Shock Flashcards
What is shock
- decreased tissue perfusion and impaired cellular metabolism
- tissue perfusion does not meet the cellular 02 requirements
- imbalance between supply and demand for 02 and nutrients
Shock is a problem with….
- pump: cariogenic
- volume: hypovolemic
- vessels: distributive and obstructive
TRUE OR FALSE: shock is defined by low blood
false
CO
SV X HR and is where perfusion comes from
CO is..
-amount of blood ejected by the heart in one minute (N= 4-8)
SV is …
-amount of blood ejected with each beat (N= 60-150)
SV is altered by…
- preload
- contractility
- afterload
how to assess preload
- weight
- I/O
- UO
- VS
- edema
- indicator of volume
How to assess afterload
- vasoconstriction (cold and clammy)
- vasodilation (red and sweating)
- BP
- Skin assessment
- peripheral pulse (weak or bounding?)
how to assess Contractility
- Echo
what happens to vitals when preload goes down
- increased HR and decreased BP
what is CO used to evaluate
- contractility but hard to pinpoint actual cause of low CO
Things that can affect CO
- decreased contractility from direct myocardial insult (from cardiogenic shock)
- inadequate myocardial stretch from preload being too low (from hypovolemic shock)
- overstretched myocardium from preload being too high
- low afterload (vasodilation from neurogenic or spetic shock)
- high afterload (vasoconstriction)
why do we use pressure as a measurement
- because its difficult to measure volume in the ventricles so we use pressure to estimate volume
- pressure indicates stretch and volume
what measures preload
- CVP
- PAWP
what measures afterload
-SVR/PVR
How is perfusion measured
-by MAP and BP
organ perfusion measures
- RN orders to titrate
- MAP > 65 OR greater (MAP > 60 needed to perfuse and sustain vital organs)
- SBP > 90 (kidneys wont produce urine below 60)
pulse pressure
- difference between systolic and diastolic
- provides info on what peripheral vessels are doing to maintain BP
- N= 40
- <40= vasoconstriction
- > 40= vasodilation
a narrowed pulse pressure and increased heart rate indicates
hypovolemia
types of shock
- Cardiogenic: pump failure
- Hypovolemic: decrease intravascular volume
- Distributive: misdistribution of circulating blood volume
- Neurogenic shock: loss of sympathetic tone
- Anaphylactic shock: massive hypersensitivity response
- Septic shock: overwhelming inflammatory response - Obstructive: physical blockage of blood flow
cardiogenic shock
- Pump failure
- Systolic or diastolic dysfunction→ decreased stroke volume→ reduced CO
causes of cardiogenic shock
- MI (systolic dysfunction)
- Cardiac tamponade or cardiomyopathy (diastolic)
- Structural issue (valvular disorder)
- Dysrhythmia
cardiogenic shock mani
- Similar to decompensated heart failure
- Tachycardia, hypotension, narrow pulse pressure
- ↑SVR
- Increase in pulmonary wedge pressure
- Tachypnea
- Crackles
- Signs of peripheral hypoperfusion (Cyanosis, pallor, diaphoresis, weak peripheral pulses, cold/clammy skin)
- ↓urine output
- Anxiety, confusion, agitation
Hypovolemic shock
- After a loss of intravascular fluid volume, inadequate circulating volume
- Fluid deficit
Absolute hypovolemia
-loss of fluid d/t hemorrhage, GI, DI, diuresis
relative hypovolemia
-fluid out of vascular into extravascular (third spacing) d/t increased capillary permeability like in burns
patho behind hypovolemic shock
-↓intravascular ↓venous return ↓decrease preload ↓SV ↓CO
when in hypovolemic shock how much of fluid loss can the body compensate for
- 15 % (750 ml fluid loss)
*15-30% RESULTS IN SNS response: ↑HR, CO, RR
↓SV, CVP, PAP
Clinical mani: anxious and decreased UO
Class one hemorrhagic shock
-(up to 15%) ≤ 750ml, S/S-normal BP/RR/UO, HR≥100, minimal to no change, anxious
class two hemorrhagic shock
- (15-30%) 750-1500ml, ↑SNS-mediated response: S/S-Increase CO, HR 100-120, ↓PP, RR: 20-25, ↓CVP, PA pressure, U/O: 20-30ml/hr, restless
class three hemorrhagic shock
- (30-40%) 1500-2000ml, significant ↓BP, HR >120, RR: 25-30, U/O 5-15ml/hr
class four hemorrhagic shock
- (≥40%) >2000ml, S/S-DECREASED BP (SBP <90), HR>120, ↓PP, RR 30-40, U/O: minimal to no U/O, Confused, lethargy, loss of autoregulation in microcirculation and irreversible tissue destruction.
TX of class 1 and 2 hemorrhagic shock
- crystalloid fluid replacement
TX of class 3 and 4 hemorrhagic shock
- crystalloid fluid and/OR blood replacement
Distributive shock
- Misdistribution of blood flow and volume
- 3 subcategories
1. Neurogenic Shock
2. Anaphylactic Shock
3. Septic Shock
distributive neurogenic shock
- Occurs within 30 minutes of spinal cord injury and can last up to 6 weeks
- Loss of SNS vasoconstrictor with massive vasodilation (hypoperfusion)
causes of distributive neurogenic shock
- T6 or above**
- Epidural anesthesia
- Drugs (opioids/benzos)
Distributive: Neurogenic ShockClinical manifestations
- Hypotension
- Bradycardia
- Unable to regulate body temperature
- warm dry skin from pooling of blood in extremeties
Distributive: Anaphylactic Shock
- sudden Hypersensitivity reaction to a sensitizing substance
- Massive vasodilation → ↑capillary permeability→ edema→ bronchospasm
- Major increase in capillary permeability= relative hypovolemic state
causes of Distributive: Anaphylactic Shock
- Drug, chemical, vaccine, food, insect venom
- Contact, inhalation, ingestion, or injection
manifestations of Distributive: Anaphylactic Shock
- Dizziness
- Chest pain
- INC
- Swelling of lips & tongue
- Wheezing
- Stridor
- Bronchospasm
- Flushing
- angioedema
Distributive: Septic Shock
- Systemic inflammatory to a suspected infection
- Hypotension despite adequate fluid resuscitation
- Inadequate tissue perfusion
- Microorganism enters body→ normal immune response →immune response exaggerated → ↑inflammation & coagulation → microthrombi
causes of Distributive: Septic Shock
- Unknown organism 50%
- Gram-negative and gram-positive bacteria*
- Parasites, fungi, virus
manifestations of Distributive: Septic Shock
- Vasodilation
- Misdistribution of blood flow
- Myocardial depression
- May be euvolemic but d/t vasodilation become hypovolemic and hypotensive
- EF decreased first few days →ventricles dilate →maintain stroke volume
- Initially hyperventilates →respiratory alkalosis →uncompensated turns to respiratory acidosis (eventually respiratory failure)
obstructive shock
Physical obstruction to blood flow with a decrease CO
causes of obstructive shock
- Impaired ventricular filling or emptying
- Cardiac tamponade, tension pneumothorax, abdominal compartment syndrome, stenotic aortic valve, PE, right ventricular thrombi
manifestations of obstructive shock
-Decreased CO, increased afterload, jugular distension, pulsus paradoxus