Chapter 26

APPLICATION OF HEAT, COLD, AND COUNTER-IRRITANTS

INFLAMMATION.--A process called inflammation sometimes occurs in tissues that have been injured or invaded by bacteria. Although painful, it is nevertheless one of the reparative processes of the body, and therefore beneficial. Common examples of inflammation are boils, sore throat, and the swollen, painful condition resulting from sprains and fractures. Characteristic symptoms of inflammation are heat, redness, swelling, and pain.

When a tissue has been invaded by bacteria, nearby blood vessels dilate, thus bringing an increased supply of blood to the affected part. This extra supply serves to wash away the offending substance, and at the same time it brings more white blood corpuscles, one function of which is to destroy bacteria. From the increased supply of blood the affected part becomes red and hot, and so much blood may come that the vessels further on are unable to carry it away fast enough. Some of the fluid part of the blood is then forced out into the tissues, and the part becomes swollen. Distension of the tissues and pressure on the nerve endings cause pain, and the injured part now exhibits the characteristic symptoms of inflammation.

At this point, if the injury begins to heal or the bacterial infection to yield, the extra blood supply is gradually carried off, the blood vessels resume their normal size, and the tissues return to their usual condition. If, however, the infection does not yield so quickly, more and more white blood corpuscles assemble and pass through the walls of the tiny blood vessels into the tissues. Here the struggle continues. Some bacteria and some white blood corpuscles are killed, and substances are formed which liquify these dead cells and also some cells of the surrounding tissues. The resulting fluid is called pus or matter, and in the case of a boil we then say it has come to a head. If the infection occurs near a cavity or near the surface of the body, the pus may escape by breaking through at the point of least resistance, and may carry most of the poisons along with it. If the pus finds no outlet it may be gradually absorbed by the blood stream, and healing may result without discharging. On the other hand, the germs may make their way into the circulation, thus causing the serious condition known as blood poisoning.

Inflammation may be treated by means of hot applications, cold applications, or counter-irritants. The effect of heat is to dilate the vessels and hence to increase the flow of blood to the injured part. This increased blood supply makes the reparative process go on more vigorously, and also makes it possible for the accumulated fluid to be more rapidly carried away. Moist heat softens the tissues so that pus, if formed, can escape more easily.

Cold acts in just the opposite way. It decreases the size of the blood vessels so that less blood comes to cause pain and swelling; at the same time it diminishes the number of white blood corpuscles and the nutritive substance brought by the blood. The nature and location of the infection determine whether heat or cold is to be preferred.

Counter-irritants, of which mustard is an example, have a complicated action. A counter-irritant affects the blood circulation of the place to which it is applied, and at the same time it irritates the superficial nerves, which in turn stimulate other more distant nerves. The latter nerves control the circulation in tissues not adjoining those to which the counter-irritant is applied, and thus it is possible for a mustard paste, for example, if applied at one point to bring about changes in the blood supply of another part of the body. The mechanism by which counter-irritation is brought about is an intricate nervous process called reflex action.

HOT APPLICATIONS

In applying either moist or dry heat the danger of burning or scalding a patient must be constantly kept in mind. This danger is always great, but it is especially great when the skin is tender like that of babies, children, and old people, or when the vitality is low as in cases of chronic or exhausting illness. Unfortunately accidents in applying heat are not uncommon; a moment's carelessness may cause serious injury and prolonged suffering.

DRY HEAT.--Hot water bags are used to apply dry heat. They should be filled not more than two-thirds full of hot water, but the water must not be so hot that there is the slightest possibility of scalding the patient if the bag should leak. Boiling water should never be used. Before the stopper is screwed on, expel the air by squeezing the bag or by resting it upon a flat surface until the water reaches the top. After closing the bag make sure that both bag and stopper are in order, by noting whether leakage occurs when the bag is inverted and pressed moderately. Before it is placed near the patient the bag should be dried and entirely covered with a towel or canton flannel bag.

