Emergency Care Textbook Professional Responders-part-22 PDF

22 Pharmacology Introduction Key Content Assisting with Medication vs Administering Medication........................... Six Rights of Medication........ Pharmacological Terminology......................... Routes of Drug Administration..................... Pharmacokinetics.................... Phar...

22 Pharmacology Introduction Key Content Assisting with Medication vs Administering Medication........................... Six Rights of Medication........ Pharmacological Terminology......................... Routes of Drug Administration..................... Pharmacokinetics.................... Pharmacodynamics................. Intravenous (IV) Therapy Maintenance........................ Preparing a Drip Set and Solution...................... Calculating IV Flow Rates.... Changing an IV Bag............. Complications....................... Discontinuing an IV............. How to Administer Medication Intranasally...... Guidelines for Injections......... Disinfection............................. 370 371 371 372 373 373 374 374 375 375 376 377 378 378 380 The administration of drugs is not part of the scope of practice for many responders. This section provides an overview of pharmacology and drug administration but must be read alongside all applicable legislation, regulations, and protocols for your particular jurisdiction. If you are under medical direction, your director may specify procedures other than those set out here. As always, follow local protocols and medical direction where applicable. PHARMACOLOGY Pharmacology is the study of drugs and how they interact with the body. Drugs do not confer any new properties on cells. They can be given locally or systemically. They tend to have actions at multiple sites, so they need to be thought of systemically even if administered locally. 369 Generally, all medications have indications, contraindications, and side effects to their administration: Indications are conditions that make administration of the drug appropriate. Contraindications are conditions that make administration of the drug inappropriate due to potential harmful effects. Side effects are any reactions to the drug other than its intended effects. For example, a drug intended to reduce pain may also cause nausea. If a drug is indicated, this does not mean it will have no negative side effects. The benefits of the desired effects are weighed against the risks of complications: A lifesaving drug may be indicated even if there are potential serious negative side effects. This set of assessment models, treatment principles, and protocols reflects the accepted medical practice for responders. Each protocol follows the current direction of the medical community, taking into consideration the limitations and special circumstances that may exist in pre-hospital care environments. PHARMACOLOGY Protocols allow the responder to perform medical procedures that are normally in the domain of a physician. This allows responders to initiate care that patients would otherwise not receive until they arrived at a medical facility. 370 Medications can be extremely beneficial, but they can also be dangerous if used incorrectly. Before administering a drug to a patient, ensure that you are aware of the patient’s drug history (any drugs that he or she is currently taking or has recently taken), as this may inform how you proceed. This information is usually gathered in the secondary assessment. For example, a patient taking erectile dysfunction (ED) drugs should never take nitroglycerin, as the two can combine to cause a fatal lowering of blood pressure. In other words, ED drugs are a contraindication for nitroglycerin. Under certain circumstances and under medical direction, you may be able to provide medication to a patient or to assist a patient with his or her own medication. ASSISTING WITH MEDICATION VS ADMINISTERING MEDICATION Assisting with medication and administering medication refer to different things. Administration means making the decision to give a medication to a patient and then actually introducing the drug into the patient’s body. Assisting with medication means following a patient’s specific direction to help with medication. Assisting can refer to a variety of activities, including locating the drug, helping the patient prepare it, guiding the patient in taking it, and reading the medication’s packaging to the patient. In many cases, a responder will be qualified to assist with medication but not to actually administer it. Administering medication is a controlled act that is governed by a specific set of standards and requires special training. Anyone can be directed by a patient to assist with medication, provided they do not cross over into administering the medication, but only very specific groups of medical professionals are legally