Chapter 24 learning objectives and vocabulary

The physician prescribes norepinephrine, a potent vasopressor, to be administered to a client in shock. The rate of the administration of the IV fluid containing the norepinephrine is: 1. maintained at a set rate of infusion 2. adjusted per protocol to maintain the patient's blood pressure 3. given at a rate not to exceed 5 mg/min 4. discontinued when the blood pressure is 100 mm Hg systolic

2. adjusted per protocol to maintain the patient's blood pressure

vasopressors

drugs that raise the blood pressure

Discuss the activity of the autonomic nervous system, specifically the sympathetic branch

-Autonomic nervous system is a system of nerves that automatically regulates bodily functions. - ANS is divided into sympathetic and the parasympathetic - Sympathetic is branch is regulated by involuntary control *often called the fight or flight response * Nerves are activated whine the body is confronted with stressful situations. * controls heart rate, breathing rate and ability to divert blood to the skeletal muscles. *Norepinephrine is a neurotransmitter produced naturally by the body. = primary neurotransmitter in the sympathetic branch of the ANS and the substance that keeps the nerve message or impulse going from the brain to the target organ. *This system is activated by the precursor of epinephrine (adrenalin) another term for the sympathetic pathway is the adrenergic branch. Thats why meds used that work like the adrenergic branch are called adrenergic drugs. ***In the sympathetic branch of the autonomic nervous system, adrenergic drugs produce activity similar to the neurotransmitter norepinephrine. Another name for these drugs is sympathomimetic (i.e., mimicking the actions of the sympathetic nervous system) drugs. The adrenergic drugs produce pharmacologic effects similar to the effects that occur in the body when the sympathetic nerves (norepinephrine) and the medulla (epinephrine) are stimulated. The primary effects of these drugs occur on the heart, the blood vessels, and the smooth muscles, such as the bronchi of the lung.

If a client uses an auto-inject epinephrine device, the best disposal would be: 1. container the injector is packaged in 2. held until seen by emergency personnel 3. hard plastic container 4. sharps box or needle container

2. held until seen by emergency personnel

What is the transmitting substance in the sympathetic branch of the nervous system? 1. serotonin 2. norepinephrine 3. dopamine 4. acetylcholine

2. norepinephrine

Shock is described as: 1. result of blood loss 2. compensation for bodily assault 3. inadequate tissue perfusion 4. the fight-or-flight response

3. inadequate tissue perfusion

Herbal considerations

Ephedra (Ma Huang) and the many substances of the Ephedra genus have been used medicinally (e.g., E. sinica and E. intermedia). Ephedra (ephedrine) preparations have traditionally been used to relieve cold symptoms and improve respiratory function, and as an adjunct in weight loss. Large doses may cause a variety of adverse reactions, such as hypertension and irregular heart rate. The use of ephedra has shifted from relief of respiratory problems to an aid to weight loss and enhanced athletic performance. Before taking this herb, the patient should consult a primary health care provider. Ephedra should not be used with the cardiac glycosides, halothane, guanethidine, monoamine oxidase inhibitor (MAOI) antidepressants, or oxytocin or by patients taking St. John's wort. The U.S. Food and Drug Administration (FDA) warns the public not to take ephedrine-containing dietary supplements. Stroke and heart attack have resulted from taking these products. Many producers of weight loss supplements are removing the ephedra component because of potential legal liability.

Discuss ways to promote an optimal response to therapy, how to manage common adverse reactions, and important points to keep in mind when educating patients about the use of adrenergic drugs.

