Diagnosing the mechanisms of circulatory failure

Abstract

The assessment of circulatory failure and shock constitutes the most frequent indication for performing an echocardiographic study in the intensive care unit. In addition to its diagnostic capabilities, echocardiography allows a close monitoring of the effects of the applied therapies. When a patient presents hypotension or signs of hypoperfusion, the role of echocardiography is to determine the main cause and suggest therapies that could improve the hemodynamic situation. Diagnostic algorithms are proposed. As cardiovascular alterations are rarely pure (e.g., septic shock in a patient with cardiac disease), we have to create a hierarchy among the potential causes, differentiating the main factor from other contributing factors. The clinical relevance of fortuitous echocardiographic diagnoses (e.g., underlying chronic cardiomyopathy or valvulopathy) needs to be addressed.Whether this abnormality is severe enough to explain the hemodynamic pattern of the patient and is compatible with the clinical presentation may be challenging to determine. Regarding therapies, the order of the interventions has to be prioritized, when considering we have to ask ourselves the following questions: is this abnormality severe enough to explain the hemodynamic pattern of the patient, and is it compatible with the clinical scenario? Regarding therapies, we also have to prioritize the order of the interventions, always considering the clinical scenario (e.g., in a septic patient with impaired cardiac function and preload responsiveness, fluids should be prioritized unless the patient also suffers from severe respiratory distress). More importantly, echocardiographic evaluation should never be performed as a single shot: it is best used when it also evaluates the effects of the selected interventions. © 2011 Springer-Verlag Berlin Heidelberg.