An 80-year-old woman is brought to the emergency department due to a day of lethargy and confusion. The patient's medical issues include hypertension, type 2 diabetes mellitus, coronary artery disease, peripheral vascular disease, and previous stroke. She smoked cigarettes for 30 years but quit after a myocardial infarction 10 years ago. The patient has been bedbound for the past 2 years due to a stroke. Temperature is 36.8 C (98.2 F), blood pressure is 74/48 mm Hg, pulse is 124/min, and respirations are 24/min. She has a sacral decubitus ulcer with purulent drainage and surrounding erythema. Chronic venous stasis changes are present on the bilateral lower extremities. Neurologic examination shows a confused patient who is unable to follow instructions. Laboratory results are as follows: Invasive hemodynamic monitoring reveals the pulmonary capillary wedge pressure is 6 mm Hg (normal: 6-12 mm Hg) and mixed venous oxygen saturation is 82% (normal: 60%-80%). Which of the following findings would most likely be associated with this patient's hypotension?

Question

An 80-year-old woman is brought to the emergency department due to a day of lethargy and confusion.  The patient's medical issues include hypertension, type 2 diabetes mellitus, coronary artery disease, peripheral vascular disease, and previous stroke.  She smoked cigarettes for 30 years but quit after a myocardial infarction 10 years ago.  The patient has been bedbound for the past 2 years due to a stroke.  Temperature is 36.8 C (98.2 F), blood pressure is 74/48 mm Hg, pulse is 124/min, and respirations are 24/min.  She has a sacral decubitus ulcer with purulent drainage and surrounding erythema.  Chronic venous stasis changes are present on the bilateral lower extremities.  Neurologic examination shows a confused patient who is unable to follow instructions.  Laboratory results are as follows:  Invasive hemodynamic monitoring reveals the pulmonary capillary wedge pressure is 6 mm Hg (normal: 6-12 mm Hg) and mixed venous oxygen saturation is 82% (normal: 60%-80%).  Which of the following findings would most likely be associated with this patient's hypotension?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d368_7e07_bc81_b774f183698e_MD0003_00 This patient with an infected sacral decubitus ulcer, hypotension, tachycardia, tachypnea, and mental status changes likely has septic shock (fever or hypothermia are not always present, especially among older patients). Septic shock is a form of distributive shock characterized by: Septic shock Decreased systemic vascular resistance (SVR) (ie, reduced afterload) due to peripheral vasodilation Decreased (or low normal) pulmonary capillary wedge pressure (PCWP) (ie, left atrial pressure) due to capillary leakage, which causes decreased preload Elevated mixed venous oxygen (MvO₂) saturation due to hyperdynamic circulation (as cardiac output is increased in response to reduced SVR to maintain peripheral tissue perfusion) with an inability of tissues to adequately extract oxygen (may develop lactic acidosis from tissue hypoperfusion) In late septic shock, cardiac output can decrease. (Choice A) Patients with decreased cardiac contractility can develop cardiogenic shock due to left ventricular dysfunction. Patients generally have elevated right atrial pressures and PCWP (due to volume overload) and a compensatory elevation in SVR. The decreased cardiac output decreases tissue perfusion, which signals tissues to extract more oxygen and thereby decreases MvO₂. cardiogenic shock ₂ (Choice B) Increased intrapericardial pressure can cause obstructive shock due to cardiac tamponade. Patients will have equalization of cardiac chamber end-diastolic pressures with increased right atrial pressure, right ventricular pressure, and PCWP (although blood flow to the left atrium is decreased, PCWP is increased due to external compression). Cardiac output is decreased, causing low MvO₂. obstructive shock ₂ (Choice C) Neurogenic shock is a form of distributive shock in which a CNS injury disrupts sympathetic pathways and leads to a reduction in SVR. Bradycardia is typical, MvO₂ is usually low (improved peripheral oxygen extraction due to lower flow), and no underlying infection is present. ₂ (Choice D) Mineralocorticoid deficiency (eg, due to primary adrenal insufficiency) is a form of distributive shock that usually presents with hypotension from low aldosterone levels. Patients have low SVR with associated hyperkalemia and hyponatremia. Educational objective: Septic shock leads to a decrease in systemic vascular resistance (cardiac afterload) due to overall peripheral vasodilation. Hemodynamic monitoring in these patients reveals a low normal or decreased pulmonary capillary wedge pressure, low systemic vascular resistance, increased cardiac output (at least initially), and high mixed venous oxygen saturation. References: Circulatory shock. (http://www.ncbi.nlm.nih.gov/pubmed/24171518)

An 80-Year-Old Woman Is Brought to the Emergency Department Due