A patient has been diagnosed with heart failure and cardiac output is decreased. Which formula can the nurse use to calculate cardiac output?
Ventricular filling time/diastolic filling time
Stroke volume x heart rate
Myocardial contractility x myocardial blood flow
Preload/afterload
The Correct Answer is B
A. Ventricular filling time and diastolic filling time are not formulas used to calculate cardiac output; they pertain to the phases of the cardiac cycle.
B. Cardiac output is calculated by multiplying stroke volume (the amount of blood ejected by the heart with each beat) by heart rate (the number of beats per minute). This formula accurately reflects the overall volume of blood the heart pumps in one minute.
C. Myocardial contractility and myocardial blood flow are important factors in cardiac function but do not directly provide a formula for calculating cardiac output.
D. Preload and afterload are factors that affect stroke volume but are not used to calculate cardiac output directly.
Free Nursing Test Bank
- Free Pharmacology Quiz 1
- Free Medical-Surgical Quiz 2
- Free Fundamentals Quiz 3
- Free Maternal-Newborn Quiz 4
- Free Anatomy and Physiology Quiz 5
- Free Obstetrics and Pediatrics Quiz 6
- Free Fluid and Electrolytes Quiz 7
- Free Community Health Quiz 8
- Free Promoting Health across the Lifespan Quiz 9
- Free Multidimensional Care Quiz 10
View Related questions
Correct Answer is B
Explanation
A. "Risk for infection related to chest x-ray procedure" is not an appropriate diagnosis because a chest x-ray is a diagnostic tool, and pneumonia itself is the concern for infection.
B. "Impaired gas exchange related to alveolar-capillary membrane changes" is correct as pneumonia causes inflammation and consolidation in the lungs, which directly impacts gas exchange.
C. "Risk for deficient fluid volume related to dehydration" does not apply specifically to pneumonia unless the patient presents signs of dehydration, which is not indicated in the scenario.
D. "Ineffective breathing pattern related to pneumonia" could also be a valid diagnosis, but the primary concern given the information provided is gas exchange impairment.
Correct Answer is C
Explanation
A. Weak quadriceps muscles can occur with electrolyte imbalances, but the provided values do not indicate hypokalemia or other issues causing muscle weakness.
B. Decreased deep tendon reflexes are generally associated with elevated calcium levels or other electrolyte disturbances but are not specifically indicated by the given lab values.
C. A calcium level of 4.5 mg/dL is significantly low (normal range is typically around 8.5-10.5 mg/dL), which can lead to hypocalcemia symptoms such as tingling of the extremities and tetany due to increased neuromuscular excitability.
D. Light-headedness when standing up (orthostatic hypotension) is more related to fluid volume status or dehydration rather than directly related to the given electrolyte levels.