Exam 2: Ch 20 Shock Flashcards
circulatory shock
hypo-perfusion of organs
too little O2 for cell functions
cellular response to circulatory shock
anaerobic metabolism – not enough ATP
Na/K pump fails
cells swell and die
compensations for circulatory shock
similar to HF – SNS, RAA
counter-productive over time
hypovolemic shock definition and compensations
not enough blood volume in system (15-20% lost)
SNS stimulation increases HR, vasoconstriction, inotrophy, venoconstriction (mobilize blood)
RAA stimulation increases ADH/Aldo to restore circulating volume
hypovolemic shock symptoms and treatment
thirst, acidosis, mentation
high HR, systemic vascular resistance, afterload
low BP, venous return, PP, SV, CO, EDV, CVP, PCWP, urine output
give volume
causes of hypovolemic shock
hemorrhage
plasma loss from burns
extracellular loss (GI)
physiology of hypovolemic shock
15% volume loss well tolerated
after 15%, SNS vasoconstriction maintains BP even though CO is low
PP is narrowed and SVR is high
45% blood loss takes CO and BP to 0
cardiogenic shock definition and causes
inadequate pumping of the heart
MI, LV aneurysm, valve dysfunction, ischemia
physiology and symptoms of cardiogenic shock
low BP, SV, CO, EF contractility, but high afterload
cyanosis, hypoxia, oliguria, high CVP and PCWP (pulmonary capillary wedge pressure)
treatment of cardiogenic shock
up inotropics
nitroprusside (arterial/venous dilator) to dec. after/preload
NTG venous dilator to decrease preload
IABP: intra aortic balloon pump
IABP
intra aortic balloon pump used to treat cardiogenic shock
deflates during systole to decrease afterload
inflates during diastole to increase CA blood floow
obstructive shock
circulation blocked by an obstuction (pulmonary emboli, tamponade, pneumothorax)
generally Rt HF with high CVP and distended neck veins
treatment of obstructive shock
pulmonary emboli may respond to thrombolytics
tamponade requires drainage
pneumothorax requires chest tube
distributive shock
blood volume adequate but vessels are dilated
low vessel tone (afterload) –> capacity of vascular space expands and blood can’t fill it
low venous return and low CO
LOW SVR
types of distributive shock
neurogenic
anaphylactic
septic
nerogenic shock
brain or cord damage causes low SNS output and vasodilation
causes: injury, general or spinal anesthesia, hypoxia
anaphylactic shock
reaction causes histamine release and vasodilation
treatment: remove allergen and give epi
septic shock
bacterial toxins recruit WBC and release cytokines
cytokines disrupt endothelium and causes vasodilation and capillaries leak protein/fluid
result is severe hypovolemia, arterial and venous dilation
treatment of septic shock
antibiotics
give volume (fluid, vasopressors)
insulin returns normal blood sugar to dec. mortality
recombinant protein C is anti-inflammatory and an anticoagulant
5 complications of shock
acute lung injury/respiratory distress syndrome (ALI/ARDS)
acute renal failure
GI complications
Disseminated intravascular coagulation (DIC)
multiple organ dysfunction syndrome
acute lung injury/respiratory distress syndrome (ALI/ARDS)
shock from trauma/sepsis
hypoxemia, hypercapnea, V/Q mismatch
pulmonary capillaries leak fluid so impaired gas exchange
cause of ALI/ARDS and Rx
cause: unknown, maybe endothelial damage
Rx: support respiration with mechanical ventilation, avoid O2 toxicity
acute renal failure
shock from trauma/sepsis
renal tubules are vulnerable to ischemia and become nectoric
ATN is the most frequent lesion… may be reversible
GI complications
shock decreases mucosal perfusion which leads to ulcers and bleeding
Rx: NG suction, proton-pump inhibitors
disseminated intravascular coagulation (DIC)
coagulation pathways become activated throughout circulation
seen in 1/3 to 1/2 of septic shock patients
clots lead to organ failure
platelet and clotting factor depletion leads to hemorrhage
treatment of DIC
give platelets and anticoagulants
multiple organ dysfunction syndrome
strikes kidney, liver, brain, heart, lungs simultaneously
very high mortality rate
can shock be progressive?
yes
