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Obstructive Shock, P

Obstructive Shock, P

CHAPTER 10

OBJECTIVES KEY TERMS

Upon completion of this chapter, the OEC Anaphylactic shock, p. 228 technician will be able to: Anticoagulants, p. 231 10-1 Define shock. , p. 228 10-2 Describe the three primary causes of , p. 228 shock. Fainting, p. 230 10-3 Describe how the body compensates , p. 227 for shock. , p. 229 10-4 Define the two stages of shock. , p. 229 10-5 List the four major types of shock. , p. 224 10-6 List the classic of Peripheral , p. 226 shock. , p. 230 10-7 Describe and demonstrate the , p. 228 management of shock. , p. 228 Shock, p. 224 volume, p. 226 , p. 226 , p. 226

HISTORICAL TIMELINE 1964. The NSP adopts the gold cross as its official emblem.

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CHAPTER OVERVIEW One of the most serious threats to life is the condition known as shock. Shock is defined as inadequate perfusion or flow of to the cells, causing cellular and due to reduced delivery. Perfusion is the circu- lation of blood within an or tissue in ade- quate amounts to meet the cells’ current needs for oxygen, nutrients, and waste removal. The body is perfused via the cardiovascular (circulatory) system. Although the potential causes of shock are numerous, shock occurs when one or more com- ponents of the cardiovascular system fail. This Figure 10-1 A patroller assisting with respirations. sets into motion a series of events that, unless © Edward McNamara. corrected, may cause other body systems to fail and to ensue. Shock is initially reversible but must be recognized and treated immedi- ANATOMY AND PHYSIOLOGY ately to prevent progression to irreversible organ The cardiovascular (circulatory) system, described dysfunction. in detail in Chapter 6, Anatomy and Physiology, in- Shock is one of the most serious problems cludes the , blood vessels, and blood. When that OEC technicians will encounter. It is caused functioning properly, the heart pumps oxygenated by various medical and traumatic conditions. Un- blood through arterial vessels to the , fortunately, the signs and symptoms of shock may where oxygen and carbon dioxide are exchanged not be apparent initially because the body com- at a cellular level. Deoxygenated blood travels pensates, maintaining normal vital signs. The pa- through venous blood vessels to the heart, which tient’s overall health, age, and taken pumps the blood on to the . There, carbon may make shock more difficult to recognize at dioxide is excreted into the atmosphere and the first. OEC technicians must be keenly aware of blood is oxygenated and returned to the heart, the causes of shock and the body’s responses to which begins the cycle again. it. Using this information, OEC technicians will be Problems affecting any part of the circulatory better able to recognize shock and initiate appro- system can disrupt this process, resulting in de- priate treatment (Figure 10-1). creased blood flow, cellular hypoxia, and shock.

CASE Presentation

On a gentle slope, you find an approximately 55-year-old man holding his left side. You identify yourself and ask if you can examine him. While talking to him, you find he fell about 10 minutes ago on his left side. As you begin your assessment, the man says he’s fine and really doesn’t think any examination is necessary. Although he appears a little pale, his radial seems normal, perhaps a little slow. As you gently touch his left upper and lower , he winces slightly. What should you do?

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Review of the anatomy and physiology of the cir- culatory system will help you understand shock. Table 10-1 The Progression of Shock If the pump (heart), blood vessels ( and Progression Signs and Symptoms ), or blood is affected, tissue will not receive oxygen and nutrients, resulting in shock. Compensated • Agitation shock • Anxiety • Restlessness CAUSES OF SHOCK • Feeling of impending doom There are different types of shock, resulting from • Altered mental status three basic causes. Any of these three conditions • Weak, rapid (thready), or results in decreased perfusion, with insufficient absent pulse oxygen or nutrients reaching vital organ tissue. • Clammy (pale, cool, moist) When two or more of these conditions occur to- gether, shock develops rapidly. • , with cyanosis about 1. Pump failure. If the heart cannot pump the lips correctly (i.e., the heart fails), then cardiac • Shallow, rapid output decreases and blood is not pumped to • Air hunger (shortness of the body adequately to sustain life. breath), especially if there 2. Failure of blood vessels to respond properly. is a chest In this condition, the veins and arteries • or expand too much, pooling blood in them. • refill of longer The smooth muscle in the arteries and veins than 2 seconds in infants does not constrict these tubes during some and children pathological conditions. • Marked 3. Low fluid volume. In this condition, there is not • Narrowing enough blood to pump through the system. Decompensated • Falling Blood can be lost through internal or external shock (systolic blood pressure of , or a medical condition can decrease 90 mm Hg or lower in an the amount of healthy blood. Also, body adult) fluids can be lost due to , from • Labored or irregular causes such as or vomiting, burns, or breathing excessive intake of diuretics (fluid pills). • Ashen, mottled, or cyanotic skin • Thready or absent periph- STAGES OF SHOCK eral Shock is a progressive disorder that can be divided • Dull eyes, dilated pupils into two stages: compensated shock and decom- • Poor urinary output pensated shock (Table 10-1).

