Q3 Shock/burns Flashcards
What is shock? 2 main reasons?
Imbalance between O2 supply and metabolic demand
Either through low perfusion or inadequate O2 reaching the tissue.
T/F: Shock can occur with a normal blood pressure.
True.
If there is low perfusion, then there will be _______ metabolic demand and _____ O2 extraction meaning the blood returning to the heart (SvO2) will _______
Increased (starved tissue), increased, decreased level of O2
If there is adequate perfusion, but O2 cannot be delivered to the cells, the blood returning to the heart (SvO2) will have -_______
Some causes?
Increased O2 levels because it couldn’t dump it off on the tissue.
Edema.
When the tissue fails to get adequate O2 what happens?
Lactate produced from anaerobic metabolism
Acidosis
Failure of NA/K pumps so Hydropic swelling with fluid accumulating in the cell
Free radical formation
Inflammatory cytokines
Activation of the autonomic response
When the tissues don’t get enough O2, the ANS is activated. How (2)?
SNS - NE, epi, dopamine and cortisol are released to cause vasoconstriction, increase HR and increase contractility (increase CO).
Renin-angiotensin axis - water and Na conservation = fluid retention + vasoconstriction. Increase blood volume and pressure.
The ANS response leading to increased HR, cardiac contractility and CO is caused by _________
SNS
The ANS response leading to increase in blood volume and blood pressure is _________. How?
Renin-angiotensin axis.
Retention of Na and water and vasoconstriction.
What is a reprerfusion injury? Likely to happen where?
When O2 is restored, ischemic cells produce a flood of free radicals which overwhelms the antioxidant system. This causes oxidative cell damage which causes the release of inflammatory cytokines and IL8 and adhesion molecules. Neutrophils attack the reperfused tissue. Lungs.
What are some possible interventions to reduce reperfusion injury?
Rapid reperfusion
Metabolite inhibitors
Metal chelations, free radical defense mechanisms
IL1 RAs and antibodies, TNF alpha antibodies.
Antibody and inhibitors to adhesion molecules
Homeostatic mechanisms are sufficient to maintain adequate tissue perfusion despite reduction in CO. This is ______ shock
Compensatory
How does the body maintain homeostasis in the compensatory shock stage?
Corticosteroid release from adrenal glands + renin from kidneys activates SNS to maintain blood pressure through vasoconstriction and shunting of blood to brain and heart. Glucose release from kidneys attempts to supply fuel for increased metabolic demand.
When the body’s compensatory mechanisms fail, you move on to ________ shock. This stage is marked by what S/s?
Progressive.
Hypotension, tissue hypoxia. Lactate production, cellular swelling, dysfunction and death.
Inflammatory cytokines are activated and the clotting cascade is activated.
How do cells respond to decreased O2 delivery?
Na/K and other ion pumps stop working. Hydropic swelling. Lactate production.
When the body is in shock, it shunts blood FROM ______ to ________
GI, MSK and kidneys
Heart and brain.
Presence of These two inflammatory markers are though to be important mediators of vascular failure and progressive organ damage
TNF alpha and IL1
Two pathologies that can arise from shock
DIC - due to inflammatory response activation of coagulation cascade and micro vascular clot formation
ARDS -
Examples of Cardiogenic shock
Pump failure.
MI
Arrhythmia
Cardiomyopathy
Myocardial contusion
Myocarditis
Sepsis is a form of ______ shock
Distributive.
Examples of Distributive shock
Sepsis, anaphylaxis, neurogenic shock, drug and toxin induced, endocrine.
Examples of hypovolemic shock
Hemorrhage
Non-hemorrhage
- burns
- pancreatitis
- dehydration
Examples of obstructive shock
PE,
Tension pneumothorax
Tamponade.
Name the type of shock:
Inadequate CO despite adequate vascular volume.
Cardiogenic.
In Cardiogenic shock, _____ is activated to ________ to maintain BP
SNS
Vasoconstrict
During Cardiogenic shock, you may see venous_______ due to __________. This causes ___________
High venous pressures due to increased after load (from vasoconstriction).
Fluid extravasation and edema.
In Cardiogenic shock, you would see ______ SvO2. Why?
Low.
Tissue is perfusing, the blood flow (CO) is just inadequate to meet the tissue demand (starved tissue) so therefore, they eat up more O2 than usual, so the returning venous blood has a low SvO2.
Cardiogenic shock therapy has 3 aims:
Improve CO (Inotropes)
improve myocardial O2 deliver
Decrease workload of the heart.
A doctor might consider an IABP, LVAD or heart transplant is someone with _________ shock.
Cardiogenic
In Cardiogenic shock, there is _____ in EF, ____ in ESV, _____ preload, ______ left atrial pressure, ______ pulmonary capillary hydrostatic pressure, _____ afterload, _____ volume retention by kidneys and _____ pulmonary edema.
Decrease
Increase
Increase
Increase
Increase
Increase
Increase
Name that shock:
Severe capillary leak, dilated vessels, decreased SVR, reduced preload.
Distributive.
CO is inadequate in distributive shock because:
Preload is decreased due to all the fluid 3rd spacing.
Difference between anaphylaxis and anaphylactoid reaction?
Anaphylaxis is IgE mediated and results from a sensitizing exposure.
Other than that, they are clinically indistinguishable.
Cell responsible for the anaphylactic response?
Mast cells release of vasodilators mediators.
When may epi be contraindicated when treating anaphylactic shock?
If patient is taking beta blockers - it could cause severe hypertension due to unopposed alpha stimulation.
Risk factor for death in anaphylactic shock?
Delay of epinephrine.