Shock Flashcards
What is shock?
Decreased tissue perfusion and impaired cellular metabolism because perfusion is not adequate to meet cellular needs
Causes an imbalance of oxygen and nutrients of supply and demand
Is shock a disease?
No, it is a clinical syndrome
What are the causes of different types of shock?
Problem with the pump, volume or vessels
What is the common shock among patients in the ICU?
septic shock
Is shock defined by low blood pressure?
Decreased BP is a hallmark sign but it does not define shock
What is CO? What is normal CO? What does CO provide for the body?
CO = SV x HR
Amount of blood ejected by the heat in one minute
Normal: 4-8L/min
Perfusion is supplied by CO
What is SV? What is SV affected by?
Amount of blood ejected with each beat
- Preload
- Afterload
- Contractility
Assessment of preload is done by?
Mainly volume indicator
- Weight (1kg = 1L of fluid)
- I/Os
- UO
- VS
- Edema
Afterload is assessed with? What affects afterload?
- BP
- Skin assessment
- Peripheral pulses (weak or bounding)
Affected by vasoconstriction (cool and clammy) or vasodilation (red and sweating)
What is contractility assessed by?
With an echocardiogram
What happens to the VS when preload (volume) goes down?
BP will decrease and HR will increase
With shock there is decreased __, but the cause of the decrease is ___
CO, difficult to pinpoint
What are some causes of decreased CO? (5)
- Decreased contractility from direct myocardial insult
- Inadequate myocardial stretch from preload being too low
- Overstretched myocardium from preload being too high
- Low after load (vasodilation)
- High after load (vasoconstriction)
What type of shock might cause decrease CO because of decreased contractility from direct myocardial insult?
Caridogenic shock
What type of shock might cause decrease CO because of inadequate myocardial stretch from preload being too low?
Hypovolemic shock
What type of shock might cause decrease CO because of low after load (vasodilation)?
Neurogenic or septic shock
How is organ perfusion measured?
Blood pressure and MAP
What MAP is needed to perfuse vital organs?
> 60 mmHG
An RN may titrate orders based on what MAP and BP?
MAP > 65 mmHG
SBP > 90 mmHG
What is pulse pressure? What is a normal pulse pressure? What indicates vasoconstriction? Vasodilation?
difference between the systolic and the diastolic pressure
Normal = 40
Vasoconstriction <40
Vasodilation >40
What information can a pulse pressure provide?
What the peripheral vessels are doing to maintain BP
Narrowed pulse pressure with an increased HR –> hypovolemia
What is more effective, MAP and BP trends or one time reading?
More effective to follow the trend
Generally pathology of shock
- Decreased CO
- Decreased cellular oxygen supply
- Decreased tissue perfusion
- Impaired metabolism
- End stage of shock (organ failure –> death)
What is cariogenic shock?
Pump failure
Systolic or diastolic dysfunction that leads to decreased SV and decreased CO
What are the causes of cariogenic shock?
- MI ((systolic dysfunction) most common cause and is leading cause of death with acute MI)
- Cardiac tamponade or cardiomyopathy (diastolic)
- Structural issue (valvular disorder)
- Dysrhythmia
What does cardiogenic shock look similar to? How does it manifest?
Similar to decompensated heart failure
- Tachycardia, hypotension, narrow pulse pressure
- Increased systemic vascular resistance
- Increase in pulmonary wedge pressure
- Tachypnea
- Crackles
- Signs of peripheral hypoperfusion (cyanosis, pallor, diaphoresis, weak peripheral pulses, cold/clammy skin)
- Decrease UO
- Anxiety, confusion, agitation
What is hypovolemic shock?
Loss of intravascular fluid volume (d/t any type of fluid loss including dehydration), inadequate circulating volume –> fluid deficit
Decreased intravascular –> decrease venous return –> decreased preload –> decrease SV –> decreased CO
What is absolute hypovolemia?
Loss of fluid d/t hemorrhage, GI, DI, or diuresis
What is relative hypovolemia?
fluid out of intravascular into the extravascular (third spacing) d/t increased capillary permeability like in burn patients
How much fluid loss can the body compensate for? what is this called?
The body can compensate for 15% or 750mL of fluid loss
Called the physiologic reserve
What happens if there is 15-30% fluid loss?
The sympathetic nervous system kick in and increase HR, CO, and RR and decreases SV, CVP, and PAP
If there is more than 15% loss and treatment is provided what happens to the tissues?
Tissue dysfunction is generally reversible
What are the clinical manifestations of hypovolemic shock?
Anxious
Decrease UO
Class 1 of hemorrhagic shock
Up to 15% or less than or equal to 750 mL
Minimal changes
Normal BP, RR, and UO
Increase HR > 100
Anxious
Class 2 of hemorrhagic shock
15-30% or 750-1500 mL
Increased SNS response
Increased CO, HR (100-120), RR (20-25)
Decreased pulse pressure, CVP, PA pressure, UO (20-30mL/hr)
Restless
Class 3 of hemorrhagic shock
30-40% or 1500-2000mL
Significant decrease in BP
HR >120
RR: 25-30
UO: 5-15ml/hr
Class 4 of hemorrhagic shock
Over 40% or over 2000mL
Decreased BP (SBP>90) HR >120 Decrease pulse pressure RR: 30-40 UO: minimal to none Confused, lethargic Loss of auto regulation in microcirculation Irreversible tissue damage
What is the general treatment for class 1 and class 2 hemorrhagic shock?
Fluid replacement with crystalloid
What is the general treatment for class 3 and class 4 hemorrhagic shock?
Fluid replacement with crystalloid and or blood
What is disruptive shock?
Misdistribution of blood flow and volume
What are the 3 subcategories of distributive shock?
Neurogenic shock
Anaphylactic shock
Septic shock
What is neurogenic shock? When does it occur? How long does it last?
Loss of sympathetic nervous system vasoconstrictor –> vasodilation and lypoperfusion
Occurs within 30 minutes of a spinal cord injury and can last up to 6 weeks
What are the causes of neurogenic shock?
- SCI T6 and above (most common)
- Epidural anesthesia
- Drugs (opiods/benzos)
What are the clinical manifestations of neurogenic shock?
- Hypotension
- Bradycardia
- Unable to regulate body temperature
- Warm dry skin d/t pooling blood in extremities
What is anaphylactic shock? What goes on with inside the body?
Sudden hypersensitivity (allergic) reaction to a substance like drug, chemical, food or insect
Massive vasodilation –> increased capillary permeability –> edema –> bronchospasm
** major increase in capillary permeability –> relative hypovolemic state
What are the causes of anaphylactic shock? How can you come in contact with these things?
- Drug, chemical, vaccine, food, insect
venom - Contact, inhalation, ingestion, or injection
How does anaphylactic shock manifest?
- Dizziness
- Chest pain
- INC
- Swelling of lips & tongue
- Wheezing and stridor
- Bronchospasm
- Flushing
- Angioedema (deeper swelling of skin often around the lips and eyes)
What is septic shock?
Systemic inflammatory response to an infection
- Hypotension despite adequate fluid
resuscitation - Inadequate tissue perfusion
- Microorganism enters body –> normal immune response –> immune response
exaggerated –> increased inflammation &
coagulation –> microthormbi
What are the causes of septic shock?
- Unknown organism 50%
- Gram-negative and gram-positive bacteria (most common)
- Parasites, fungi, virus
What are the s/s of septic shock?
- Vasodilation
- Misdistribution of blood flow
- Myocardial depression
- Respiratory failure (common with sepsis)