allowed to administer medication. In the workplace, first aid attendants are required to know the provincial or territorial regulations specific to their workplaces regarding assisting a patient with medications. Examples of assisting with medication and administering medication are shown in Table 22–1. TABLE 22–1: EXAMPLES OF ASSISTING WITH MEDICATION AND ADMINISTERING MEDICATION ASSISTING Opening the lid of a pill bottle Placing pills in a patient’s hand Opening an epinephrine autoinjector Unwrapping a transdermal patch Reading a medication’s label aloud Pushing pills out of a blister pack ADMINISTERING Injecting a medication Placing medication in a patient’s mouth P  lacing a transdermal patch on a patient’s skin Spraying medication into the patient’s nose SIX RIGHTS OF MEDICATION When administering or assisting a patient with medication, the responder has a responsibility to know the medication’s therapeutic benefits, side effects, indications, and contraindications. The responder should use proper technique and monitor the drug’s effects (and side effects). Prior to having the patient take any medication, it is the responder’s responsibility to ensure that the Six Rights of Medication have been met: 1. Right person: Make sure the patient receiving the medication is the one whose name is on the label of the medicine container. 2. Right medication: Read the label and confirm the name of the medication. 3. Right dosage: Accurately measure the indicated quantity of medication. 4. Right time: Give the medication at the right time. 5. Right route: Read the directions carefully and administer with the correct method. 6. Right documentation: Completely document your actions and findings, including: Time Dose Route Effect Also check the medication’s colour, clarity (no particles), concentration, and expiration date. Document all of the circumstances around the medication, including the patient’s initial presentation and any changes in the patient’s condition after taking the medication. PHARMACOLOGICAL TERMINOLOGY Addiction: A strong dependence on a drug; it may be physiological, psychological, or both, and it may be due to a decreased response to a drug with repeated use. Agonists: Drugs that bind with a receptor in the body to produce a biological response. Antagonists: Drugs that combine with a receptor to prevent a biological response. Contraindication: A medical or physiological factor that makes it harmful to administer a medication that would otherwise have therapeutic value. Depressant: A substance that decreases a body function or activity. Drug allergy: A reaction to a drug resulting from previous sensitizing exposure and the development of an immunological mechanism. Drug interaction: A modification, which can be beneficial or detrimental, of the effects of one drug by the administration of another drug. Indications: The conditions that make the administration of a drug appropriate. Potentiation: An increase in the effect of a drug due to the administration of a second drug. Side effect: An often unavoidable effect of a drug; an effect other than those for which the drug was originally given. Synergism: The combined effects of two drugs such that the total effect exceeds the sum of the individual effects of each agent (sometimes expressed as “1 + 1 = 3”). Therapeutic action: The desired, intended effect(s) of a drug. PHARMACOLOGY In some cases, a physician (who is allowed to administer medication) can authorize a responder to administer medication through medical direction or standing protocols. In these cases, the physician is essentially authorizing the responder to administer the drug on his or her behalf. 371 Drug Names Each drug has several names. The two most important are the generic name and the trade name. Chemical name: The scientific name for the drug’s atomic or molecular composition (e.g., the chemical name for Aspirin® is acetylsalicylic acid). Generic name (also known as a non-proprietary name): An abbreviated form of the chemical name of the drug. Generic medications usually have the same therapeutic efficacy as the non-generic medication and are generally less expensive. Trade name (also known as a brand name or proprietary name): A copyrighted name designated by the drug company that develops and requests approval for the medication. Trade names of drugs are considered to be proper nouns and, therefore, the first letter is capitalized (e.g., Demerol). Official name: Followed by the initials “USP” or “NF,” this name denotes the medication’s listing in one of the official publications; it is usually the same as the generic name (e.g., meperidine hydrochloride USP). ROUTES OF DRUG ADMINISTRATION PHARMACOLOGY Drugs can be introduced into a patient’s body through a number of routes. These are broadly categorized as enteral (through the digestive system) or parenteral (not through the digestive system). Regardless of the route selected, a patient should be monitored closely for complications and side effects after taking any medication. 