Shock Flashcards
What are three reasons for hypoperfusion?
Inadequate pump
Inadequate fluid
Inadequate container
What are the five aspects of an inadequate pump that cause hypoperfusion?
Inadequate preload Inadequate stroke volume Inadequate cardiac output Inadequate heart rate Excessive afterload
What is the aspect of inadequate fluid that causes hypoperfusion?
Hypovolemia
What are the two aspects of an inadequate container that cause hypoperfusion?
Inadequate systemic vascular resistance
Over dilation
How does shock affect the cellular level?
It causes a state of acute nutritional insufficiency for oxygen and other essential substrates, resulting in cellular anoxia, cellular dysfunction and eventually, cell death
What is the 60-40-20 rule?
60% of the body weight is water
40% of body weight is intracellular fluids
20% of body weight is extracellular fluid
What is stroke volume?
It is the amount of blood released from the heart per beat
What is the formula for cardiac output?
Cardiac output = stroke volume x heart rate
CO = SV x HR
What is cardiac output?
It is the amount of blood circulated from the heart in a minute
What are three principle factors that affect cardiac output?
Preload
Afterload
Myocardial contractility
What is preload?
It is the amount of blood delivered to the heart during diastole
What is preload dependent on?
Venous return
What happens if there is an increase in preload?
There is an increase in stroke volume
What is afterload?
It is the pressure at which the ventricle pumps against
With afterload, when is blood ejected?
Only after the resistance is overcome
What is afterload dependent on?
The degree of peripheral arterial vasoconstriction
What is myocardial contractility? (2)
The force generated by the myocardium on contraction
Remember Starling’s Law (the rubber band theory)
What is the formula for blood pressure?
Blood pressure = cardiac output x peripheral vascular resistance
What may peripheral vascular resistance be also seen as?
Systemic vascular resistance (SVR)
What is blood pressure?
THe resistance of blood flow by the force of friction between the blood and walls of the vessels
What is blood flow?
Systemic vascular resistance is dependent on the internal diameter of the vessels and viscosity of blood
What two vessels do not significantly change diameter?
Aorta
Arteries
How large can the arterioles change their lumen?
Factor of 5
What are baroreceptors?
They are sensory fibers located in the aortic and carotid tissues
What do the baroreceptors help control?
They help control the BP by using two negative feedback mechanisms
What are the two negative feedback mechanisms used by the baroreceptors?
Lower BP in response to increased arterial pressure
Increase BP in response to decreased arterial pressure
What are two systemic pressures?
Venous
Arterial
What does the venous systemic pressure control?
Venous system constriction increases preload and stroke volume
What does the arterial systemic pressure control?
Arterial system constriction increases afterload and BP
What are the four components of microcirculation?
It is a capillary network
It is responsive to the needs of local tissues
It will adjust to supply/bypass tissues in need/or without need
Utilizes the pre and post capillary sphincters to facilitate these needs
What are ten affects on microcirculation?
Local control by tissues Nervous control of blood flow Baroreceptors Chemoreceptors CNS ischemia response Hormonal response Adrenal-medullary response Renin-Angiotensin-Aldosterone mechanism Vasopressin Reabsorption of tissue fluid
What is the function of oxygen?
It bends to hemoglobin and diffuses across the capillary membrane
What is the normal percentage of hemoglobin that is saturated by oxygen?
97-100%
What is Fick’s principle?
It recognizes the five conditions required for effective movement of oxygen within the body
What are the five conditions of Fick’s principle?
Adequate FiO2 Appropriate O2, diffusion from blood to the capillaries Adequate number of RBC's Proper tissue perfusion Effective tissue offloading
What are the four Weil-Shubin classifications of shock?
Distributive
Hypovolemic
Cardiogenic
Obstructive
What is psychogenic shock? (2)
It is relative hypovolemia due to severe vasodilation
It is caused by sudden and temporary sympathetic nervous system failure
What is neurogenic shock? (5)
AKA Spinal shock
Massive relative hypovolemia due to severe vasodilation
Damage caused to the nervous system inhibiting its involuntary/voluntary control of homeostasis
Sudden loss of sympathetic tone to the smooth muscles of the vessels below the point of injury
Without constant stimulation widespread relaxation of these muscles causes a decrease in PVR and a drop in BP
What is respiratory shock? (6)
Airway obstruction Hypoventilation Toxic inhalation Severe pulmonary edema Exacerbation COPD Multi-lobe bilateral pneumonia
What is hypovolemic shock? (3)
Inadequate perfusion of tissues caused by a volume deficiency other than blood
AKA third space loss
Severe dehydration: diarrhea/vomiting, peritonitis, heat exhaustion, severe burns
What is hemorrhagic shock? (2)
Internal/external hemorrhage resulting in hypovolemia and a systemic reduction in tissue perfusion
Mortality rate dependent on etiology, early recognition, and aggressive intervention
What is cardiogenic shock? (3)
Failure of the pump to supply O2 rich blood to the tissues
Potentially a combination shock, depending on the etiology: Massive AMI, Valvular insufficiency, Lethal dysrhythmia, Cardiac arrest
Has a 60-90% mortality rate
What is metabolic shock?
