A 72-year-old man is brought to the emergency department after being intubated by emergency medical services personnel at the scene. The patient was found at home, unconscious, with a weak pulse and agonal respirations. His medical problems include hypertension, hyperlipidemia, type 2 diabetes, coronary artery disease, and metastatic prostate cancer. Blood pressure is 80/40 mm Hg, and pulse is 120/min and regular. Patchy rales are present. A grade 2/6 apical systolic murmur is present. The upper and lower extremities are cold and clammy. A nonhealing wound is noted in the right foot. Pulmonary artery catheterization results are obtained and shown below: Which of the following is the most likely diagnosis?

Question

A 72-year-old man is brought to the emergency department after being intubated by emergency medical services personnel at the scene.  The patient was found at home, unconscious, with a weak pulse and agonal respirations.  His medical problems include hypertension, hyperlipidemia, type 2 diabetes, coronary artery disease, and metastatic prostate cancer.  Blood pressure is 80/40 mm Hg, and pulse is 120/min and regular.  Patchy rales are present.  A grade 2/6 apical systolic murmur is present.  The upper and lower extremities are cold and clammy.  A nonhealing wound is noted in the right foot.  Pulmonary artery catheterization results are obtained and shown below: Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

This patient with a history of metastatic cancer (which creates a hypercoagulable state) was found unconscious and has severe hypotension and shock. He has elevated right atrial (RA) pressure, a reflection of central venous pressure, and elevated pulmonary artery (PA) pressure, indicating pulmonary hypertension. Pulmonary capillary wedge pressure (PCWP) reflects left atrial pressure and left-sided heart function. An elevated PCWP combined with elevated right-sided pressures suggests left-sided heart failure leading to right-sided heart failure. However, low or normal PCWP suggests intact left ventricular function, and indicates that elevated pulmonary pressures are most likely due to an intrinsic pulmonary process. An acute massive pulmonary embolism can cause abrupt increases in RA pressure to >10 mm Hg and PA pressure to >40 mm Hg. This can lead to decreased blood flow through the pulmonary circulation to the left atrium, resulting in decreased cardiac output (CO) and hypotension (obstructive shock), as in this patient. obstructive shock (Choice A) Aortic dissection commonly presents with hypertension but complications can cause hypotension and shock via varying mechanisms. Aortic rupture into the pericardium with resulting cardiac tamponade can cause obstructive shock, but elevated RA pressure, PA pressure, and PCWP are expected due to compression of the heart. Full-thickness rupture of the aorta into the chest or abdomen can cause hemorrhagic (hypovolemic) shock with low RA pressure, PA pressure, and PCWP. (Choice B) Patients with hypovolemic shock (or volume depletion) have low intravascular volume causing low RA, PA, and PCWP. Systemic vascular resistance (SVR) is increased to maintain adequate perfusion to the vital organs. hypovolemic shock (Choice C) Left anterior descending artery occlusion causing anterior myocardial infarction with extensive left ventricular damage (>40% of left ventricle) can lead to cardiogenic shock. This usually increases PCWP, decreases CO, and increases SVR. RA and PA pressures are also usually elevated. cardiogenic shock (Choice E) Septic shock is a form of distributive shock leading to peripheral vasodilation and decreased SVR. The low blood flow back to the heart causes decreased RA, PA, and PCWP. CO is increased in an effort to maintain adequate tissue perfusion. Septic shock Educational objective: An acute massive pulmonary embolism can present initially with syncope and shock. Right heart catheterization will show elevated right atrial and pulmonary artery pressures along with normal pulmonary capillary wedge pressure. References: Pathophysiology and treatment of haemodynamic instability in acute pulmonary embolism: the pivotal role of pulmonary vasoconstriction. (http://www.ncbi.nlm.nih.gov/pubmed/11033105) Hemodynamics and gas exchange in acute lung embolism. (http://www.ncbi.nlm.nih.gov/pubmed/2656454)

A 72-Year-Old Man Is Brought to the Emergency Department After