Pharmacology · chapter 22 · Cardiac Emergency and Shock Drugs
Introduction to Cardiac Emergencies and Shock
The 14 things this section of the textbook says that you are most likely to be asked about — quoted word for word, not retold. Then 6 practice questions with the reasoning.
Key points
Myocyte damage and infarction
If cardiac myocytes are damaged, then the pumping ability of the heart is decreased. If cardiac myocytes die, an acute myocardial infarction (commonly referred to as a heart attack) occurs.
Common causes of coronary occlusion
However, the coronary arteries may become occluded due to various causes, with atherosclerosis, atherosclerotic plaque rupture, and emboli being the most common.
Stable angina is relieved by rest
Stable angina occurs during exercise or exertion and improves with rest because the cardiac myocytes no longer require an increased oxygen supply.
Unstable angina is an emergency
Because oxygen supply is decreased, the angina will not be relieved with rest. Unstable angina is a medical emergency.
Electrolytes and dysrhythmias
The generation and conduction of electrical impulses rely heavily on various electrolytes: potassium, sodium, and calcium. Disturbances in the balance of these electrolytes can lead to serious dysrhythmias.
Signs of unstable angina and AMI
Clinical manifestations of both unstable angina and AMI include chest pain that may radiate down the left arm or up to the neck, jaw pain, back pain, shortness of breath, diaphoresis (excessive sweating), nausea and vomiting, anxiety, and a feeling of impending doom.
AMI without chest pain
Nurses must be aware that signs and symptoms of AMI vary quite a lot, and some individuals may not feel chest pain at all. Furthermore, female clients often experience symptoms that are more vague or subtle than the ones reported by male clients.
Why dysrhythmias cause fainting
Life-threatening dysrhythmias often cause syncope to occur rapidly because cardiac output and blood pressure are not maintained.
First steps for angina or AMI
Nonpharmacologic treatment for both unstable angina and AMI includes stopping the activity that caused the pain, having the individual rest, and transporting them by ambulance to the nearest emergency department as soon as possible.
What shock is
Shock is caused by decreased tissue perfusion that occurs when cells, tissues, and organs do not receive adequate oxygenated blood.
Vessel diameter drives resistance
Of these three components, blood vessel diameter is by far the most important. A small change in blood vessel diameter can cause a major difference in vascular resistance and overall blood pressure.
Airway danger in anaphylaxis
The inflammatory mediators also cause smooth muscle constriction. Because the bronchioles are surrounded by smooth muscle, the airways narrow, and breathing is severely restricted.
Causes of hypovolemic shock
Causes of hypovolemic shock include blood loss due to external or internal bleeding, fluid loss from third-degree burns, and excessive vomiting or diarrhea.
Signs that point to shock
Low blood pressure accompanied by clinical signs such as cool, clammy skin; an elevated heart rate; elevated respiratory rate; change in mental status; or reduced level of consciousness are indicative of shock.
Terms to know
- Angina
- Angina is the medical term for chest pain caused by cardiac ischemia.
- Systemic vascular resistance
- Systemic vascular resistance is the amount of resistance in the blood vessels; in other words, it is the pressure that the arterial wall exerts against the circulating blood volume.
- Distributive shock
- Distributive shock occurs when the normally circulating volume of fluid shifts from intravascular (within the blood vessels) to extravascular (outside of the blood vessels or in the area of the tissues).
- Cardiogenic shock
- Cardiogenic shock occurs when the heart has been damaged in some way and can no longer maintain adequate cardiac output.
- Preload
- Preload is the amount of blood that returns to the heart (venous return), afterload is the resistance that the heart must pump against, and contractility is the force of the cardiac contraction.
- pulmonary edema
- In the lungs, the extreme vasodilation causes plasma to leak from blood vessels directly into lung tissue. This is referred to as pulmonary edema.
Practice questions
Stuck on select-all-that-apply? How to take them one option at a time.
The graded version needs JavaScript. Every question is below anyway, with the answer and why.
Every question here, with the answer
A client reports chest pain that started while walking up stairs and has not eased after 20 minutes of rest. Which condition should the nurse suspect?
- Stable angina
- Anaphylaxis
- Unstable angina
- Hypovolemic shock
Answer: Unstable angina
Stable angina occurs with exertion and improves with rest; pain that is not relieved by rest points to unstable angina, a medical emergency. Shock and anaphylaxis are not described by chest pain alone.
A nurse is assessing a client with suspected acute myocardial infarction. Which findings are consistent with AMI? Select all that apply.
- Jaw pain
- Diaphoresis
- Nausea and vomiting
- Relief of pain with rest alone
- A feeling of impending doom
Answer: Jaw pain, Diaphoresis, Nausea and vomiting, A feeling of impending doom
Jaw pain, diaphoresis, nausea and vomiting, and a feeling of impending doom are all listed manifestations of unstable angina and AMI. Relief with rest describes stable angina.
A female client reports lightheadedness and pressure in her upper back but denies chest pain. What should the nurse keep in mind?
- Upper back pressure points to stable angina only.
- AMI is ruled out because there is no chest pain.
- Lightheadedness is never linked to cardiac problems.
- Female clients often have more vague or subtle AMI symptoms.
Answer: Female clients often have more vague or subtle AMI symptoms.
Signs of AMI vary, some people feel no chest pain, and female clients often have vaguer symptoms such as upper back pressure or lightheadedness. Absence of chest pain does not rule out AMI.
A client with severe vomiting and diarrhea for three days has low blood pressure, cool clammy skin, and a heart rate of 118. Which type of shock is most likely?
- Cardiogenic
- Obstructive
- Hypovolemic
- Anaphylactic
Answer: Hypovolemic
Excessive vomiting or diarrhea is a listed cause of hypovolemic shock, and hypotension, tachycardia, and cool clammy skin are signs of shock. The other types arise from heart damage, a blockage in the chest, or an allergic response.
A client on the telemetry unit has new frequent dysrhythmias. Which laboratory result should the nurse review first?
- Basic metabolic profile for potassium, sodium, and calcium
- Lipid profile
- Blood type and screen
- Blood culture
Answer: Basic metabolic profile for potassium, sodium, and calcium
Impulse conduction relies on potassium, sodium, and calcium, and imbalances can cause serious dysrhythmias, so a basic metabolic profile is checked. The other tests do not assess these electrolytes.
A client who was stung by a bee develops anaphylactic shock. Which findings should the nurse expect? Select all that apply.
- Stridor
- Bradycardia with warm, dry skin
- Rash
- Hypotension
- Wheezing
Answer: Stridor, Rash, Hypotension, Wheezing
Anaphylaxis causes systemic vasodilation and hypotension, signs of allergy such as rash, and bronchoconstriction with wheezing or stridor. Shock produces tachycardia and cool, clammy skin, not bradycardia with warm, dry skin.
Where every quote comes from
Section 22.1 Introduction to Cardiac Emergencies and Shock of Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver, OpenStax, 2024. Read the whole section free at openstax.org.
The textbook is licensed under CC BY-NC-SA 4.0. This page quotes it word for word and adds the headings, the order and the practice questions; references to the book's figures and stray spaces left by its formatting are removed. The page is shared under the same licence. Nothing here is sold.