The Persistence of High Body Sodium in Previously Edematous Patients with Heart Disease

Is the osmotically inactive sodium storage pool fixed or variable?

Recently, there is renewed interest in the role of osmotically inactive Na(+) storage during Na(+) retention. Although it is well accepted that a portion of the total exchangeable Na(+) reservoir is osmotically inactive, there is current controversy as to whether the osmotically inactive Na(+) storage pool is fixed or variable during Na(+) retention. In this article, we analyze the current scientific evidence to assess whether the osmotically inactive Na(+) storage pool can be dynamically regulated. Our analysis supports the assertion that the osmotically inactive Na(+) storage pool is fixed rather than variable.