Shock Flashcards
What is shock?
Maldistribution of blood flow causing an imbalance between oxygen delivery and demand –> Leading to tissue hypoxia
Beta1 agents…
Increase HR and contractility
What are the etiologies of shock?
Cardiogenic Hypovolemic Distributive Obstructive Neurogenic
What quantities affect shock?
Arterial O2 content
O2 delivery (heart rate, stroke volume, cardiac output)
Perfusion pressure
Systemic vascular resistance
How do you treat shock?
Optimize volume status (Frank-Starling)
Optimize oxygen demand (Intubation)
Support circulation (vasopressors/inotropes)
What three things is cardiac function dependent on?
Preload
Contractility
Afterload
Alpha agents …
cause vasoconstriction
How does preload (initial sarcomere length) affect cardiac function?
Stroke volume INCREASES in response to an increase of the volume of blood filling the heart (increase in sarcomere length)
What are extrinsic controls on hemodynamics?
Baroreceptors (change in BP –> CNS, negative feedback via inhibition of symp, activation of parasymp)
Cardiopulmonary receptors (detect changes in central blood volume)
What are intrinsic controls on local blood flow hemodynamics?
Nitric oxide
hypoxia
Beta2 agents…
cause smooth muscle dilation within vessels and bronchioles
What type of shock is sepsis?
Distributive shock: uncontrolled inflammation and dysregulated immune response (cytokine storm) –>
systemic vasodilation, endothelial dysfunction, hypovolemia, cardiac depression
What is failing in cardiogenic shock?
The pump!
May be due to MI, cardiomyopathy, myocarditis, arrhythmia, valve malformation
What is failing in hypovolemic shock?
Tank is empty!
Intravascular volume loss, depleted body fluids/volume
Hemorrhage, trauma, GI loss, body cavity loss, severe hypovolemia/dehydration
SVO2 measurements are NORMAL/HIGH in ________________ but are low in _________________
Normal/high in DISTRIBUTIVE shock
low in LOW-FLOW state or ANEMIA
