Resuscitation from circulatory shock

Shock can be defined as a state of circulatory failure to deliver sufficient oxygen to balance the demands of the tissues, which results in tissue hypoxia: a deficiency in the bioavailability of oxygen to the tissues of the body. Clinical management of shock is often challenging. In fact, therapy is focused on the optimization of preload (by means of fluid administration), heart function, and afterload (systemic vascular tone) to avoid the detrimental effects of over-resuscitation or under-resuscitation. Circulatory shock is a clinical diagnosis based on signs and symptoms of inadequate tissue perfusion and unbalanced metabolic demand, which can be present irrespective of normal or even high values of cardiac output and mean arterial pressure. Several simple and reliable clinical markers of the shock condition can be used in the clinical practice: capillary refill time, skin mottling level, lactates, central venous saturation, and gap of carbon dioxide have been tested in several clinical trials to support the assessment of shock occurrence and reversal at the bedside.