 For watching nursing school explained to this topic is plural effusion. So let's look at how this happens So remember that normally we have about five to fifteen milliliters of lubricating fluid Between the visceral and the parietal plura. So these are the different layers that surround the lungs that allow for expansion of the chest and the lungs with inhalation and exhalation So that there is no there. There's no rubbing Against those two cavities and everything happens smoothly. So that's just like oil in a car allows for lubrication and smooth movement Now in a fusion basically means an increased fluid in that space And a fusion can apply to anything for example You can have a joint effusion in your knee if you have an injury and that fluid escapes the joint capsule So in a fusion is always an abnormally high amount of fluid in a specific place where it doesn't belong And so a plural effusion means an abnormal amount of fluid in the plural cavity So normally the the way that this fluid is regulated is a nice balance of hydrostatic pressure Oncotic pressure as well as capillary membrane permeability So what that means is the hydrostatic pressure? Remember is the pressure that's exerted against the blood vessels by a fluid as well as the oncotic pressure which helps to draw fluid into the blood vessels and that's usually done with the help of Plasma proteins such as albumin and then capillary membrane permeability basically meaning how Likely is the capillary bed to let things seep through this the membrane and regulate the fluid that way So now when this regulation is out of balance, then we'll have a plural effusion So this abnormal regulation usually happens because of increased pulmonary capillary pressure decreased oncotic pressure or Increased pulmonary a plural membrane permeability or obstruction of lymphatic flow that can be another reason and Pro effusions there are two different types one of them is exodative and the other one is trans-udative So exodative thing think about exodate as in pus And that usually is because of inflammation So some sort of inflammation is happening which makes all the inflammatory cells attracted to that site and increases the plural cavity Permeability and that is usually because of infection or malignancy and that fluid is then usually cloudy and yellow thick kind of pus look in Exodative type of fluid Where in trans-udative plural effusion? Those are non inflammatory conditions that cause that and so when the hydrostatic pressure increases the blood pressure increases the hard works hard Work the heart works harder It causes hard failure and therefore all that fluid is Backing up into the lungs causing the plural effusion as well as with when we have decreased oncotic pressure So decreased blood albumin usually because of liver and renal disorders But we'll have trans-udative plural effusions and that fluid is usually clear and very pale yellow not so Inflamed infected looking as in the exodative and that's just kind of a background so that you understand how these Mechanisms happen and mostly the most common Causes for probe effusions that I've seen in my practice was heart failure liver failure as well as Malignancy so tumors can cause that