372 Enteral administration of drugs includes the following routes: Oral: ◆ Drugs are swallowed and absorbed through the digestive system. ◆ Solid drugs must first dissolve before absorption: The slower absorption rate means the patient must be monitored for a longer period after taking the medication. ◆ The patient must be responsive and able to control his or her own airway. Sublingual: ◆ Medications are delivered under the tongue and are rapidly absorbed into the blood. ◆ Sublingual drugs are not to be swallowed or inhaled. ◆ The patient should not take anything else by mouth until the drug is completely absorbed. Buccal: ◆ The drug is placed between the cheek and the gum and is absorbed across mucous membranes. ◆ This route is not common in a pre-hospital setting. Rectal: ◆ Suppositories are solid at room temperature and dissolve with body heat when placed in the rectum. ◆ Liquids can be instilled with a syringe. ◆ This route is not common in a pre-hospital setting. Parenteral administration of drugs includes the following routes: Intravenous: ◆ The drug is administered directly into the vein. ◆ This route requires an IV line to be started (aseptic technique). Endotracheal: ◆ This route is common in a pre-hospital setting for specific medications. ◆ This route is restricted to advanced life support (ALS) practitioners. Subcutaneous: ◆ The drug is administered into the layer of fat between the patient’s muscle and skin. ◆ This route involves smaller volumes and slower onset than intramuscular (IM) administration. Intradermal ◆ The drug is administered into the dermis, just below the epidermis. Intramuscular: ◆ The drug is administered directly into a large muscle. ◆ The drug absorbs well due to the rich blood supply of muscle tissue. PHARMACOKINETICS Pharmacokinetics is the study of how the body handles a drug over a period of time, including: Drug absorption. Drug distribution. Biotransformation. Excretion. Drug Absorption Absorption involves the movement of drug molecules from the site of entry into general circulation. Variables that affect drug absorption include: Blood flow to the site of administration. Solubility of the drug. pH of the body. Concentration of the drug. Route of drug administration. Drug Distribution Distribution is the transport of a drug through the bloodstream to various tissues of the body and, ultimately, to its site of action. The rate of distribution depends on the permeability of the capillaries to the drug molecules. Cardiac output and regional blood flow also affect the rate and extent of distribution. Biotransformation Biotransformation is the process by which a drug is chemically converted to a metabolite. This detoxifies a drug and renders it less active. The liver is the primary site of drug metabolism. If drug metabolism is delayed, drug accumulation and cumulative drug effects may occur. Excretion Excretion is the elimination of toxic or inactive metabolites from the body. The organs of excretion include the kidneys, intestines, lungs, sweat glands, salivary glands, and mammary glands. PHARMACODYNAMICS Factors That Influence the Actions of Drugs The following factors can influence the actions of drugs: Age of patient Body mass Gender Environment Time of administration Pathological state Genetic factors Psychological factors Drug–Receptor Interaction Most drug actions result from a chemical interaction between the drug and various receptors throughout the body. Drugs bind to drug receptors to produce their desired effect. Many drugs used in the pre-hospital setting directly or indirectly affect the nervous system, often the autonomic nervous system (ANS). The sympathetic nervous system (a component of the ANS) prepares the body for stress and emergencies. Epinephrine is one of the chemical messengers released by the sympathetic nervous system (also referred to as the sympathetic division of the ANS). It can act on three different receptor types: 1. Alpha1 receptors: When stimulated, they cause peripheral vasoconstriction. 