Chapter 12: Shock

Types of shock

- Cardiogenic Shock - Obstructive Shock - Distributive Shock - Hypovolemic Shock - Respiratory insufficiency

Requirements for perfusion

- a working cardiovascular system 1. Adequate oxygen exchange in the lungs 2. Adequate nutrients in the form of glucose in the blood 3. Adequate waste removal, primarily through the lungs

Describe perfusion

-The circulation of blood within an organ or tissue in adequate amounts to meet the cells' current needs. 1. The body is perfused via the circulatory system. 2. The circulatory system is a complex arrangement of connected tubes, including the arteries, arterioles, capillaries, venules, and veins. 3. There are two circuits in the body: the systemic circulation in the body and the pulmonary circulation in the lungs. a. The systemic circulation carries oxygen-rich blood from the left ventricle through the body and back to the right atrium. b. In the systemic circulation, as blood passes through the tissues and organs, it delivers oxygen and nutrients. c. Adequate perfusion is also important for the removal of waste products such as carbon dioxide, which is picked up from cells as blood circulates through the organs and returns to the heart and lungs. d. Organs, tissues, and cells must have adequate oxygenation or they may die. e. Each time you take a breath, the alveoli, which are microscopic, thin-walled air sacs, receive a supply of oxygen-rich air. f. Oxygen diffuses through the walls of the alveoli into the bloodstream and attaches to hemoglobin circulating on red blood cells. g. If oxygenated blood is not properly circulated, cell death may occur.

Respiratory insufficiency

1. A patient with a severe chest injury, such as flail chest, or obstruction of the airway may be unable to breathe in an adequate amount of oxygen. a. This affects the ventilation process of respiration because not enough oxygen can be inspired to meet the metabolic demand. b. An insufficient concentration of oxygen in the blood can produce a life-threatening situation as rapidly as the vascular causes of shock. 2. Anemia is an abnormally low number of red blood cells. a. Anemia may be the result of either chronic or acute bleeding, a deficiency in certain vitamins or minerals, or an underlying disease process. b. Tissues may become hypoxic because the blood is unable to deliver adequate amounts of oxygen to the tissues, even though the available hemoglobin is fully saturated with oxygen and the lungs are delivering enough oxygen to the blood. 3. Certain types of poisoning may also affect the ability of cells to metabolize or carry oxygen. a. Carbon monoxide poisoning b. Cyanide poisoning

3 pts of the cardiovascular system

1. A pump (the heart) 2. A set of pipes (blood vessels or arteries that act as the container) 3. The contents of the container (the blood) a. These three parts can be referred to as the "perfusion triangle." b. When a patient is in shock, one or more of the three parts is not working properly.

History taking of patient assessment for shock

1. After life threats have been managed, determine the chief complaint. 2. Obtain a SAMPLE history.

Describe Cardiogenic Shock

1. Cardiogenic shock is caused by inadequate function of the heart, or pump failure. 2. A major effect is the backup of blood into the lungs. 3. The resulting buildup of pulmonary fluid is called pulmonary edema. a. Edema is the presence of abnormally large amounts of fluid between the cells in body tissues, causing swelling of the affected area. b. Pulmonary edema leads to impaired respiration, which may be manifested by: i. An increased respiratory rate ii. Abnormal lung sounds 4. Cardiogenic shock develops when the heart cannot maintain sufficient output to meet the demands of the body. a. Cardiac output is the volume of blood that the heart can pump per minute, and it is dependent upon several factors. i. The heart must have adequate strength, which is largely determined by the ability of the heart muscle to contract (myocardial contractility). ii. The heart must receive adequate blood to pump. iii. The resistance to flow in the peripheral circulation must be appropriate.