Strong bottles, jugs, and jars, if they can be securely stoppered, may be used sometimes instead of hot water bags. The same precautions are necessary. Bricks, flat irons, or thick flannel bags containing salt or sand may be heated in the oven and used in the same way. Salt and sand retain heat for a long time, but are correspondingly slow to heat; therefore one bag should be heating in the oven while the other is in use. Their effect on the skin must be no less carefully watched than the effects of other hot applications.

Hot dry flannel may be used without fear of burning a patient, and it sometimes yields sufficient warmth to relieve pain, particularly abdominal pain of babies. After it has been heated on a radiator or in an oven, it should be applied quickly and covered closely with another flannel to prevent escape of heat.

Dry heat can be applied conveniently by an electric pad. The part to be heated may be wrapped in flannel or placed directly above or below the pad. The pad should be carefully watched to see that the switch is not accidentally turned, as it is possible for the pad to become hot enough to burn the patient or to set fire to the bed covers.

MOIST HEAT.--To apply moist heat poultices or fomentations (stupes) are used.

_Poultices_ may be made of various heat-retaining substances, but flaxseed meal is generally used. The poultices when ready should be applied without delay, therefore all preparations should be made in advance. To prepare a poultice, first provide a piece of gauze or thin old muslin about two inches wider than you wish the poultice to be when finished, and about two inches more than twice as long. In a shallow saucepan boil water, varying in amount according to the size of the poultice desired; about equal parts of water and meal will be needed. When the water is boiling briskly add the meal gradually, beating constantly with a spatula or knife. The poultice is done when the mixture coheres and is thick enough to drop from the spatula leaving it clean. Quickly spread a layer of the hot flaxseed from a quarter to half an inch thick on one-half of the muslin, leaving a margin on three sides of about an inch (Fig. 25). Fold in the margins of the cloth (Fig. 26) and then bring the other half of the cloth over the flaxseed so that the top of the poultice is covered. Tuck the free end of the upper half of the cloth under the turned in edges of the long sides.

Carry the poultice on a hot plate, or rolled in a newspaper or hot towel. Test it carefully with the back of the hand, apply it to the skin gradually, cover it with cotton batting, oiled muslin, or several thicknesses of flannel, and keep it in place with a bandage or towel. Remove it as soon as it has become cold, and unless the skin is much reddened apply a fresh poultice. If the skin is much reddened, anoint it with vaseline or sweet oil, wrap it warmly, and apply the next poultice as soon as the appearance of the skin is normal.

_Stupes_ or _hot fomentations_ are cloths, preferably of flannel or flannelette, wrung out of boiling water and applied to the skin. Each stupe should be three or four times as large as the area to be covered. Two are needed, so that one may be prepared before removing the other. To prevent escape of heat and moisture the stupe should be covered after it has been applied, first with a piece of rubber cloth or oiled silk or muslin, and next with several thicknesses of flannel, or cotton batting made into a pad. The whole should be kept in place with a bandage or towel used as a binder. The doctor will tell how often the stupes are to be applied, but if the skin becomes irritated they must be stopped until its appearance is again normal.

Great care must be taken in applying fomentations. They do little good unless very hot, but if applied too hot the patient is likely to be scalded. They must be wrung as dry as possible; but it is difficult to wring them without scalding the hands unless stupe wringers are used. Stupe wringers are heavy pieces of cloth, like roller towels or pieces of ticking, long enough to extend over opposite sides of the basin in which the stupe is to be boiled, and wide enough to hold the stupe easily. The wringer should be placed in the basin with the stupe arranged upon it. Boiling water should then be added, or the water, stupe, and wringer may be boiled together in the basin. After the stupe is ready, the wringer with the stupe upon it should be removed from the water by grasping the dry ends of the wringer. Then the ends should be twisted in opposite directions until the stupe inside is as dry as possible. Wringing is made easier if the wringer has wide hems into which sticks such as pieces of broom handles are inserted. By twisting the sticks in opposite directions the stupe may be wrung out easily.