2. Beta1 receptors: When stimulated, they cause increased heart rate and increased force of cardiac contraction. PHARMACOLOGY The  volume given must be carefully assessed based on the patient’s size and the site of administration. Inhalation: ◆ This  route produces rapid onset of the effects if the drug reaches the lower airways and passes into general circulation. Intranasal: ◆ The  drug is administered into the patient’s nostril in mist form. ◆ This  route allows rapid absorption of medication into the bloodstream through the mucous membrane. ◆ 373 3. Beta2 receptors: When stimulated, they cause bronchodilation. The parasympathetic division of the ANS restores the body to normal conditions. Parasympathetic receptors are called cholinergic receptors; when stimulated, they cause bronchodilation and a decreased heart rate. INTRAVENOUS (IV) THERAPY MAINTENANCE Maintaining intravenous (IV) administration is an advanced skill that may or may not be part of your scope of practice. You may be expected to maintain IV therapy in specific cases, such as during patient transport. At times, you may be asked to set up a peripheral IV line, replace a solution bag, or prepare an IV line (Figure 22–1). A peripheral intravenous (IV) line allows the administration of fluids, including saline and blood, and solutions containing substances such as medications. Once established, an IV line can be used to introduce medication directly into a patient’s circulatory system. You should wear gloves, eye protection, and other appropriate PPE whenever you are working with an IV line. PHARMACOLOGY A drip set consists of tubing that can connect to the catheter in the patient’s arm on one side and the drip bag on the other. It includes the drip chamber, which is where you can monitor the rate at which fluid drips into the line, and a medication port that allows other medication to be introduced into the line with a syringe. The drip set also includes a line lock that allows you to adjust the drip rate or suspend the flow entirely. Finally, there is a check or back-flow valve that prevents fluid from moving up the line. 374 Crystalloid solutions that are commonly used with an IV line include the following: Normal saline: a 0.9% sodium chloride solution; an isotonic volume expander Dextrose: 3.3% dextrose and 0.3% sodium chloride (2/3 and 1/3) Figure 22–1: Intravenous therapy. Ringer’s lactate: a solution containing sodium chloride, potassium chloride, calcium chloride, and sodium lactate in distilled water D5W: 5% dextrose in water Preparing a Drip Set and Solution To prepare a drip set and solution for use: 1. Inspect the solution and packaging prior to assembling the drip set. Confirm that the solution is the one that was requested, that it has not expired, and that the fluid is clear and uncontaminated. Ensure that you are using the correct drip set. 2. Assemble the drip set and use the line lock to close off the line. 3. Hold the solution bag upside down and remove the protective cap on the port using aseptic technique. 4. Support the inverted solution bag and insert the spiked end of the IV drip chamber into the port with a straight push. 5. Place the solution bag in the proper vertical position, and squeeze the drip chamber until it is half to two-thirds full. 6. Release the line lock and purge all air from the line. 7. Confirm that the solution is flowing, then lock off the line. 8. Once IV therapy has been initiated, adjust the drip rate until the correct flow rate is achieved. Example 2: Calculating IV Flow Rates gtt/min = 166.6 There are three factors used to calculate gtt/min: 1. Volume to be infused: This represents the total volume of fluid or solution required for the patient. 2. gtt/mL of administration set: This refers to the size of the drops created by different drip sets. Drip sets can be grouped into micro-drip (with drops of 60 gtt/mL) and macro-drip (with drops of 20, 15, or 10 gtt/mL). 3. Total time of infusion: This is the total time over which the fluid or solution should be administered to the patient. When you are asked to set up a drip set and solution by an authorized person, you will be given most or all of this information. For example, you may be asked to infuse 1,000 mL over 120 minutes. METHOD FOR CALCULATING FLOW RATES To calculate flow rates for infusion of IV fluids, use the following formula: gtt/min = volume to be infused x gtt/mL of administration set total time of infusion (in minutes) Example 1: gtt/min = 500 mL x 10 gtt/mL 60 min gtt/min = 83.3 This works out to just under 1.5 drops per second. 90 min This works out to just under 3 drops per second. Changing an IV Bag Changing an IV bag is indicated in the following circumstances: The bag is empty or has less than approximately 50 mL remaining inside it. You are given instructions from the medical staff that the IV is to be changed en route during a transfer. In this circumstance, you can request that the nursing staff change the bag prior to the transfer or obtain a replacement bag from the hospital so that you can change the bag en route. Follow this procedure when changing an IV bag: 1. Ensure aseptic technique. 2. Remove a new bag of solution from the outer wrappings and inspect it for leaks and discoloration. Ensure that it has the correct contents and concentration and that it has not expired. 3. Close the line lock on the tubing. 4. Note how much solution remains in the old bag and invert it. 5. Remove the spike on the administration set from the old bag. Taking care not to contaminate the spike, remove the protective cap from the IV port on the new bag. Insert the spike into the IV port on the new bag. 6. Invert the new bag, unlock the line, and confirm the flow rate. Adjust the flow rate if necessary. 