Management of the patient receiving an adrenergic agent varies and depends on the drug used, the reason for administration, and the patient's response to the drug. In most instances, adrenergic drugs are potent and potentially dangerous. Minimize distractions and exercise great care in the calculation and preparation of these drugs for administration. Although adrenergic drugs are potentially dangerous, proper supervision and management before, during, and after administration will minimize the occurrence of any serious problems. Report and document any complaint the patient may have while taking an adrenergic drug. However, nursing judgment is necessary when reporting adverse reactions. Report adverse effects, such as the development of cardiac arrhythmias, immediately, regardless of the time of day or night. Yet, other adverse effects, such as a nervous feeling, need not be dealt with on an emergent basis. Once a patient has experienced an allergic reaction, he or she is at risk for having another reaction. Triggers can include foods, stinging insects, latex, chemical or environmental items, and even exercise. Patients who have experienced an allergic reaction may be instructed in the use of epinephrine via the EpiPen (Fig. 24.3) so they may carry on normal daily activities. Sometimes patients are fearful and wonder if the situation calls for use of the drug, or if they should seek out care instead. During an allergic reaction, the drug should be administered first, then medical care obtained. It is important that patients be taught how to recognize symptoms and use the device. Teach the patient to recognize the symptoms of an allergic reaction, which include hives, itching, flushing, and swelling of the lips, tongue, or inside of the mouth. Patients may feel tightness of the throat or chest if the airway is affected. Other symptoms can include chest pain, dizziness, and headache as the blood pressure gets lower. Specific instructions for using auto-injecting epinephrine are provided in Patient Teaching for Improved Patient Outcomes: Using an Auto-Injector for Allergic Reactions.

general drug actions associated with the administration of adrenergic vasopressor drugs.

The purpose of stimulating the sympathetic (adrenergic) nerves is to divert blood flow to the vital organs so that the body can deal with a stressful situation (the fight-or-flight response). In general, adrenergic drugs produce one or more of the following responses in varying degrees: • Central nervous system—wakefulness, quick reaction to stimuli, quickened reflexes • Autonomic nervous system—relaxation of the smooth muscles of the bronchi, constriction of blood vessels, sphincters of the stomach, dilation of coronary blood vessels, decrease in gastric motility • Heart—increase in the heart rate • Metabolism—increased use of glucose (sugar) and liberation of fatty acids from adipose tissue Neurotransmitter (e.g., norepinephrine), is released by the presynaptic nerve, crosses the synapse, and binds with α and β receptors in the cell membrane of the postsynaptic nerve, continuing the transmission of the nerve impulse. Whether an adrenergic drug acts on α, β, or α and β receptors accounts for the variation of responses to this group of drugs. Table 24.1 lists the type of adrenergic nerve receptor that corresponds with each action of the autonomic nervous system on the body. The α and β receptors can be further grouped as α1- and α2-adrenergic receptors and β1- and β2-adrenergic receptors.

norepinephrine

neurotransmitter that transmits impulses across the sympathetic branch of the autonomic nervous system

interactions associated with the administration of adrenergic vasopressor drugs.

-Antidepressants = increased sympathomimetic effect -Oxytocin = Increased risk of hypertension *There is an increased risk of seizures, hypotension, and bradycardia when dopamine is administered with phenytoin (Dilantin). Metaraminol is used cautiously in patients taking digoxin because of an increased risk for cardiac arrhythmias. There is an increased risk of hypertension when dobutamine is administered with the β-adrenergic blocking drugs.

An adult with an allergy to honeybees is stung and calls the nurse at the clinic. The client has two EpiPens at home. The solution is 1 mg/mL and each EpiPen contains 0.3 mL. What drug dose has the client taken if two injections were already given? _____

0.6 mg

Beta

1. Heart - increased heart rate, increased heart contractions 2. Peripheral BV - bronchial smooth muscle - dilate BV- bronchioles

Alpha

1. Peripheral BV - Constrict 2. Regulatory- regulate neurotransmitters

At what intervals would the nurse monitor the blood pressure of a client administered norepinephrine? 1. continuously 2. every 30 minutes 3. every hour 4. every 4 hours

1. continuously

Select the terms that describe drugs that stimulate the sympathetic branch of the ANS. Select all that apply. 1. sympathomimetic 2. sympatholytic 3. adrenergic 4. cholinergic

1. sympathomimetic 3. adrenergic

When norepinephrine is transmitted in the sympathetic nervous, which of the following occurs? 1. heart rate slows 2. blood pressure lowers 3. GI system speeds up 4. bronchi relax

