Hemodynamics Practice Questions

Question 1

A peripheral artery is found to have 50% stenosis (50% reduction in cross-sectional area). Therefore, compared to a normal artery with no stenosis, by what factor has the flow of blood been decreased?

Accepted Answer

4

Answer

8

Answer

2

Answer

32

Answer

16

Question 2

A 28-year-old research assistant is brought to the emergency department for severe chemical burns 30 minutes after accidentally spilling hydrochloric acid on himself. The burns cover both hands and forearms. His temperature is 37°C (98.6°F), pulse is 112/min, respirations are 20/min, and blood pressure is 108/82 mm Hg. Initial stabilization and resuscitation is begun, including respiratory support, fluid resuscitation, and cardiovascular stabilization. The burned skin is irrigated with saline water to remove the chemical agent. Which of the following is the most appropriate method to verify adequate fluid infusion in this patient?

Accepted Answer

Urinary output

Answer

The Parkland formula

Answer

Blood pressure

Answer

Pulmonary capillary wedge pressure

Answer

Heart rate

Question 3

What is the primary mechanism for maintaining constant cerebral blood flow despite changes in systemic blood pressure?

Accepted Answer

Myogenic autoregulation

Answer

Endothelial factors

Answer

Baroreceptor reflex

Answer

Metabolic control

Question 4

A 34-year-old male is brought to the emergency department by fire and rescue following a motor vehicle accident in which the patient was an unrestrained driver. The paramedics report that the patient was struck from behind by a drunk driver. He was mentating well at the scene but complained of pain in his abdomen. The patient has no known past medical history. In the trauma bay, his temperature is 98.9°F (37.2°C), blood pressure is 86/51 mmHg, pulse is 138/min, and respirations are 18/min. The patient is somnolent but arousable to voice and pain. His lungs are clear to auscultation bilaterally. He is diffusely tender to palpation on abdominal exam with bruising over the left upper abdomen. His distal pulses are thready, and capillary refill is delayed bilaterally. Two large-bore peripheral intravenous lines are placed to bolus him with intravenous 0.9% saline. Chest radiograph shows multiple left lower rib fractures.

Which of the following parameters is most likely to be seen in this patient?

Accepted Answer

Decreased pulmonary capillary wedge pressure

Answer

Increased cardiac output

Answer

Increased mixed venous oxygen saturation

Answer

Decreased systemic vascular resistance

Answer

Increased right atrial pressure

Question 5

A 71-year-old man is admitted to the hospital one hour after he was found unconscious. His pulse is 80/min and systolic blood pressure is 98 mm Hg; diastolic blood pressure cannot be measured. He is intubated and mechanically ventilated with supplemental oxygen at a tidal volume of 450 mL and a respiratory rate of 10/min. Arterial blood gas analysis shows:
PCO2 43 mm Hg
O2 saturation 94%
O2 content 169 mL/L
Pulmonary artery catheterization shows a pulmonary artery pressure of 15 mm Hg and a pulmonary capillary wedge pressure of 7 mm Hg. Bedside indirect calorimetry shows a rate of O2 tissue consumption of 325 mL/min. Given this information, which of the following additional values is sufficient to calculate the cardiac output in this patient?

Accepted Answer

Pulmonary artery oxygen content

Answer

Left ventricular end-diastolic volume

Answer

Partial pressure of inspired oxygen

Answer

End-tidal carbon dioxide pressure

Answer

Total peripheral resistance

Question 6

A 29-year-old man is brought to the emergency room 6 hours after the onset of severe epigastric pain and vomiting. His heart rate is 110/min and blood pressure is 98/72 mm Hg. He is diagnosed with acute pancreatitis, and fluid resuscitation with normal saline is initiated. Which of the following is the most likely immediate effect of fluid resuscitation in this patient?

Accepted Answer

Increase in myocardial oxygen demand

Answer

Increase in plasma oncotic pressure

Answer

Increase in glomerular filtration fraction

Answer

Increase in volume of distribution

Answer

Increase in cardiac afterload

Question 7

A 27-year-old man is running on the treadmill at his gym. His blood pressure prior to beginning his workout was 110/72. Which of the following changes in his cardiovascular system may be seen in this man now that he is exercising?

Accepted Answer

Decreased systemic vascular resistance

Answer

Decreased blood pressure

Answer

Increased systemic vascular resistance

Answer

Decreased stroke volume

Answer

Decreased heart rate

Question 8

A 27-year-old man is brought to the emergency department by emergency medical services. The patient was an unrestrained passenger in a head-on collision that occurred 15 minutes ago and is currently unresponsive. His temperature is 99.5°F (37.5°C), blood pressure is 60/33 mmHg, pulse is 180/min, respirations are 17/min, and oxygen saturation is 95% on room air. A FAST exam demonstrates fluid in Morrison’s pouch. Laboratory values are drawn upon presentation to the ED and sent off. The patient is started on IV fluids and an initial trauma survey is started. Twenty minutes later, his blood pressure is 95/65 mmHg, and his pulse is 110/min. The patient is further stabilized and is scheduled for emergency surgery. Which of the following best represents this patient’s most likely initial laboratory values?

Accepted Answer

Hemoglobin: 11 g/dL, Hematocrit: 33%, MCV: 88 µm^3

Answer

Hemoglobin: 10 g/dL, Hematocrit: 30%, MCV: 110 µm^3

Answer

Hemoglobin: 19 g/dL, Hematocrit: 55%, MCV: 95 µm^3

Answer

Hemoglobin: 7 g/dL, Hematocrit: 21%, MCV: 75 µm^3

Answer

Hemoglobin: 15 g/dL, Hematocrit: 45%, MCV: 90 µm^3

Question 9

An 83-year-old male presents with dyspnea, orthopnea, and a chest radiograph demonstrating pulmonary edema. A diagnosis of congestive heart failure is considered. The following clinical measurements are obtained: 100 bpm heart rate, 0.2 mL O2/mL systemic blood arterial oxygen content, 0.1 mL O2/mL pulmonary arterial oxygen content, and 400 mL O2/min oxygen consumption. Using the above information, which of the following values represents this patient's cardiac stroke volume?

Accepted Answer

40 mL/beat

Answer

30 mL/beat

Answer

70 mL/beat

Answer

60 mL/beat

Answer

50 mL/beat

Question 10

A 69-year-old woman is admitted to the hospital with substernal, crushing chest pain. She is emergently moved to the cardiac catheterization lab where she undergoes cardiac angiography. Angiography reveals that the diameter of her left anterior descending artery (LAD) is 50% of normal. If her blood pressure, LAD length, and blood viscosity have not changed, which of the following represents the most likely change in LAD flow from baseline?

Accepted Answer

Decreased by 93.75%

Answer

Increased by 6.25%

Answer

Decreased by 25%

Answer

Decreased by 87.5%

Answer

Increased by 25%

Hemodynamics

Study Resources

Lessons

Questions

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Lessons

Principles of blood flow (Poiseuille's law)

Vascular resistance concepts

Laminar vs. turbulent flow

Pressure gradients across circulation

Compliance of blood vessels

Arterial pressure waveform

Venous pressure and return

Pulmonary circulation hemodynamics

Autoregulation mechanisms

Orthostatic changes in hemodynamics

Shock states pathophysiology

Hemodynamic monitoring principles

Microcirculation physiology

Practice Questions

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About Hemodynamics for USMLE

Lessons in Hemodynamics

Master Hemodynamics