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Flashcards in Pressure - Exam 4 MORS 113 Deck (101):

  • 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.



  • Actual 
  • Blood
  • Differential 
  • Injection
  • Intravascular
  • Potential

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.

Actual Pressure


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.

Blood Pressure


Difference between potential and actual pressure.

Differential Pressure


Amount of pressure produced by an injection device to overcome initial resistance within (intravascular) or on (extravascular) the vascular system (arterial or venous).

Injection Pressure


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.

Intravascular Pressure


Pressure indicated by the injector gague needle when the injector motor is running and the arterial tubing is clamped off.

Potential Pressure


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.

Pressure Filtration


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).

Flow Meter


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.

  • Swelling

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.

Body Temperature


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.

Postmortem Caloricity


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.

Solution Temperature


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


  1. Hot water
  2. High index (30+)
  3. 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).

Solution Characteristics


  • 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.

Drainage Volume


____ 1____ will reduce the arterial injection pressure requirements, while ___ __2___ will increase them.

  1. Copious Drainage
  2. Poor Drainage


A back pressure can be created to overcome vascular resistance and lossen clots, which will in turn decrease the pressure requirements from the machine.

Restricting Drainage


Vascular resistance rises progressively during injection. As the fluid moves from the larger vessels to the smaller vessels, the saturation of the tissues with arterial solution will decrease the rate of penetration until the arterial solution appears in drainage.

The Progress of the Embalming Process


Many embalmers have rejected this practice because as more and more fluid accumulates in the tissues and vessels, it offers a greater resistance to the entrance of still more solution. It may also cause feature swelling and distortion, known as water logging.



As you fill the ____, the pressure needle will not move. Once the ____ is filled, the pressure needle should twitch.



That pressure which will overcome vascular resistance and cause a moderate, uniform movement of arterial solution from the injector into the vascular system and ultimately into the tissue cells.

Ideal (recommended) Injection Pressure


  • Dislodge congested drainage (blood clots)
  • Stimulate capillary filtration
  • Minimize fluid loss due to excessive drainage.
  • Saturate the capillary bed without causing ruptures.
  • Penetrate surface tissue and not cause feature swelling.

Ideal Pressure Must be Sufficient to:


Becomes a variable factor and is often inaccurate. In some bodies, a gague reading of two pounds will cause A.F.S. to enter the body rapidly. In other bodies, ten pounds may be required.

Ideal (recommended) Pressure


Directly related to intravascular and extravascular factors affecting resistances to fluid distribution.

  • Intravascular resistances
  • Extravascular resistances
  • Cause and manner of death
  • Postmortem interval
  • Types of apparatus used

Factors Affecting Injection Pressure


To fluid distribution, meaning within the vessels.

  • Can also hinder diffusion (extravascular)
  • Condition of the vascular system
  • Local congestion
  • Surface Tension

Intravascular Resistances


Diseases such as sclerosis, arteritis, phlebitis and syphillis, in addition to creating a demand for increase in pressure, may reduce the lumen of the vessels and create and abnormally high resistance to fluid distribution.

  • Danger
  • Fricitional resistance

Condition of the Vascular System


Late stages will damage the lining in blood vessels/the vascular system.



When pressure and rate of flow are increased, there is a chance of ruptures occurring throughout the vascular system. Most times these kind of cases end up being six pointers.

Danger- Condition of the Vascular System


Indicates the drag of the fluid solution or of the blood against the interior of the blood vessels or lumina.

  • Determined by 4 Factors

Frictional Resistance


  • Viscosity of blood
  • Amount of the inner surface presented
  • Nature of the inner surface
  • Age- frictional resistance is normally less in the young, normally more noticable in the elderly.

4 Factors Determining Frictional Resistance


Any obstruction in the vascular system causing an increase in injection pressure demand.

  • Drainage
  • Liquid Blood
  • Coagulated Blood

Intravascular Resistances- Local Congestion


One of the major causes of resistance variation is the break in continuity of the venous system, which is necessary for blood drinage. When this happens, it will cause short circuits and uneven distribution. Two points of drainage is the first step in correcting this problem.

Drainage - Local congestion


  • Anuerysm - ruptured may require a 6-point injection.
  • Capillaries - fixing a burst capillary would mean slower pressure and flow, use a drain tube.

Types of Short Circuits


Its most important influence is on the uniformity of fluid distribution. Vessels of the high part of the body (such as the face, neck and head in general) will contain little or no blood and will swell immediately, even under medium rates of pressure and flow. One of the leading faults of new embalmers if the overuse of pressure and flow on cases recently dead, with liquid drainage and few clots.

Liquid blood- Local Congestion


Concentrates vascular resistances at a limited number of points. These will be at vascular bifurcations and will create immovable barriers. Thrombi, emboli, and chicken fat clots are usually the culprits.