The Stages in the progression of shock

1. Compensated shock a. In early stages of shock, the body can still compensate for blood loss. b. Signs and symptoms: i. Agitation ii. Anxiety iii. Restlessness iv. Feeling of impending doom v. Altered mental status vi. Weak, rapid (thready), or absent pulse vii. Clammy (pale, cool, moist) skin viii. Pallor, with cyanosis about the lips ix. Shallow, rapid breathing x. Air hunger (shortness of breath), especially if there is a chest injury xi. Nausea or vomiting xii. Capillary refill of longer than 2 seconds in infants and children xiii. Marked thirst xiv. Narrowing pulse pressure 2. Decompensated shock a. The late stage, when blood pressure is falling b. Signs and symptoms: i. Falling blood pressure (systolic blood pressure of 90 mm Hg or lower in an adult) ii. Labored or irregular breathing iii. Ashen, mottled, or cyanotic skin iv. Thready or absent peripheral pulses v. Dull eyes, dilated pupils vi. Poor urinary output 3. When shock has progressed too far a. It is irreversible. b. No way to assess when a patient has reached this point c. It is imperative to recognize and treat shock early—well before the patient transitions into the decompensated phase. 4. Blood pressure may be the last measurable factor to change in shock. a. When a drop in blood pressure is evident, shock is well developed. b. This is particularly true in infants and children, who can maintain their blood pressure until they have blood loss that is more than half their blood volume. c. By the time blood pressure drops in infants and children who are in shock, they are close to death. 5. Expect shock in many emergency medical situations. 6. Also expect shock if a patient has any one of the following conditions: a. Multiple severe fractures b. Abdominal or chest injury c. Spinal injury d. A severe infection e. A major heart attack f. Anaphylaxis

What to do when treating Hypovolemic Shock

1. Control all obvious external bleeding. a. The best initial method to control external bleeding is direct pressure. b. If bleeding is not controlled with direct pressure, consider using a tourniquet. 2. Handle the patient gently and keep him or her warm. 3. Recognize internal bleeding and provide aggressive general support. 4. Secure and maintain an airway, and provide respiratory support, including supplemental oxygen and, if needed, assisted ventilations. a. Watch to ensure the patient does not aspirate blood or vomitus. 5. Transport the patient as rapidly as possible to the ED.

Distributive Shock

1. Distributive shock results when there is widespread dilation of small arterioles, small venules, or both. 2. The circulating blood volume pools in the expanded vascular beds and tissue perfusion decreases. 3. Septic shock a. Septic shock occurs as result of severe infections, usually bacterial, in which toxins are generated by the bacteria or by infected body tissues. i. The toxins damage the vessel walls, causing increased cellular permeability. ii. The vessel walls leak and are unable to contract well. iii. Widespread dilation of vessels, in combination with plasma loss through the injured vessel walls, results in shock. b. Septic shock is a complex problem. i. There is an insufficient volume of fluid in the container, because much of the plasma has leaked out of the vascular system (hypovolemia). ii. The fluid that has leaked out often collects in the respiratory system, interfering with respiration. iii. The vasodilation leads to a larger-than-normal vascular bed to contain the smaller-than-normal volume of intravascular fluid. 4. Neurogenic shock a. Neurogenic shock is usually the result of high spinal-cord injury. b. Causes include: i. Brain conditions ii. Tumors iii. Pressure on the spinal cord iv. Spina bifida c. In neurogenic shock, the muscles in the walls of the blood vessels are cut off from the sympathetic nervous system and nerve impulses that cause them to contract. i. All vessels below the level of the spinal injury dilate widely, increasing the size and capacity of the vascular system and causing blood to pool. ii. The available 6 L of blood in the body can no longer fill the enlarged vascular system. iii. Even if there is no blood or fluid loss, perfusion of organs and tissues becomes inadequate, and shock occurs. iv. Signs of this type of shock are the absence of sweating below the level of injury; normal and low heart rate in the presence of hypotension; and normal, warm skin. 5. Anaphylactic shock a. Anaphylaxis, or anaphylactic shock, occurs when a person reacts violently to a substance to which he or she has been sensitized. i. Sensitization means becoming sensitive to a substance that did not initially cause a reaction. ii. Each subsequent exposure after sensitization tends to produce a more severe reaction. b. Four categories of exposure include: i. Injections (tetanus antitoxin, penicillin) ii. Stings (wasps, bees, hornets, ants) iii. Ingestion (fish, shellfish, nuts, eggs, medication) iv. Inhalation (dust, pollen, mold) c. Anaphylactic reactions can develop within minutes or even seconds after contact with the substance. d. There may also be a second phase reaction that occurs 1 to 8 hours after the initial reaction. e. The signs are very distinct and not seen with other forms of shock (see Table 12-2). f. Note that cyanosis (blue discoloration of the skin) is a late sign of anaphylactic shock. g. The combination of poor oxygenation and poor perfusion in anaphylactic shock may easily prove fatal. 6. Psychogenic shock a. A patient in psychogenic shock has had a sudden reaction of the nervous system that produces a temporary, generalized vascular dilation, resulting in fainting, or syncope. b. The fainting episode is temporary, and the patient rouses soon after. c. Syncope occurs when blood pools in the dilated vessels, reducing the blood supply to the brain. i. As a result, the brain ceases to function normally, and the patient faints. d. It is important to realize that some of the causes of syncope are of a serious nature, but others are not. e. Life-threatening causes include irregular heartbeat and brain aneurysm. f. Non-life-threatening events may include receipt of bad news or experiencing fear or unpleasant sights (like the sight of blood).

