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ABSTRACT
Shock is a life-threatening condition, resulting from different causes, and leading to tissue hypoperfusion. Symptomatic therapy associates fluids and vasoactive agents. Vasopressor and inotropic adrenergic agents remain the most commonly used to correct hypotension and/or to increase cardiac output. These agents have different haemodynamic and metabolic profiles, but the relevance of these differences on outcome has long been challenged. Recent randomized trials have shaded some light on this issue. Dopamine and norepinephrine have been the most extensively studied. These trials raised major concerns on the use of dopamine, which was associated with tachycardia and increased arrhythmic events, and may be associated with an increased risk of death especially in the subgroup of patients with cardiogenic shock. The place of epinephrine is not well defined, this agent is associated with tachycardia, increased incidence of arrhythmic events, and undesired metabolic effects.
INTRODUCTION
Shock, or circulatory failure, defi nes a generalized state of inadequate supply or inappropriate use of oxygen and nutrients by the cells, resulting in tissue hypoxia (1). Unless transient, this will lead to irreversible tissue damage and death. Hypotension is a cardinal sign of shock, and the severity of hypotension is associated with poor outcome. Although less common, shock may present in the absence of hypotension and its recognition will be more diffi cult. Diff erent aetiologies can lead to shock, and prompt diagnosis of the cause of shock is essential to initiate causative therapy (i.e. antibiotics, coronary angioplasty,...). Whatever its cause, shock is associated with high mortality (around 50%). Supportive therapy should aim at preserving tissue perfusion and should be initiated without delay as both the severity and the duration of hypotension and hypoperfusion are associated with a poor outcome (2). The administration of fl uids is often the fi rst line therapy but vasopressor agents are frequently administered to maintain blood pressure within an acceptable range. In addition, inotropic agents may be required to support cardiac output.
HOW TO RECOGNIZE THAT MY PATIENT IS IN SHOCK?
There are several "clinical windows" that can be used to recognize the patient is in shock. Hypotension is of course the easiest to recognize. Hypotension is usually defi ned a systolic blood pressure below 90 mmHg (or a 25% decrease from its usual level...