It is shock that is a result of a change in the chemistry of the endocrine system in the body
What are some causes of metabolic shock? (7)
Insulin shock Diabetic ketoacidosis Adrenal gland failure Thyroid failure Pituitary gland failure Renal failure Toxic ingestion
What is septic shock? (3)
Massive infection and toxin production resulting in the inability of the cell to exchange O2/CO2 resulting in cellular death
Relative hypovolemia due to pool of blood in extremities
1 month morality rate 35-45%
What is the progression of shock? (4)
Follows a sequence of stages related to changes in capillary perfusion and cellular necrosis
Various shock states may interrelate clinically to produce a mixed picture
Hypovolemic shock may lead to acidosis and result in cardiogenic shock
Septic shock may lead to hypovolemia as a result of microbal toxins, cytokines, and capillary permeability
What are the four stages of shock?
Initial stage of shock
Compensatory stage
Progressive stage
Refractory stage
What happens in the initial stage of shock? (3)
Cellular changes occur in response to shock
Anaerobic metabolism due to the lack of oxygen
Clinical signs not detectable
What happens in the compensatory stage of shock? (3)
Neural compensation: baroreceptors in aortic and carotid sinus are stimulated by a drop in MAP, sympathetic nervous system stimulated via vasomotor and cardiac centers of the medulla, catecholamine response causes arteriole constriction, venous reservoir constriction, inotropic and chronotropic effect on the heart
Hormonal compensation causes the RAAS system to start
Chemical compensation, increased respiratory rate to clear CO2
What happens in the progressive stage of shock? (2)
Compensatory mechanisms not effective
Severe hypoperfusion causes MODS
What happens in the refractory stage of shock? (2)
It is the irreversible stage
Cell and organ destruction are severe enough that death is inevitable
What are the brain specific effects of shock? (4)
The brain is essential
Adrenergic stimulation to maintain cerebral blood flow
Irritability and agitation (early stage)
Unresponsive (late)
What is the heart specific effects of shock? (2)
The heart is essential
The protective flow, except in cardiogenic shock
What is the skeletal, muscle and integumentary specific effects of shock? (1)
Vasoconstriction limits flow to non-essential areas
What are the kidney specific effects of shock?
Decreased GFR
What are the lung specific effects of shock? (2)
Tachypnea
Increased pulmonary muscle oxygen consumption
What are the liver specific effects of shock? (3)
Glucose release as stimulated by catecholamines
May result in hyperglycemia due to lack of cell usage
Loss of clotting factors may cause DIC
What are the mesenteric specific effects of shock? (2)
Decreased blood flow to the gut and causes nausea and vomiting
Necrosis by digestive enzymes cause damage to the protective mucosal barrier. Bacteria and toxins are released into the bloodstream
What are the pancreas specific effects of shock? (2)
Release of amylase and lipase into the circulation
Myocardial depressant factor (MDF) released decreasing myocardial contractility
What are the four classifications of hemorrhage?
