Asepsis and Antisepsis

Before the introduction of Lister's methods of treating wounds, it was considered proper, in accidental and operative wounds, to have profuse suppuration, pyemia, erysipelas, etc., and it was not remarkable, therefore, that the mortality following accidental and operative wounds was very high. Lister's method of wound treatment was largely based upon the conception that the infection of wounds occurred from contact with the air which contained spores and germs, and his method of treatment therefore, was directed chiefly to their destruction. The air can be a medium of wound infection to a certain extent, and dry air contains more spores and bacteria than moist air, but Koch demonstrated the fact that atmospheric microbes were chiefly of innocuous character, and wound infection usually could be traced to bacteria or spores being brought into direct contact with wounds, by the clothing, or by the skin of the patient, or by the hands of the surgeon, or by unclean surgical instruments and dressings. The antiseptic qualities of the blood serum and cell activities in healthy tissues, are sufficient to destroy or remove a certain number of microorganisms, and suppuration occurs only when the tissues are completely overwhelmed by the number of these organisms or when their power of resistance is lessened by injury or disease.

Sepsis. Sepsis is due to the entrance and multiplication of microbes, or to the absorption of their products in the body. Local inflammation and marked constitutional symptoms characterize sepsis.

Asepsis. Asepsis aims at thorough sterilization of the parts and of all the objects brought into contact with the wounds, and the exclusion of germs by the use of occlusive bandages and dressings.

Antisepsis  is that method of wound treatment which keeps germicidal agents continuously in direct contact with the wound. Its object, therefore, is to produce asepsis. It is the duty of the surgeon to guard against the contact of microorganisms in the wound and to employ whatever means science has evolved for their destruction. He must, however, be careful to employ means of disinfection or destruction that will not have an injurious effect upon the normal tissues.

Mechanical disinfection does not apply to wounds but is employed as a preventive measure by the operator and his assistants for instruments and for the skin surrounding the wounds. Mechanical disinfection is accomplished by the use of soap and water and a friction brush; germicidal solutions of one kind or another are also employed.

In the modern aseptic operating room germicides and antiseptics do not play so important a part as they formerly did. This is largely due to the fact that heat is used wherever possible in the preparation of sutures, ligatures, dressings and instruments, and to the farther fact that in uninfected tissues no antiseptic solutions are employed. It must also be remembered that the germicidal agents possess the disadvantage of exercising a more or less destructive action on the body cells, and consequently their use is not warranted in clean wounds. We still, however, sufficiently often meet with infected wounds that render the use of these agents necessary.

Heat  is the most valuable of all sterilizing agents, its only drawback being that it is not universally applicable. Wherever possible it should be employed in preference to chemical agents. It can be employed either dry or moist. Moist heat is a much more efficacious germicide than dry heat, for it destroys the organisms at a much lower temperature. Boiling water at a temperature of 212°F. will destroy nearly instantaneously all pus-producing organisms. Spores, however, require a moist heat of 284°F. kept up for at least a half-hour. A dry heat of 212°F. will not destroy pus-producing organisms under an hour and a half of treatment, and spores will live for three hours at a dry temperature of 284°F.

Although moist heat is very much quicker and more satisfactory in its action, yet it is often inconvenient to employ it in the sterilization of gowns, towels, operating suits, etc. However, sterilization by heat has been greatly facilitated by the introduction of the autoclave, by means of which a very high temperature under pressure can be obtained. This is the most satisfactory method of sterilizing dressings, towels, sheets, operating suits and aprons. A similar and less expensive method of sterilizing these articles is by the use of one of the simple steam sterilizers which are sold by all dealers. In an emergency, an ordinary bake oven can be employed as a sterilizer. It is best, however, where the temperature cannot be estimated, to boil the articles and dry them between sheets moistened with bichloride solution.

Disinfection or Sterilization. Sterilization of a wound, or of the substances coming in contact with it, may be accomplished by using the aseptic or antiseptic method; by combining these two methods we obtain the best results. The aseptic method, which employs antiseptic substances for the purpose of sterilization of objects coming in contact with the wound when their disinfection by heat is impossible, is the method perhaps most generally favored by modern surgeons.

Antiseptic Method. In the antiseptic method, the field of operation, the hands of the operator and of his assistants, and the instruments, must be treated in germicidal solution and, in addition, the wound should be frequently irrigated during the operation with a solution that has germicidal properties.

Recent investigations show that many germicidal substances have not the power that was formerly attributed to them. Furthermore, substances which are really active germicides very often produce a marked toxic effect upon the patient and produce a very decided irritation of the skin with which they come in contact.

Aseptic Methods. The aseptic method for the treatment of wounds admits of the use of germicidal solutions and heat upon the field of operation, upon the hands of the operator and of his assistants, and upon the instruments employed. After this has been accomplished, placing absolute dependence upon this sterilization, no germicidal or antiseptic substances are brought into contact with the wound, sterilized salt solution or plain sterilized water being used, if necessary, to flush the wound, the dressings employed having been sterilized by dry heat or moist heat.

