Heller Ch. 11 Flashcards
What is circulatory shock?
Severe reduction in blood supply
Does not meet metabolic demand
What causes cardiogenic shock?
Compromised pumping…
Severe arrhythmias, abrupt valve malfunction, coronary occlusion, MI
What causes hypovolemic shock?
Hemorrhage (>20% blood loss) Severe burns Chronic diarrhea Prolonged vomiting PE
What causes shock under anaphylactic conditions?
Substantial peripheral vasodilation
Reduced TPR
Increased microvascular permeability
What causes shock under septic conditions?
Endotoxin–>NO formation–>vasodilation
What causes neurogenic shock?
Inhibition of sympathetic vasoconstrictors–>loss of vascular tone
What is the end result of the body’s compensatory responses to shock conditions?
Increase MAP
Decrease in organ blood flow
What is the body’s major compensatory response?
Medullary sympathetic/parasympathetic control via decreased arterial baroreceptor activity and cerebral ischemic response
How does rapid, shallow breathing help with shock?
Respiratory pump…promotes venous return
What role do the kidneys play in shock compensatory response?
Release of renin–>increased angiotensin II–> vasoconstriction
Besides neurogenic control, what other effect does baroreceptor activity have in the compensatory response?
Increased ADH released by pituitary gland–> vasoconstriction
What effect does increased circulating epinephrine have on arteriolar constriction and glycogenolysis?
Increased arteriolar constriction
Increased glycogenolysis
How does increasing arteriolar constriction help under shock conditions?
Increased arteriolar constriction→reduced capillary hydrostatic pressure w/ same oncotic pressure→fluid flows from interstitium to vascular space
How does increasing glycogenolysis help under shock conditions?
Glycogenolysis in liver→increased extracellular osmolarity→fluid from intracellular to extracellular
I think this is synergistic to increasing arteriolar constriction…this draws fluid from intracellular to extracellular, then constriction draws fluid from extracellular to vascular space…I think
How can a sudden increase in blood volume be seen on a CBC?
Low hematocrit caused by “autotransfusion”
There are various circumstances where shock can lead to irreversible shock…
…there is a decrease in CO and TPR causing a further drop in MAP
What is indicative of systolic heart failure?
EF <40%
What causes diastolic heart failure?
Stiffened ventricles
What is the EF of diastolic heart failure?
> 40%
How is acute heart failure compensated for?
Sympathetics
How is chronic heart failure compensated for?
Increased renin
What are the advantages of fluid accumulation during heart failure?
Raises venous function curve
Decreases sympathetic activity–>less myocardial oxygen demand
What does a person have if his/her mean pulmonary artery pressure is >20mmHg
Pulmonary hypertension
What are the systolic/diastolic values for systemic hypertension?
140/90
