Showing posts with label drainage. Show all posts
Showing posts with label drainage. Show all posts

Tuesday, July 3, 2018

→ High Speed Low Drag - Physical Science & Embalming

As an embalmer, you may be a fan of good drainage. Good drainage has long been linked with great distribution. If you have been reading, you now better understand why.
Great drainage requires high flow. Flow in and out at high speed will yield many positive effects. Distribution, blood or staining removal, and “whip,” to name a few. We might agree “whip” is not something we often hear discussed among embalmers. To be put simply, “whip” is the desaturation of tissue. It is an effect that happens when flowing fluid travels fast enough to pull from surrounding tissue. Take the time to concentrate on how this works. Visualize a car traveling under 5 MPH in a straight line. Air in front of the car will be pushed around the car and air will replace the space behind that car as the car moves forward. Now picture this same car traveling above 190 MPH, also in a straight line. The car will cut through the air, leaving a trail in the vehicle’s wake empty. Air will rush to fill this space rapidly from the surrounding area. This is much like what happens as fluid travels fast through the vascular system. The vessels will draw fluid from the surrounding tissue. This is a physical means that can be used to reduce edematous tissue. The embalmer must consider and account for drainage being near equal to the displacement of fluid via injection. To utilize this method to its full potential, the embalmer must also consider the injection point and drainage point.
As an example, consider the injection site at the right common carotid artery with injection south towards the heart, with drainage via the jugular vein. Generalized edema is observed within the legs. This method is going to promote fluid remaining within the body, and be only partially effective to desaturate the legs. Compare the above method to an injection site at the right common carotid artery with a cannula deep within the abdominal aorta and drainage via the femoral arteries. With delivery of the fluid closer to the target location, fluid has less of an ability to travel via other vessels, therefore increasing the volume of fluid being delivered to the area. Subsequently, the drainage from this area can now be greater. By being closer to the target location, the embalmer can affect or influence the drainage with more control, using drainage instruments designed to pull fluid. These instruments which pull fluid will only increase the speed of drainage and therefore increase the desaturation of tissue.
It is wise of the embalmer to consider their approach to be certain that they have spent the proper amount of time desaturating tissues, as well as saturating tissues, to achieve proper preservation. From injection to drainage, where, why and how. Furthermore, the particular case circumstances of as example edema location is necessary to maximize the results of the embalming process.
-The Mortuary Scientist

→ Fast & Slow - Physical Science & Embalming

To address how distribution is directly affected by drainage, one must thoroughly understand “fluid in motion” vs. “fluid not in motion.” Fluid which is moving or flowing, as we better understand, is considered to be low in pressure. Conversely, if fluid is not moving or flowing, the fluid is considered to have high pressure. As an example, fluid within a vessel flowing in and out equally is without pressure, and so will not saturate the surrounding tissue. If drainage was restricted, pressure would accumulate within the vessel and saturate the surrounding tissue. To have a greater understanding of this, considering reading more on “Bernoulli Principle.”
In our previous chapter, our example described how low pressure could have a greater ability to distribute fluid. Without pressure, how could this be? It is important to realize that flow and pressure are not mutually exclusive. For example, you can have fluid moving very fast at high pressure, and moving slowly with low pressure. For our purposes, please continue to allow slow to be high pressure, and fast to be low pressure. The result of greater distribution with low pressure or fast flowing fluid traces back to vascular design. There are many cross-sections of vessels throughout the vascular system, on both the arterial side and the venous side. After death, pooled or still blood will coagulate, forming thick masses which can obstruct or impact the flow of fluid. Other circumstances, such as true clots or obstructions, may also exist and pose greater challenges to the embalmer. When we flow fluid across these section of vessels, we enact a “Venturi effect” upon the obstructions. The Venturi effect is a vacuum, or suction effect, that works much like a hydro-aspirator. The obstructions are pulled into the larger vessels where they then can easily travel out. This process is known as vascular clot removal.
While fast moving fluid or low pressure does not always have the ability to saturate tissue, it most certainly has the greatest ability to remove obstructions. Conversely, though slow moving fluid or high pressure will certainly saturate tissue, it does not have the easiest time pushing a clot out of the body. The arterial system narrows towards extremities, and so the idea behind pushing an obstruction through a narrower and narrower vessel is just not plausible. Furthermore, the pressure needed to achieve this poses a risk of swelling the features everywhere in circulation from injection site to obstruction.
-The Mortuary Scientist