7. Document the procedure by noting the time you changed the IV bag and the amount and type of solution hung, as well as the amount of solution that was discarded with the old bag. Example: 0930 (time) to 1,000 mL N/S started at 500 mL/hr/50 mL solution discarded [your signature]. PHARMACOLOGY IV flow rates are measured in drops per minute, written as gtt/min (gtt stands for the Latin guttae, meaning drops). By watching the drops in the drip chamber, you can calculate the number of drops per minute (similar to taking a pulse). gtt/min = 250 mL x 60 gtt/mL 375 Complications In the course of monitoring an IV, complications may arise that require intervention. If any of these complications occur, contact the appropriate medical personnel for instructions on how to proceed. If you are qualified under medical direction or your scope of practice to decide that an IV should be discontinued, you may do so as a result of some of these complications (see Discontinuing an IV on page 377). If discontinuing an IV is not part of your scope of practice, contact the appropriate medical personnel for direction. INTERSTITIAL IV If an IV is interstitial, this means that the IV fluid is flowing into the surrounding tissues instead of into the vein due to complete or partial perforation of the vein through the opposite wall. This is identified by swelling around the injection site, and the skin will be cool to the touch. Flow rate may be diminished, and pain may or may not be present. Once you have identified that the IV is interstitial, perform the following interventions: 1. Discontinue the IV. 2. Record the time at which the IV was discontinued and the amount infused. 3. If the swollen area is small, apply a cold pack. 4. If the swollen area is large, apply warm, wet compresses to promote reabsorption of the fluid. CIRCULATORY OVERLOAD PHARMACOLOGY Circulatory overload occurs when the patient’s system is unable to manage the extra fluids administered, leading to cardiac and pulmonary complications similar to congestive heart failure or pulmonary edema. This can be caused by excessive fluid administration or rapid fluid delivery. Monitor the patient’s vital signs and IV drip rate and watch for any changes. 376 Should the patient develop signs of fluid overload, perform the following interventions: 1. Immediately slow the IV rate to keep the vein open (abbreviated to TKVO). 2. Place the patient in a semi-sitting position and apply oxygen if indicated. 3. Transport the patient as quickly as possible and notify the hospital of your arrival. 4. Closely monitor the patient’s vital signs while en route, and make sure you keep the patient warm to promote peripheral circulation. 5. Document your findings and actions, including slowing the IV rate. Someone with circulatory overload should be treated as a patient with congestive heart failure. THROMBOSIS AND THROMBOPHLEBITIS Thrombosis is the formation of a clot and usually occurs at the tip of the catheter. Thrombophlebitis is inflammation of a vein due to the formation of a blood clot (thrombus means blood clot and phlebitis means inflammation of a vein). A clot may form if: The IV is running too slowly. There is injury to the vein wall, either from the insertion or from mechanical irritation (e.g., excessive movement of the patient). The catheter is too large for the lumen (hollow) of the vein. The vein is too small to handle the amount or type of solution being administered. There is irritation to the vein by medications (e.g., drug infusions). Keeping the infusion flowing at the established rate helps prevent the formation of a thrombus at the end of the needle. Stabilizing the IV site with an arm board or splint will prevent mechanical irritation. If thrombophlebitis develops, perform the following steps: 1. Discontinue the IV. 2. Record the time at which the IV was discontinued and the amount of fluid infused. 3. Apply warm, wet compresses to decrease the pain and promote healing. Refrain from massaging or rubbing the affected arm, as this may dislodge the clot that has formed. CATHETER EMBOLISM A catheter embolism occurs when the catheter or a portion of it breaks off and is carried away in the bloodstream. This rare complication occurs when the IV is initiated. SITE INFECTION You are most likely to encounter a site infection when transporting a patient who already has an IV in place. The majority of infections are due to skin flora (micro-organisms such as bacteria) entering the wound when the IV is initiated because of non-aseptic techniques. Infection is usually recognized by redness in the area around the catheter, swelling of the site, or possible discharge. If you are transferring a patient and have not departed, inform hospital staff immediately. They will address the infection. When infection of a site occurs while you are en route with a patient, perform the following steps: 1. Contact the hospital and request direction. 