What to do when treating for obstructive shock

1. For cardiac tamponade a. Increasing cardiac output should be the priority in treating cardiac tamponade. b. Apply high-flow oxygen. c. Surgery is the only definitive treatment. d. Pericardiocentesis involves penetrating the pericardium with a needle to withdraw the accumulated blood from the pericardial sac. i. This procedure is an advanced skill, and it is rarely performed in the field. 2. For tension pneumothorax a. Administer high-flow oxygen via nonrebreathing mask early to prevent hypoxia. b. Usually the only action that can prevent eventual death from a tension pneumothorax is decompression of the injured side of the chest, relieving the pressure in the chest and allowing the heart to expand fully again. c. Chest decompression is an ALS skill. Ask for ALS assistance early in the call if available; however, do not delay transport waiting for the arrival of ALS.

What to do when treating neurogenic shock

1. For the spinal cord injury patient, use a combination of all known supportive measures. a. The patient who has sustained this kind of injury usually will require hospitalization for a long time. 2. Emergency treatment must be directed at: a. Obtaining and maintaining a proper airway b. Providing spinal immobilization c. Assisting inadequate breathing as needed d. Conserving body heat e. Ensuring the most effective circulation possible 3. Keep the patient as warm as possible with blankets. 4. Transport the patient promptly to a facility capable of managing spinal injuries.

Hypovolemic Shock

1. Hypovolemic shock is the result of an inadequate amount of fluid or volume in the circulatory system. a. There are hemorrhagic causes and nonhemorrhagic causes. b. Injuries involving bleeding may result in hemorrhagic shock, while vomiting and diarrhea may result in nonhemorrhagic hypovolemic shock. 2. Hypovolemic shock also occurs with severe thermal burns. a. Intravascular plasma is lost. b. Plasma leaks from the circulatory system into the burned tissues that lie adjacent to the injury. 3. Dehydration, the loss of water or fluid from body tissues, can cause or aggravate shock. a. Fluid loss may be a result of severe vomiting and/or diarrhea.

What to do when treating respiratory insufficiency

1. Immediately secure and maintain the airway. 2. Clear the mouth and throat of any obstructions, including mucus, vomitus, and foreign material. 3. If necessary, provide ventilations with a BVM. 4. Administer supplemental oxygen, and transport the patient promptly.

What to do when treating psychogenic shock

1. In an uncomplicated case of fainting, once the patient collapses and becomes supine, circulation to the brain is restored and, with it, a normal state of functioning. 2. Psychogenic shock can worsen other types of shock. 3. If it appears the patient fell as a result of psychogenic shock, check for injuries, especially in older patients. 4. If the patient reports not being able to walk after a fall thought to be related to psychogenic shock, you should suspect another problem, such as head injury. 5. Transport the patient promptly. a. It is not safe to assume based on EMT assessment that any fainting was caused by psychogenic shock alone. b. All patients with loss of consciousness should be transported to the ED for evaluation even if they appear normal once you arrive on scene. 6. Record your initial observations and try to learn from bystanders whether the patient complained of anything and how long he or she was unconscious.

Describe Obstructive Shock

1. Obstructive shock is caused by a mechanical obstruction that prevents an adequate volume of blood from filling the heart chambers. 2. Three of the most common examples: a. Cardiac tamponade (pericardial tamponade) i. A collection of fluid between the pericardial sac and the myocardium is called a pericardial effusion. If the effusion becomes large enough, it can prevent the ventricles from filling with blood—a condition called cardiac tamponade. ii. It is caused by blunt or penetrating trauma that causes hemorrhage around the heart. iii. Cardiac tamponade occurs when blood leaks into the space between the tough fibrous membrane known as the pericardium and the outer walls of the heart, an area called the pericardial sac. iv. As more blood or fluid accumulates in this confined space, the outer walls of the heart become compressed. v. The accumulated blood or fluid in the pericardial space eventually exerts pressure back onto the outer walls of the heart, compressing the walls of the heart and preventing the heart from completely refilling with blood. vi. Continued pressure within the pericardial sac obstructs the flow of blood into the heart, resulting in decreased outflow from the heart. vii. Signs and symptoms of cardiac tamponade are referred to as Beck triad: the presence of jugular vein distention, muffled heart sounds, and a narrowing pulse pressure where the systolic and diastolic blood pressures start to merge. b. Tension pneumothorax i. It is caused by damage to lung tissue. ii. The damage allows air normally held within the lung to escape into the chest cavity. iii. The lung collapses, and if the pneumothorax is left untreated, air will accumulate in the chest cavity and apply pressure to the organs, including the heart and great vessels. c. Pulmonary embolism i. A blood clot that occurs in the pulmonary circulation that blocks the flow of blood through the pulmonary vessels. ii. When a massive pulmonary embolism occurs, it can prevent blood from being pumped from the right side of the heart to the left, resulting in complete backup of blood in the right ventricle and leading to catastrophic obstructive shock and complete pump failure.

Diffusion is a passive process in which molecules move from an area with a higher concentration of molecules to an area of lower concentration.

1. Oxygen molecules move from the alveoli into the blood. 2. Carbon dioxide moves out of the blood into the alveoli. 3. Whereas the majority of oxygen is carried to the tissues attached to hemoglobin, carbon dioxide can be transported in the blood from tissues back to the lungs in three ways: a. Dissolved in the plasma b. Combined with water in the form of bicarbonate c. Attached to hemoglobin 4. Carbon dioxide waste products released from cells can combine with water in the bloodstream to form bicarbonate. Bicarbonate concentrations become higher as more carbon dioxide is produced and blood moves back toward the lungs. 5. Once it reaches the lungs, the bicarbonate breaks back down into carbon dioxide and water and the carbon dioxide is exhaled. 6. In cases of poor perfusion (shock), the transportation of carbon dioxide out of the tissues will become impaired, resulting in a dangerous buildup of waste products, which may cause cellular damage.

secondary assessment for patient assessment for shock

1. Physical examinations a. The secondary assessment begins by repeating the primary assessment followed by a focused assessment. b. Perform a secondary assessment of the entire body if: i. Your patient is a trauma patient with a significant mechanism of injury or multiple injuries ii. Your patient gives you a poor initial general impression iii. You found problems in the primary assessment iv. Your patient has a medical problem but is not responsive v. Your patient has problems that were not noted in the primary assessment c. These assessments should be performed quickly but thoroughly to ensure that you do not miss any significant or life-threatening problems or delay needed care. d. If your patient has only a simple mechanism of injury, such as a twisted ankle, focus your examination on the specific area affected. e. Whether your examination is of the entire body or of a specific area, if a life-threatening problem is found, treat it immediately. 2. Vital signs a. Obtain a complete set of baseline vital signs. i. If the patient's condition is unstable or could become unstable, reassess vital signs every 5 minutes. ii. If the patient is in stable condition, reassess vital signs every 10 to 15 minutes. b. Monitoring devices i. Use monitoring devices to quantify the patient's oxygenation and circulatory status. ii. Use a noninvasive technique to monitor blood pressure and a pulse oximeter to evaluate the effectiveness of oxygenation.

Scene size-up for patient assessment of shock

1. Scene safety a. As you approach the scene, be alert to potential hazards to your safety. b. If this is a trauma scene or bleeding is suspected, put on gloves and eye protection, at a minimum. c. Put several pairs of gloves in your pocket for easy access in case your gloves tear or there are multiple patients with bleeding. d. In incidents involving violence, such as assaults or gunshot wounds, make sure that police are on scene. 2. Mechanism of injury/nature of illness a. Observe the scene and patient for clues to determine the nature of the illness or the mechanism of injury. b. This could help you anticipate the potential for development of shock.

What to do when treating shock in older patients

1. The EMT must use caution when caring for older patients. 2. Older patients generally have more serious complications than younger patients. 3. Although illness is a common complaint among older patients, understand that it is not just part of aging. 4. Many older patients take numerous medications that could either mask or mimic signs of shock. a. Keep in mind the following signs of the normal aging process when managing geriatric patients: i. The central nervous system often has a delayed response. ii. The cardiovascular system has a variety of changes that result in a decrease in the efficiency of the system. On assessment, be alert for higher resting heart rates and irregular pulse rates. iii. The respiratory system undergoes significant changes as the elasticity of the lungs and their size and strength decrease. On assessment, be alert for higher respiratory rates, lower tidal volume, and a decreased gag reflex. In addition, remember that cervical arthritis may be present and that dentures may cause an airway obstruction. iv. The skin becomes thinner, drier, less elastic, and more fragile, thus providing less protection and thermal regulation (cold and hot). v. The renal system decreases in function and may not respond well to unusual demands such as illness or dehydration. vi. The gastrointestinal system sustains changes in gastric motility that may lead to slower gastric emptying. b. Treating a pediatric or geriatric patient in shock is no different than treating any other shock patient: i. Provide in-line spinal stabilization if indicated. If spinal immobilization is not indicated, maintain the patient in a position of comfort. ii. Control life-threatening hemorrhage immediately with direct pressure or tourniquet application when appropriate. iii. Suction as necessary and provide high-flow oxygen via a nonrebreathing mask. iv. Maintain body temperature. v. Provide rapid transport.

What to do when treating anaphylactic shock

1. The only really effective treatment for a severe, acute allergic reaction is to administer epinephrine by way of intramuscular injection. a. A patient who is aware of having a specific sensitivity may carry a kit containing epinephrine. b. If he or she is unable to inject the medication, you may have to do so if you are allowed by local protocol. c. If the patient's signs and symptoms recur or the patient's condition deteriorates, consult medical control for authorization to administer a repeat injection, if available. 2. A patient with anaphylaxis requires immediate transport. a. Additional emergency care includes high-flow oxygen (10 to 15 L/min via a nonrebreathing mask). b. Assist ventilations with a BVM if necessary. c. Try to find out what agent caused the reaction and how it was received. 3. Keep in mind that a mild reaction may worsen suddenly or over time. 4. Because of the potential for airway compromise, consider requesting ALS backup, if available.

What to do when treating cardiogenic shock

1. The patient who is in shock as a result of a heart attack simply cannot generate the necessary power to pump blood throughout the circulatory system. 2. Chronic lung disease will aggravate cardiogenic shock. a. The patient is often able to breathe better in a sitting or semi-sitting position. 3. Usually, patients with cardiogenic shock do not have any injury, but they may be having chest pain. a. The patient may have taken nitroglycerin before EMS arrives and may want to take more. 4. Patients in cardiogenic shock should not receive nitroglycerin; by definition they are hypotensive. 5. Other signs and symptoms include: a. Weak, irregular pulse b. Cyanosis about the lips and underneath the fingernails c. Anxiety d. Nausea 6. Place the patient in a position that eases breathing as you give high-flow oxygen. a. Assist ventilations as necessary and have suction nearby in case the patient vomits. b. Provide prompt transport. c. If ALS is not already on the scene, consider a rendezvous en route to the hospital if available. d. Provide calm reassurance to a patient who has had a suspected heart attack.

