Aids to aseptic technique

Front matter

Practical Lessons

Nursing

B 7 A. D. Whiting MD.

Preface

The object of this work is to aid those whose duty it is to prepare materials for an operation. No attempt has been made to write a treatise on the subject of asepsis, but only to furnish aids to aseptic technique, and to explain why certain procedures are undertaken, and why they give the desired results. It was thought that the subject might be made clearer to the reader by bo doing, and that it might be of more interest than would a dry statement of the various methods which must be undertaken in order to furnish aseptic results.

The task of those who prepare the materials, etc., for an operation is no slight one. At times it becomes so burdensome that it would gladly be dropped for something more interesting and less irksome. If the hints given in this work will aid them in their task, making it better understood and of more interest, the object of the author will be fulfilled.

Contents

CHAPTEE I.

PAGE

History of Antisepsis and Asepsis — Principles upon which all Technique depends 9

Chapter I. History

Aseptic and antiseptic procedures have been practised since the earliest times. It is almost needless to state that there was but little knowledge of the true principles of the subject in those days, and that no scientific reasons were ascribed for the methods undertaken. The whole amount of knowledge was limited to the fact that wounds did putrefy and that the bodies of the dead did undergo changes that destroyed all of the semi-solid tissues. In regard to the changes in their wounds, the ancients thought that the air, itself, was the direct cause of the purulent conditions. In order to prevent the access of air, they covered their wounds with clay, and thus, to an extent, lessened putrescence. While the clay formed a very poor and inefficient dressing for a wound, yet it answered fully one of the requirements of a good dressing, — namely, the power to prevent access of germs from the exterior.

In order to preserve the bodies of their dead the ancients took more active measures, and used strong antiseptics in conjunction with their methods to prevent the access of air. After having removed the viscera of the abdominal and thoracic cavities, they completely filled the cavities with herbs of various descriptions, and then submerged the bodies in a solution of natron, where they were allowed to remain for varying lengths of time. The bodies were then wrapped with different materials, and in this condition either buried or placed in sarcophagi. That their methods accomplished the purpose for which they were intended is well demonstrated in the mummies found to-day.

From ancient times, all who have been interested in wounds and in the preservation of both animal and vegetable matter have striven to explain why wounds that are exposed to the air undergo purulent changes, and why putrefaction takes place. The following anecdote is told of Sir Joseph Lister, before the germ theory of putrefaction had gained much strength. " While going round his wards in the Glasgow Royal Infirmary one day, Sir Joseph, then plain Mr. Lister, came to the bedside of a patient whose arm had been severely crushed without the skin having received any injury. Turning to the assembled students, he said : — ' Gentlemen, I have frequently noticed that when severe injuries are received without the skin being broken, the cases nearly always recover. On the other hand, trouble is always apt to follow, even in trivial injuries, when a wound in the skin is present. How is this? I cannot help thinking that the man who is able to explain this problem will be one who will gain undying fame.' "

Lister had little idea at that time that he, himself, would be the one to solve the problem and the one to advance a theory the results of which have formed one of the greatest blessings mankind has ever received.

But before Lister did this there were other scientists at work, and it was mainly through their endeavors and from the results of their researches that he was able to advance his theory. Different conjectures had been advanced from time to time in the great endeavor to explain the mooted question. It had been well known for years that micro-organisms did exist, the first having been demonstrated by Leeuwenhoeck, in 1675. About one hundred years later, in 1773, Miiller made an attempt to classify these minute organisms. The origin and life of these germs were not understood, and but little was known of them beyond the fact that they did exist. They were supposed to be the result of spontaneous generation, which was the accepted theory among the scientists of that day. This theory claimed that some of the lower forms of both animal and vegetable life sprung from lifeless matter without the intervention of any previously existing parent.

Spallanzani, in 1776, Franz Schulze, in 1836, Schwann, in 1839, Henholz, in 1843, Schroder and Von Dusch, in 1854, Pasteur, Hoffmann, and Tyndall were all trying to solve the problem of spontaneous generation. The experiments made by them were not only highly interesting and instructive, but they also gave results of which we take advantage to-day. One of the most important of these was the demonstration by Schroder and Von Dusch that a plug of cotton used as a stopper would allow a free circulation of air, but at the same time would filter all micro-organisms from the air. Another was TyndalPs method of applying discontinuous heat for the purpose of destroying germ life.