2. Discontinue the IV and record the time. 3. Document the amount of solution infused. 4. Dispose of the catheter in a sterile container and give it to hospital personnel for testing. 5. Dress the site with a sterile dressing and apply a warm pack. ALLERGIC REACTION An allergic reaction to an IV can be caused by a hypersensitivity to an IV solution or an additive and may result in a generalized rash, shortness of breath, rapid heart rate, and a drop in blood pressure. If the patient has an allergic reaction, perform the following interventions: 1. Decrease the IV rate to keep the vein open or discontinue the IV (see note). 2. Record the time the IV rate was changed. 3. Notify the hospital. 4. Administer oxygen if indicated. Search for other substances that may have caused the reaction. If unable to find another cause for the reaction, discontinue the IV. AIR EMBOLISM An air embolism can be caused by allowing an IV bag to run dry or attaching a line that has not been fully purged of air, or by loose connections between the IV tubing and the catheter or at any other connection point. When setting up an IV, make sure you thoroughly clear all tubing of air bubbles. Change the IV bags before they are empty, and make sure all connections are secure. If an air embolism has occurred, perform the following interventions: 1. Turn the patient on his or her left side. Angle the patient’s body 30 degrees to keep the head lower than the rest of the body. If air has entered the heart’s chambers, this position may keep the air bubbles on the right side of the heart, where they can then enter the pulmonary circulation and be absorbed. 2. Check the IV system for leaks. 3. Administer oxygen if indicated. 4. Notify the hospital and transport immediately. Discontinuing an IV If you are qualified under medical direction or your scope of practice to discontinue an IV, you may need to do so in the following situations: Interstitial IV Thrombophlebitis Catheter embolism Site infection (do not remove an IV catheter if a “do not remove” order has been given) The procedure for discontinuing an IV is as follows: 1. Ensure aseptic technique. 2. Gather and prepare your supplies (gauze, tape, disposable biohazard bag). 3. Stop the flow using the line lock. 4. Remove the transparent dressing and the tape from the site while minimizing movement of the IV and catheter. This is simplest if you PHARMACOLOGY If a catheter embolism occurs, perform the following interventions: 1. Discontinue the IV but do not discard the catheter. Give the catheter to hospital personnel for examination and follow-up. 2. Record the time at which the IV was discontinued and the amount of fluid infused. 3. Be careful not to obstruct the arterial flow; check the distal pulse to ensure its presence. 4. Administer high-flow oxygen to the patient if indicated. 5. Notify the hospital and ensure that the patient is in the rapid transport category. 377 5. 6. 7. 8. 9. stabilize the hub of the catheter with one hand while removing the tape with the other. Hold sterile gauze over the puncture site. Grasping the catheter by the hub, pull straight back. Do not use an alcohol swab for this procedure, as this may interfere with blood clotting and be painful for the patient. Place gauze over the site and immediately apply firm pressure until bleeding stops (3 to 5 minutes). Cover the puncture site with an adhesive bandage. Inspect the catheter (to ensure there has not been a catheter embolism). Document the time the IV was discontinued, the amount of solution infused, and the condition of the catheter. HOW TO ADMINISTER MEDICATION INTRANASALLY The following steps represent an overview of one method for the intranasal administration of medication. As there are several types of devices available, familiarize yourself with the device you are using and any local protocols or instructions from your medical director. PHARMACOLOGY To administer medication through intranasal injection (IN), first remove the nasal spray device from the packaging. Place your thumb on the plunger and hold the nasal spray tip between your middle and index fingers. If the device is too large, use one hand to operate the plunger and your other hand to hold the spray tip. 378 Gently tilt the patient’s head back slightly and support it in this position. If using both hands for administration, have another responder support the head. Insert the tip of the device into one of the patient’s nostrils until your fingers come into contact with the bottom of the patient’s nose. Administer the entire dose of medication by pressing firmly on the plunger, and then remove the device from the