During intense exercise, the heart rate may accelerate to 150 beats/min and the stroke volume may rise to 130 mL/beat. Calculate the cardiac output.

1. A

   19.5 L/min

2. B

   10 L/min

3. C

   1.95 L/min

4. D

   195 L/min

Appeared in: BTSC 3 August 2025

Explanation

• The fundamental formula for cardiac output (CO) is Heart Rate (HR) multiplied by Stroke Volume (SV).
• The given values are an HR of 150 beats/min and an SV of 130 mL/beat.
• Multiplying these values gives a product of 19,500 mL/min (150 × 130).
• The final step is to convert the result from milliliters per minute (mL/min) to liters per minute (L/min) by dividing by 1000.
• This conversion yields the correct answer: 19,500 / 1000 = 19.5 L/min.

Why Other Options Were Wrong

• Option B: This value is an arbitrary distractor and does not correspond to the mathematical product of the given heart rate and stroke volume.
• Option C: This answer reflects a decimal placement error. It is the result of dividing the product (19,500) by 10,000 instead of the correct conversion factor of 1,000.
• Option D: This answer also reflects a decimal placement error. It is the result of dividing the product (19,500) by 100 instead of 1,000.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Cardiac Output as background academic context rather than a clinical decision trigger.
• Monitoring cardiac output is a fundamental assessment in critical care to evaluate the heart's efficiency as a pump and ensure adequate tissue perfusion.
• A low cardiac output can signify conditions like heart failure, hypovolemia, or shock, prompting immediate nursing and medical interventions.
• A high cardiac output, as seen in this exercise scenario, is a normal physiological response but can also be seen in pathological states like sepsis or hyperthyroidism.

How to Approach the Question

• First, identify the question type. This is a calculation-based question requiring knowledge of a specific physiological formula.
• Recall the formula for cardiac output: CO = HR × SV.
• Identify the given values from the question stem: HR = 150 beats/min and SV = 130 mL/beat.
• Perform the multiplication: 150 × 130 = 19,500. Note that the unit is mL/min.
• Carefully check the units of the answer options. They are in L/min, which requires a conversion.
• Convert your calculated value by dividing by 1000 (since 1 L = 1000 mL) to get 19.5 L/min.

Concept Tested & Keywords

• Concept Tested: Calculation of Cardiac Output
• Stem keywords: intense exercise, heart rate, stroke volume, cardiac output
• Lead-in keywords: Calculate
• Clinical cues: intense exercise (indicates physiological stress and increased demand)
• Clinical cues: heart rate of 150 beats/min (tachycardia)

Question ID

QvluqKNq5TJd7D-SKxzKh6

Copy ID

Reference Book

E6 Nursing Fundamentals Potter Perry 12e Part 4 p. 231-233

E6 Physiology Ganong 27e Vol 2 Part 1 p. 91-93