After the theory of spontaneous generation had been disproved by the experiments of Pasteur in 1860 and 1865, the scientific battle was waged in support of two main ideas, both of which were advanced to explain the cause of putrefaction. According to one of these, " the changes which occur during the process (of putrefaction) are held to be from the first the result of chemical decomposition in the organic substance, whose atoms are in a state of motion or activity, which is capable of being communicated by catalytic action to other organic material in contact with it." The second theory, and the one universally adopted by the scientists of to-day, is, to a great extent, the result of the researches of Pasteur. According to this explanation, putrefactive changes are due to the agency of organic germs. These micro-organisms are ever present in the atmosphere, and eagerly seek a suitable feeding-ground in the putrescible mass, where they may lodge, feed, multiply, and thrive, producing chemical decomposition as the result of their action. The advocates of the first theory took this result to be the cause of the putrefaction and, naturally, failed to establish their claim.

After Pasteur had advanced his theory and had given some proof of its correctness, there were several scientists who at once took up the battle and endeavored to substantiate all that he had claimed. One of the most active of these was Tyndall, who worked coincidently with Pasteur, but independently of him. Both scientists endeavored to prove that germs are necessary for the production of putrefaction : and Tyndall, especially, endeavored to prove that the germs are always present in the air. Tyndall's work was done not only to sustain the assertions of Pasteur, but also to destroy the theory of spontaneous generation, which was prominent at that time.

Pasteur and Tyndall also claimed that putrefaction might be prevented by such means as would preclude the entrance of germs to any putrescible mass ; and that these germs lived, or rather showed signs of life, only under certain conditions. For example, it was demonstrated that micro-organisms lost all signs of active life in high temperatures and also in extreme cold (as was shown by the perfect preservation of the mammoth found in the Siberian cave thousands of years after life had become extinct). Another valuable demonstration was that micro-organisms could live in a much higher degree of dry heat than of moist heat; and that certain solutions greatly affected the life of the germs.

After Lister had thoroughly studied the ideas of Pasteur, he endeavored to apply the same to the purulent changes that were so evident in the wounds of that time. He then advanced a theory which has proved the correctness of the prophecy he had made years before. And it is to him that the medical fraternity is obligated for our present knowledge of asepsis and antisepsis. Details of methods may change with the ideas of the individual surgeon, great advancements may be made in regard to them, but the principle which Lister advanced, and which is the foundation of all aseptic and antiseptic procedures, will always remain intact and cannot vary. This principle is "that the decomposition of fluids in wounds, their putrefactive changes, in short, are directly dependent on their impregnation with organic matter floating in the air and thence deposited or in other way conveyed to them, fermentative and putrefactive changes being thus at once set up in the fluids of the wound; that such local actions are capable of producing general septic infection of the fluids of the body; and further, that these organic products may be excluded from the wound, either by their destruction in the air by chemical agents, such as carbolic acid, or their separation from it by filtration, as by layers of muslin or cotton-wool." (Erichsen.)

It is upon this principle that so much has been done to revolutionize the practice of modern surgery. Every one dealing with wounds should thoroughly understand the main points, — namely, that germs are carried into, or deposited in, the wounds ; that these germs cause the various troubles which the surgeon dreads, — pus, pyaemia, septicaemia, etc. ; and that these troubles maybe prevented, in the vast majority of cases, by such procedures as will destroy the germs or prevent their access to the wounds.

Lister and his immediate followers used the famous carbolic acid spray as a chemical means to prevent the access of the dreaded germs. This was fairly successful in accomplishing its purpose, in that it did prevent the access of germs from the air. But it was unsatisfactory in many ways. It was troublesome to handle ; it was necessary to operate on a wet field and in a wet atmosphere ; the acid was irritating to the wound and to the face and hands of the operator and his assistant. The spray was also discarded, because science soon demonstrated that there were other avenues of access for the germs besides through the air, avenues which were not attacked by the carbolic spray. Various ways have been devised to overcome the danger from germ life during operative procedures ; strong antiseptic solutions have been used during the operation ; means have been taken to keep the micro-organisms away from the field ; methods have been advanced by which the germs might be destroyed if present.

