The nurse is caring for a patient receiving a continuous norepinephrine (Levophed) IV infusion. Which patient assessment information indicates that the infusion rate may be too high?
A.
Mean arterial pressure is 55 mm Hg.
B.
Systemic vascular resistance (SVR) is elevated.
C.
Pulmonary artery wedge pressure (PAWP) is low.
D.
Heart rate is 58 beats/min.
The correct answer and Explanation is :
The correct answer is B. Systemic vascular resistance (SVR) is elevated.
Explanation:
Norepinephrine (Levophed) is a potent vasopressor used to treat hypotension, especially in conditions like septic shock. It works by stimulating alpha-adrenergic receptors, causing vasoconstriction, and beta-adrenergic receptors, increasing heart contractility, both of which help raise blood pressure. However, if the infusion rate of norepinephrine is too high, it can result in excessive vasoconstriction, leading to negative cardiovascular effects.
- Systemic Vascular Resistance (SVR) and Norepinephrine:
Systemic vascular resistance (SVR) reflects the resistance the heart must overcome to pump blood through the circulatory system. Norepinephrine’s primary effect is increasing SVR through vasoconstriction. While this is desirable to raise blood pressure in hypotensive patients, an excessively high norepinephrine dose can elevate SVR to dangerous levels, leading to potential complications such as reduced tissue perfusion, ischemia, or end-organ damage. Elevated SVR indicates excessive vasoconstriction, which can suggest that the norepinephrine infusion rate may be too high. - Other Options:
- A. Mean arterial pressure (MAP) is 55 mm Hg: This is indicative of hypotension, which means that the norepinephrine dose might be too low, not too high. An appropriate MAP target is typically around 65 mm Hg or higher for adequate organ perfusion.
- C. Pulmonary artery wedge pressure (PAWP) is low: PAWP reflects left atrial pressure and is more related to fluid status and left heart function. A low PAWP might suggest hypovolemia but is not directly indicative of an excessive norepinephrine dose.
- D. Heart rate is 58 beats/min: Norepinephrine can cause reflex bradycardia due to increased blood pressure, but a heart rate of 58 beats/min is not necessarily concerning and doesn’t indicate that the norepinephrine dose is too high.
In conclusion, elevated SVR suggests that the norepinephrine infusion rate may be too high, as it reflects excessive vasoconstriction. Proper titration of norepinephrine is essential to balance increasing blood pressure without causing harmful vasoconstrictive effects.