Function of ARTERIAL Fluids (Preservative) Preservation Disinfection - germicidal & bactericidal Anti-coagulation Restoration It is important to achieve these without objectionable changes in skin and tissues.
Action of Preservatives chemicals ( or purpose for use ) Inactivate active chemical groups of protein and/or amino acids inhibit further decomposition inactivate enzymes kill microorganisms destroy odors and eliminate their future production.
Action of Preservatives chemicals PRESERVATIVE chemicals inhibit or arrest (retard) decomposition not reverse
Formaldehyde Chemical formula HCHO or H 2 CO HCHO or H 2 CO
Formaldehyde colorless gas has pungent, irritating odor strong dehydrating agent strong oxidizing agent accessory chemicals must be used to suppress the undesirable effects without loss of germicidal action
Formaldehyde prepared or created by oxidation of alcohols specifically the burning of methanol
Formaldehyde In aqueous solution is called formalin = HCHO gas dissolved in water Alternately described as a solution and a mixture
Formaldehyde = Formalin HCHO mixed with H 2 O is converted to methylene glycol (a mixture) Methylene glycol is an unstable compound (like hydrogen peroxide)
Formaldehyde = Formalin Formalin is an aqueous solution of HCHO saturated solution 40% HCHO by volume 37% HCHO by weight
Formaldehyde In embalming applications typically described by index Very little free formaldehyde is present in the aqueous solution that has little or no impact b/c the ability to preserve /disinfect is due to the donation of a methylene group CH 2 (= Methylene glycol)
Formaldehyde In solid form known as PARAFORMALDEHYDE ParaHCHO is white powder When HCHO converts to solid (powder) the process is known as polymerization
Formaldehyde Methanol is the anti-polymerant used to inhibit polymerization to para HCHO
Formaldehyde Ammonia NH 4 OH is a good true deodorant for HCHO HCHO & nitrogen products have an affinity for one another when mixed the result is UROTROPIN
polymerizes to PARAFORMALDEHYDE Ammonia NH 4 OH is a good true deodorant for HCHO ----> UROTROPIN Methanol is the anti-polymerant used to inhibit polymerization to para HCHO ***CONFUSION WARNING*** Methan a l is another name for HCHO
Index IS: amount of formaldehyde measured in grams dissolved in 100 ml. of water i.e. the % of HCHO gas in a fluid or solution
Index measurements Strong / high ~33-40% HCHO (difficult cases) Medium / average ~20-30% HCHO (routine cases) Weak / low / mild ~10-18% HCHO (jaundice and special cases)
other CLASSIFICATION methods Color General properties Index
deep penetration i.e. total diffusion controlled firming thorough preservation dehydration control controlled pH uniform results (esp. when used with staining dyes) compatible with additives.
Glutaraldehyde patented for use in embalming fluid in 1943, but really came to the attention of the industry in 1950's has 2 functional aldehyde groups v. 1 for HCHO (di-aldehyde) is capable of reacting w/ protein over a wider pH range than other aldehyes
has relatively low volatility, low odor, & low toxicity -is naturally a liquid is an effective cold chemical sterilant
Glutaraldehyde v. HCHO more effective as a disinfectant than HCHO (fixes protein rapidly) removes less water in the chemical reaction (so less of a dehydrating effect) disinfects quicker at lower concentrations than HCHO creates more cross linkages than HCHO and the bonds are more stable has better penetrating quality
Q: So why hasn’t Glutaraldehyde replaced HCHO? A: more expensive than HCHO to produce
Glyoxal More potent than HCHO (produces many more cross-links; the more links the firmer the tissue and the less flexible the protein) tends to stain tissue yellow so primarily used in cavity fluids; works best in ph of 9-10
MOST PRESERVATIVES (especially HCHO) preserve best in an acid pH, BUT in acid pH environment: BUT in acid pH environment: - the greatest dehydration takes place and - the greatest graying action takes place Advantage : dialdehydes
Alcohols cross link protein, but not as effectively as aldehydes isopropyl has best germicidal qualities alcohols have strong dehydrating effect on protein ethanol, methanol, propanal, etc. methanol is good methylene group donor & anti polymerizing agent for aldehydes; is the most highly used alcohol
Why use alcohols? 1.outstanding preservative 2. good solvent for chemicals that do not dissolve in water 3. excellent penetrator; some bleaching action 4. stabilizes HCHO 5. serves as vehicle for other ingredients in fluid 6. more toxic to bacteria than other alcohols