The details of the methods have changed and kept abreast with the knowledge of the habits and lives of the germs, until, at the present time, all preventive measures are taken before the operation begins. Through this advancement has arisen the aseptic course of procedure, in contradistinction to the antiseptic methods of Lister. The principal difference in the two methods is that means are used in the aseptic to preclude the entrance of germs into a wound ; in the antiseptic, the means are employed during the operation to prevent the access of germs and to destroy those that may be present. The former is the more prominent in surgery to-day, although there are still a few advocates of the latter method. And yet it is seldom that we see what is generally known as an antiseptic operation, if the case with which we have to deal be " clean," or aseptic. In all clean cases, — that is, in those that are free from septic material at the time of operation, — no antiseptic solutions are used. They are omitted because they are unnecessary, if the proper care has been taken to render aseptic the field of operation, the hands of the operator and of his assistants, and the instruments and materials brought in contact with the wound ; and also because the principal antiseptics used, carbolic acid and bichloride of mercury, are escharotic in character, and must, therefore, cause destruction of tissue- cells if the solutions used be at all strong. This escharotic action of the chemicals may be aseptic or even antiseptic, yet it is bound to cause irritation of the wound and interfere with its rapid healing. Naturally there are many cases, among them accidents, abscesses, infected wounds, etc., where it is absolutely necessary to use strong antiseptics, not only to thoroughly cleanse the wound, but also to destroy all hidden germs. In these cases it is essential that antiseptics should be used, and often very freely. The rapidity of healing and the freedom from further sepsis will be in almost direct ratio with the thoroughness with which the wound has been rendered clean and free from living organisms, the only hindrance to rapid healing being the necrosed superficial cells.

Ordinary warm distilled water was for a long time advocated as the best solution to be used for irrigating and cleansing aseptic wounds. This was soon found to be irritating to the tissues, especially to the peritoneum and meninges, and also very difficult to keep sterile. There seems to be a decided tendency in distilled water to undergo changes which render it irritating and septic, a tendency that is more marked in distilled than in ordinary boiled water. To overcome the unfavorable action of the distilled water salt was added, and a solution was obtained which answered every purpose. This solution is the " deci-normal salt solution," sterilized. It has proved to be non-irritating and very cleansing, and at the same time easily rendered sterile and kept in that condition. In all " clean" cases, and especially where they relate to the peritoneum or meninges, nothing but the sterilized salt solution should be brought in contact with the wound. After the latter has been closed, the antiseptics may be used to again cleanse the field of operation and the surrounding parts, if deemed advisable.

The main points to remember are that infection of a wound is due to the entrance of micro-organisms; that these germs maybe prevented from entering the wound by certain measures undertaken before the time of operation, or destroyed in the wound, if present ; that no antiseptic should be used during an operation on a " clean" case ; that a sterilized salt solution is the best to use for all irrigating and cleansing purposes during an operation on a " clean" case.

Chapter II. Bacteriology

It is essential that every one dealing with wounds should have some understanding of the micro-organisms that are the direct cause of wound infection. The operator should have a thorough insight into the habitats of germs, their modes of living, the difficulty with which they are destroyed, the ease with which they may be introduced into a wound. To obtain this knowledge the operating-room and the bacteriological laboratory should work in conjunction with each other, the investigations of the latter being applied in the former, and the results of these applications thoroughly reinvestigated in the laboratory. Without a bacteriological research that is thorough and complete no surgeon is able to tell positively why suppuration occurred in this wound and not in that one ; why this case of infection was so much more intense than that one; why no suppuration was 22 found in this case, when micro-organisms were found in one or more of the tests ; why marked infection took place in that case, where every test showed what was considered a condition of perfect " asepsis." A thorough knowledge of the subject, together with a complete investigation, will, however, clear up the whole difficulty and show almost exactly why perfect results were obtained or why infection resulted.

One very important fact is often overlooked by surgeons, and that is that one may be ever so careful in regard to antiseptic and aseptic procedures and yet have infected wounds. A knowledge of bacteriology will often clear this up and show that infection may take place, and often does, through no fault of the operator or his assistants. This may be explained by the fact that certain bacteria inhabit the skin not only of the field of operation but also of the hands of the operator and his assistants, and that they are so deeply situated that no method yet advanced is able to reach them and either inhibit their action or entirely destroy them. In these cases no one is open to censure for faulty technique; but, on the other hand, no one should ever rely on this excuse when suppuration occurs, without a thorough investigation of the other sources of infection. Again, the condition of the patient should be studied, for many of the operative cases are only too prone to afford a suitable feeding-ground for infective germs. Many cases may be flooded with micro-organisms of various descriptions with no resultant infection, while others will become infected from the slightest amount of germ life possible to communicate to them. This, also, should never be taken as an excuse for infected wounds, unless all other sources of infection have been thoroughly investigated and proved faultless.

