CURRENT Essentials of Critical Care.pdf

Chapter 6 Shock 75■■■Cardiogenic ShockEssentials of Diagnosis• Severely low cardiac output state caused by myocardial orvalvular dysfunction leading to inadequate tissue perfusion• Hypotension, cool extremities, distended neck veins, third heartsound, oliguria, respiratory distress due to pulmonary edema• Pulmonary artery catheter typically demonstrates elevatedcentral venous pressure, increased pulmonary capillary wedgepressure, high systemic vascular resistance, low cardiac index( 2 L/min/m 2 )• Acute myocardial infarction most common cause• Other etiologies: acute valvular abnormalities, septal defects orrupture, free wall rupture, traumatic myocardial contusionDifferential Diagnosis• Hypovolemic shock • Septic shock• Aortic dissection • Severe aortic stenosisTreatment• When cardiogenic shock results from acute myocardial infarction,efforts to improve myocardial perfusion and reduce ischemiaare priority; consider prompt thrombolytic therapy or cardiaccatheterization with primary coronary intervention• Intravascular volume should be optimized; pulmonary arterycatheter may help; goal pulmonary capillary wedge pressure17–18 mm Hg• Dobutamine useful in congestive heart failure and cardiogenicshock given its positive inotropic effects, minimal chronotropicand peripheral vasoconstricting properties• Dopamine or norepinephrine for persistent hypotension• Vasodilators such as nitroglycerin and nitroprusside can lowerleft ventricular afterload; use often limited by hypotension• Diuretics helpful in treatment of pulmonary edema• Intra-aortic balloon pump can be utilized for refractory hypotensionwith poor organ perfusion■ PearlIn patients with acute myocardial infarction, the onset of cardiogenicshock is often delayed, with median onset of shock occurring 5.5–7hours after the initial ischemic insult.ReferenceHollenberg SM: Cardiogenic shock. Crit Care Clin 2001;17:391. [PMID:11450323]