patient’s nostril immediately (Figure 22–2). Figure 22–2: Intranasal administration of medication. GUIDELINES FOR INJECTIONS Injecting medication safely requires adherence to specific procedures before, during, and after administration of the medication. Place the needle and syringe directly into a proper sharps disposal bin as soon as they have been used. Never, under any circumstances, replace the needle guard on the needle or attempt to break the needle and syringe. Medicines for injection are supplied either in rubber-capped vials or in glass ampoules. The use of multi-dose vials carries a risk of contamination; a new needle and syringe must always be used when drawing medicines from a multi-dose vial. Glass ampoules may have a coloured band around the neck, indicating the level at which the top of the ampoule will break off cleanly. The rubber cap of a vial is held on by a metal cap with a small tear-off seal; do not remove this seal until the drug is required. How to Prepare Medication for Injection Check that the name and strength of the medication are marked on the vial or ampoule. If you cannot see or decipher the name of the medication, discard the vial or ampoule. If the medication is in a multiple-dose vial, clean the rubber diaphragm on the vial with alcohol. If the medicine is in an ampoule, tap the ampoule gently with a finger to ensure that all the liquid is below the neck of the ampoule; then break off the top with a sharp snap. If you are not experienced in this procedure, hold the top of the ampoule with a cloth or swab to avoid being cut by the edge of the glass. Remove the guard from the needle without touching the needle. If the medication is in a vial, inject an amount of air into the vial that is equal to the amount of medication to be withdrawn. This will make it easier to withdraw the medication. Withdraw the correct amount of medication. How to Administer a Subcutaneous Injection A subcutaneous injection is given into the layer of fat just below a patient’s skin. To administer a subcutaneous injection, begin by assembling the following items: A disposable syringe A 19- or 21-gauge needle for drawing the medication into the syringe A disposable 23- or 25-gauge needle for injecting the medicine Alcohol swabs The medication the needle. If blood appears, repeat the procedure at a new site, using new sterile equipment. Place the needle, together with the syringe, directly into a proper sharps disposal bin. How to Give an Intradermal Injection This type of injection delivers medication into the dermis, the layer of skin just below the epidermis. It is usually performed on the inside of the forearm. To begin, assemble the following items: A disposable syringe A 19- or 21-gauge needle for drawing the medicine into the syringe A disposable 25- or 27-gauge needle, only 1 to 1.6 cm (3/8 to 5/8 in.), for injecting the medicine Alcohol swabs The medication Draw the correct amount of medication into the syringe with the 19- or 21-gauge needle (as described above). Change the needle to one that is the appropriate gauge for the injection. Point the needle upward and push the plunger to expel any air in the syringe. Select a site for the injection and disinfect the skin with an alcohol swab. Between your thumb and forefinger, grasp a fold of skin large enough to offer plenty of space between the site of injection and your fingers. Insert the needle firmly and quickly at a 30- to 45-degree angle to a depth of about 2 cm (3/4 in.). Once the needle is under the skin, draw back the syringe plunger (Figure 22–3). If no blood appears in the syringe, inject the medicine and withdraw Figure 22–3: Administering a subcutaneous injection. PHARMACOLOGY Draw the correct amount of medication into the syringe with the 19- or 21-gauge needle (as described above). Change the needle to the appropriate gauge for the injection. Point the needle upward and push the plunger to expel any air in the syringe. Select a site for the injection and disinfect the skin with an alcohol swab. 379 Grasp the forearm firmly in one hand, with the syringe in the other hand. With the bevel of the needle facing away from the skin, insert the needle into the skin, almost parallel with the arm (at an approximately 5- to 7-degree angle). Once the needle is inserted, inject the medicine and withdraw the needle. Place the needle, together with the syringe, directly into a proper sharps disposal bin. How to Give an Intramuscular Injection Assemble the following items: A disposable syringe A disposable 19- or 21-gauge needle Alcohol swabs The medicine Draw the correct amount of medication into the syringe (as described above). Expel any air from the syringe. Select a site for the injection: The preferred sites are the outer upper quadrant of either buttock or the outer thigh muscle; do not use other parts of the buttock. In babies, use only