Nonpharmacologic management of cardiac arrest and cardiogenic shock.

P harmacologic management of patients with cardiac arrest or cardiogenic shock may be insuI cient in restoring adequate circulatory support. This has led physicians to investigate and develop more aggressive interventions for these problems. Cardiogenic shock most frequently occurs in the following clinical settings: (1) acute myocardial infarction; (2) postcardiotomy; (3) an acute exacerbation in someone with chronic cardiac dysfunction and congestive heart failure; (4) cardiac arrest secondary to an arrhythmia; (5) cardiac dysfunction secondary to a complication from a percutaneous interventional cardiac procedure, eg, coronary angioplasty; and (6) less often as other acute illnesses, eg, myocarditis. Although initial management often requires immediate intervention to restore circulatory support, even prior to knowing the definitive cause of the patient’s shock, it is important that an extensive diagnostic evaluation, particularly pursuing reversible causes of shock, be undertaken at the earliest possible time. During this evaluation, it is important to determine the degree of both left and right ventricular dysfunction, as interventions may differ particularly when mechanical circulatory assist devices are being considered. Despite recent pharmacologic advances, which have led to the development of newer inotropic agents (eg, amrinone) and to thrombolytic therapy, recent studies have demonstrated that the incidence and mortality of cardiogenic shock in patients with an acute myocardial infarction, treated predominantly with medical therapy, have not changed significantly over a recent 13-year period.’ The inhospital mortality rate in patients with acute myocardial infarction and cardiogenic shock, treated predominantly with pharmacologic agents, has been reported to be between 70 and 100 percent. ‘-“ Even when pharmacologic therapy is able to provide adequate circulatory support, many patients may still need a nonphannacologic intervention (eg, coronary artery bypass surgery to reverse ischemia) to restore adequate cardiac function and therefore allow one to be weaned from pharmacologic therapy. Nonpharmacologic treatment for cardiogenic shock and cardiac arrest consist of (1) interventions (eg, mechanical circulatory assist devices, cardiac transplantation) that provide circulatory support to the patient no matter what the underlying cause of the circulatory deterioration, and to (2) interventions (eg, percutaneous interventional or surgical corrective procedures) that correct or reverse the specific cause of the underlying shock (Table 1). This article will discuss the nonpharmacologic interventions that have been helpful in restoring circulatory support and reversing underlying causes of cardiogenic shock and cardiac arrest. These nonpharmacologic interventions have had a significant impact on the survival of these patients. Tables 1 and 2 list the various mechanical circulatory assist devices and cardiac procedures that have been used in patients with cardiogenic shock. Patients with cardiogenic shock or cardiac arrest who require nonpharmacologic intervention generally fall into three categories: