Shock - Pathophysiology & Types Flashcards
Inadequate cellular perfusion
Shock
When the cells cannot create energy they are categorized as ___
Hypoperfused
In the early stages of shock, the body will attempt to compensate by maintaining ___
Homeostasis
A balance of all systems of the body
Homeostasis
The circulation of blood to the tissues in adequate amounts to meet the cells needs
Perfusion
Carbon dioxide can be transported back to the lungs in three ways
- Dissolved in the plasma
- Combined with water in the form of bicarbonate
- Attached to hemoglobin
To protect vital organs from hypoperfusion, the body attempts to compensate by ___
Directing blood flow away from organs that are more tolerant of shock to organs that cannot tolerate shock
Perfusion triangle
- Heart (pump function)
- Blood vessels (container function)
- Blood (content function)
Blood flow through the capillary beds is regulated by ___
The capillary sphincters
The capillary sphincters are under the control of ___
The autonomic nervous system
Regulation of blood flow is determined by ___ and is accomplished by ___
- Cellular need
- Vessel contraction or dilation and capillary sphincter contraction or dilation
Pressure within the capillary bed
Capillary hydrostatic pressure
Pressure around the capillary bed and between the cells
Interstitial fluid hydrostatic pressure
The ___ side of the autonomic nervous system assumes more control of the body’s functions during a state of shock
Sympathetic
The shock response by the autonomic nervous system causes the release of the hormones ___
Epinephrine and norepinephrine
Eventually, a shifting of body fluids to help maintain pressure within the system also occurs by ___
Reabsorption of fluid into the bloodstream when it passes through the kidneys
Types of shock caused by pump failure
- Cardiogenic shock
- Obstructive shock
- Tension pneumothorax
- Cardiac tamponade
- Pulmonary embolism
Types of shock caused by poor vessel function
Distributive shock
- Septic shock
- Neurogenic shock
- Anaphylactic shock
- Psychogenic shock
Types of shock caused by low fluid volume
Hypovolemic shock
- Hemorrhagic shock
- Nonhemorrhagic shock
Caused by inadequate function of the heart
Cardiogenic shock
Cause of a pulmonary edema
After a heart attack, backup of blood in the pulmonary vessels. The buildup forces fluid out of the capillary beds that surround the alveoli
The presence of abnormally large amounts of fluid between the cells in body tissues, causing swelling of the effected area
Edema
Oxygen cannot diffuse across the fluid filled alveoli during a pulmonary edema, resulting in ___
Tachypnea and crackles, or rales
Rapid respiration
Tachypnea
Rattling sound that may be heard during breathing, typically on inhalation
Rales
Cardiogenic shock develops when the heart cannot maintain ___
Sufficient cardiac output to meed the demands of the body
The ability of the heart to contract
Myocardial contractility
Factors of cardiac output
- Myocardial contractility
- Heart must receive adequate blood to pump
- Resistance to flow in the peripheral circulation must be appropriate
As the volume of the blood coming to the heart increases, the pressure in the heart builds up. This pressure is called ___
Preload
When the heart muscle is stretched, ___ increases
Myocardial contractility
The force, or resistance against which the heart pumps
Afterload
As after load increases, cardiac output ___
Decreases
Increased after load may also cause the heart to ___ while trying to maintain adequate cardiac output
Overwork
Cardiogenic shock may result from low cardiac output due to ___
- High afterload
- Low preload
- Poor contractility
- Any combination of the 3
Caused by an obstruction that prevents an adequate volume of blood from being distributed to the body
Obstructive shock
Three most common examples of obstructive shock
- Cardiac tamponade
- Tension pneumothorax
- Pulmonary embolism
Collection of fluid between the pericardial sac and the myocardium
Pericardial effusion
If pericardial effusion becomes large enough, it can prevent ___
The ventricles from filling with blood
Compression of the heart as the result of buildup of blood or other fluid in the pericardial sac, leading to decreased cardiac output
Cardiac tamponade
Cardiac tamponade is also called ___
Pericardial tamponade
Cardiac tamponade can be caused by ___
- Blunt or penetrating trauma that causes hemorrhage around the heart
- Blood leaking 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
- Seen in patient’s with cancer and autoimmune diseases
The pericardium has a limited ability to ___
Stretch
Signs and symptoms of cardiac tamponade are referred to as the ___
Beck triad
Beck triad
- Presence of jugular vein distention
- Muffled heart sounds
- Narrowing pulse pressure
Narrowing pulse pressure
Systolic and diastolic BP begin to merge
A tension pneumothorax is caused by ___
Damage to the lung tissue
The damage to the lung tissue with a tension pneumothorax allows ___
Air normally held within the lung to escape into the chest cavity. The lung eventually collapses, causing a pneumothorax
If a pneumothorax is allowed to progress, air will ___
Accumulate with in the chest cavity and begin applying pressure to the heart and greater vessels
When the trapped air begins to shift the chest organs toward the uninjured side, a pneumothorax becomes known as a ___
Tension pneumothorax
As pressure from one side of the chest beings to push the mediastinum toward the other side, the vena cava loses its ability to ___
Stay fully expanded
The compression of the vena cava leads to ___
Reduced blood return to the right side of the heart and BP drops
Signs of tension pneumothorax
- Difficulty ventilating with a bag-mask device
- The affected side will have absent lung sounds
- Patient may become cyanotic
- Tracheal deviation (late sign)
A blood clot that occurs in the pulmonary arteries and blocks the flow of blood through the lungs
Pulmonary embolism
When a pulmonary embolism occurs, it can prevent blood from ___
Being pumped from the right side of the heart to the left
A pulmonary embolism results in ___
A complete backup of blood in the right ventricle and catastrophic obstructive shock
Results when there is widespread dilation of the small arterioles, small venules, or both
Distributive shock
Result of distributive shock
Circulating blood volume pools in the expanded vascular beds and tissue perfusion decreases
Most common types of distributive shock
- Septic shock
- Neurogenic shock
- Anaphylactic shock
- Psychogenic shock
Occurs as a result of severe infections, usually bacterial, in which toxins are generated by the bacteria.