Class I (vasoconstriction)
Class II (Capillary and venule opening)
Class III (Disseminated intravascular coagulation)
Class IV (Multiorgan dysfunction syndrome)
What is class I (vasoconstriction) hemorrhage? (3)
It is approx 15% blood loss (500-750 mls)
The healthy body can easily accommodate for the loss
No effect on BP, pulse pressure or renal output
What is the compensation for class I (vasoconstriciton) hemorrhage? (6)
Catecholamine release RR (normal ranges) HR (mild tachycardia to maintain CO due to reduced SV) BP (possible orthostatic hypotension) Cap refill (normal) CNS (mild anxiety)
What is class II (capillary and venule opening) hemorrhage? (3)
15-25% blood loss (750-1250 mls)
First line compensatory mechanisms can no longer maintain BP
Secondary mechanisms now employed
What are signs of early decompensation of class II (capillary and venule opening) hemorrhage? (6)
RR (Tachypnea) HR (Tachycardia) BP (Hypotension may be prevalent/decreased pulse pressures) CR (delayed) CNS (anxiety) Pale, cool, clammy skin
What is capillary washout? (3)
Accumulated cellular waste products cause post-capillary sphincter to relax
Waste products, cellular contents and coagulated cells dumped into venous circulation. Profound metabolic acidosis and the release of microscopic emboli
The body quickly moves towards death
What is class III (Disseminated intravascular coagulation) hemorrhage? (2)
25-35% blood loss (1250-1750 mls)
Compensatory mechanisms unable to cope
What are signs of late decompensation in class III (disseminated intravascular coagulation)? (6)
Without intervention, patient survival is unlikely
RR (Tachypnea)
HR (Tachycardia)
BP (Moderate/severe hypotension/narrowing pulse pressures)
CR (delayed)
CNS (anxiety/confusion)
What is disseminating intravascular coagulopathy (DIC)? (2)
Phospholipids released due to injured/lysed cells
Prolonged low CO also triggers phospholipids release due to endothelium injury
What is the result of disseminating intravascular coagulopathy (DIC)? (4)
Systemic coagulation
Diffuse fibrin formation (results in multiple microscopic emboli)
Exhaustion of clotting factors
Fibrinolytic system activate due to coagulation activation
What is class IV (multiorgan dysfunction syndrome) hemorrhage? (2)
> 35% blood loss (>1750 mls)
Irreversible shock
What are signs of class IV (multiorgan dysfunction syndrome) hemorrhage irreversible shock? (7)
Survival is unlikely RR (Tachypnea) HR (Thready, rapid pulse) BP (Severe hypotension) CR (delayed) CNS (unresponsive) Decreased to absent urine output
What are some physiological responses, variations and determining factors in response to shock? (8)
Age and relative health Older adults Children General physical condition Preexisting disease Ability to active compensatory mechanisms Medications Specific organ system affected
What are three keys to shock assessment? (3)
Early recognition is the key to patient survival
Look for subtle signs both initially and ongoing
Frequent ongoing assessments and trending
What are the five points of shock management?
Airway and breathing
Hemorrhage control
Fluid resuscitation
Temperature control
Pharmacological intervention
What should we assume the shock is until we prove otherwise?
Hypovolemic shock
How do we differentiate cardiogenic shock from hypovolemic shock? (4)
Chief complaint: Chest pain, dyspnea, tachycardia
Heart rate
Signs of congestive heart failure
Dysrhythmias
How do we differentiate distributive shock from hypovolemic shock? (3)
Mechanism suggesting vasodilation: spinal cord injury, drug overdose, sepsis, anaphylaxis
Warm, flushed skin
Lack of tachycardic response (not a reliable finding)
How do we differentiate obstructive shock from hypovolemic shock? (4)
Signs and symptoms of:
Cardiac tamponade
Tension pneumothorax
Pulmonary embolism
What are key vital signs for the detailed physical examination of shock? (4)
Pulse
Blood pressure
Orthostatic vital signs
Evaluate patients ECG
What are four key points to resuscitation of shock patients?
Restore adequate tissue oxygenation by:
Ensuring adequate oxygenation
Maintaining effective volume-to-container size ratio
Rapid transport to appropriate medical facility
How do we ensure red blood cell oxygenation in shock patients? (3)
Patent airway
Support ventilation with high FiO2, positive pressure ventilation PRN
Correct airway abnormalities that interfere with adequate ventilation
How do we accomplish the ratio of volume to container size? (3)
Decrease the size of the container, especially in shock states not associated with hemorrhage
Vasoactive medications in some distributive shock (sepsis and cardiogenic)
Volume replacement as needed
What are eight key principles in managing shock?
Open airway High-concentration oxygen Assist ventilation as needed Control external bleeding if present IV fluid replacement PRN Maintain body temperature Monitor ECG and oxygen saturation Reassess vital signs
What are the key treatment guidelines for hypovolemic shock? (3)
Fluid volume replacement
Large volume fluid replacement if: systolic BP 90mmHg
What are the key treatment guidelines of cardiogenic shock? (5)
Improve pumping action of the heart and manage the dysrhythmias
Fluid replacement
Drug therapy if needed
Cardiogenic shock due to myocardial ischemia or infarction requires: reperfusion strategies or possible circulatory support
Manage tension pneumothorax and cardiac tamponade
What are the key treatment guidelines for neurogenic shock? (4)
Treatment is similar to hypovolemia
Avoid circulatory overload
Monitor lung sounds for pulmonary congestion
Vasopressors may be indicated
What are the key treatment guidelines of septic shock? (6)
Management of hypovolemia if present
Correction of metabolic acid-base imbalance
Fluid resuscitation
Respiratory support
Vasopressors to improve cardiac output
Thorough history to the find the source of sepsis
What are the key treatment guidelines for severe hemorrhagic shock? (5)
Rapid recognition Initiation of treatment Prevention of additional injury Rapid transport to appropriate hospital Advanced notification to receiving facility
What is shock? (3)
It is a state of inadequate perfusion relative to the demands of the tissues
It is the transitional stage between homeostasis and death
Underlying killer of all trauma patients
What is a hemorrhage?
