Fluid exchange between capillaries and the interstitial fluid. takes place between the blood and interstitial fluid across the thin endothelial walls of the capillaries. blood pressure drives fluid out of the capillaries, blood proteins pull fluid back in the capillaries by osmotic pressure. Difference in osmotic pressure and blood pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end.
Premarket approval (PMA) is the FDA process of scientific and regulatory review to evaluate the safety and effectiveness of Class III medical devices.remarket approval (PMA) is the FDA process of scientific and regulatory review to evaluate the safety and effectiveness of Class III medical devices.
Therefore, these devices require a premarket approval (PMA) application under section 515 of the FD&C Act in order to obtain marketing clearance. Please note that some Class III preamendment devices may require a Class III 510(k).f the regulation in the CFR states that âNo effective date has been established of the requirement for premarket approval,â a Class III 510(k) should be submitted. Please note that PMA devices often involve new concepts and many are not of a type marketed prior to the Medical Device Amendments.