A 49-year-old woman comes to the emergency department with a 2-day history of fever, dysuria, and flank pain. The patient has a history of poorly controlled type 2 diabetes mellitus. Temperature is 38.3 C (101 F) , blood pressure is 80/44 mm Hg, pulse is 134/min, and respirations are 34/min. On physical examination, the patient appears lethargic, flushed, and diaphoretic. Neck veins are flat. The lungs are clear on auscultation and heart sounds are normal. There is right-sided costovertebral tenderness. Which of the following hemodynamic parameters are most likely to be present in this patient?

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11ec160b_3a9d_bd1a_9249_1f90f8628b78_MD0001_00 This patient with fever, dysuria, flank pain, and right costovertebral angle tenderness likely has pyelonephritis. In addition, her hypotension in the setting of infection suggests septic shock. Septic shock is the most common type of distributive shock; other types include anaphylactic shock and neurogenic shock. The primary disturbance in septic shock is widespread vasodilation leading to decreased systemic vascular resistance (SVR). Increased vascular permeability (third-spacing) and peripheral venous dilation also cause a reduction in central venous pressure and pulmonary capillary wedge pressure (PCWP) (Choice B). Initially, the hypotension and inflammation from sepsis trigger a compensatory increase in sympathetic drive that increases heart rate and myocardial contractility, leading to increased cardiac index (cardiac output per body surface area). The high blood flow rates prevent complete extraction of oxygen by the tissues, resulting in high mixed venous oxygen saturation. As shock progresses, tissue ischemia and accumulation of cytotoxic mediators eventually cause a reduction in cardiac output with end-organ dysfunction. (Choice A) Low cardiac index with high PCWP is consistent with cardiogenic shock. The primary disturbance is typically left ventricular failure with a compensatory increase in SVR in an effort to maintain adequate blood pressure for organ perfusion. (Choice C) Low PCWP with low cardiac index and high SVR occurs in both hypovolemic shock and some types of obstructive shock (eg, pulmonary embolism, tension pneumothorax). Central venous pressure is low in hypovolemic shock and high in obstructive shock. (Choice D) Low PCWP with low cardiac index and low SVR occurs in neurogenic shock. As in sepsis, the primary disturbance is peripheral vasodilation. However, due to nerve injury there is no sympathetic-mediated increase in heart rate and myocardial contractility; therefore, cardiac output is low. These parameters are also seen in the late stages of septic shock; however, this patient's flushing is consistent with the high cardiac output seen in early septic shock. Educational objective: Septic shock causes widespread arteriolar vasodilation, which leads to a decrease in systemic vascular resistance and a compensatory increase in cardiac output. Central venous pressure and pulmonary capillary wedge pressure are also decreased due to pooling of blood in the dilated veins. Increased flow rates through the peripheral capillaries lead to incomplete oxygen extraction by the tissues and high mixed venous oxygen saturation. __________ References: Circulatory shock. (http://www.ncbi.nlm.nih.gov/pubmed/24171518)

A 49-Year-Old Woman Comes to the Emergency Department with a 2-Day