Hypotensive shock Flashcards
Define circulatory shock
Generalized inadequate blood flow through body resulting in significant decreased tissue/organ perfusion
What are the types of shock?
- Cardiogenic
- Hypovolemic
- Obstructive
- Distributive
A. Neurogenic
B. Anaphylactic
C. Septic
What is compensated shock?
Normal circulatory compensatory mechanisms take over
What is progressive shock?
Shock progressively worsens
What is decompensated shock/Irreversible?
Leads to death
What is the pathophys of compensated shock?
- Compensatory mechanisms activated to maintain cardiac output & perfusion to brain & heart
- Baroreceptors sense drop in BP
A. Epi & NE released - ↑ peripheral resistance, BP, & contractility
- RAAS activated
What is the pathophys of progressive shock?
- Tissue hypoxia
- Cells switch to anaerobic metabolism
A. Lactic acid accumulates - Endothelial mediators released 2° to hypoxia
A. Venous pooling & ↑ capillary permeability
B. Sluggish blood flow increases risk of DIC
What is the pathophys of irreversible shock?
- Inadequate perfusion damages cell membranes
A. Lysosomal enzymes released, energy stores depleted, leading to cell death - Perfusion to coronary arteries reduced due to low BP
- Decreased CO
- Circulatory & respiratory failure follow
What is cardiogenic shock?
- Low output cardiac failure resulting from inadequate cardiac pumping (MI)
- Survival rate often less than 15%
- Most common cause of shock in hospital setting
- Vicious cycle which is difficult to change
- In ischemic heart, BP as low as 80-90 mm Hg can set off vicious cycle leading to cardiac deterioration
What are the causes of cardiogenic shock?
- Arrhythmias
- MI
- Heart failure
- Valve disorders
- Cardiomyopathies
- HTN
What is the results of cardiogenic shock?
Often a patient dies of cardiogenic shock before normal compensatory mechanisms begin
What are the general treatment guidelines for cardiogenic shock?
- Treatment extremely important in management of acute MI’s
2. Treatment includes inotropic drugs & pressors
What are the sxs of cardiogenic shock?
- Low BP
- Tachycardia
- Oliguria
- Altered mental status
- Cool & mottled extremities
- JVD
What dx studies are used for cardiogenic shock?
- EKG
- ECHO
- ABG
- CBC, PT, PTT, thrombin time, Plts
- BMP
- Trop, CK MB
What is seen on an echo in cardiogenic shock?
- Decreased left ventricular contractility
- Seen as hypokinesis of ventricular wall
- Decreased ejection fraction (EF)
What is seen on ABG in cardiogenic shock?
Metabolic acidosis
What is the most common cause of hypovolemic shock?
- Hemorrhage
- Hemorrhage decreases venous return & filling pressure
- As a result, cardiac output decreases
- End result is shock
What is the pathophys of hemorrhagic hypovolemic shock?
- Decrease in arterial pressure w/ hemorrhage causes sympathetic stimulation
A. Baroreceptors - Leads to vasoconstriction throughout body
- Heart rate also increases
What is involved in compensated hemorrhagic hypovolemic shock?
- Several feedback mechanisms attempt to return cardiac output & arterial pressure back to normal
- These include:
A. Baroreceptor reflexes
-Powerful sympathetic stimulation of CNS
B. CNS ischemic response
-Powerful sympathetic stimulation when SBP
What is involved in decompensated hemorrhagic hypovolemic shock?
- Decompensated shock
A. Decreased BP leads to decreased blood flow to myocardium -> decreased cardiac output - Vasomotor failure
A. Due to decreased BP, there is decreased perfusion of brain, specifically, the vasomotor center
B. Leads to decrease in sympathetic stimulation
What is involved in progressive hemorrhagic hypovolemic shock?
- Blockage of small vessels with sludge
- Increased capillary permeability
- Release of toxins by ischemic tissue
- Cardiac depression caused by endotoxin
- Generalized cellular deterioration
- Tissue necrosis
- Metabolic acidosis
What are the sxs of hemorrhagic hypovolemic shock?
- Low BP
- Tachycardia
- Oliguria
- Altered mental status
- Cool and mottled extremities
- JVD
What are the dx studies for hemorrhagic hypovolemic shock?
- EKG
- TEE
- ABG
- CBC, PT, PTT, thrombin time, plts
- BMP
- Trop, CK MB
What are the TEE results in hemorrhagic hypovolemic shock?
- Decreased left ventricular volume due to decreased filling
- Contractility preserved
What are the ABG results in hemorrhagic hypovolemic shock?
Metabolic acidosis