To make sure that the hands and arms of the operator and his assistants are sterile, that the instruments and materials brought in contact with the wound have been thoroughly asepticized, test cultures must be made before the operation takes place. The tests of the hands and arms will be of no value for that particular operation, as one could not wait twenty-four hours for the result to become known before operating. They will, however, serve to show whether the hands and arms were surgically clean or not at the time of the operation, and will also demonstrate whether sufficient care has been taken to render them sterile. All materials should be tested by implantation of small portions or scrapings on several of the various artificial foods supplied by the bacteriological laboratory. If no growth result, the surmise may well be made that the articles tested are sterile and therefore suitable for use. Should one or all of these show a growth, the material from which the piece was taken should either be discarded or again put through the asepticizing process. Especially is it essential that every coil of catgut should be tested, for there is no material used at an operation that may be more faulty. This condition is due not to negligence in the preparation, but to the fact that the gut is often a most favorable hiding-place for micro-organisms and a most difficult material from which to remove them.

The hands of the operator and those of his assistants should also be carefully tested, with special tests for the under surface of the finger-nails. As before stated, the results of these tests cannot be utilized for an immediate operation, but they will show afterward whether the methods of asepticizing have been complete and thorough. They also act as a check on hasty and careless preparation, as a growth in a tube will show undeniably that there were germs present at the time the test was made, and every conscientious person will do his best to obtain a report of " no growth" from his test-tubes.

Care must be exercised in making these tests, for without the greatest amount of thoroughness they may show growths that have not been caused by any micro-organism taken from the article tested. The wire loop used for planting the material on the medium must be absolutely sterile. This can be accomplished by bringing it to a white heat in a flame of an alcohol lamp, as the heat will destroy all germs that may be present, but will not affect the platinum wire. The various media must be sterile; allow them to stand twenty-four hours before using them. This length of time will be sufficient for the development of any germs that may be present ; if no growth result, the tubes may be used. The tubes must be free from any septic material, as the wire is liable to touch the sides of the tube in reaching the culture medium, and thus cause infection of the latter with germs that were not obtained from the material being tested. The tube should be held mouth downward, in order to prevent gravitation of germs into it while the cotton plug is removed for the purpose of allowing the entrance of the wire. The cotton plug should not be removed until the tube has been inverted, nor should it be kept out of the tube longer than is absolutely necessary.

The reader is referred to works on bacteriology for the methods of making and sterilizing the various culture media that are always used in bacteriological investigations.

The principal micro-organisms which the beginner should understand are those that are liable to give rise to local suppuration. From a point of local suppuration absorption may take place, with consequent septicaemia, pyaemia, etc. The most important of these organisms are the staphylococcus pyogenes aureus, the streptococcus pyogenes, the staphylococcus epidermidis albus, the bacterium coli commune, the staphylococcus pyogenes albus, the staphylococcus pyogenes citreus, the bacillus pyocyaneus, and the diplococcus pneumoniae. Of these, the first five are those with which the surgeon will most frequently come in contact, and the following descriptions of them are given simply as aids to the beginner in surgical procedures. Those who wish a full description of germs and germ life must consult the various books published on bacteriology.

The staphylococcus pyogenes aureus is the most common micro-organism found in suppurative processes, and hence of the greatest interest to the surgeon. It has been found in the air, in the salivary secretions, in nasal mucus, in the earth, etc., but the most frequent soils on which it lives are the surface of the body and the mucous membranes. It is a spherical cell, occurring singly, in pairs, and in groups. It stains quickly in aqueous solutions of the aniline dyes. It is not discolored by Gram's method. It grows rapidly in the various liquid and solid media. It liquefies gelatin, producing a yellow deposit in the bottom of the tube after the micrococci have come in contact with the air. At first the growth is opaque. As the cocci come in contact with the air at the top of the culture medium the yellow color or pigment is formed. This pigment is formed only in the presence of oxygen, and in this way the aureus can be distinguished from some other forms of liquefying cocci. It has a remarkable vitality, living for about two weeks on a dried cover glass. In media it lives for more than a year, and when transplanted will give a new growth. Its thermal death-point, as determined by Passet, " is between 56° C. and 58° C, the time of exposure being ten minutes. When in a desiccated condition a much higher temperature is required, 90° C. to 100° C, for its destruction."

Tests made by mixing certain antiseptic solutions with gelatin and then impregnating the mass with the aureus showed that growth was prevented by carbolic acid, 1 to 814, by mercuric chloride, 1 to 81,400, and by boracic acid, 1 to 327. These strengths simply inhibit the growth but do not destroy the organism. Exposures to bichloride of mercury, 1 to 1000, or carbolic acid, 1 to 100, were successful in destroying the organism in varying lengths of time.

