shock Flashcards
What is shock
- Inadequate supply of oxygen to tissues to meet the bodys metabolic demands
- -> anaerobic metabolism -> acidosis -> hypotension
equation for delivery of oxygen
delivery of oxygen = CO x CaO2
- cardiac output x arterial oxygen content
What is the normal arterial and venous O2 content
- arterial: 98%
- venous 70%
what is the normal o2 content in SVC and IVC? Why?
- SVC: 65%
- IVC: 75%
- kidneys get 15-20% CO for filtering but don’t take alot of oxygen and they drain into IVC
What is the normal difference between arterial and venous Oxygen saturation?
- < 25-30
- the higher the difference, the worse it is
What are ways to increase supply of oxygen
- maximaze CO
- increase preload, decrease afterload, increase contractility, appropriate HR
- maximize CaO2
- Hct
- supplemental O2
What are ways to decrease demand for oxygen
- tx fever
- support respiratory effort
- sedation/pain control
what is ohm’s law related to BP
BP = flow x resistance
stroke volume is composed of what two things
- intravascular volume : preload
- contractility
List the key clinical features of shock
- tachycardia
- tachypnea
- +/- hypotension (depending on degree)
- signs of poor end-organ perfusion
- AMS
- oliguria
- lactic acidosis
- cool, mottled extremities, thready pulses
List DDx for hypovolemic shock
- hemorrhage
-
fluid loss
- internal
- external
In hypovolemic shock, how will the following parameters be affected
- Preload
- CO
- Afterload
- Preload: decreased
- CO: decreased
- Afterload: increased
In hypovolemic shock, how will the following parameters be affected
- BP
- Organ perfusion
- A-V O2 difference
- BP: low
- Organ perfusion: decreased
- A-V O2 difference: High
List the “big 5” tissues affected in shock
- Cardiovascular
- Respiratory
- Skin
- CNS
- Renal
Is the following signs of compensated or decompensated shock
- increased pulse
- vasoconstriction
- weak pulse, cool, clammy skin, anxiety, thirst, weak
- compensated - early
- baroreceptor mediated vasconstriction
Is the following signs of compensated or decompensated shock
- loss of radial pulse
- hypotension
- loss of consciousness
- dec RR
decompensated - late
define hypovolemic shock
- reduction in intravascular volume/preload leading to decreased cardiac output and insufficienct oxygen delivery to cells
List DDX for non hemorrhage hypovolemic shock
- vomiting, diarrhea
- dehydration
- evaporative -> burns
- third spacing
- diabetes insipidus/mellitus
Body can compensate for what % blood loss
< 20%
what % blood loss is considered uncompensated (progressive)
20-40%
what % blood loss is considered profound/irreversible
> 40%
What organs take priority and perfusion to them remains normal during hypovolemic shock
- brain
- heart
- kidneys
- liver
What organs become blood volume deficient and perfusion to them decreases during hypovolemic shock
- skin
- GI tract
- skeletal muscle
What is the most common type of shock
- hypovolemic shock
List important managment steps of acute external bleeding
- direct pressure to wound site
- elevate wound site above level of victim’s heart
- press on proximal “pressure points”
- radial, ulnar brachial, axillary, femoral (not carotid )
- apply tourniquet above injury site - last resort, note time of application
What is obstructive shock. give some examples
- mechanical block to heart’s outflow/inflow
- pulmonary embolus
- cardiac tamponade
- tension pneumothorax
How are the following parameters affected in cardiogenic shock?
- preload
- cardiac output
- afterload
- preload: increased
- cardiac output: decreased
- afterload: increased
How are the following parameters affected in cardiogenic shock?
- blood pressure
- organ perfusion
- A-VO2 difference
- blood pressure: low
- organ perfusion: decreased
- A-VO2 difference: high
What is cardiogenic shock?
- failure of heart to pump effectively
- acute hypotension -> low CO -> inadequate LV outflow -> poor end organ perfusion
what is the most common cause of cardiogenic shock
acute myocardial infarction
What is Distributive shock
- insufficient volume of blood or “relative” hypovolemia resulting from dilation of all blood vessels
- “tank” is much larger
List the three main types of Distributive shock
- Septic shock: overwhelming infection -> profound systemic vasodilation
- Anaphylactic shock
- Neurogenic shock: trauma to spinal cord resulting in loss of autonomic and motor reflexes below injury level
What is septic shock
- an exaggerated endogenous inflammatory response to invasive infection leading to
- circulatory collapse
- multiple organ failure
- death
What is SIRS: systemic inflammatory response syndrome? what are the criteria
- systemic inflammatory response to a variety of severe clinical insults. Manifested by > or = two of the following
- temperature < 36 or > 38 C
- HR > 90 bpm
- RR > 20 or PaCO2 < 32 mm Hg
- WBC > 12,000, < 4,000 or > 10% bands
Define infection
inflammatory response to microorganisms or invasion of normally sterile tissues
define sepsis
- systemic response to infection
- i.e. confirmed or suspected infection plus
- > or = 2 SIRS criteria
define severe sepsis
sepsis associated with organ dysfunction (CV, respiratory, renal, hepatic, and/or hematologic)
define septic shock
- sepsis with refractory hypotension and impaired organ perfusion despite adequate fluid resuscitation
what is ARDS
adult respiratory distress syndrome
Are the following characteristics consistent with warm (hyperdynamic) or cold (hypodynamic) shock?
- hypotensive
- tachycardia
- tachpnea
- bounding pulse
- warm, well perfused extremities
- skin flushed, moist
- warm hyperdynamic shock
Are the following characteristics consistent with warm (hyperdynamic) or cold (hypodynamic) shock?
- hypotensive
- tachycardia
- tachypnea
- narrow, thready pulse
- cold, poorly perfused extremities
- skin pale, dry
- col hypodynamic shock
How do the following parameters change in Septic shock
- preload
- cardiac output
- afterload
- preload: decreased/normal
- cardiac output: increased
- afterload: decreased
How do the following parameters change in Septic shock
- blood pressure
- organ perfusion
- A-VO2 difference
- blood pressure: normal/low
- organ perfusion: decreased
- A-VO2 difference: low
How do the following parameters change in spinal shock
- preload
- cardiac output
- afterload
- preload: decreased
- cardiac output: increased
- afterload: decreased
How do the following parameters change in spinal shock
- blood pressure
- organ perfusion
- A-VO2 difference
- blood pressure: low
- organ perfusion: normal
- A-VO2 difference: normal
