Final answer:
Hydrostatic pressure is responsible for the excess fluid accumulation in the interstitial compartment of a patient with dependent edema. This pressure is a result of the heart's pumping force, which, when exceeding osmotic pressure in the capillaries, leads to fluid buildup and edema.
Step-by-step explanation:
Understanding Dependent Edema and Its Causes
A nurse is caring for a patient who has dependent edema. Hydrostatic pressure is the driving force behind the accumulation of excess fluid in the interstitial compartment. This type of pressure is created by the pumping action of the heart, pushing fluid out of the capillaries. As the blood flows through the capillary beds, hydrostatic pressure tends to push water and other solutes out of the blood into the tissue fluid. Conversely, osmotic pressure, often referred to as oncotic pressure due to the presence of plasma proteins like albumin, draws fluid back into the blood vessels. However, when hydrostatic pressure exceeds osmotic pressure, particularly at the venous end of the capillaries, fluid accumulates in the interstitial space, resulting in edema. The correct answer to which pressure has caused the excess fluid in the interstitial compartment is hydrostatic pressure. When assessing a patient with dependent edema, it is crucial to understand this balance between hydrostatic and osmotic pressures to determine the underlying cause and appropriate treatment strategies.