Sterilization of the Hands. Experimental investigation has shown that the failure of the surgeon's efforts to render his hands absolutely aseptic, has been the productive cause of infection in many wounds.

The hands and finger nails may be best sterilized by first rubbing them with spirits of turpentine; then scrubbing them with soap and water; and then using a sterilized nail brush freely. The scrubbing should be done for several minutes. The hands should then be rinsed to remove the soap, and then soaked for about ten minutes in a solution of bichloride, strength, 1 to 2500. If turpentine has not been used before washing with the soap, strong alcohol or ether should be well rubbed over the hands before they are immersed in the bichloride solution. Perhaps the best way of rendering the hands sterile is to scrub them with green soap and water, then mix a tablespoonful of commercial chloride of lime and half a tablespoonful of carbonate of soda with enough water to make a paste. When this has assumed a thick creamy consistency, it should be rubbed into the hands until the grains of lime disappear and the skin feels cool; then rinse the hands in sterile water.

Sterilization of Instruments. Instruments may be sterilized by boiling them for fifteen minutes in water in which a tablespoonful of washing soda has been added for each quart. This prevents rusting of the instruments and also makes the water a better solvent for any fatty matter which may be upon the instruments, thus increasing the sterilizing effect of the heat.

Sterilization of the Feet. As most patients do not apply water as freely or as frequently to the feet as to other portions of the body, there is usually present an excessive amount of thickened epidermis, which is very difficult to render sterile. For operations in chiropody the feet should be thoroughly moistened with soap and water, scrubbed vigorously with a brush, then soaked in a solution of bichloride of mercury of 1 to 1000 strength, and then wrapped up in a towel soaked in the same solution while waiting for the operator.

Agents Employed to Secure Asepsis

Bichloride of Mercury  is used for the disinfection of the hands and skin and for the irrigation of wounds. Biniodid of mercury is extensively employed and in the same strengths as the bichloride. It is, however, a more powerful germicide, while being less irritative, and neither forms a mercuric albuminate nor tarnishes metal instruments.

Carbolic Acid. This acid is derived from coal tar, and although known as early as 1834 as the first antiseptic recommended and used by Lister, is not so popular since the discovery that bichloride of mercury possesses more germicidal action.

Gangrene of the skin and subjacent tissues has often been traced to the long continued use of dilute solutions of carbolic acid or of ointments containing small quantities of the drug. Gangrene of the fingers and toes is by no means infrequent as a consequence of its use. Another condition frequently seen is the systemic poisoning through absorption. One of the first symptoms noticed from such absorption is irritation of the urinary tract and carboluria. This poisoning is more apt to take place when the weaker solutions are used than when the pure acid is used, as the destruction produced by the pure acid prevents its absorption.

The effect of carbolic acid upon the urine (See Chapter II, “Carbolic Acid ”) is to cause it to become smoky a short time after it is voided. The urine shows a complete absence or diminution of the sulphates, and albumin is generally present. When these symptoms present themselves, the use of carbolic acid should be withdrawn, and the administration of sulphate of soda and atropin begun. If the condition has existed for any length of time and the patient is weak and exhausted, stimulants are indicated.

Lysol  is a saponified phenol, and possesses some germicidal power. It is used in strengths of 1 to 3 per cent. solutions.

Creolin  is mildly germicidal and is used a great deal in from 2 to 4 per cent. solutions.

Both lysol and creolin act very much like carbolic acid, but neither possess its irritating qualities.

Formaldehyde Gas  is an active germicide and very valuable as a disinfectant. It is used in the shape of formalin which is a 4 per cent. solution of the gas in water. This agent is very irritating to the normal tissues in the stronger solution, but a 2 per cent. solution of formalin may be used for the sterilization of the hands, instruments, etc.

The formaldehyde fumes are employed for the disinfection of clothing, rooms, bedding, and also for the sterilization of catheters. The fumes of the gas are very irritating to the mucous membrane and when this agent is used for the disinfection of rooms, every crevice and crack must be tightly sealed to prevent the escape of the gas.

Iodoform. The action of iodoform is not due directly to its ability to destroy germs but to its undergoing decomposition in the presence of moisture, liberating iodin and thus rendering inert ptomains that have resulted from the growth.

Iodoform Powder  is rapidly absorbed by the skin and fatal cases of iodoform poisoning have occurred from treating burns with it. Iodoform is also used in ointment form and in suppositories. As it is insoluble in water it is commonly used in a 10 per cent. emulsion. The gauze is also greatly used.

The symptoms of iodoform poisoning are: delirium; odor of iodoform on the breath; presence of iodoform in the urine; eruption over the skin, and finally, coma. Iodoform is also capable of producing a localized dermatitis, with great irritation, and must therefore be used with care on all delicate skins.