  • 4 Major bifurcations

Coagulated Blood


  1. External and Internal Carotids
  2. Ulnar and Radial Arteries
  3. Common Iliac Arteries
  4. Anterior and Posterior Tibial Arteries

4 Major Bifurcations


Originate at the bifurcation of the left and right common carotid arteries at the superior border of the thyroid cartilage. The bifurcation will occur front to back and not side to side.

Internal and External Carotids


Originate at the bifurcation of the brachial artery.

Ulnar and Radial Arteries


Originate at the bifurcation of the descending abdominal aorta.

Common Iliac Arteries


Originate at the bifurcation at the popliteal artery.

Anterior and Posterior Tibial Arteries


Postmortem clots almost always form in:



Antemortem clots may occur in:

Either Arteries or Veins


Arterial clots restrict 1.___ ___ _____, Venous clots restrict 2. ______.

  1. Arterial fluid distribution
  2. Drainage


The solution to the problems of poor fluid distribution and poor drainage is:

Multiple Points of Injection and Drainage


When a solution having a relatively high surface tension is injected quite rapidly, it has a tendency to enter low resistance areas only. This results in sweling, short circuits, and uneven distribution of the arterial fluid. A solution having a low surface tension and injected at a moderate to slow rate of flow and pressure will overcome most of the vascular resistances and will produce fairly even distribution and saturation.

Surface Tension- Intravascular Resistances


  • Measured in dymes
  • Water has a dyme is 72
  • Alcohol has a dyme of 22
  • Surfactants increase diffusion into the tissues and cells.
  • Surfactants increase saturation

Surface Tension- more info


Those that compress or collaspe the vessel externally.

  • Weight of thoracic and abdominal viscera
  • Gas formation
  • Tumors
  • Liquid accumulations
  • Contact pressure
  • Edema of the extremities

Extravascular Resistances


Against the aorta and the vena cava may compress or collaspe the vessel.

Weight of the Thoracic and Abdominal Viscera- Extravascular Resistances


Exerting pressure against various arteries and veins. The most troublesome is gas formation in the abdominal cavity because it also compresses the aorta and vena cava.

  • 4 Causes

Gas Formation


  • Infection
  • Decomposition
  • Visceral Gas
  • Pathological Antemortem Causes

4 Causes of Gas Formation


Even more troublesome is gas formation in the tissue, primarily due to:


  1. Tissue gas (not pathological)- Gas gangrene (pathological)
  2. Subcutaneous emphysema


Can be removed by aspiration prior to, or during, injection. Care and skill with the trocar is most necessary to avoid puncturing the major vessels. Gas formation such as tissue gas is the embalmer's biggest headache and often results in total failure. (Most be treated early and aggressively)

Gas Formation in the Cavities and Organs


Any kind of growth will cause pressure and compression on the adjacent vessels.

  • Malignant
  • Goiters and Benign
  • Death during advanved pregnancy

Tumors- Extravascular Resistances


Needed to excise any kind of tumor.

A Release


Meaning cancerous, may also cause degeneration and rupture the major vessels.

Malignant Tumors


As much trouble as malignant tumors and will often cause the embalmer to raise and inject various vessels to accomplish results.

Goiters and Benign Tumors


This is rare

  • Not possible to embalm the fetus through the mother's arterial system.
  • Written permission from PRD- Remove the fetus by making an incision in the anterior abdominal wall. (midline from the umbilicus to pubic symphysis).
  • Remove fetus and placenta and place in viscera bag- solution of 50% cavity fluid and 50% water.
  • Embalm mother- Left common iliac artery, drainage from Inferior vena cava through the right common iliac vein.
  • Aspirate the mother and inject cavity fluid immediately. Never aspirate the fetus. Line uterus with hardening compound.
  • Return the fetus, still in viscera bag to place it in the foot of the casket. Found out gender if the family wants to know.
  • Seal and suture the incision

Death During Advanced Pregnancy


Liquid in the viscera, cavities or tissues will create a pressure and vascular compression similar to the problems associated with gas accumulations.

  • Ascites is most often the biggest culprit.
    • Recommended the embalmer carefully aspirate prior to or during injection.
    • Remove point of the trocar to avoid puncturing the aorta or vena cava.
  • Anasarca
  • Pitting Edema

Liquid Accumulations- Extravascular Resistances


The worst situation. It can be corrected by utilizing a high index a.f.s. (arterial fluid solution) injected at increased pressure and rate of flow or by the restricted cervical method.

  • Severe cases most often require a 6-point injection and drainage.

Anasarca (generalized edema)


Indicates anasarca, 6 pointer, 1 bottle/gallon, 36 index (maybe even cavity fluid, but must read label to see if it can be injected). Use unionalls and, if suturing is not possible, use duck tape to seal incisions.

  • Edema that occurs between the cells.