PHENOLIC COMPOUNDS Phenol aka Carbolic Acid (C 6 H 5 OH) is a coal-tar derivative reliable disinfectant very good penetrating action b/c it is very rapidly absorbed into protein structures of skin
PHENOL bleaches tissues to a putty gray color (i.e., good for external packs on stains and discoloration) chiefly used in cavity formulations does not produce the readily detectable firmness of aldehydes tends to create putty gray when combined w/ aldehydes
the most powerful phenolic compounds are not soluble in water found in triple or double base fluids with alcohol and/or HCHO (together these improve the bacteria killing power of phenols)
Quaternary Ammonium Compounds (QUATS) good germicidal and deodorizing qualities used as topical antiseptic prior to surgery in aqueous solution pH is neutral primary embalming use primary embalming use cavity fluids cavity fluids cold sterilization cold sterilization deodorant sprays deodorant sprays mold-proofing mold-proofing
QUATERNARY AMMONIUM COMPOUNDS Disadvantages: not compatible with wetting & coloring agents in most arterials any alkaline substance i.e. soap will render useless used for disinfection of cavities, nose, skin, etc. but lose their capabilities in presence of HCHO
Germicides Chemicals which kill disease causing microorganisms or render them incapable of reproduction (same list as for preservatives)
Anti coagulants postmortem processes naturally make blood become more viscous Anti-coagulants retard this tendency & / or prevent adverse reactions between blood and other embalming chemicals
Anti coagulants are responsible to maintain blood in liquid state facilitate blood removal Anticoagulants may be the principal ingredients of co &/or pre-injection fluids
Anti coagulants Oxalates & citrates were the original anticoagulants used but oxalates are toxic to the embalmer Ionized calcium is a key factor in blood coagulation. calcium ions cause hard water therefore contributing to blood clotting & difficulties with drainage
Vehicles aka solvent / diluent / carrier serve as a solvent for the many ingredients incorporated into an embalming fluid. Water*****Alcohol
Vehicles may be a mixture of solvents which keeps the active ingredients in a stable and uniform state during transport thru the circulatory system must not react w/ the active components and make them useless should not react w/ the tissues of the circ. system, because this would interfere w/ distribution & diffusion.
Water as chief vehicle composes more than half of formalin anyway vascular system is about 50% water our bodies are 75-80% water. 90% of our fluids use water as the vehicle.
Alcohols as vehicles Methanol aka methyl alcohol / wood alcohol Ethanol aka ethyl alcohol – in some special purpose and cavity fluids. Glycerine, sorbitol, glycols
Surfactants reduce the molecular cohesion of a liquid and thereby enable the liquid to flow through smaller apertures (spaces)
Advantages - promote diffusion of preservatives thru capillary walls for uniform saturation - promote uniform distribution of coloring agents - the lower the surface tension the faster the rate of penetration - promote diffusion of preservatives thru capillary walls for uniform saturation - promote uniform distribution of coloring agents - the lower the surface tension the faster the rate of penetration -increase the germicidal action of solution.
Surfactants work best in low concentrations must be carefully selected for compatibility with other chemicals Massage, manipulation and intermittent drainage aid the action of surfactants
Dyes Staining (active) v. non-staining (inactive) Create cosmetic &/or non cosmetic fluids May be part of the fluid formulation Or Added to the solution at discretion of embalmer
examples Ponceau (cherry red – inactive) Carmine red (natural vegetable color) Fuchsin Erythrosine Amaranth Eosine (yellow to orange)
Reodorants/deodorants Chemicals having the capability of displacing or altering an unpleasant odor so that it is converted to a more pleasant one Perfuming materials / masking agents Primary function is to enhance odors R is false D only – masks does not eliminate
Reodorants/deodorants Most used in embalming are floral compounds which have been found to be most effective in mitigating odors. Intended to give a more pleasant odor, not to cover harshness of HCHO
Examples Benzaldehyde Cloves Sassafras Oil of Wintergreen (is Methyl salicylate) Spices such as Lavender, rosemary, etc. (true low odor chemicals are result of using donor compounds for slow release of aldehyde, not due to use of re/deodorants