The streptococcus pyogenes is one of the most frequent bacteria found in pus. It may occur either alone or in connection with other bacteria, especially with the staphylococcus aureus. It is found on the healthy mucous surfaces of the mouth and nose. It occurs in chains of varying lengths, from four to twenty cells being found in the chains. The cells stain readily in the aniline dyes and by Gram's method. It grows rapidly on almost all of the ordinary media used in the laboratory. The streptococcus does not liquefy gelatin. In stick cultures, it will grow along the sides of the stick, with but little growth on the surface. The growth is semi-opaque and of a slightly grayish color. The thermal death-point is between 52° C. and 54° C. when exposed for ten minutes. Under exposure for two hours to the following strengths of solutions all germs were destroyed : carbolic acid, 1 to 300; mercuric chloride, 1 to 2500; peroxide of hydrogen, 1 to 50.

The staphylococcus epidermidis albus, as shown by Welch, of Johns Hopkins University, is the most common micro-organism found on the surface of the body. It is so deeply situated, at times, in the skin that we are unable to reach it by any known means of cutaneous disinfection.

Dr. Welch says, " So far as our observations extend, this coccus may be regarded as a nearly, if not quite, constant inhabitant of the epidermis." It is almost identical with the staphylococcus pyogenes albus, but is not so virulent. It differs from the aureus in being much less virulent, in liquefying gelatin much more slowly, and in being almost white in color. It is an almost constant bacteria in the skin and in wounds, and even in otherwise aseptic wounds. It is said to cause suppuration along drainage-tubes, and to be the most frequent cause of " stitch abscesses." The bacterium coli commune is a constant inhabitant of the alimentary tract of man, and is nearly always present in the fecal discharges. It is usually found as a short rod with rounded ends, but sometimes as an oval cell. It stains readily in aniline colors, but is discolored by Gram's method and by dilute alcohol. It is supposed to possess a slight to-and-fro motion. It does not form spores. It will grow on almost all of the media found in the bacteriological laboratory. The growths on gelatin differ in form and appearance, sometimes being spherical, at other times oval; the color varies from an amber to a dark brown. Upon potato, the growth is brownish yellow in color. It has the power of causing local suppuration ; when absorbed into the system it causes toxaemia rather than septicaemia. It is usually found on an inflamed peritoneum, and is supposed to be the cause of this inflammation. Peritonitis is often the result of the transmission of the coli bacterium from the intestine, where it is normally found, to the peritoneal cavity, where it finds a much more suitable ground for rapid development.

The staphylococcus pyogenes albus is identical with the staphylococcus aureus in size and shape. It is less virulent in its action. It liquefies gelatin about as rapidly as does the aureus, but the sediment at the bottom of the tube is milk-white instead of golden in color. It is found in abscesses, either alone or in combination with one of the other forms of pyogenic organisms.

Other forms of pathogenic micro-organisms are found in septic wounds and in abscesses. They are generally associated with one or more of the forms above described, and seldom are they found alone — that is, as pure cultures.

Remember that a somewhat thorough knowledge of bacteriology is necessary for every one who has to deal with wounds of any description ; that bacteria are found normally in the skin and organs of the body ; that it is impossible to reach some of these forms by any known means of disinfection ; that every possible endeavor should be made to be as free from micro-organisms as possible.

Chapter III. Sources Of Infection

Wounds become infected usually from one or more of four sources. These are the air, the field of operation, the hands of the operator or of his assistants, and the materials used during" the operative procedure. These probable sources of infection should always be borne in mind when arranging for an operation, in order that the greatest care may be exercised in freeing them from germs.

The air contains myriads of germs of various kinds. Experiments made by Tyndall and others demonstrated this fact conclusively. Tyndall's experiments were very comprehensive, extending over long periods of time and being widely distributed geographically. He determined that the air in cities and in low regions is much more contaminated than it is in the country and in high altitudes. He showed that all ordinary air contains some germs, which gradually settle, if 34 the air be undisturbed, until the latter become absolutely free from all micro-organisms. His experiments with the beam of light are not only highly instructive but also very interesting.

From various researches it has been learned that germs are present in the air at almost all times and places, but that their abundance varies from time to time under certain conditions. When the air in a room has been allowed to remain undisturbed for some length of time, all germs will gradually settle to the floor. As soon as one walks in the room, however, or as soon as the air is disturbed by other means, the germs are stirred up and distributed through the air. They again settle if the air remain quiet.

The air in the wards of a hospital is especially full of germs, many of which are of marked pathogenic significance. This is not to be wondered at when one considers the various diseases and septic wounds that are generally found in a hospital. But they are not so numerous as one might expect, for the reason that the moisture of the wounds and of the different pathological processes prevents the migration of the germs through the air. As soon as the micro-organisms become dry, however, they are wafted hither and thither by the currents of air, and gradually gravitate to the floor or to the surfaces of the patients, the beds, etc.