- Quality of methanol
Factors Influencing Stability of Fluids (Shelf Life)
- High over 1000 F accelerates polymerization/precipitation of HCHO and tends to break down disinfectants and preservatives.
- Extreme cold less than 320F causes polymerization/precipitation of solutes.
- Ideal is 550F
- Methanol is incorporated into embalming fluid as an anti-polymerization agent for HCHO.
- Without methanol, HCHO will polymerize to form para-formaldehyde thus causing formalin to form formic acid.
- Once methanol breaks down, the fluid becomes useless as far as AFS.
The average shelf life of embalming fluid is between:
Two and Five Years
Paraformaldehyde is used in:
Shelf life is prolonged by adding buffers to embalming fluid.
Cause "cannizzaro's reaction", that is a breakdown of HCHO.
Strongly Alkaline Solutions
Highly Acidic Solutions
Ideal pH for arterial fluid.
pH of 7.3 or 7.4 (Slightly Alkaline)
Has two effects on embalming fluid:
- It causes a color change
- It increases polymerization of the formaldehyde
Interferes with the eventual reaction of the cosmetic dyes.
Light Causes a Color Change
The breakdown of active dyes and precipitation/polymerization can be delayed and shelf life extended by the utilization of these or leaving it in a cardboard box until you need it. Avoid sunlight.
Tinted Bottles and Containers
Quality of Methanol
Caustic in nature and will damage tissue and mucous membranes of the careless embalmer. Nitril gloves should be worn; eyes should always be protected. Exhaust ventilation, to protect the embalmer's respiratory tract, should always be utilized. (Universal Precautions).
All Embalming Chemicals are Caustic in Nature
- Primary dilution
- Secondary dilution
Arterial Fluid Dilution
Occurs in the tank of your injector. It is the dilution of the concentrated fluid with water to form the arterial fluid solution.
The union of the tissue juices and liquids of the body with the arterial fluid solution to further reduce the concentration of the preservative ingredients. Always occurs within the body.
Is the key variable in determining both primary and secondary dilution. Since this content is a highly variable factor, the degree of secondary dilution is also variable; therefore, it is the degree of secondary dilution which largely determines variation in the primary dilution.
The Moisture Content in the Body
Is said to be as high as 75% of the total body weight.
The Moisture Content of a Normal Adult Body
Can be as high as 85%.
The Moisture Content of an Edematous Body
Can be as high as 65% of the total body weight.
Moisture Content of a Dehydrated Body
Certain solid chemical substances commonly known as "salts" play an important part in determining the characteristics of the different embalming fluids and in controlling to a large extent the reactions between the cellular tissues and the chemical solution.
Density- Specific Gravity
If a "salt" is added to a liquid.
A Solution Results
The more concentrated the solution becomes. In other words, the strength of the solution actually indicates how much "solute" is present. The amount of the solute in a solution has a direct effect on the density of a solution.
The More "Solute" Added to the "Solvent"
Weight per unit volume and is expressed in such terms as grams per cubic centimeter of pounds per cubic foot.
Comparing the weight of a given volume of a substance with an equal volume of water.
- 1.5= When compared with an equal volume of water, the substance weighs 1.5 times more than water.
- Will necessarily vary with the concentration.
In solutions used in medicine, the density of salt concentration of a solution is frequently compared to that of _____.
- If a solution contains less of a dissolved substance, it is hypotonic.
- If it contains a greater quantity it is hypertonic.
- If it is the same, it is isotonic (equal)
A solution will penetrate to the side or region containing the more _____ solution. This fact is used in compounding fluids and establishing proper concentrations to use in embalming.
When diluted according to the recommended useage, the resultant solution will be slightly ______ to the blood and body liquids.
If less of the concentrated fluid is used, then the resultant solution may be more hypotonic than desired for proper embalming results. The tissues may tend to become ________, which eventually results in skin slip due to ack of sufficeint preservative material.
No more than _____ ________ of preinjection (8-10 ounces).
- Exception: Jaundice
If too much concentrated fluid is used, a _____ solution results and it will have the effect of removing too much moisure. This causes over-dehydration.
- Can be used to remove access moisture- edamatous cases.
- The "special" fluids for this purpose
This are the only hypertonic fluids.
