Pharmacotherapy of circulatory shock

Current Problems in Cardiology, 1983

Seminars in Anesthesia, Perioperative Medicine and Pain, 1999

Shock is recognized at the bedside when hemodynamic instability leads to hypoperfusion of several organ systems. Accordingly, shock is a clinical diagnosis. Successful management of shock requires a primary survey directed at formulation of a working diagnosis and urgent initial resuscitation. The clinical response to initial measures to restore organ perfusion then confirms or changes the working diagnosis. This allows the clinician a pause to ponder the broader differential diagnosis of the types of shock and the pathophysiology of shock, which leads to early definitive therapy of the underlying cause of shock. Shock has a hemodynamic component, which is the initial focus of resuscitation, but shock also has a systemic inflammatory component that leads to multiple system organ failure. In this article, we present a simplified approach to diagnosis and management of shock and emphasize the tempo of resuscitation. The ultimate goal is to restore tissue perfusion in a timely fashion to prevent the development of multiple organ failure, which has a high mortality.

More than 1 million cases of shock are estimated to present to U.S. hospital EDs each year.The presentation may be cryptic, as in the patient with compensated heart failure, or obvious as in the ultimate shock state of cardiac arrest. Despite aggressive treatment, mortality from shock remains high. Approximately 30 to 45 percent of patients in septic shock, and 60 to 90 percent for those with cardiogenic shock, die within 1 month of presentation The definition and treatment of shock continues to evolve. With a contemporary understanding of the disease and new evolving technology, the emergency physician can recognize shock at an earlier stage and initiate expert, timely intervention. The general approach to a patient in the initial stages of shock follows similar principles regardless of the inciting factors or etiology. Keywords: Shock, peripheral circulatory failure, cardiogenic shock ,anaphylactic shock.

Critical Care Nursing Clinics of North America, 2014

In health, functional components of the microcirculation provide oxygen and nutrients and remove waste products from the tissue beds of the body's organs. Shock states overwhelmingly stress functional capacity of the microcirculation, resulting in microcirculatory failure. In septic shock, there is abundant evidence that inflammatory mediators cause or contribute to hemodynamic instability. In nonseptic shock states, the microcirculation is better able to compensate for alterations in vascular resistance, cardiac output (CO), and blood pressure. Autoregulation at the arteriolar level and the endothelium and erythrocyte at the cellular level maintain oxygen diffusion gradients sufficient to support aerobic metabolism. In comparison with septic shock, hypovolemic and cardiogenic shock states are not challenged with the additional burden of infection and its consequential effects on the microcirculation. Global hemodynamic and oxygen delivery (D : O 2) parameters are appropriate for assessing, monitoring, and guiding therapy in hypovolemic and cardiogenic shock but, alone, are inadequate for septic shock.

Surgery (Oxford), 2012

Haemodynamics is the study of blood flow around the body. The factors influencing haemodynamics are complex and include cardiac output, circulating blood volume, vessel diameter, resistance and blood viscosity. These, in turn, are interlinked and affected by factors such as exercise, posture, disease, drugs and obesity. In this article we shall explore the physiology and control of blood flow and pressure in health, moving on then to look at what happens when control mechanisms break down, resulting in cardiovascular shock.

Anaesthesiology intensive therapy, 2015

Shock is defined as a state in which the circulation is unable to deliver sufficient oxygen to meet the demands of the tissues, resulting in cellular dysoxia and organ failure. In this process, the factors that govern the circulation at a haemodynamic level and oxygen delivery at a microcirculatory level play a major role. This manuscript aims to review the blood flow regulation from macro- and micro-haemodynamic point of view and to discuss new potential therapeutic approaches for cardiovascular instability in patients in cardiovascular shock. Despite the recent advances in haemodynamics, the mechanisms that control the vascular resistance and the venous return are not fully understood in critically ill patients. The physical properties of the vascular wall, as well as the role of the mean systemic filling pressure are topics that require further research. However, the haemodynamics do not totally explain the physiopathology of cellular dysoxia, and several factors such as inflamma...

Clinical Practice and Systems Oversight, 2015

World Journal of Surgery, 1987

Descriptions of the sequence of hemodynamic and oxygen transport patterns in the various types of shock syndromes have shown reduced oxygen consumption (VO2) as the earliest pathop.hysiologic event that precedes the initial hypotensive crisis. Inadequate VO2 may be produced by low flow, as in hemorrhagic and cardiogenic shock, by increased metabolic need, as in traumatic and septic shock, and/or by maldistribution of flow in all types of shock. These physiologic patterns are also related to the degree of the shock State and its outcome; the patterns of the survivors and nonsurvivors can be predicted from these patterns with a high degree of sensitivity and specificity by multivariate analysis. Therapy directed toward optimizing the "~O2 and its compensations to the range of survivors of life-threatening shock was shown to improve outcome in prospective clinical trials. A branched chain decision tree was developed for fluid resuscitation of critically ill postoperative patients. The algorithm was developed from decision rules based on objective physiologic heuristic data from survivors as the criteria. The improved mortality in prospective studies supports the hypothesis that compensatory responses of the survivors are major determinants of outcome. Therefore, therapy that supports these compensations and produces the survivor pattern will improve survival rates. These prospective studies confirm the validity of an organized, coherent physiologic approach in contrast to the traditional approach, the objectives of which are to restore hemodynamic and biochemical abnormalities to normal if and when they are discovered. The use of a branched chain decision tree helps to achieve these therapeutic goals expeditiously by providing a coherent, organized patient management plan. It is not necessary to wait for patients to develop cardiorespiratory deficits before initiating therapy. Therapy should be started to optimize the important variables as soon as possible after the onset of accidental trauma or before, during, and immediately after surgery in the high-risk patient. Traditional Approach to Shock Evaluation and therapy of shock have traditionally been approached by separating shock syndromes according to their etiologies. These etiologic categories usually include the hemorrhagic, cardiogenic, traumatic, and septic shock syndromes. Each of these etiologic types of shock are then described by their clinical signs and symptoms, laboratory findings, and primary pathophysiologic derangements. On the basis of this analysis, therapeutic principles are developed for each etiologic type. Table 1 exemplifies this approach. The tacit assumptions