If 0.9% NaCl isotonic solution is infused, is there no movement (of particles) at all btwn. the compartments?
Isotonic says it all. If a solution is isotonic then it doesn’t change the osmolarity of the ECF compared to the ICF. Of course, if the patient vascular volume is not normal, or if the patient is dehydrated, of if the patient is already fluid overloaded, or if the patient has electrolyte imbalances, etc…. then there would be some movement depending on the new concentration gradient. So, there will always be a some movement because no one is completely normal. Patients will be in a normal “range” if they have no fluid or electrolyte issues. Note: The gradient is dynamic. By this I mean there is a constant movement of fluid from areas of different concentrations through osmosis and various pumps as your body attempts to maintain homeostasis. There are also pumps for moving various electrolytes into and out of the cell. Your body uses this constant movement to remain constant.