Compensated Shock KEY POINT The human body can compensate to maintain even during times of or harm. The body’s systems have built-in redundancy and Blood Pressure and Shock flexibility that correct adverse conditions with- During the early stages of shock, the out incurring a total shutdown of body systems patient’s blood pressure is maintained. or long-term organ damage. In times of increased metabolic demand, the body activates various compensatory mechanisms that help restore ho- If the body detects a decrease in the amount meostasis, but those mechanisms can function of blood being circulated or a sudden decrease in only for a while unless the problem is corrected. the amount of oxygen reaching the cells, the

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sends signals that stimulate the release of epi- to vital tissues under adverse conditions. If left un- nephrine, a hormone that causes tachycardia (the corrected, shock would inevitably lead to death heart to beat faster) and the ventricles to contract (Figure 10-2). It is important to keep in mind that more forcefully. Both changes increase the stroke the body’s ability to compensate for shock early can volume (amount of blood pumped out of the left mask a gravely serious uncorrected condition, giv- ventricle into the aorta during one heartbeat), ing you the false impression that the patient is less which enables more blood, oxygen, and nutrients sick or less injured than is in fact the case. to reach the body’s tissues and organs. The first signs of shock are tachycardia, In addition, the controls tachypnea ( greater than 20 breaths smooth muscles in the blood vessels, contracting per minute), delayed capillary refill (greater than the vessels (decreasing their diameter) or dilat- 2 seconds), cool skin, anxiety or restlessness, ing them (increasing their diameter). Peripheral and a normal blood pressure. Treated early, this vascular resistance refers to the tightening of the form of shock is correctable and generally has no smaller-diameter blood vessels in the extremities. long-term adverse effects. Untreated, however, By increasing resistance of blood flow to the ex- shock will progress until the body is no longer able tremities, blood flow to the vital organs increases, a to compensate. Treatment involves correcting the key compensation in the early phases of shock. condition causing shock. At the same time, the brain sends signals to increase the rate and depth of respirations to bring more oxygen into the body and expel more Decompensated Shock carbon dioxide. This combination of tachycardia, If the body’s compensatory mechanisms are un- increased stroke volume by the heart, increased able to restore blood perfusion to the tissues, cel- peripheral vascular resistance, and increased ox- lular hypoxia will worsen, and the body’s organs ygen, by faster breathing, helps to stabilize the in- and systems will fail. will continue to ternal environment, at least temporarily. rise, systolic blood pressure will now begin to fall Compensated shock, therefore, is the body’s (to below 90 mm Hg), and respirations may be- ability to maintain blood perfusion and oxygenation come shallow. The skin will become grossly pale

Trauma of any kind

External blood loss and Tissues and organs Unresponsiveness and pooling of blood in large receive inadequate death may result internal vessels depress supply of blood circulation

Blood loss causes rapid heart rate and Leaking capillaries lead weak pulse to loss of vital causing circulatory depression Blood vessels constrict and thirst in extremities to conserve blood causing cold, clammy skin

Low levels of oxygen to fails Nervous system breathing control centers and blood pressure reaction results in of brain make drops profuse sweating respirations rapid and shallow

Figure 10-2 The progression of shock. © Jones & Bartlett Learning.