If the solution is _______ to the tissue liquids, it will flow rapidly through the capillary wall into the soft tissue areas.
If the solution is ________ (greater density) to the tissue liquids, it will draw tissue liquid through the capillary wall into the circulatory system and away from the soft tissue areas.
- Lowers surface tension of the preservative fluid
- Reduces the capillary attraction
- Increases the ability of fluid to filter through semi-permeable capillary walls in an even and uniform manner.
Why Surfactants are Used
To aid or cause the solution to flow more rapidly and readily through the capillaries so that all of the millions of tissue cells are literally bathed by the chemical preservative.
Surfactants- Lowering Surface Tension
A phenomenon of surface tension of the blood and body liquids, these chemical substances cause the almost immediate clearing of blood from the capillaries; surface tension is reduced, and the liquid easily lets loose and flows out. Since two things cannot occupy the same space at the same time, the capillaries must be emptied before injected fluid can reach the tissues. It is only the fluids that osmosis through the capillary walls into the intracellular spaces that have any chance of being absorbed by the cells of the body.
Surfactants- Reducing Capillary Attraction
It is possible to incorporate coloring agents in the fluid and obtain a natural coloring and texture of the skin. Active dye: synthetic and natural.
By Increasing the Ability of the Fluid to Filter Through the Semi-permeable Capillary Walls in an Even and Uniform Manner
Play an important role in causing the preservative elements to be moved through the tiny capillary wall openings into the tissue cells to produce disinfection and preservation.
- Moisture Content of the Body
A process by which the solvent of a solution passes through a semipermeable membrane from a less dense or more dense solution, that is, from a dilute solution to a more concentrated one. (Solvent concentration).
Osmosis (Hindered Diffusion)
When a crystalloid solution is separated by a semipermeable membrane, which permits the penetration of crystalloids but excludes colloids, then as water is drawn by osmotic attraction into the collodial mixture, the dissolved crystalloids will be drawn in as well. The embalming significance of this phenomenon lies in the fact that many of the essential agents in an arterial solution are dissolved crystalloids.
Dialysis (Selective Diffusion)
The degree of acidity or alkalinity of the medium in which the chemical reaction takes place controls to a great extent the type of action that occurs between the preservative chemicals and tissues.
Tissues tend to retain their natural color and better internal cosmetic effect is possible. However, under prolonged periods, aldehydes tend to lose their potency in the presence of these conditions.
- It is for such reasons that ____ water conditioning preparations are added to embalming solutions at the time of use.
- Use water conditioners if using well water
- The short period involved in which the aldehyde is ____, pH does not cause it to deteriorate and lose its preservative strength.
Tend to produce rapid coagulation of proteins. Also, tissues tend to assume an ashen-gray color.
Relases HCHO faster.
Releases HCHO slower.
The pH of blood drops from 7.4 to 7.0
First (Primary) Stage of Flaccidity
pH lowers from 7.0 to 6.0-5.5, then back up to 7.0.
Stage of Rigor
pH raises from 7.0 to 8.0.
Secondary Stage of Flaccidity
The pH of the tissue varies at different times in the same body. The pH condition of the body tissues at the time of embalming depends upon this and to some extent, the specific cause of death.
The class of chemicals used a controls in embalming fluids. Some sort of control should be used to maintain a more of less uniform chemical medium in all cases. This is necessary to obtain constantly a more uniform result in the various types of remains embalmed.
- Have the ability to absorb excess amounts of acid or alkali so that they condition remains at the desired pH for proper acid and alkaline condition to maintain the preservative ingredients at full strength.
- Also keeps preservative ingredients at full strength (keeps them stable under pH ranges)
The amount of fluid to be used in an aqueous solution. Tissue capacity is perhaps the factor of primary importance in determining this. There is no rule to determine the amount of fluid to be injected. To establish the probable HCHO demand (preservative demand), it is necessary to include all of them.
- Index of the primary dilution in the tank
- Drainage loss- arterial fluid solution lost in drainage
- HCHO residual- The amount of HCHO left in tissue after HCHO demand has been satisfied.
- Volume- The amount of solution used (too little causes water-logging, too much causes dehydration/desiccation).
Factors Directly Related to HCHO Demand