Pitting Edema


  • Edematous fluid- hypertonic
  • Wicking- making an incision, use web rolled cotton to make a wick and place in the incision to draw the edema out.
  • Ace bandage combined with wicking.

Ways to Treat Edema


The capillaries of the dorsal surface of the body will be compressed by external surface pressure from the embalming tables, cots, morgue trays, bandages, tight clothing, casts, etc.

Contact Pressure- Extravascular Resistances


After injecting directly into the edematous area high index arterial (or injectible cavity fluid), apply jelly; then wrap with a plastic wrap.

  • Example: Edematous hans, after injection, apply heavy coat of jelly. Slide on heavy duty nitril gloves, elevate hands and wrap together tightly with a towel. This will force liquid from hands over a period of time.

Edema of the Extremities


Involves the largest scope and range of injection pressure from the minimum to the maximum.

Cause and Manner of Death


The amount of time that has elasped from death to embalming. In this situation, we are concerned with postmortem physical and chemical changes.

  • 3 changes having influence on factors affecting injection pressure.

Postmortem Interval


  1. Rigor Mortis
  2. Generalized Decomposition
  3. Discolorations/Stains

3 Postmortem Changes Having Influence on Factors Affectng Injection Pressure


Could also be classified as an extravascular resistance to fluid distribution. Causes a contraction or compression of all voluntary skeletal muscles as well as the involuntary muscles of the blood vessels and viscera. Should always be relieved as soon as possible prior to injection to decrease the pressure demand and prevent swelling of the tissues.

Rigor Mortis


Will more often than not lead to a 6-point injection at least; in most cases hypoing and pack applications will also be required.

Generalized Decomposition


  • Raise both common carotids, both femorals, both axillary, and all of their corresponding veins.
  • Since drainage is non-existent, it will not be necessary to use high pressure. A low pressure and implemented backpressure will give the best results.
  • Hot water and high index arterial fluid in a high concentration constitutes the proper chemistry. (waterless embalming as well)
  • With all of these precautions, most of these cases will still swell and seldom firm.

Procedure- Generalized Decomposition


  • Livor Mortis
  • Postmortem Stain

Discolorations/ Stains


Will only require a medium pressure with thorough manual massage to flush the vascular system. Too rapid an injection will cause severe swelling.

Livor Mortis (Cadaveric Lividity, Postmortem Lividity)


Indicates that the remains is entering decomposition; low pressure, multiple points of injection and drainage, strong solution, induced backpressure, moderate flow, etc. will be the solution.

  • Cannot be cleared with injection/drainage
  • Will require the drain tube

Postmortem Stain (Laking)


Cases showing little or no _________ can usually be injected safer at higher rates of pressure and flow.

  • Exception: Ruptured aorta or vena cava, six-point injection.



Because of the development of the many new high speed, high pressure injectors with automatic cut off devices, automatic rate of flow and pressure increasers and decreasers, many standard traditional rules will be altered.

  • Commit to memory the operating procedures
  • Cost 3K to 7K

Types of Apparatus Used


The speed with which the solution enters the body. The amount of embalming solution injected over a period of time, with a recommendation to use whichever rate of flow is necessary to achieve uniform distribution without distension.

Rate of Flow


Will create a pressure.

Rate of Flow Itself


Vary from one machine to another, even identical bands and models.

  • Some will maintain a constant flow
  • Some cut off automatically on contact with vascular obstruction.
  • Some will establish greater rates of pressure and flow than others.

Rate of Flow Controls


It should never exceed the rate of flow of the blood drainage leaving the body.

The General Rule Regarding Rate of Flow of Arterial Solution


Are interdependent and should work together.

Rate of Flow and Pressure


Measures the rate of flow in gallons/hour; is attached to exterior of injector.

Flow Meter


  • May be regarded as a form of liquid vibration.
  • The great increase in tissue saturation is well demonstrated by the fact that a gallon of solution can be injected in as few as 5 minutes without distension and without excessive loss of fluid in the drainage. This is true, but only in a small percentage of the cases.

Pulsating Pressure


  • It accelerates the embalming time.
  • There is a more even distritbution of the fluid solution.
  • There is less swelling of the facial features.
  • It minimizes post-embalming dehydration.
  • There is improvement of preservation.

Advantages of Pulsation (list question)


Created by restricting the flow of drainage. This in turn forces the flow of the arterial fluid solution to overcome vascular resistances and causes an increase in distribution of fluid in the capillary beds.



Backpressure should not be created unless the rate of flow and _____ are reduced.



Backpressure should not be created until all blood is out of the ____ ____.

Drainage Flow


Whenever embalming an ______ body, a backpressure should be created. If not, short circuits will result and the fluid will end up in the drainage.



The single biggest danger in creating backpressure is:

Swelling and the Possible Rupture of Major Vessels

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