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or cyanotic and will be cool and moist to the touch. Due to severe constriction of the blood vessels in Upper the extremities, capillary refill will be significantly extremity delayed and may become undetectable. The pa- tient’s level of responsiveness will decrease (less

than A on the AVPU scale) due to decreased ox- Chest ygen in the brain. Treated early, decompensated shock may be corrected, but serious complications Abdomen can result. Once the body’s compensating mechanisms fail, vital signs deteriorate very rapidly as cells be- Pelvis gin to die. This sets into motion a cascading effect that cannot be reversed. As more cells die, the tis- Thigh sues of various organs die, resulting in organ system failure and eventually death. Despite even aggres- sive treatment, this form of shock is not reversible Leg and is fatal. It is difficult for a first responder to determine when shock can no longer be reversed. Ankle/foot

TYPES OF SHOCK Figure 10-3 Potential blood loss from in As previously noted, shock occurs when one or various parts of the body. Each bottle equals 1 pint more of the ’s components (473 mL). are adversely affected by or injury. These © Jones & Bartlett Learning. problems can be either volume related (e.g., not enough blood), pump related (e.g., heart not Of the two, hemorrhagic shock is more common pumping correctly), or container related (e.g., di- and has more far-reaching effects. lated blood vessels). With these possible causes Blood loss that results in hemorrhagic shock firmly in mind, OEC technicians must be famil- can be caused by a variety of problems, including iar with four major types of shock: hypovolemic trauma, gastrointestinal bleeding, vascular dis- shock, cardiogenic shock, distributive shock, and ruption, , and bleeding that is a obstructive shock. Hypovolemic shock is caused complication of pregnancy. Bleeding disorders and by loss of circulating or body flu- certain medications (discussed later) may increase ids. Cardiogenic shock is caused by the heart not the severity of bleeding by preventing blood from pumping correctly. Distributive shock is a result of clotting normally. poor vessel function, resulting in the circulating Blood loss can be external and obvious, or it blood pooling in the blood vessels. Obstructive can be internal and hidden. The American College shock is caused by a blockage in the cardiovascular of Surgeons divides blood loss due to hemorrhage system preventing blood flow. into four classes, ranging from class I, mild blood loss (less than 15% of total blood volume, or the equivalent of donating 1.5 units of blood) to class Hypovolemic Shock IV, extremely life threatening (blood loss of 40% of Hypovolemic shock results from a critical de- total blood volume or greater). Due to the body’s crease in circulating fluid volume from bleeding compensating mechanisms, a decrease in blood or a loss of internal body fluid (Figure 10-3). This pressure may not be noted until more than 20% to is the most common type of shock an emergency 30% of total blood volume is lost. medical responder will see from a patient who has The body can typically compensate for blood excessive bleeding. There are hemorrhagic and loss. Only with significant hemorrhage do alter- nonhemorrhagic causes of hypovolemic shock. ations in blood pressure occur. An early indicator of Injuries involving bleeding result in hemorrhagic hemorrhage is a relative tachycardia, but it can be shock, while severe dehydration from vomiting difficult to attribute increased heart rate to shock in and diarrhea may result in nonhemorrhagic shock. the context of someone who may be experiencing

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anxiety due to pain from an injury, for example. In or stings; consumption of shellfish, nuts, or other some people, a loss of up to 30% of blood volume ; and use of certain medications (Table 10-2). may be required before a decrease in blood pres- Normally, when an offending source is introduced sure is observed. Another way of looking at this is into the body, the responds by re- that if a person manifests signs of unmistakable leasing chemicals that aid the to shock immediately after an injury, it is very likely neutralize the foreign substance. In a susceptible that the person has suffered severe blood loss. person, these chemicals cause generalized dilation due to excessive or fluid loss of the blood vessels and a host of other patholog- (nonhemorrhagic hypovolemia, meaning no blood ical problems. Without intervention, anaphylactic loss) can occur with severe burns, dehydration, ex- shock can quickly lead to and cessive vomiting, diarrhea, sweating, and the use of death. A complete description of , in- diuretic medications (“water pills”) such as furose- cluding causes, assessment, and treatment, is pro- mide (Lasix). As water is lost from the body, com- vided in Chapter 14, Allergies and Anaphylaxis. pensatory mechanisms draw water away from the plasma and direct it to the spaces between the cells. Septic Shock This shift in fluid removes water from the blood- Septic shock is caused by a severe systemic in- stream, thereby decreasing the circulating blood fection known as sepsis and is the most com- volume and lowering blood pressure. This type of mon cause of distributive shock. Normally the shock occurs over a much longer period of time. immune system’s white blood cells are released from the capillaries and attack and destroy patho- Cardiogenic Shock gens such as invasive . If the pathogens or their overwhelm the body and get into the Cardiogenic shock is a condition in which the heart cannot adequately pump blood, resulting in poor . Although the heart is a robust organ, it may fail for a variety of reasons, inclu- ding valve problems, which prevent the heart from filling or emptying properly; heart attack, which results from heart muscle damage; slow or fast heart rates, which decrease cardiac output; legal and illegal medications; and trauma to the heart.