Septic shock
How septic shock works
Severe infections, usually bacterial, in which toxins are generated by the bacteria. The toxins damage vessel walls, causing increased cellular permeability. The vessel walls leak and are unable to constrict well. Widespread dilation of vessels, in combination with plasma loss through the injured vessel walls, results in shock
Loss of plasma
Hypovolemia
Complex factors of septic shock
- Insufficient volume of fluid in the container, due to loss of plasma
- Fluid that leaks out often collects in the alveoli, interfering with respiration
- Vasodilation leads to a larger than normal vascular volume
Usually the result of high spinal cord injury
Neurogenic shock
Medical causes of neurogenic shock
Brain conditions, tumors, pressure on the spinal cord, and spinabifida
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
All vessels below the spinal injury ___
Dilate widely, increasing the size and capacity of the vascular system, causing blood to pool
Signs of neurogenic shock
- Absence of sweating below the level of injury
- Normal and low HR in the presence of hypotension
- Normal, warm skin
Neurogenic shock is the only type of shock that presents without the ___, because ___
- Characteristic pale, cool skin
- The peripheral vasoconstriction cannot be triggered through the autonomic nervous system
With neurogenic shock, in an acute injury setting, the ability to control body temperature is ___
Lost, and can rapidly fall to match that of the environment
___ can occur in a patient with neurogenic shock due to the inability to control body temperature
Hypothermia
A condition in which the internal body temperature falls below 95º
Hypothermia
Occurs when a person reacts quickly to a substance to which they have been sensitized
Anaphylaxis or anaphylactic shock
Becoming sensitive to a substance that did not initially cause a reaction
Sensitization
Each subsequent exposure after sensitization tends to produce a ___
More severe reaction
Categories of exposure for instances that cause severe allergic reactions
- Injections
- Stings
- Ingestion
- Inhalation
In anaphylactic shock, there is no ___, instead there is ___
- Loss of blood or vascular damage
- Widespread vascular dilation, increased permeability, and bronchoconstriction
Signs and symptoms of anaphylactic shock in the order they appear (skin)
- Flushed, itchy, or burning, especially over the face and upper part of the chest
- Urticaria, which may spread over large areas of the body
- Edema, especially over the face, tongue, and lips
- Pallor
- Cyanosis about the lips
Urticaria
Hives
Signs and symptoms of anaphylactic shock in the order they appear (circulatory system)
- Dilated peripheral blood vessels
- Increased vessel permeability
- Drop in BP
- Weak, barely palpable pulse
Signs and symptoms of anaphylactic shock in the order they appear (respiratory system)
- Sneezing or itching in the nasal passages
- Stridor
- Upper airway obstruction
- Tightness in the chest, with a persistent dry cough
- Wheezing and dyspnea
- Secretions of fluid and mucus into the bronchial passages, alveoli, and lung tissue, causing coughing
- Constriction of the bronchi; difficulty drawing air into the lungs
- Forced expiration, requiring exertion and accompanied by wheezing
- Cessation of breathing
Signs and symptoms of anaphylactic shock in the order they appear (other)
- Abdominal cramping
- Nausea
- Vomiting
- Altered mental status
- Dizziness
- Fainting and coma
A sudden reaction of the nervous system that produces a temporary, generalized vasodilation, resulting in fainting or syncope
Psychogenic shock
Occurs when blood pools in the dilated vessels, reducing the blood supply to the brain, resulting in the brain temporarily ceasing to function normally, and fainting
Syncope
Life-threatening causes of syncope
Irregular heartbeat or a brain aneurysm
Non-life-threatening events that cause syncope
Receiving bad news, experiencing fear, or encountering an unpleasant sight
Those experiencing syncope should receive a ___
Full assessment
The result of an inadequate amount of fluid in the circulatory system
Hypovolemic shock
Two types of causes of hypovolemic shock
Hemorrhagic and nonhemorrhagic
How do severe burns cause hypovolemic shock?
Intravascular plasma loss is caused when fluid leaks from the capillaries into the surrounding tissue
How do crushing injuries cause hypovolemic shock?
Loss of blood and plasma from damaged vessels into injured tissues
Dehydration can cause ___ shock
Hypovolemic
How does dehydration cause hypovolemic shock?
Insufficient volume of fluid within the vascular system to provide adequate circulation to the organs of the body
