A patient in the ICU is diagnosed with third spacing due to excessive IV fluids. What priority intervention should the nurse implement?

Third spacing is the pathological shift of fluid from the intravascular compartment into the interstitial or transcellular spaces due to increased capillary permeability, decreased oncotic pressure, or fluid overload, resulting in hypovolemia within the vascular system and tissue edema despite total body fluid excess. Rationale: A. Increasing fluid intake worsens intravascular overload and further exacerbates capillary leakage and interstitial accumulation. In third spacing, the issue is not fluid deficit but maldistribution. This intervention increases edema and risk of pulmonary congestion. B. Administration of a colloid solution such as albumin restores oncotic pressure, drawing fluid from the interstitial space back into the intravascular compartment. This improves circulating volume, tissue perfusion, and hemodynamic stability. It directly targets the pathophysiological mechanism of third spacing. C. Strict input/output monitoring is essential for assessment but does not actively correct fluid shifts. It provides diagnostic and evaluative data rather than therapeutic effect. Therefore, it is supportive but not the priority intervention. D. Upright positioning improves respiratory mechanics in cases of pulmonary compromise but does not address intravascular fluid deficit or capillary leakage. It has no direct effect on restoring vascular volume in third spacing conditions.