Distributive Shock Distributive shock occurs when blood vessels lose their ability to constrict appropriately. The result- ing decrease in arterial vascular resistance causes Figure 10-4 This patient is suffering from an blood to pool within the capillary beds, producing a anaphylactic reaction. sudden drop in blood pressure and cellular hypoxia. Courtesy of Carol B. Guerrero. Thus, distributive shock is a container-related problem. Under normal conditions, arterial resis- tance (the diameter of the blood vessels) is reg- Table 10-2 Causes of Allergic Reactions ulated by certain body chemicals, the nervous system, and local nerve receptors that help to en- • Foods (peanuts, sesame seeds, tree nuts, soy, sure blood is delivered to where it is needed. Based milk, eggs, chocolate, shellfish) on the underlying cause, distributive shock (when • Environmental irritants (smoke, airborne the blood vessels dilate, pooling blood in the ves- particles) sels) is subdivided into three subtypes: anaphylac- • Pollen (weeds, grasses, trees) tic shock, septic shock, and neurogenic shock. • Molds (mildew, spores) • Animal dander (skin flakes, fur) Anaphylactic Shock • Medications (, pain medications) • Chemicals (latex) Anaphylactic shock is caused by a severe aller- • Other causes (blood transfusions, organ gic reaction to a substance (Figure 10-4). Com- transplants, radiographic dyes) mon causes of anaphylaxis include insect bites

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bloodstream, sepsis occurs, resulting in a poten- tially life-threatening illness that involves severe , shaking “chills,” and shock. Although most resolve quickly, a variety of factors can increase the likelihood of sepsis, including how resistant the body is to the pathogens, how virulent the pathogens are, how well the immune system is functioning, and the overall health of the individual. Underlying med- ical conditions may also affect one’s ability to fight . Additionally, medications can ad- versely affect the immune system. Unless sepsis is corrected, the pathogens will multiply beyond Figure 10-5 A tension is control, causing profound , cellular accumulation of air in the space between the hypoxia, and death. inside of the chest cavity and the that causes the lung to collapse. Neurogenic Shock © Tomatheart/Shutterstock. Neurogenic shock, sometimes called , is caused by a marked drop in blood pressure re- sulting from disruptions of the central nervous contracting during inhalation and expiration. If the system, most often from a injury. When integrity of the chest wall or lung is compromised the spinal cord is damaged, normal neurologic in- (most often by trauma), air can seep into the pleural put to the blood vessels is disrupted, causing the space causing a tension pneumothorax (air in the vessels to dilate. pleural space compressing the lung) (Figure 10-5). Fortunately, this process is not generally seen Unless the air is given a way to escape, pressure immediately after a , usually within the chest cavity will rise, causing the lung to occurring hours or possibly days later. OEC tech- collapse and obstruction of venous blood return- nicians should never attribute low blood pressure ing to the heart, thus impeding the heart’s ability () seen with a recent traumatic spinal to pump effectively. This obstruction can signifi- cord injury to neurogenic shock only. The most likely cantly reduce the amount of blood that enters and cause of shock in any trauma patient presenting with exits the heart, causing a corresponding drop in signs and symptoms of shock is hemorrhagic shock blood pressure and shock. Thus, tension pneumo- due to blood loss. thorax is a pump-related disorder caused by ob- struction of blood flow. A complete description of tension pneumothorax, its causes, and treatment Obstructive Shock are covered in Chapter 23, Chest Trauma. Obstructive shock results when a blockage pre- vents oxygenated blood from reaching vital or- Pericardial Tamponade gans. The cause can be either external pressure Obstructive shock can occur if fluid accumulates being placed on the heart or a blockage within the within the , the sac surrounding the body’s vascular system. Thus, the problem can be heart. This fluid accumulation is called pericardial pump-related (heart) or container-related (blood tamponade (Figure 10-6). As a result, the right side vessels). The most common causes of obstructive of the heart, which pumps blood to the lungs, cannot shock are tension pneumothorax, pericardial tam- expand (collapses) from the pressure of the fluid, de- ponade, and pulmonary embolism. creasing cardiac output and causing shock. The right side of the heart is more vulnerable to such collapse Tension Pneumothorax than the left side because the walls of the right side Between the membrane on the outside of each lung are thinner and less muscular than those on the left and the membrane on the inside of the chest cavity side. Pericardial tamponade is thus a pump-related is a potential space, called the pleural space. This problem. Fluid that accumulates in the pericardial space is filled with a very small amount of pleu- space may be free blood caused by penetrating ral fluid, the lubricating properties of which al- chest trauma, fluid that slowly accumulates from a low the lungs to move freely while expanding and medical condition, or pus resulting from a massive