COLD APPLICATIONS

DRY COLD.--Cold, like heat, may be used either dry or moist. Bags of rubber or of Japanese paper filled with small pieces of ice are used to apply dry cold. When weight is to be avoided, the bag should not be completely filled. After the bag has been filled and the air has been expelled, it should be stoppered securely and wrapped in a towel or piece of flannel, since it is possible for an uncovered ice bag to freeze the skin. Ice bags are easily punctured, and care should be taken not to bring pressure upon them especially when filled with sharp pieces of ice. An ice bag not in use should be thoroughly dry inside and out; it should be put away with enough absorbent cotton inside to keep the surfaces from adhering. Bags of Japanese paper are less costly than rubber, but less durable. To close them one should roll the top over and then tie it tightly with string.

MOIST COLD.--Cold compresses for the head are often used for patients with fever or headache; they sometimes quiet a patient who is restless. An old handkerchief or piece of soft linen folded with the raw edges inside may be used as a compress. It should be large enough to cover the forehead. Two compresses at least should be provided, and a large piece of ice in a basin. One compress should be wrung so that it will not drip, and then applied to the head. The other meanwhile should be placed on the ice to cool. As soon as the first compress becomes warm, the second should be applied in its place.

_Cold Compresses for the Eyes._--Soft material should be selected for eye compresses. Each one should be cut only a little larger than the eye and should fit neatly over it. Several compresses should be placed on a block of ice while one is applied to the eye, and every few minutes the compress should be changed. If there is discharge from the eye, each compress should be used but once; when used, they should be collected in a paper and afterward burned. Separate compresses should be used if both eyes are being treated. Definite directions in regard to changing compresses and the length of time the applications should be continued are generally given by the physician.

COUNTER-IRRITANTS

To some extent all hot applications are counter-irritants, but mustard pastes, mustard leaves, and the mustard foot-bath already described are the counter-irritants most commonly used.

_Mustard Paste._--To make a mustard paste, mix dry mustard with flour, using for adults one part of mustard and six of flour to make a weak paste; increase the proportion of mustard up to equal parts of mustard and flour, according to the strength required. Use a smaller proportion of mustard for children; one part of mustard with from 6 to 10 parts of flour is generally enough. Add to the mustard and flour enough tepid water to make a paste, which must be absolutely free from lumps. Do not use hot water for this purpose, because it destroys some of the active properties of the mustard. Spread the paste on thin muslin, apply it to the skin, and remove it as soon as the skin is reddened so that its color resembles that of a strong sun-burn. If the skin is especially sensitive, mix a little sweet oil or vaseline with the paste.

_Mustard leaves_ should be dipped in tepid water and may then be applied to the skin directly, but if specially sensitive, the skin should be protected by thin muslin or gauze. The leaf should remain until the skin is well reddened; a few minutes are generally sufficient.

Care must be taken not to leave either a mustard leaf or a paste in place long enough to blister the skin. After the application has been removed; the part should be protected by a soft cloth until redness disappears. Vaseline or sweet oil should be applied to the skin if it is greatly irritated.

Other counter-irritants in common use are iodine, turpentine, ammonia, kerosene, camphorated oil, capsicum vaseline, and various liniments. Tincture of iodine may be diluted with alcohol for especially sensitive skins; it sometimes causes blisters, and should not be applied more than once a day at most. Ammonia and turpentine cause blisters; they should not be used as counter-irritants except by a doctor's order, and then only after exact directions have been obtained. Turpentine and kerosene are inflammable and hence dangerous to use. It should be remembered that the action of all counter-irritants is physiologically the same, so that no advantage is obtained from the use of dangerous substances like kerosene and turpentine.

EXERCISES

1. What are the causes and symptoms of inflammation?

2. Describe the process of inflammation.

3. What is the effect of heat on an inflamed area? of cold?

4. What are the dangers from hot applications, and how may they be guarded against?

5. How should you fill a hot water bag? How should you cover it?

6. Describe the method of preparing and applying a flaxseed poultice.

7. Tell how to prepare and apply fomentations.

8. How should you apply cold compresses to the head? to the eyes?

9. How should you make a mustard paste for a baby six months old? for a grown person only slightly ill? for a feeble old person with a sensitive skin?

FOR FURTHER READING

Essentials of Medicine--Emerson, Chapter I.

The Human Mechanism--Hough and Sedgwick, Chapter IX.