Chapter 3: Shock Flashcards
Cardiac output definition
Stroke volume ( volume of blood ejected by the L ventricle) x HR ( ejection cycles /minute)
What dictates stroke volume
Filling volume of the ventricle( preload)
Myocardial contractility (Starling’s curve)
Systemic vascular resistance ( afterload)
What controls the HR
Vagus nerve and endogenous catecholamine release
In times of stress what happens with an infant’s Cv system
Infants have relatively less myocardial contractility - increased cardiac output depends on increasing the HR rather than stroke volume - bradycardia is not that well tolerated in infants
What is microcirculatory dysfunction
maldistribution of capillary blood flow
By how much does hydrostatic pressure fall by in shock states
30-40 %
What does endotoxin do to capillary beds during septic shock
Damages vascular endothelium
Damaged cells can then generate procoagulant activity - which may explain why fibrin is deposited into the microcirculation
Norepinephrine -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - hypovolemia and head trauma
Release by sympathetic NS
Effects - vascocontriction - B1 and B2 stimulation
Epinephrine -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - hypovolemia and hypercapnea
Release by adrenal medullae
Effects - vascocontriction - a1 and B2 stimulation
Angiotensin II -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - hypovolemia
Release by kidneys and brain
Effects - vascocontriction
Leukotrienes-stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - tumor necrosis factor
Release by macrophages
Effects - capillary permeability
Thromboxane A2 -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Hypoxia
Release by Platelets
Effects - Vasoconstriction and platelet aggregation
Prostaglandins F2 -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Hypoxia
Release by Platelets and vascular smooth muscle
Effects -Vasoconstriction
Prostaglandins I2 -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Hypoxia
Release by Healthy vascular endothelium
Effects -Vasodilator counterbalances thromboxane A2
Mycocardial depressant factor -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Ischemia/tissue damage
Release by Pancreas
Effects -Direct negative ionotropic effects
Opiates -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Hypoxia
Release by Pituitary
Effects -Decreased myocardial contractility, decreased sympathetic tone
Hypotension
Inducible Nitrous Oxide -stimulus, sources and effects as an endogenous vasoactive mediator
Stimulus - Inflammatory cytokines
Release by Leucocytes
Effects -Vasodilation of vascular smooth muscle
How much ATP is produced by aerobic and anerobic respiration per mole of glucose
2 moles compared to 38
What are deleterious effects of anerobic metabolism
Depletion of glycogen stores and accumulation of lactic and associated acidosis -
Decresed ATP lead to K efflux, Na and Ca influx with water causing cells to swell