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Normal heart Cardiac (pericardial) tamponade

Figure 10-6 Pericardial tamponade. © Jones & Bartlett Learning.

cardiac infection. Pericardial tamponade is covered in more detail in Chapter 23, Chest Trauma.

Pulmonary Embolism A pulmonary embolism, or thromboembolism, is a condition where a blood clot becomes stuck in and blocks a pulmonary (Figure 10-7). The connects the heart to the lung,

KEY POINT

Fainting Fainting, or , is a loss of consciousness that results from a lack of blood flow to the brain. This condition may occur suddenly, resulting from the temporary dilation of the body’s veins and pooling of blood in those vessels. Hypotension or low blood pressure of brief Embolus duration occurs. Because less blood is Infarcted area getting to the brain, a syncopal episode Figure 10-7 A Pulmonary embolism. occurs. Syncope is usually caused by fear, bad news, or an upsetting stimulus such © Jones & Bartlett Learning. as the sight of blood. It is resolved by placing the patient, or helping the patient where oxygen enters the blood. When a blood clot, to lie, in a supine position with the feet called a , breaks loose at a distant loca- raised 12 inches. tion, usually a in the legs or pelvis, it can travel Syncope is not a type of shock. as an embolism through the right side of the heart Although usually a benign condition, it can and lodge in the pulmonary artery. The resulting be the result of an or other blockage disrupts the flow of blood through the serious medical condition. The patient lungs and back to the heart and prevents gas ex- should be advised to seek medical care. change in the lungs. Pulmonary embolism is rap- idly fatal if it occurs in a large pulmonary artery

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CASE Update

You suspect the man may be injured and secure the area by placing both your skis and his in an “X” several yards above your location. When you return, you obtain a more complete history. He tells you that his doctor recently put him on a blood thinner to prevent clots. He also tells you that he is taking a beta-blocker for high blood pressure. As you are talking with him, the man appears slightly confused and says, “I don’t feel very well.” You radio for help, oxygen, and ALS transport. What do you think the problem is? What should you do next?

and is not treated immediately. A more detailed the classic signs of shock by preventing the body’s description of pulmonary embolism is presented compensatory mechanisms from working properly. in Chapter 13, Respiratory Emergencies. One group of prescribed medications that can affect the presentation of shock is the beta-blockers, which are used to treat heart disease FACTORS AFFECTING SHOCK and high blood pressure. Because beta-blockers Young and healthy individuals have the greatest limit the heart’s ability to beat faster, users of capacity to compensate for shock, especially in these medications may not be able to generate a its early stages, whereas very young and older or faster heart rate when the body is in shock. If the chronically ill individuals have less effective com- heart rate cannot increase, then the body’s abil- pensatory mechanisms and may abruptly decom- ity to compensate for shock by increasing cardiac pensate after an initial period of apparent stability. output is limited. Among the most widely used Other factors can influence how the body com- beta-blockers are (Tenormin), metoprolol pensates for shock. (Lopressor), and (Inderal). Children maintain vital signs even though Another group of medications of which you they are in shock for a while. They have better should be aware are anticoagulants, which inhibit early compensating mechanisms than adults, with the blood’s natural ability to clot (Table 10-3). tachycardia and tachypnea present early. However, Anticoagulants can prolong bleeding, which can when they reach a certain point in shock, they worsen hemorrhagic shock. Thus, even a seem- “crash” rapidly into irreversible shock. The symp- ingly minor injury can result in profound shock toms of shock in children usually appear late or due to the body’s inability to stop bleeding. Any delayed. A reliable indicator to the onset of shock patient who is taking one or more of these medica- in children is sudden lethargy or fussiness. Do not tions must be carefully assessed for any evidence rely on blood pressure, which is maintained in of hemorrhaging, both external and internal. As- early shock in children. Hypovolemic shock is the pirin will also prolong bleeding. You must control most common type in children, due to blood loss bleeding in all patients. or hypovolemia from vomiting and/or diarrhea. The presence of injury or illness, for example, can affect the severity of shock and can have cu- mulative effects. Preexisting medical conditions such as , heart disease, or anemia (a reduc- Table 10-3 Anticoagulants tion in the number of circulating red blood cells) • Warfarin (Coumadin) can hasten the effects of shock. Mind-altering sub- • Enoxaparin (Lovenox) stances can mask or mimic the signs of shock by al- • Clopidogrel (Plavix) tering vital signs and also can eliminate pain from • Dabigatran (Pradaxa) an injury. Even prescribed medications can alter • Rivaroxaban (Xarelto) the body’s response to shock. OEC technicians • Apixaban (Eliquis) must be aware that certain medications can mask

