→ Displacement - Physical Science & Embalming
Flowing fluid may travel fast or slow, it can be in large vessels or small vessels, or it can be in some vessels but not others. Due to the complexity of the vascular system, its beauty, for one, it is easier to disregard all this knowledge and continue as operated. If this information makes your head hurt as much as mine, try and remember the old phrase, “No pain no gain!”
As common hand pumps, syringes, machine pumps, and even gravity feeds are provided to the embalmer, please accept that they do not aid the embalmer very well to calculate displacement. The embalmer is left to calculate this all on his or her own, and it is done usually from memory and frame of reference. Displacement is the measure of volume over time. It is not a complicated concept for us to understand; like miles per hour, so, ounces per minute. All of the above mentioned instruments used to inject or displace fluid have a force that can be calculated. Some of the above have the ability to restrict or regulate flow as well. It should be noted that when we regulate or restrict flow, we conversely influence or affect pressure. Yet when we measure displacement, it remains constant until we adjust one of the previous two variables: pressure or flow, if available. This is why perhaps our most significant frame of reference as we embalm is not the dials, numbers, and switches, but the displacement. We can calculate this visually with our imagination, yet however well this might work for us, we can do better using a flowmeter. As we connect a flowmeter to an embalming machine, we can better understand how adjusting these variables can affect the displacement of fluid from the machine. From our machine, pump settings as “high pressure with very restricted flow” can yield a displacement value the same as “low pressure with moderate rate of flow.” So what is the difference, you might ask? Sorry to disappoint you, that is not covered yet.
To answer the question, there isn’t much of a difference in either of these examples. Both methods rely on pressurizing the arterial system slowly. The pressurized arterial system next begins to dilate the smaller vessels, and so on and so forth. It is important to move slowly at the beginning stages of embalming, for reasons best known to the vascular system itself. Factors such as time of death and refrigeration, to name a few, will lead to pooled blood throughout the arterial system. Pushing the pooled blood deeper into smaller vessels will cause distribution issues for the embalmer. The goal of the embalmer initially would be to distribute the fluid well, and next to pressurize all of the vascular pathways that have been opened. See our former chapter about why fast moving fluid will aid the embalmer in distributing fluid.
The embalmer’s ability to learn more about Physical sciences as it relates to embalming can prove as useful a tool as an aneurysm hook. Holding the vascular system in high regard and understanding how fluid will or will not move within it will aid the embalmer during challenging cases where there are multiple pressure systems being encountered, from air, to fluid within the abdomen, and everything else.
-The Mortuary Scientist