Primary assessment for patient assessment for shock

1. The primary assessment for a patient with suspected shock should include a rapid exam to: a. Determine level of consciousness b. Identify and manage life-threatening concerns as they are found c. Determine priority of the patient and transport i. A patient with massive hemorrhage may require a tourniquet (or direct pressure dressings when tourniquets are not feasible or available) before the airway is opened. ii. If the patient has life-threatening external bleeding, it should be addressed first (even before airway and breathing), then the ABCs can be assessed and treated, and treatments for shock provided. 2. Provide high-flow oxygen to assist in perfusion of damaged tissues. a. If the patient has signs of hypoperfusion, treat aggressively and provide rapid transport to the hospital. b. Request advanced life support (ALS) as necessary to assist with more aggressive shock management. 3. Form a general impression. a. This will help you develop an early sense of urgency for care of a patient who appears "sick." b. Determine the need for manual spinal stabilization and assess the patient's level of consciousness using the AVPU scale. c. A patient who has an altered level of consciousness (LOC) may need emergency airway management. d. If the patient is awake and alert, determine a chief complaint. 4. Airway and breathing a. Assess the airway to ensure it is patent. b. Quickly assess breathing. i. Observe the patient for signs of accessory muscle use such as the muscles of the neck, intercostal retractions, or abnormal use of the abdominal muscles. ii. An increased respiratory rate is often an early sign of impending shock. iii. Assess for wheezes or other abnormal breath sounds. c. Administer high-flow oxygen or, if needed, assist respirations with a BVM. 5. Circulation a. Assessing the patient's circulatory status can reveal important clues regarding the presence of shock. b. Check for a distal pulse. c. If there is none, check for a central pulse. d. Determine if the pulse is fast, slow, weak, strong, or altogether absent. i. A rapid pulse suggests compensated shock. ii. In shock or compensated shock, the skin may be cool, clammy, or ashen. e. If the patient has no pulse and is not breathing, immediately begin cardiopulmonary resuscitation (CPR). 6. Transport decision a. Assess for and identify any life-threatening bleeding in trauma patients; if serious bleeding is discovered, treat it at once. b. You must also quickly assess skin temperature, condition, and color, and check for capillary refill time. c. Determine whether the patient should be treated as high priority, whether ALS is needed, and which facility to transport to. d. Trauma patients with shock, or a suspicious MOI, generally should go to a trauma center.

What to do when treating septic shock

1. The proper treatment of septic shock requires complex hospital management, including administration of antibiotics. 2. Use appropriate standard precautions and transport as promptly as possible. 3. Administer high-flow oxygen during transport. 4. Ventilatory support may be necessary to maintain adequate tidal volume. 5. Use blankets to conserve body heat. 6. Notify a specialized "sepsis team" if available to meet the patient in the ED. a. Sepsis teams can decrease the amount of time spent in identification of the infectious agent and initiation of the appropriate treatment, thereby decreasing the mortality from septic shock.

Mechanisms in place to help support the respiratory and cardiovascular systems when the need for perfusion of vital organs is increased

1. These mechanisms include the autonomic nervous system and hormones. a. They are triggered when the body senses that the pressure in the system is falling. b. The sympathetic side of the autonomic nervous system, which is responsible for the fight-or-flight response, will assume more control of the body's functions during a state of shock. c. This response by the autonomic nervous system causes the release of hormones such as epinephrine and norepinephrine. d. Hormones cause an increase in heart rate and in the strength of cardiac contractions and vasoconstriction in nonessential areas, primarily in the skin and gastrointestinal tract (peripheral vasoconstriction). e. Together, these actions are designed to maintain pressure in the system and, as a result, sustain perfusion of all vital organs. f. The autonomic nervous system and hormones respond within seconds. g. It is this response that causes all the signs and symptoms of shock in a patient.

Reassessment of patient assessment for shock

11. Reassess the patient's: a. Vital signs b. Interventions c. Chief complaint d. ABCs e. Mental status 2. Determine what interventions are needed for your patient based on the assessment findings. a. Focus on supporting the cardiovascular system. b. Treat for shock early and aggressively by providing oxygen and keeping the patient warm.

Introduction to Shock

A. In this chapter, shock (hypoperfusion) describes a state of collapse and failure of the cardiovascular system. 1. In the early stages of shock, the body will attempt to compensate by maintaining homeostasis (a balance of all systems in the body). 2. As shock progresses, however, blood circulation slows and eventually ceases. B. Shock can occur because of medical or traumatic events. 1. Heart attack 2. Severe allergic reaction 3. Motor vehicle crash 4. Gunshot wound C. EMTs respond to different types of emergencies to provide care and transportation. D. They must be constantly alert to the signs and symptoms of shock.

Pathophysiology of Shock

A. Perfusion is the circulation of blood within an organ or tissue in adequate amounts to meet the cells' current needs. B. Diffusion is a passive process in which molecules move from an area with a higher concentration of molecules to an area of lower concentration. C. Shock refers to a state of collapse and failure of the cardiovascular system that leads to inadequate circulation. D. The cardiovascular system consists of three parts: E. Blood pressure is the pressure of blood within the vessels at any moment in time. F. Blood flow through the capillary beds is regulated by the capillary sphincters (circular muscular walls that constrict and dilate). G. Perfusion requires more than just having a working cardiovascular system. H. Mechanisms are in place to help support the respiratory and cardiovascular systems when the need for perfusion of vital organs is increased.

