Chapter 43

Question 1

1. A patient is taking a beta1-adrenergic drug to improve the stroke volume of the heart. The nurse caring for this patient knows that this drug acts by increasing:
   a. cardiac afterload.
   b. cardiac preload.
   c. myocardial contractility.
   d. venous return.

Answer 1

C.
Beta1-adrenergic agents help increase the heart’s stroke volume by increasing myocardial contractility. Cardiac afterload is determined primarily by the degree of peripheral resistance caused by constriction of arterioles; increasing afterload would decrease stroke volume. Beta1-adrenergic agents do not affect afterload. Cardiac preload is the amount of stretch applied to the cardiac muscle before contraction and is determined by the amount of venous return. Beta1-adrenergic agents do not affect cardiac preload. Venous return is determined by the systemic filling pressure and auxiliary muscle pumps and is not affected by beta1-adrenergic agents.

Question 2

2. A nurse is caring for a patient who is receiving a drug that causes constriction of arterioles. The nurse expects to observe which effect from this drug?
   a. Decreased stroke volume
   b. Increased stroke volume
   c. Decreased myocardial contractility
   d. Increased myocardial contractility

Answer 2

A.
Constriction of arterioles increases the load against which the heart must pump to eject blood. Increased constriction of arterioles would decrease, not increase, the stroke volume of the heart. Myocardial contractility is determined by the sympathetic nervous system, acting through beta1-adrenergic receptors in the myocardium.

Question 3

3. A patient with a history of hypertension is admitted for a procedure. If the patient’s arterial pressure decreases, which clinical manifestation would the nurse expect to see?
   a. Decreased heart rate
   b. Increased heart rate
   c. Decreased blood pressure
   d. Syncope

Answer 3

B.
When arterial pressure decreases, the vasoconstrictor center causes constriction of nearly all arterioles, leading to an increase in peripheral resistance, constriction of veins, increasing venous return, and subsequent acceleration of the heart rate. A decrease in arterial pressure would not cause a decrease in the heart rate or blood pressure, nor would it cause syncope.

Question 4

7. A patient is taking a drug that interferes with venous constriction. The nurse will tell the patient to:
   a. ask for assistance when getting out of bed.
   b. expect bradycardia for a few days.
   c. notify the provider if headache occurs.
   d. report shortness of breath.

Answer 4

A.
A drop in venous pressure reduces venous return to the heart, and as blood pools in the extremities, orthostatic hypotension can occur. Patients taking drugs that reduce venous constriction should be cautioned to ask for assistance when getting out of bed. Bradycardia, headache, and shortness of breath are not expected effects.