Cardiac Output
What is the formula for cardiac output (CO)?
A. CO = SV × HR
B. CO = MAP ÷ SVR
C. CO = HR ÷ SV
D. CO = BP × HR
Answer: A. CO = SV × HR
Rationale: Cardiac output is determined by stroke volume × heart rate.
Which best describes preload?
A. The pressure the heart must pump against to eject blood
B. The volume of blood returning to the heart that stretches the ventricles before contraction
C. The force of the heart’s contraction
D. The amount of blood pumped by the heart per minute
Answer: B. The volume of blood returning to the heart that stretches the ventricles before contraction
The nurse reviews a patient’s hemodynamic values: SVR is elevated. Which interpretation is correct?
A. Normal afterload
B. Low afterload
C. High afterload
D. Inconclusive without cardiac output
Answer: C. High afterload
Rationale: A high SVR indicates systemic vasoconstriction → high afterload, often seen in hypertension or vasopressor use.
A patient in septic shock is started on norepinephrine. Which receptor action primarily explains its therapeutic effect?
A. β2 stimulation → bronchodilation
B. β1 stimulation → increased contractility and HR
C. α1 stimulation → vasoconstriction, ↑ SVR
D. Dopamine receptor stimulation → renal perfusion
Answer: C. α1 stimulation → vasoconstriction, ↑ SVR
Rationale: Norepinephrine is the first-line vasopressor in septic shock. It strongly stimulates α1 receptors, causing vasoconstriction and increased afterload, improving MAP. It has some β1 effects, but α1 predominates.
A patient with hypovolemic shock develops AKI. The nurse recognizes this as which type of kidney injury?
A. Intrarenal
B. Postrenal
C. Prerenal
D. Chronic renal failure
Answer: C. Prerenal
Rationale: Hypoperfusion (from shock, dehydration, hemorrhage) leads to prerenal AKI. Intrarenal (A) is due to direct renal parenchymal damage. Postrenal (B) is from obstruction. Chronic renal failure (D) is gradual and progressive.
Which normal range reflects cardiac output in a healthy adult?
A. 1–2 L/min
B. 2–3 L/min
C. 4–6 L/min
D. 7–9 L/min
Answer: C. 4–6 L/min
Rationale: Normal CO is 4–6 L/min; below this suggests poor perfusion.
Which condition most likely contributes to increased preload?
A. Hypovolemic shock
B. Mitral valve stenosis
C. Dehydration
D. Tachycardia
Answer: B. Mitral valve stenosis
Rationale: Valve stenosis and fluid overload lead to increased filling pressures (↑ preload). Hypovolemia and dehydration (A, C) decrease preload. Tachycardia (D) reduces filling time, lowering preload.
Which condition most likely contributes to decreased afterload?
A. Septic shock
B. Systemic hypertension
C. Hypothermia
D. Aortic stenosis
Answer: A. Septic shock
Rationale: Septic shock causes profound vasodilation, lowering afterload. Hypertension (B), hypothermia (C), and aortic stenosis (D) increase afterload.
A patient on dobutamine for cardiogenic shock demonstrates improved cardiac output but persistent hypotension. Which drug would most likely be added?
A. Phenylephrine
B. Vasopressin
C. Nicardipine
D. Sildenafil
Answer: B. Vasopressin
Rationale: Dobutamine improves contractility but can lower BP due to vasodilation. Vasopressin, a pure vasoconstrictor (not adrenergic), can be added to improve MAP. Phenylephrine (A) is pure α1 but may reduce stroke volume. Nicardipine (C) and sildenafil (D) lower afterload/PVR, worsening hypotension.
The nurse reviews labs for a patient with AKI: BUN 55 mg/dL, creatinine 3.2 mg/dL, potassium 6.0 mEq/L. Which intervention is priority?
A. Administer IV calcium gluconate
B. Restrict dietary protein
C. Insert Foley catheter
D. Prepare patient for dialysis education
Answer: A. Administer IV calcium gluconate
Rationale: Hyperkalemia is life-threatening in AKI. IV calcium gluconate stabilizes cardiac membranes and prevents arrhythmias. Protein restriction (B) and dialysis (D) may be needed later. Foley catheter (C) addresses obstruction, not hyperkalemia.
If preload decreases, what happens to cardiac output?
A. CO increases
B. CO decreases
C. CO stays the same
D. CO doubles
Answer: B. CO decreases
Rationale: Less preload = less ventricular filling = lower stroke volume = lower CO.
A patient with CVP of 15 mmHg is restless, has crackles in lung bases, and reports dyspnea. Which nursing intervention is priority?
A. Administer prescribed IV diuretic
B. Increase IV fluid rate
C. Place patient supine with legs elevated
D. Administer albumin infusion
Answer: A. Administer prescribed IV diuretic
Rationale: Elevated CVP (normal 2–6) = high preload/volume overload → pulmonary congestion. Diuretics reduce intravascular volume and preload. Increasing fluids (B, D) worsens overload. Supine positioning (C) worsens dyspnea.
A patient with cardiogenic shock has an elevated SVR (systemic vascular resistance). Which medication order would the nurse anticipate?
A. Norepinephrine
B. Nicardipine
C. Phenylephrine
D. Vasopressin
Answer: B. Nicardipine
Rationale: Nicardipine (a calcium channel blocker) causes systemic vasodilation, lowering afterload. The others (A, C, D) are vasoconstrictors that would increase afterload further.
The nurse reviews a patient’s orders: milrinone infusion for advanced heart failure. Which finding would require the nurse to question continuing therapy?
