→ 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