- The force required to destribute an embalming fluid solution throughout the body.
- Action of force against an opposing force (a force applied or acting against resistance).
With any mechanical injector, desired pressure should be set ______ it is permitted to flow into the body. This is accomplished by running the machine against a closed rate of flow while setting the pressure control.
Types of Pressure
That pressure indicated by the injector gague needle when the arterial tube is open and the arterial solution is flowing into the body.
Pressure exerted by the blood on vessel walls measured in millimeters of mercury.
- When this pressure is too high, it can cause capillaries to pop.
Difference between potential and actual pressure.
Amount of pressure produced by an injection device to overcome initial resistance within (intravascular) or on (extravascular) the vascular system (arterial or venous).
Pressure deveoped as the flow of embalming solution is established and the elastic arterial walls expand and then contract, resulting in filling the capillary beds and development of pressure filtration.
Pressure indicated by the injector gague needle when the injector motor is running and the arterial tubing is clamped off.
Passage of embalming solution through the capillary wall to diffuse wtih the interstitial fluids by application of positive intravascular pressure. Embalming solution passes from an intravascular to an extravascular position.
A supplemental piece of equipment attached to the embalming machine which measures the flow of fluids in both galls per hour and ounces per minute (more common is ounces per minute).
Speed at which fluid is injected; measured in ounces per minute.
Rate of Flow
To force a fluid through (an organ or tissue), especially by way of the blood vessels; Injection during vascular (arterial) embalming.
Indicated by the amount of vascular resistance and the speed of fluid flow.
- No fluid flow without this.
- Calculated by subtracting the potential pressure from the actual pressure.
Note: Differential Pressure
In vascular injection, the arterial fluid solution moves toward tissue saturation by way of the arteries, to the arterioles, into the capillaries pushing the congested blood into the venules. From there into the veins, and then most importantly to:
The Point of Least Resistance or Easy Exit (Open Drain Tube or Forceps)
- The condition of the remains
- Body Temperature
- Solution Temperature
- Solution Characteristics
- Postmortem Interval
- The arterial tube (canula) lumen
- Drainage volume
- The progess of the embalming process
Factors Which Will Alter or Distort Pressure Requirements
The general vascular condition and degree of resistance will be th factors of cheif significance.
Pressure Requirements- The Condition of the Remains
Fluid moving to the areas of least resistance due to excessively rapid injector and may often necessitate multiple points of injection and drainage. The condition of the vascular system is most significant. If you should see this, turn the machine off and abduct the arteries and veins required. (Restricted cervical method may be used).
Swelling- The condition of the Remains
Time, as well as _________ are both unreliable indicators of pressure requirements.
Warmth stimulates fluid penetration, and _____ ______ indicates the remains to tbe recently deceased. This situation tends to reduce pressure requirements, but it is also possible that a remains in ____ ______ may have severely sclerosed arteries or had a lingering agonal illness causing extensive agonal clot formation. This would raise the pressure requirements.
The warmer the temperature, the more rapid the liberation of formaldehyde gas. This causes a decrease in pressure requirements, but only for short distances. Blood drainage will coagulate and harden in the vascular system, thus causing severe swelling when the pressure is increased to overcome drainage blocks.
Should only be used in desperation and cases of decomposition. Cold water embalming should be the norm in the vast majority of the cases. The rapid liberation of formaldehyde gas is not as important as the maximum fluid distribution and maximum drainage.
Hot Water Embalming
- Hot water
- High index (30+)
- Waterless embalming
3 Ways to do Instant Tissue Fixation (Head Freeze)
With today's modern fluids, they play a very minor role. The lone exception is the improper use of humectant based restorative pre- and co-injections. These require an increase in pressure requirements and may lead to swelling and feature distortion. Use of the femoral artery for injection is recommended (only in last gallon).
- Adds moisture in the body
- Maintains moisture loss
- Only used as a coinjection
- More viscous
- May lead to feature distortion and swelling
- Femoral is recommended for injection (as well as for active dyes).
Characteristics of Humectants
Their progress plays a major role in determining pressure requirements. Rigor mortis is the major change that affects pressure requirements because it exerts extravascular pressure, a compression of the vascular system.
Postmortem Interval (Postmortem chemical and physical changes)
One of the most popular of the many misconceptions is the belief that a small arterial tube can be used effectively to reduce injection pressure.
- As the diameter is decreased, pressure increases.
The Arterial Tube (canula) Lumen
Some of the more modern, so-called electronic machines have a built in rate of flow switch that functions on low speed when the rate of flow is constricted by vascular resistance. That is, the rate of flow will automatically decrease or increase depending on the diameter of the arterial tube.
Exception: The Arterial Tube (Canula) Lumen
The diameter of the drain tube and the volume of drainage has a measurable effect on the pressure requirements.
____ 1____ will reduce the arterial injection pressure requirements, while ___ __2___ will increase them.