An 80-year-old man is admitted to the cardiac care unit after a complicated percutaneous coronary intervention procedure. He has chest discomfort and shortness of breath. The patient's blood pressure is 82/50 mm Hg and pulse is 114/min and regular. Hemodynamic readings from the pulmonary artery catheter are shown below. Which of the following is the most likely cause of this patient's hypotension?
A)Early stages of septic shock
B)Impaired myocardial contractility
C)Pericardial tamponade
D)Pulmonary embolism
E)Retroperitoneal bleeding

Question

An 80-year-old man is admitted to the cardiac care unit after a complicated percutaneous coronary intervention procedure.  He has chest discomfort and shortness of breath.  The patient's blood pressure is 82/50 mm Hg and pulse is 114/min and regular.  Hemodynamic readings from the pulmonary artery catheter are shown below.  Which of the following is the most likely cause of this patient's hypotension?
A)Early stages of septic shock 
B)Impaired myocardial contractility 
C)Pericardial tamponade 
D)Pulmonary embolism 
E)Retroperitoneal bleeding

Quizplus · Accepted Answer

Explanation: 11ec2b69_c112_d51d_8f63_4df83e0f6748_MD0005_00 This patient's clinical presentation (chest discomfort, tachycardia, hypotension) and hemodynamic findings are consistent with cardiogenic shock after a complicated percutaneous coronary procedure. This is most likely due to an abrupt coronary occlusion leading to impaired contractility of the involved myocardium. Hemodynamic parameters from pulmonary artery catheterization in cardiogenic shock show low cardiac index (CI) due to impaired cardiac contractility, elevated pulmonary capillary wedge pressure (PCWP) due to volume overload, with a compensatory elevation in systemic vascular resistance (SVR). (Choice A) Patients with early sepsis or neurogenic shock (distributive shock) have a compensatory increase in cardiac output/index. PCWP and SVR are typically decreased, which is useful in differentiating septic shock from other causes of shock. (Choice C) In cardiac tamponade, rapid accumulation of fluid in the limited pericardial space leads to increased right atrial and ventricular pressures, but there is also a characteristic equalization of right atrial, right ventricular end diastolic, and PCWPs (not seen in this patient whose PCWP is higher than his right ventricular end diastolic pressure). (Choice D) Patients with pulmonary embolus have elevated right atrial, right ventricular, and pulmonary artery pressures. They may have hyperdynamic left ventricular function with increased CI. PCWP and SVR are generally not affected. (Choice E) Patients with retroperitoneal bleeding and/or intravascular volume depletion will have low right atrial and PCWP. CI is slightly reduced and SVR is increased. Educational objective: Patients with significant left ventricular dysfunction and cardiogenic shock have reduced cardiac index and elevated pulmonary capillary wedge pressures. Systemic vascular resistance is typically increased to maintain adequate tissue perfusion pressure. References: The ability to achieve complete revascularization is associated with improved in-hospital survival in cardiogenic shock due to myocardial infarction: Manitoba cardiogenic SHOCK Registry investigators. (http://www.ncbi.nlm.nih.gov/pubmed/21547996)

An 80-Year-Old Man Is Admitted to the Cardiac Care Unit