the outer thigh muscle. Swab the skin at the injection site with alcohol swabs. PHARMACOLOGY standards to follow when disinfecting surgical instruments. Stretch the skin with your thumb and forefinger and, after finding the landmark, insert the needle at a right angle to the skin to a depth of about 2 cm (3/4 in.) so as to penetrate the subcutaneous fat and enter the muscle (Figure 22–4). Disinfectants are solutions used to inactivate any infectious agents that may be present in blood or other bodily fluids. This will decrease the number of bacteria and viruses on an object, but will not sterilize it. Disinfectants may reduce the risk of infection for people who will be handling the objects during further cleaning and sterilization. There are various types of disinfectant solutions, which also have varying degrees of effectiveness. Sodium hypochlorite, or bleach, is one of the most common worldwide disinfectant solutions. Draw back the syringe plunger. If no blood appears, inject the medicine and withdraw the needle. If blood appears, repeat the procedure at another site, using new sterile equipment. Place the needle, together with the syringe, directly into a proper sharps disposal bin. Disinfectant solutions must always be available for: Disinfecting working surfaces. Disinfecting equipment that cannot be sterilized further (e.g., in an autoclave). Dealing with any spills involving bodily fluids or other known infectious material. DISINFECTION 380 Figure 22–4: Giving an intramuscular injection. Used instruments that have passed through the skin of a patient pose an increased risk of infection for the patient. For this reason, there are certain All instruments should be soaked in a disinfectant solution for 30 minutes before cleaning. Gloves should always be used when disinfecting equipment. Thick gloves should be worn when needles and sharp instruments are being cleaned. Soiled linen should be placed in leak-proof bags stay in contact with the infected material for a longer period of time. This is known as contact time, and it is the time that the infectious material requires to become completely inactivated by the disinfectant solution. Some situations, such as a large spill of infected bodily fluid, may require higher concentrations of disinfectant, as lower concentrations of solution will actually be inactivated by the large amount of organic matter. Not only should a higher concentration be used, but the solution should No matter which disinfectant solution is used, you must ensure that it is used before its expiry date. Always follow the manufacturers’ guidelines or other specific guidelines for that particular solution. PHARMACOLOGY for transport. To further clean soiled linen, wash it in cool water first, then disinfect with a diluted chlorine solution. After this, wash the linen with detergent at a temperature of at least 71°C (160°F) for 25 minutes. 381 SUMMARY ASSISTING WITH MEDICATION Responder follows the patient’s specific directions to help with medication. Does not require special training. ADMINISTERING MEDICATION Responder actually introduces the drug into the patient’s body after deciding to give medication. Requires special training or authorization from a physician who: 1. Is allowed to administer medication. 2. Will provide medical direction. SIX RIGHTS OF MEDICATION 1. Right Person Ensure the patient receiving the medication is the one whose name is on the label of the medicine container. 2. Right Medication Read the label and confirm the name of the medication. 3. Right Dosage Accurately measure the indicated quantity of medication. 4. Right Time Give the medication at the right time. 5. Right Route Read the directions carefully and administer with the correct method. 6. Right Documentation Completely document your actions and findings, including time, dosage, route, and effect. ELEMENTS OF PHARMACOKINETICS Drug Absorption The movement of drug molecules from the site of entry into general circulation Drug Distribution The transport of a drug through the bloodstream to various tissues of the body and to its site of action; rate of distribution is affected by capillary permeability and cardiac output of regional blood flow Biotransformation The process by which a drug is chemically converted to a metabolite; liver is primary site Excretion The elimination of toxic or inactive metabolites from the body; organs of excretion include the kidneys, intestines, lungs, sweat glands, salivary glands, and mammary glands PHARMACOLOGY General Guidelines for Injections 382 Immediately discard needles and syringes directly into a proper sharps disposal bin. Never replace the needle guard or attempt to break the needle or syringe. Always use a new needle and syringe when drawing medicines from a multi-dose vial. Do not remove the small tear-off seal on rubber-capped vials until the drug is required.