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Table 10-4 Signs and Symptoms of Shock KEY POINT • Tachycardia (fast heart rate) • Hypotension (low blood pressure), occurs later Beta-Blockers and Shock • Tachypnea () Beta-blockers prevent the heart from • Thirst, weakness, and nausea speeding up, much like a governor on a • Pale, cool, diaphoretic skin car motor prevents the engine from over- • Restlessness or combativeness revving. During shock, the heart cannot • Altered mental status (occurs later) respond to pump more blood to the tissues.

Obtain vital signs and repeat them, noting each value; even subtle changes in the pulse rate, blood pressure, or respiratory rate could indicate PATIENT ASSESSMENT an underlying shock state. Be ever vigilant for the FOR SHOCK “classic” signs and symptoms of shock (Table 10-4). Assessment of patients in shock is no different Although it is important to recognize the clas- than it is for any other patients. It begins with a sic signs and symptoms of shock, remember that scene size-up, during which potential threats to shock is a developing condition that may not be ob- rescuer safety are identified and mitigated. Try to vious when the patient is first examined due to the identify the mechanism or injury or nature of ill- compensatory mechanisms previously described. ness, including evidence of trauma, heart attack, Normal age-specific vital signs can be seen in the external or , allergy, or infection. early stages of shock. It is important to note that The scene size-up is followed by a primary pa- hypotension and altered mental status come later tient assessment, looking at the ABCDs (airway, in shock. Frequent reassessment of the patient is breathing, circulation, and disability). Remember, essential and should include the vital when a responsive or unresponsive patient has signs and mental status at regular intervals. life-threatening bleeding, it is more appropriate When assessing a patient for shock, keep in to address this life threat first, following a CABD mind the types of shock, the conditions with which sequence (circulation, airway, breathing, and dis- they are associated, and whether the clinical picture ability). If there is a life threat, correct it or start you are seeing fits the situation. Pay close atten- CPR if needed. After the ABCDs are addressed, if tion to the pulse pressure (the difference between the patient is in shock, call for help, request ALS if systolic and diastolic pressures) because a narrow- available, and transport immediately. ing of pulse pressure is an early indicator of shock When obtaining the history, pay close atten- in . Hot, dry skin, especially tion to known allergies, as they may have precip- when combined with fever and low blood pressure, itated or contributed to the patient’s condition. may indicate septic shock. Assess the patient’s face Determine if the patient is taking any medications and hands for evidence of swelling, which could in- that could alter the body’s compensatory response dicate an anaphylactic reaction. Neurogenic shock to shock. Additionally, consider the patient’s age typically presents with warm, dry skin as opposed and determine whether the patient has taken any to the more classic presentation. mind-altering . If you begin to suspect impending shock during your secondary patient assessment of a MANAGEMENT OF SHOCK patient who appears stable initially, immediately Management of a patient in shock centers on re- shift gears, correcting the ABCDs and arranging turning the patient to a state of homeostasis. transport. Examine the patient carefully for any ev- Given that shock is caused by inadequate tissue idence of injury, both external and internal. Care- perfusion and oxygenation, initial treatment is fo- ful consideration of the mechanism of injury, along cused on correcting any problems causing shock. with your knowledge of the locations of internal Follow the steps in OEC Skill 10-1 for the organs, could lead you to suspect internal bleeding. treatment of a patient in shock.

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OEC SKILL 10-1 Managing Shock

1 Assess scene safety and follow standard 2 Perform a primary patient assessment. precautions. Control major bleeding and assess ABCDs. Correct any problems found. If the patient has no pulse, begin CPR.