An abnormal internal or external discharge of blood
What is homeostasis?
The natural tendency of the body to maintain a steady and normal internal environment
What are the three types of hemorrhage?
Capillary
Venous
Arterial
What is clotting?
The body’s three step response to stop the loss of blood
What are the three phases of the clotting process?
Vascular phase
Platelet phase
Coagulation
What is the vascular phase of clotting?
It is the first step in the clotting process in which smooth blood vessel muscle contracts, reducing the vessel lumen and the flow of blood through it
What is the platelet phase of clotting?
It is the second step in the clotting process in which platelets adhere to blood vessel walls and to each other
What is the coagulation phase of clotting?
It is the third step in the clotting process, which involves the formation of a protein called fibrin that forms a network around a wound to stop bleeding, ward off infection, and lay a foundation for healing and repair of the wound.
What is to aggregate?
To cluster or come together
What is fibrin?
Protein fibres that trap red blood cells as part of the clotting process
What are four factors that hinder the clotting process?
Movement of the wound site
Aggressive fluid therapy
Low body temperature
Medications, such as aspirin, heparin, or warfarin
What is to apply direct pressure to a wound?
It is a method of hemorrhage control that relies on the application of pressure to the actual site of bleeding
What is a tourniquet?
It is a constrictor used on an extremity to apply circumferential pressure on all arteries to control the bleeding
What is lactic acid?
Compound produced from pyretic acid during anaerobic glycolysis
What does it mean to be anaerobic?
The ability to live without oxygen
What is fascia?
A fibrous membrane that covers, supports, and separates muscles and may also unite the skin with underlying tissue
What is a hematoma?
A collection of blood beneath the skin or trapped within a body compartment
What is epistaxis?
It is bleeding from the nose resulting from injury, disease or environmental factors, a nosebleed
What is an esophageal varice?
They are enlarged and tortuous esophageal veins
What is melena?
Black, tar-like fees due to gastrointestinal bleeding
What is anemia?
A reduction in the hemoglobin content in the blood to a point below that required to meet the oxygen requirements of the body
What are pulse pressures?
The difference between the systolic and diastolic blood pressure
What are catecholamines?
A hormone, such as epinephrine or norepinephrine, that strongly affects the nervous and cardiovascular systems, metabolic rate, temperature, and smooth muscle
What are four early signs or symptoms of internal hemorrhage?
Pain, tenderness, swelling or discolouration of suspected injury site
Bleeding from mouth, rectum, vagina or other orficie
Vomiting of bright red blood
Tender, rigid and/or distended abdomen
What are twelve late signs or symptoms of internal hemorrhage?
Anxiety, restlessness, combativeness, or altered LOC Weakness, faintness or dizziness Vomiting of blood the color of dark coffee grounds Thirst Melena Shallow, rapid breathing Rapid, weak pulse Pale, cool, clammy skin Cap refill greater than 2 seconds Dropping blood pressure Dilated pupils sluggish in responding to light Nausea/vomiting
What is hematochezia?
The passage of stools containing red blood
What is orthostatic hypotension?
A decrease in blood pressure that occurs when a person moves from a supine to a sitting or upright position
What is metabolism?
The total changes that take place in an organism during physiological processes
What is ischemia?
A blockage in the delivery of oxygenated blood to the cells
What is hydrostatic pressure?
The pressure of liquids in equilibrium; the pressure exerted by or within liquids
What is a rouleaux?
A group of red blood cells that are stuck together
What is washout?
The release of accumulated lactic acid, carbon dioxide (carbonic acid), potassium, and rouleaux into the venous circulation
What is compensated shock?
Hemodynamic insult to the body in which the body responds effectively. Signs and symptoms are limited, and the human system functions normally
What is decompensated shock?
The continuing hemodynamic insult to the body in which the compensatory mechanisms breakdown. The signs and symptoms become very pronounced, and the patient moves rapidly toward death
What is irreversible shock?
The final stage of shock in which organs and cells are so damaged that recovery is impossible
What is overdrive respiration?
Positive pressure ventilation supplied to a breathing patient