4. bronchi relax

Which of the following are the common adverse reactions the nurse would expect with the administration of the adrenergic drugs? 1. bradycardia, lethargy, bronchial constriction 2. increase in appetite, nervousness, drowsiness 3. anorexia, vomiting, hypotension 4. headache, nervousness, nausea

4. headache, nervousness, nausea

When dobutamine is administered with the β-adrenergic blocking drugs, the nurse is aware of an increased risk for_____. 1. seizures 2. arrhythmias 3. hypotension 4. hypertension

4. hypertension

contraindications associated with the administration of adrenergic vasopressor drugs.

Adrenergic drugs are contraindicated in patients with known hypersensitivity. Isoproterenol is contraindicated in patients with tachyarrhythmias, tachycardia, or heart block caused by digitalis toxicity, ventricular arrhythmias, and angina pectoris. Dopamine is contraindicated in those with pheochromocytoma (adrenal gland tumor), unmanaged arrhythmias, and ventricular fibrillation. Epinephrine is contraindicated in patients with narrow-angle glaucoma and as a local anesthetic adjunct in fingers and toes. Norepinephrine is contraindicated in patients who are hypotensive from blood volume deficits. Midodrine causes severe hypertension in the patient who is lying down (supine).

adverse reactions associated with the administration of adrenergic vasopressor drugs.

Adverse reactions associated with the administration of adrenergic drugs depend on the drug used, the dose administered, and individualized patient response. Some common adverse reactions include: • Cardiac arrhythmias (bradycardia and tachycardia) • Headache • Nausea and vomiting • Increased blood pressure (which may reach dangerously high levels)

Epinephrine works on both

Alpha and Beta

List nursing diagnoses particular to a patient taking an adrenergic drug.

Drug-specific nursing diagnoses are the following: Risk for Allergy Response related to response to substance trigger (insect sting, drug allergy, specific food) Ineffective Tissue Perfusion related to hypovolemia, blood loss, impaired distribution of fluid, impaired circulation, impaired transport of oxygen across alveolar and capillary bed, other (specify) Decreased Cardiac Output related to altered heart rate and/or rhythm Disturbed Sleep Pattern related to adverse reactions (nervousness) to the drug and the environment

Discuss important ongoing assessment activities the nurse should perform on the patient taking an adrenergic drug.

During the ongoing assessment, observe the patient for the effect of the drug, such as improved breathing of the patient with asthma, or response of blood pressure to the administration of the vasopressor. During therapy, evaluate and document the drug effect and vital signs. Comparison of assessments made before and after administration may help the primary health care provider determine future use of the drug for this patient. It is important to report adverse drug reactions to the primary health care provider as soon as possible. When a patient has self-administered a drug for a life-threatening allergic reaction, try to get as much information as possible from the patient about the incident leading up to using the drug. If the patient was with family or friends, gain subjective data from these people regarding the events leading up to the need for drug injection.

Drug Classes

Sympathomimetics Short-acting beta (β)-2 agonists Long-acting β2 agonists Optic agents (alpha 2 agonists/sympathomimetics)

Nursing Alert

Supine hypertension is a potentially dangerous adverse reaction in the patient taking midodrine. The drug should be given only to patients whose lives are impaired despite standard treatment offered. This reaction is minimized by administering midodrine during the day while the patient is in an upright position. The suggested dosing schedule for the administration of midodrine is shortly before arising in the morning, midday, and late afternoon (not after 6:00 p.m.). Drug therapy should continue only in the patient whose orthostatic hypotension improves during the initial treatment.

precautions associated with the administration of adrenergic vasopressor drugs.

These drugs are used cautiously in patients with coronary insufficiency, cardiac arrhythmias, angina pectoris, diabetes, hyperthyroidism, occlusive vascular disease, or prostatic hypertrophy. Patients with diabetes may require an increased dosage of insulin. Adrenergic drugs are classified as pregnancy category C and are used with extreme caution during pregnancy.