Patient assessment for shock

A. Scene size-up B. Primary assessment C. History taking D. Secondary assessment E. Reassessment

Causes of shock

A. Shock can result from many conditions, including bleeding, respiratory failure, acute allergic reactions, and overwhelming infection. 1. In all cases, the damage occurs because of insufficient perfusion of organs and tissues. B. Pump failure 1. Causes: heart attack, trauma to heart, obstructive causes 2. Types of shock a. Cardiogenic shock b. Obstructive shock i. Tension pneumothorax ii. Cardiac tamponade iii. Pulmonary embolism C. Poor vessel function 1. Causes: infection, drug overdose (narcotic), spinal cord injury, anaphylaxis 2. Types of shock a. Distributive shock i. Septic shock ii. Neurogenic shock iii. Anaphylactic shock iv. Psychogenic shock D. Low fluid volume 1. Causes: trauma to vessels or tissues, fluid loss from GI tract (vomiting/diarrhea can also lower the fluid component of the blood) 2. Types of shock a. Hypovolemic shock i. Hemorrhagic shock ii. Nonhemorrhagic shock

Blood flow through the capillary beds

Blood flow through the capillary beds is regulated by the capillary sphincters (circular muscular walls that constrict and dilate). 1. These sphincters are under the control of the autonomic nervous system, which regulates involuntary functions such as sweating and digestion. 2. Capillary sphincters also respond to other stimuli, such as: a. Heat b. Cold c. The need for oxygen d. The need for waste removal 3. Keep in mind that, under normal circumstances, not all cells have the same needs at the same time (eg, the stomach and intestines have a high need for blood flow during digestion).

Blood pressure

Blood pressure is the pressure of blood within the vessels at any moment in time. 1. Systolic pressure is the peak arterial pressure, or pressure generated every time the heart contracts. 2. Diastolic pressure is the pressure maintained within the arteries while the heart rests between heartbeats. 3. Pulse pressure is the difference between the systolic and diastolic pressures (systolic - diastolic = pulse pressure). a. It signifies the amount of force the heart generates with each contraction. b. A pulse pressure less than 25 mm Hg may be seen in patients with shock.

What is shock

Shock refers to a state of collapse and failure of the cardiovascular system that leads to inadequate circulation. 1. Like internal bleeding, shock is an unseen life threat caused by a medical disorder or traumatic injury. 2. To protect vital organs, the body directs blood flow from organs that are more tolerant of low flow (such as the skin and intestines) to organs that cannot tolerate low blood flow (such as the heart, brain, and lungs). 3. If the conditions causing shock are not promptly addressed, death may soon occur. 4. By recognizing the signs and symptoms of shock early, you can minimize organ damage and save lives. 5. Shock is life threatening and requires immediate recognition and rapid treatment.

What to do when treating for shock

You must begin immediate treatment for shock as soon as you realize that the condition may exist. 1. Follow standard precautions. 2. Control all obvious external bleeding. a. Place dry, sterile dressings over the bleeding sites, and secure with bandages. b. If direct pressure is not rapidly successful in the control of bleeding from an extremity, apply a tourniquet proximal to the bleeding site according to local protocol. 3. Make sure the patient has an open airway. 4. Maintain manual in-line stabilization if necessary, and check breathing and pulse. 5. Comfort, calm, and reassure the patient, while maintaining the patient in the supine position. 6. Never allow patients to eat or drink anything prior to being evaluated by a physician. 7. If spinal immobilization is indicated, splint the patient on a backboard. 8. Remember that inadequate ventilation may be a major factor in the development of shock. a. Always provide oxygen, assist with ventilations, and use airway control adjuncts as needed, and continue to monitor the patient's breathing. 9. To prevent the loss of body heat, place blankets under and over the patient, but try to help the patient maintain a normal body temperature. 10. Transport the patient and treat additional injuries en route. 11. Consider rendezvous with ALS if possible, and consider aeromedical transport. 12. Do not give the patient anything by mouth, no matter how urgently you are asked. a. To relieve the intense thirst that often accompanies shock, give the patient a moistened piece of gauze to chew or suck. 13. Accurately record the patient's vital signs approximately every 5 minutes throughout treatment and transport. 14. Table 12-4 lists the general supportive measures for the major types of shock.