pressure
Unable to display preview. Download preview PDF.
- 5.Schneider AJ, Teule GJJ, Groeneveld ABJ, Nauta J, Heidendal GA, Thijs LG (1988) Biventricular performance during volume loading in patients with early septic shock, with emphasis on the right ventricle: a combined hemodynamic and radionuclide study. Am Heart J 116: 103–112PubMedCrossRefGoogle Scholar
- 11.Soubrier S, Saulnier F, Hubert H, et al (2007) Usefulness of dynamic indicators to predict fluid responsiveness in spontaneously breathing critically ill patients. Intensive Care Med (in press)Google Scholar
- 38.Ridel C, Lamia B, Monnet X, et al (2006) Passive leg raising and fluid responsiveness during spontaneous breathing: pulse contour evaluation. Intensive Care Med 32:S81 (abst)Google Scholar