Aristol , a substitute for iodoform, is a compound of iodin and thymol, producing no toxic effects and having no disagreeable odor; it does not, however, possess the germicidal qualities of iodoform. Nosophen, iodol, and airol are among the more recent substitutes.

Iodin. This drug no doubt possesses more germicidal properties than was at one time supposed. It is probably the most powerful antipyogenic known. The 7 per cent. tincture is the one most frequently used.

Acetate of Aluminum , or more properly, aluminium, is prepared by adding five parts of sugar of lead to a solution of five parts of alum in 500 parts of distilled water. Burow's solution, see page 35, is chiefly employed as a wet dressing.

Chloride of Zinc  in a solution of 15 to 30 grains to the ounce, has marked antiseptic properties, but it blanches the tissues when applied to infected wounds.

Sulphocarbonate of Zinc  is less irritating than the chloride of zinc and is of the same value as a germicide.

Peroxide of Hydrogen  when used as a 15 volume mixture or diluted, seems to have a direct action upon pus generation by destroying microorganisms of the pus. It is frequently employed for sterilizing abscess cavities, and for hastening the separation of necrotic tissue.

This agent has also a marked hemostatic power and is used to some extent on this account in nose and throat work. Its hemostatic power is also observed in bone cavities. Care should be taken never to use it unless there is a free exit, as it increases rapidly in volume after coming in contact with dead tissue or pus, and serious accidents have happened from its improper use; for instance, if it is injected into an abdominal sinus where free escape is not provided for, the distention will result in ruptures of the sinus and infiltration of the surrounding tissues; possibly of the peritoneal cavity. The distention produced by it is also quite painful and therefore only a small quantity, or a much diluted solution should be introduced into cavities.

Boric Acid  is not very actively antiseptic, but even in a saturated solution it is not irritating. Where bichloride or carbolic dressings have produced irritation of the skin, or burns, a boric acid ointment is a very satisfactory substitute.

Salicylic Acid  is an antiseptic of value. It is generally used in the form of an ointment. It is but slightly soluble in water.

Potassium Permanganate  by its rapid liberation of oxygen, acts as an antiseptic of proven merit for the disinfection of foul wounds and ulcers. It is also used satisfactorily for disinfecting the hands in preparation for operations, in the form of a 5 per cent. solution, any stain being removed later by a saturated solution of oxalic acid.

Alcohol  possesses marked antiseptic properties and is one of the best agents for the sterilization of the hands of the surgeon, and for the skin of the patient. A 60 or 75 per cent. solution of alcohol is much more efficacious as a skin disinfectant than a 95 per cent. solution. This is because the purer alcohol is much less penetrating than the dilute. It is also used when diluted with water, one part to four, as a dressing for granulating wounds. It is efficacious in limiting the action of carbolic acid, when this agent has been applied in full strength.

It is a useful agent in which to store certain materials such as ligatures, sutures, etc.

Silver Nitrate  possesses undoubted antiseptic properties, and solutions of varying strengths are decidedly antiseptic. These solutions are from 5 grains to the ounce, to 60 grains to the ounce.

The solid stick of nitrate of silver is used for destroying exuberant granulations. Among the different silver preparations on the market, protargol and argyrol are the best known. Both of these are extensively used in the treatment of inflammations of the mucous membranes.

The unguentum of Crede, is an ointment of silver which is used in cases of septic infection and also in localized inflammations. From 15 to 45 grains of silver can, in this form be rubbed into the skin. It is absorbed and undoubtedly exercises an antiseptic influence on the infecting microorganisms.

Saline Solution , or normal, or isotonic salt solution, as it is called because of its close approximation to the blood serum, consists of a solution of 7 per cent. of sodium chloride in plain sterilized water. Roughly speaking and for ordinary purposes, this solution can be made by adding an even teaspoonful of ordinary table salt to one pint of boiled water and then reboiling the mixture.

It can be stored for a limited time in sterile glass jars, which are sealed with sterile cotton. The jars can be heated to whatever temperature is required for use. This solution is the one which is generally used for irrigating wounds and cavities; it is non-irritating and possesses no antiseptic quality. When a moist dressing is desired there is no solution comparable to it, largely because of its non-irritating quality. It has at times a slight irritating effect upon the kidneys and when large quantities of it are used it is better to dilute it.

Pure Oxygen and Ozone  have been used, and the latter is more effectual. It has been found that oxygen but slightly retards the growth of bacteria, but both ozone and oxygen produce a hyperemia, and retard the growth, especially of anaerobic organisms. Pure oxygen in the abdominal cavity produces a marked hyperemia and a leukocytosis. Ozone has been put to some practical use in this country but the results have not been sufficiently studied.

Sunlight  has a marked retarding effect on some bacteria and actually destroys them. The anthrax spore is said to be killed very promptly by exposure to strong sunlight and it is claimed that the tubercule bacillus is slowly destroyed by it.

Electricity and the X-rays  also produce a marked retarding effect on the propagation of certain microorganisms.