Question

The nurse is discussing cardiac hemodynamics with a nursing student. The nurse explains preload to the student and then asks the student what nursing interventions might cause decreased preload. The student correctly answers which of the following?

1) Application of antiembolytic stockings
2) Administration of a vasodilating drug (as ordered by a physician)
3) Maintaining the client's legs elevated
4) Ambulation

Answer 1

The correct answer is the administration of a vasodilating drug, which decreases preload by reducing resistance in blood vessels and subsequently lowering venous return.

Step-by-step explanation:

The student correctly answers that the nursing interventions which might cause decreased preload include the administration of a vasodilating drug, as ordered by a physician. Vasodilating drugs reduce the resistance in blood vessels, leading to decreased venous return and thus lower preload. This is because preload refers to the end-diastolic volume (EDV), which is the volume of blood in the ventricles at the end of diastole, before the heart contracts. Vasodilators, which include classes of drugs like dihydropyridine, phenylalkylamine, and benzothiazepine calcium channel blockers, reduce the tension in vessel walls, allowing them to dilate and thereby decrease the amount of blood returning to the heart, consequently reducing preload.

Other options such as application of antiembolytic stockings and maintaining the client's legs elevated actually help to prevent venous pooling and might improve venous return, potentially increasing preload. Ambulation also increases venous return through the action of the skeletal muscle pump, which might lead to increased preload.