3 Call for help and arrange for transport 4 Monitor the airway and administer high- that includes ALS. flow oxygen.

5 To prevent heat loss, keep the patient warm and dry. Provide rapid transport.

Photos 1, 3, 4, and 5, © Edward McNamara; Photo 2, © Deborah Endly.

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Major bleeding and problems affecting the the patient’s hand is warm, titrate oxygen so ABCDs identified during the primary assessment that the reading on the pulse oximeter remains must be corrected. If the patient has no pulse, im- between 94 and 99%. If oxygen is not easily mediately begin CPR. Ensure that the patient’s available, do not delay transport of the critical airway is open and clear, using airway adjuncts, patient. Control external hemorrhage (severe and suction as necessary. Support the patient’s bleeding) using the techniques presented in ventilatory efforts as needed. If the patient is not Soft-Tissue Injuries and Burns is Chapter 19 Keep breathing or if breathing is slow or shallow, assist the patient warm and dry. Additional treatment ventilations using either a pocket mask or a bag- depends on the nature of other problems that are valve mask connected to supplemental oxygen. If present. If you can, correct the cause of shock. the patient is unresponsive, insert a properly sized The treatments for specific causes of shock, such oropharyngeal airway or a nasopharyngeal airway. as anaphylaxis, heart attack, and tension pneu- For a patient who is breathing, adminis- mothorax, are covered in other chapters. ter high-flow oxygen at 15 liters per minute via Other therapies, such as , nonrebreather mask to maximize tissue oxy- blood, or medications, can be administered by ad- genation. If a pulse oximeter is available and vanced care providers and are often lifesaving.

CASE Outcome

Two other patrollers arrive on scene. You inform them you believe the patient is suffering from shock due to internal injuries from the fall. The situation has been made worse because he takes a beta-blocker and an anticoagulant. Working with the other patrollers, you quickly put the man on high-flow oxygen and place him into a toboggan. You ski down with the toboggan team and help them move the patient into the first-aid hut. Soon after, a helicopter arrives and transports the patient to a local . Several months later, you are in the ski area’s cafeteria when someone taps you on the shoulder. It’s the man and he thanks you for “saving my life” and informs you that your suspicions were confirmed. Lifting his sweater, he shows you an abdominal scar. He tells you that the impact of the crash ruptured his and that had you not stopped and insisted that he be treated, he likely would have died of shock.

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9781284189599_CH10_223_238.indd 234 4/14/2020 4:38:30 PM Chapter 10 Shock 235

CHAPTER REVIEW

In Summary • A patient’s blood pressure may be normal during the early phase of shock. • Shock is caused by inadequate perfusion, • Elderly patients do not compensate well or flow of blood to the cells, causing for shock. cellular and tissue hypoxia due to reduced • Children maintain vital signs better than oxygen delivery. adults, until they go into irreversible shock. • Review of the anatomy and physiology of the circulatory system will help you understand shock. If the pump (heart), Key Terms blood vessels (arteries and veins), or blood Anaphylactic shock A type of distributive is affected, tissue will not receive oxygen shock that occurs when a person reacts and nutrients, resulting in shock. violently to a substance to which he or she has • There are different types of shock, become sensitized. resulting from three basic causes: pump Anticoagulants Medications that prevent failure, failure of blood vessels to respond blood from clotting; “blood thinners.” properly, and low fluid volume. Cardiogenic shock A type of shock caused • Shock is a progressive disorder that can by inadequate function of the heart, or pump be divided into two stages: compensated failure, resulting in poor cardiac output. shock and decompensated shock. Distributive shock A type of shock resulting • There are four major types of shock: from widespread dilation of the small • Hypovolemic shock results from a arterioles, venules, or both. critical decrease in circulating fluid Fainting A loss of consciousness that results volume from bleeding or a loss from a lack of blood flow to the brain. This of internal body fluid. There are condition may occur suddenly, resulting from hemorrhagic and nonhemorrhagic the temporary dilation of the body’s veins and causes of hypovolemic shock. pooling of blood in those vessels. May also be • Cardiogenic shock is a condition in referred to as syncope. which the heart cannot adequately Hypovolemic shock A type of shock caused by pump blood, resulting in poor cardiac an inadequate amount of fluid or volume in output. the circulatory system. • Distributive shock occurs when blood Neurogenic shock A type of distributive vessels lose their ability to constrict shock that is caused by disruptions of the appropriately. central nervous system, most often from a • Obstructive shock results when a spinal cord injury. blockage prevents oxygenated blood Obstructive shock A type of shock caused by a from reaching vital organs. The blockage that prevents oxygenated blood from most common causes of obstructive reaching vital organs. shock are tension pneumothorax, Perfusion The circulation of blood within an pericardial tamponade, and organ or tissue in adequate amounts to meet pulmonary embolism. the cells’ current needs for oxygen, nutrients, • Shock is a life-threatening condition. and waste removal. • It is important to quickly identify the Peripheral vascular resistance The cause of shock and correct it if possible. tightening of the smaller-diameter blood The longer shock goes uncorrected, the vessels in the extremities, enabling increased less likely the patient is to recover. blood flow to the vital organs.

