New advances in the pharmacologic approach to circulatory shock

Abstract

Anesthesiologists continue to play important roles in all aspects of critical care medicine. Although a unique pharmacology has evolved for use in the intensive care unit (ICU),’ much of the pharmacologic approach to the critically ill patient remains similar to the pharmacologic approach used for other perioperative conditions. Perhaps no area of critical care pharmacotherapy has evolved with more rapidity or more frustration than the pharmacologic approach to the treatment of circulatory shock. The purpose of this review is to detail our present approach to the treatment of this life-threatening condition, and to provide insight into the new avenues for therapy. Circulatory shock is an important cause of morbidity and mortality in acutely ill, hospitalized patients. Although commonly divided into four major types of circulatory shock (cardiogenic, hypovolemic, obstructive, and distributive), all forms of circulatory shock involve inadequate tissue perfusion and inadequate cellular oxygen (0,) delivery.* Cardiogenic shock is most often a consequence of acute myocardial infarction (MI), but it can also be a secondary consequence of valvular heart disease, worsening of congestive heart failure, myocardial trauma, and. so forth. Hypovolemic shock is usually due to hemorrhage, but it may also be a consequence of adrenal insufftciency or diabetes insipidus. Obstructive shock is usually due to pulmonary embolism or pericardial tamponade. Finally, distributive shock includes circulatory shock due to anaphylaxis, spinal cord shock, or, most commonly, septic shock. It is in the area of the treatment of septic shock that most new information has been realized. F!ecent evidence supports the concept that we may be missing the potential for cardiogenic or obstructive shock by failing to recognize myocardial injury in critically ill patients,3 and failing to recognize the extremely high prevalence of deep venous thrombosis in medical ICU patients despite the administration of prophylactic therapy.4 Thus, it may be that patients are predisposed to myocardial injury, which may develop into cardiogenic shock, and that patients may be at risk for the development of obstructive shock due to pulmonary emboli. Theise two recent realizations prompt me to suggest that screening critically injured patients for the possibility of myocardial injury if they have been traumatically injured is reasonable, and that patients should probably be screened with Doppler ultrasound for deep venous thrombosis. Before getting into some of the new treatment strategies used in septic shock