Discuss important pre administration activities the nurse should perform on the patient taking an adrenergic drug.

When a patient is to receive an adrenergic agent for shock, obtain the blood pressure, pulse rate and quality, and respiratory rate and rhythm. Assess the patient's symptoms, problems, or needs before administering the drug, and document any subjective or objective data on the patient's record. In emergencies, assessments are made quickly and accurately. This information provides an important database that is used during treatment. A general survey of the patient also is necessary. It is important to look for additional symptoms of shock, such as cool skin, cyanosis, diaphoresis, and a change in the level of consciousness. Other assessments may be necessary if the hypotensive episode is due to trauma, severe infection, or blood loss.

peripheral nervous system

all nerves outside of brain and spinal cord shock • inadequate blood flow to the bodily tissues

sympathomimetic

drugs that mimic the actions of the sympathetic nervous system; see adrenergic

neurotransmitter

chemical substances released at the nerve ending that facilitate the transmission of nerve impulses

autonomic nervous system

division of the peripheral nervous system concerned with functions essential to the life of the organism and not consciously controlled (e.g., blood pressure, heart rate, gastrointestinal activity)

extravasation

escape of fluid from a blood vessel into surrounding tissue

parasympathetic

pertaining to the part of the autonomic nervous system concerned with conserving body energy (i.e., slowing the heart rate, digesting food, and eliminating waste)

adrenergic

pertaining to the sympathetic branch of the nervous system, which controls heart rate, breathing rate, and ability to divert blood to the skeletal muscles

sympathetic

pertaining to the sympathetic nervous system

Adrenergic nerves have either alpha (α) or beta (β) receptors. Drugs that act on the receptors are called selective or nonselective. Adrenergic drugs may be

selective (act on α receptors or β receptors only) or nonselective (act on both α and β receptors). For example, isoproterenol acts chiefly on β receptors; it is considered a selective drug. Epinephrine is a nonselective drug and acts on both α and β receptors.

stroke volume

the volume of blood ejected (leaving) from a ventricle at each heart beat

Discuss the uses associated with the administration of adrenergic vasopressor drugs.

• Hypovolemic and septic shock • Moderate to severe episodes of hypotension • Control of superficial bleeding during surgical and dental procedures of the mouth, nose, throat, and skin • Cardiac decompensation and arrest • Allergic reactions (anaphylactic shock, angioneurotic edema) • Temporary treatment of heart block • Ventricular arrhythmias (under certain conditions) • Respiratory distress (as bronchodilators) • Nasal congestion and glaucoma (topical formulation) Adrenergic drugs may also be used as a vasoconstricting adjunct to local anesthetics to prolong anesthetic action in the tissues. The adrenergic drugs used primarily as vasopressors (drugs that raise the blood pressure because of their ability to constrict blood vessels) Sympathomimetics are also used as bronchodilators in the treatment of respiratory problems or topically in the treatment of glaucoma

Key Points

• The sympathetic branch of the autonomic nervous system regulates involuntary body functions. The neurotransmitter of the sympathetic branch is norepinephrine; activation of this system is often called the fight-or-flight response. • The purpose is to divert blood flow to the vital organs so the body can deal with the stressful situation. A person becomes wakeful with quicker reflexes and pupils dilate. The smooth muscles of the bronchi relax as do the coronary vessels and the heart rate increases. Blood flow is constricted to areas such as the GI and genitourinary systems. • Drugs that mimic the response are called sympathomimetic or adrenergic (because the primary transmitter is adrenalin or epinephrine). Actions in the body are modified depending on how the drug acts on different cell receptors. Drugs can be selective for α or β receptors. Drugs can also be nonselective. • These drugs are used to treat shock, hypotension, allergic reactions, heart conditions, and bronchodilation. Topical formulas are used for glaucoma and nasal congestion. Older individuals are very susceptible to adverse reactions, especially to epinephrine. • Adverse reactions include increased blood pressure, nausea, vomiting, headache, and cardiac arrhythmias.