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Pulmonary embolism A condition where c. Obstructive a blood clot becomes stuck in and blocks a d. Distributive pulmonary artery. May also be referred to as 4. You have been treating a patient with thromboembolism. severe head injuries. His pulse is rising, Sepsis A serious medical condition caused his systolic blood pressure is falling, by the presence of pathogenic organisms or his respirations are shallow, his skin is their toxins in the blood, leading to a systemic cyanotic, and he has an altered mental inflammatory response. status. In which stage of shock is this Septic shock A type of distributive shock that patient? is caused by severe systemic infection. a. Compensated Shock Inadequate perfusion, or flow of b. Decompensated blood to the cells, causing cellular and tissue c. Irreversible hypoxia due to reduced oxygen delivery. d. Neurogenic Stroke volume The amount of blood pumped out of the left ventricle into the aorta during 5. A man has a laceration on his arm and is one heartbeat. bleeding. A woman nearby tells you that Tachycardia A heart rate greater than she cannot stand the sight of blood and 100 beats per minute in adults. then faints. Her fainting is the result of: Tachypnea A respiratory rate greater than a. temporary dilation of the body’s veins, 20 breaths per minute in adults. resulting in the pooling of blood in those vessels. Chapter Questions b. the heart not adequately pumping blood, resulting in poor cardiac 1. Shock is defined as: output. a. failure of the cardiovascular c. a critical decrease in circulating blood (circulatory) system to maintain volume from bleeding or a loss of adequate blood flow to tissues. internal body fluid. b. failure of the to maintain d. blockage within the body’s vascular adequate output. system preventing oxygenated blood c. failure of the nervous system to send from reaching vital organs. signals to the tissues. d. failure of the heart to beat correctly. 6. Your patient has received a crushing injury to the abdomen. You do not find 2. In order to compensate for shock, the any external injuries. You notice that your brain sends signals to the body causing: diaphoretic patient’s skin has become a. blood vessels in the extremities to pale and cool. Your patient is anxious dilate. and complains of thirst and nausea. Your b. blood vessels of the heart to constrict. emergency care should include: c. rate and force of heart contractions to a. cooling the patient with damp towels increase. or ice packs to the neck, armpits, and d. rate and depth of respirations to groin. decrease. b. transporting the patient in the 3. A patient who is stung by a bee goes into toboggan with the head uphill. anaphylactic shock. Blood vessels dilate, c. arranging for rapid transport to a causing blood to pool in the vessels. What medical facility. type of shock is this? d. providing water. a. Hypovolemic b. Cardiogenic

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7. A patient has a possible ruptured spleen, 8. A patient with signs of shock attributed to with a fast heart rate and dropping blood pump failure has: pressure. This type of shock is called: a. poor cardiac output. a. hypovolemic. b. femoral arterial bleeding. b. cardiogenic. c. tension pneumothorax. c. obstructive. d. sepsis.

d. distributive.

7. a, Objective 10-5, p. 227; 8. a, Objective 10-2, p. 225 p. 10-2, Objective a, 8. 227; p. 10-5, Objective a, 7.

4. b, Objective 10-4, p. 226; 5. a, Objective 10-6, p. 230; 6. c, Objective 10-7, p. 232; 232; p. 10-7, Objective c, 6. 230; p. 10-6, Objective a, 5. 226; p. 10-4, Objective b, 4.

Answers: 1. a, Objective 10-1, p. 224; 2. c, Objective 10-3, p. 226; 3. d, Objective 10-5, p. 228; 228; p. 10-5, Objective d, 3. 226; p. 10-3, Objective c, 2. 224; p. 10-1, Objective a, 1.

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