This method of giving drugs is growing steadily in favor. The best location for the injection of a drug is in the extensor surfaces of the extremities, and in the back, chest, or abdomen, avoiding the region of large blood-vessels and nerves. The amount administered is about one half the dose usually given by mouth. Nearly all drugs used hypodermically are put up in tablet form, being made readily soluble and especially for the purpose. The nurse becomes familiar with the various forms and sizes of syringes in use for the giving of hypodermics, and the care and sterilization of these is a part of her instruction from nursing textbooks and in practice in the wards of her hospital.
There are two ways of making the injections, superficial and deep. In the first, after having used at least two successive applications of alcohol by means of a sterile sponge or a bit of absorbent cotton to cleanse the part, the skin is grasped between the thumb and fingers of the left hand while the needle is thrust with the right hand on a slant to the depth of one centimetre, when it is withdrawn a short distance and the fluid is slowly forced into the tissues. Gentle kneading around, but not on, the point of injection and slight pressure over the part will aid in the absorption of the fluid, help to prevent abscess formation, and allay pain.
The second method, deep or intramuscular injection, is useful with irritant drugs, and with the same precautions as in the other method the needle is inserted deeply and swiftly into the muscular tissues of the back, chest, abdomen, buttocks, or preferably the anterior surface of the thigh, to the depth of three to five cm., at the same time stretching the skin tight over the part. The fluid is forced quickly out of the syringe, and the tissues around the point of its insertion are kneaded deeply for about five minutes.
These drugs are usually injected superficially about the fleshy part of the shoulder. They may be put in lower down on the arm or in other parts of the body.
This is usually administered as a local anaesthetic, and in this way may be injected into any part of the body, or dropped into the eye or ear, or sprayed into the nose or throat. For hypodermic injections, the needle should be inserted along the line of the proposed incision - when one is to be made - and the cocaine forced in, a little at a time, removing the needle and reinstating it within the limit of anaesthesia with every mil of the fluid used. The injection should be completed at least five minutes before the incision is made. Not more than two grains of cocaine should be administered at one time for fear of poisoning.
One usually administers this remedy into the tissues of the back, buttocks, or thigh, preferably between the shoulder-blades or in the lumbar muscles. Rubbing and kneading the region adjacent to the point of injection is an aid to the efficiency of the injection.
The apparatus necessary for this is a graduated bottle, a rubber tube, and a needle. Sterilized normal salt solution (.9 of 1 %) should be kept on hand, and when wanted for use heated to a temperature of 110° F. and maintained at that point, employing a thermometer to register it. The bottle should be suspended at a height of three to six feet above the patient. The fluid is injected into the tissues behind the breast or into the thigh. The needle should be inserted well into the tissues, and withdrawn a little way. An adhesive strip may be used to hold it in place. Do not become alarmed if a large swelling occurs. Persistent kneading of the tissues around this will reduce it. A linen band may be placed about the patient's chest to prevent swelling, but this is unnecessary. Twenty minutes to one-half hour is usually required for 500 mils. to infiltrate the tissues.
Mercury is used in the form of the bichloride, or gray oil, and is injected deep into the buttocks, as a rule.
Digitaline, ergotine, and arsenic in the form of atoxyl, are put in deep.
Gelatin has been injected subcutaneously, but its use is becoming limited. Other drugs may be used hypodermically.
The Italians administer iron, arsenic, and strychnine, as well as guaiacol and other drugs, as tonics by hypodermic injection, calling the custom the giving of "piqures." The drug is prepared and hermetically sealed in a thin glass tube about 3 cm. long and containing 3 mils. of the fluid ready to be used in the syringe after the neck of the tube is broken off by snipping it with a pair of scissors. One injection is given each day into the gluteal muscles, on alternate sides. The injection is administered deep as above described. About 30 minims or an ordinary syringeful is the amount given, and the fluid is forced in rapidly, the quicker the less painful. Abscesses are not known to occur except through gross carelessness in technique. Strict asepsis is, of course, necessary.