A. Ejection fraction 15%
B. Frequent PVCs on telemetry
C. Cardiac index 1.8 L/min/m²
D. Pulmonary artery wedge pressure 20 mmHg
Answer: B. Frequent PVCs on telemetry
Rationale: Milrinone (a PDE inhibitor) improves contractility and causes vasodilation but increases risk of ventricular dysrhythmias. PVCs indicate arrhythmic instability. Low EF and CI (A, C) are indications, and elevated PAWP (D) may improve with therapy.
A patient with suspected postrenal AKI reports flank pain and has a bladder scan showing 900 mL of urine. Which intervention should the nurse anticipate?
A. Administer IV furosemide
B. Insert an indwelling urinary catheter
C. Prepare for renal biopsy
D. Begin fluid restriction
Answer: B. Insert an indwelling urinary catheter
Rationale: Postrenal AKI is due to obstruction (e.g., BPH, stones, strictures). Foley catheter insertion relieves obstruction and restores flow. Diuretics (A) are ineffective in obstruction. Biopsy (C) is for intrarenal causes. Fluid restriction (D) does not address obstruction.
Which medication increases cardiac output by improving contractility?
A. Norepinephrine
B. Dobutamine
C. Nicardipine
D. Vasopressin
Answer: B. Dobutamine
Rationale: Dobutamine is a positive inotrope (β1 agonist) → ↑ contractility → ↑ CO.
A patient in hypovolemic shock has CVP = 1 mmHg and MAP = 60 mmHg. Which order should the nurse question?
A. Administer normal saline bolus
B. Administer norepinephrine infusion
C. Elevate lower extremities
D. Insert two large-bore IV catheters
Answer: B. Administer norepinephrine infusion
Rationale: In hypovolemia, fluids must be replaced before vasopressors. Pressors on an empty tank worsen tissue perfusion. Fluids (A), positioning (C), and IV access (D) are appropriate.
A patient has pulmonary hypertension with a high PVR = 400 dynes/sec/cm⁵ (normal = 100–250). Which medication would most likely be used?
A. Sildenafil
B. Norepinephrine
C. Vasopressin
D. Phenylephrine
Answer: A. Sildenafil
Rationale: Sildenafil (Revatio) is a PDE-5 inhibitor that selectively causes pulmonary vasodilation, lowering PVR. The others are systemic vasoconstrictors that would worsen pulmonary pressures.
Which medication would be most appropriate for a patient with hypertensive emergency and an SVR of 2000?
A. Norepinephrine
B. Nicardipine
C. Phenylephrine
D. Vasopressin
Answer: B. Nicardipine
Rationale: Nicardipine (a calcium channel blocker) causes systemic vasodilation, lowering SVR in hypertensive crises. Norepinephrine, phenylephrine, and vasopressin all increase afterload, which is contraindicated.
Which nursing intervention is most important for a patient receiving continuous renal replacement therapy (CRRT)?
A. Monitor hourly fluid balance and net ultrafiltration
B. Restrict protein intake to prevent waste buildup
C. Flush dialysis catheter with heparin every 4 hours
D. Encourage ambulation during CRRT therapy
Answer: A. Monitor hourly fluid balance and net ultrafiltration
Rationale: CRRT requires hourly monitoring of fluid removal to avoid hemodynamic instability. Protein restriction (B) is less strict with CRRT since waste is continuously removed. Flushing dialysis catheters (C) is contraindicated—done by dialysis staff. Ambulation (D) is not possible during CRRT.
A patient with low cardiac output is most likely to have which signs?
A. Warm skin, bounding pulses, high urine output
B. Hypertension, tachycardia, flushed skin
C. Cool clammy skin, hypotension, low urine output
D. Normal BP, warm extremities, clear lungs
Answer: C. Cool clammy skin, hypotension, low urine output
Rationale: Low CO = poor perfusion → cool skin, ↓ BP, ↓ urine output.
A patient has PAWP of 20 mmHg after aggressive fluid resuscitation. The provider decreases IV fluids and prescribes nitroglycerin. The nurse recognizes this order will:
A. Increase preload by venous constriction
B. Decrease preload by venous dilation
C. Increase contractility via β1 stimulation
D. Decrease afterload by arterial constriction
Answer: B. Decrease preload by venous dilation
Rationale: Nitroglycerin is a venous vasodilator → promotes pooling in veins, reducing venous return and preload. It does not increase preload (A), contractility (C), or afterload (D).
A patient with severe aortic stenosis has low cardiac output. Which hemodynamic principle best explains this finding?
A. Increased preload reduces cardiac filling
B. Increased afterload reduces left ventricular ejection
C. Decreased contractility lowers stroke volume
D. Decreased afterload reduces systemic perfusion
Answer: B. Increased afterload reduces left ventricular ejection
Rationale: Aortic stenosis creates an outflow obstruction, raising LV afterload. This increases myocardial workload and reduces stroke volume and cardiac output.
A patient with pulmonary hypertension is receiving epoprostenol (Flolan). Which nursing intervention is most critical?
A. Monitor for rebound hypertension if infusion is stopped
B. Ensure continuous infusion without interruption
C. Flush IV tubing with saline after each use
D. Administer via central line only to prevent irritation
Answer: B. Ensure continuous infusion without interruption
Rationale: Epoprostenol has a half-life of ~6 minutes. Any interruption → life-threatening rebound pulmonary hypertension. While central line use (D) is recommended, the absolute priority is preventing interruption (B).
A patient with CKD is scheduled for hemodialysis. Which lab finding requires immediate intervention before treatment?
A. Hemoglobin 9 g/dL
B. Potassium 6.5 mEq/L
C. Sodium 132 mEq/L
D. BUN 80 mg/dL
Answer: B. Potassium 6.5 mEq/L
Rationale: Severe hyperkalemia (>6.0) is a life-threatening emergency and must be addressed immediately to prevent fatal arrhythmias. Anemia (A), mild hyponatremia (C), and elevated BUN (D) are expected findings in CKD.