We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Pathophysiology of fluid administration in critically ill patients.
- Authors
Messina, Antonio; Bakker, Jan; Chew, Michelle; De Backer, Daniel; Hamzaoui, Olfa; Hernandez, Glenn; Myatra, Sheila Nainan; Monnet, Xavier; Ostermann, Marlies; Pinsky, Michael; Teboul, Jean-Louis; Cecconi, Maurizio
- Abstract
Fluid administration is a cornerstone of treatment of critically ill patients. The aim of this review is to reappraise the pathophysiology of fluid therapy, considering the mechanisms related to the interplay of flow and pressure variables, the systemic response to the shock syndrome, the effects of different types of fluids administered and the concept of preload dependency responsiveness. In this context, the relationship between preload, stroke volume (SV) and fluid administration is that the volume infused has to be large enough to increase the driving pressure for venous return, and that the resulting increase in end-diastolic volume produces an increase in SV only if both ventricles are operating on the steep part of the curve. As a consequence, fluids should be given as drugs and, accordingly, the dose and the rate of administration impact on the final outcome. Titrating fluid therapy in terms of overall volume infused but also considering the type of fluid used is a key component of fluid resuscitation. A single, reliable, and feasible physiological or biochemical parameter to define the balance between the changes in SV and oxygen delivery (i.e., coupling "macro" and "micro" circulation) is still not available, making the diagnosis of acute circulatory dysfunction primarily clinical. Take-home messages: Fluids are drugs used in patients with shock to increase the cardiac output with the aim to improve oxygen delivery to the cells. The response to fluid administration is determined by the physiological interaction of cardiac function and venous return. In septic shock, the beneficial clinical response of fluid administration is rapidly reduced after few hours and fluid titration is crucial to avoid detrimental fluid overload. The fluid challenge is a fluid bolus given at a defined quantity and rate to assess fluid responsiveness. The ideal fluid for critically ill patients does not exist; however, crystalloids should be used as first choice. Balanced crystalloid solutions may be associated with better outcomes but the evidence is still low. Albumin infusion may have a role in already fluid resuscitated patients at risk of fluid overload. Fluid administration is integrated into the complex management of pressure and flow "macro" hemodynamic variables, coupled to the "micro" local tissue flow distribution and regional metabolism. Macro-variables are managed by measuring systemic blood pressure and evaluating the global cardiac function. The critical threshold of oxygen delivery to the cells is difficult to estimate, however, several indexes and clinical signs may be considered as surrogate of that, and integrated in a decision-making process at the bedside.
- Subjects
CRITICALLY ill; PATHOLOGICAL physiology; VENOUS pressure; SEPTIC shock; COMPLEX regional pain syndromes; HYPERVOLEMIA
- Publication
Intensive Care Medicine Experimental, 2022, Vol 10, Issue 1, p1
- ISSN
2197-425X
- Publication type
Article
- DOI
10.1186/s40635-022-00473-4