Cardiac Pathophysiology Flashcards
What are the 4 different categories used to categorize shock?
Distributive
Obstructive
Hypovolemic
Cardiogenic
What is the common pathology behind s/s of shock?
inadequate tissue perfusion
What are compensatory mechanisms for shock?
Vasoconstriction, tachycardia, tachypnea, restlessness, interstitial fluid moves into capillaries, increased vasopressin, glucocorticoids, renin, aldosterone, erythropoeitin, plasma protein synthesis
What is refractory shock?
shock state that persists for hours, patients do not die immediately but do not get better either, eventually have no response to vasopressor drugs or volume replacement, “irreversible shock”
What are 3 factors that lead to refractory shock?
decreased cerebral perfusion
myocardial failure
pulmonary damage (ARDS)
What is the etiology of hypovolemic shock?
inadequate blood volume
What is the presentation of hypovolemic shock?
rapid and thready pulse, cold, pale, clammy skin, intense thirst, rapid respiration, restlessness, decreased urine output
What are the 4 categories of hypovolemic shock?
hemorrhagic
traumatic
surgical
burn
What is classified as moderate hemorrhage in someone with surgical/hemorrhagic shock?
5-15 mL/kg body weight
What are some manifestations of moderate hemorrhage in hypovolemic shock?
Reduced pulse pressure
Normal BP initially but eventually tachycardia and hypotension
Lost plasma proteins in blood take 3-4 days for liver to synthesize
Increase in circulating erythropoietin takes 4-8 weeks to restore RBCs to normal
What causes traumatic hypovolemic shock?
- damage to muscle and bone - bleeding into injured areas, more blood usually lost than meets the eye, thigh muscles can accommodate 1 L of extravasated blood with an increase in thigh diameter of only 1 cm
- Crush syndrome - when pressure is relieved from previously crushed skeletal muscles, muscles are re-perfused and free radicals are generated which cause further muscle damage which include calcium, potassium, myoglobin, and fat)
What things can occur in someone with cardiogenic shock?
dysrhythmia
acute valvular dysfunction
ruptured ventricle
pump failure
What is cardiogenic shock?
the pumping action of the heart is impaired to the point that tissue perfusion needs are not met
What is surgical hemorrhagic shock?
combination of external hemorrhage, bleeding into tissues, and dehydration
What is distributive shock?
all of the signs of shock except the skin is warm
What is characteristic of anaphylactic shock?
massive peripheral vasodilation which causes warm extremities and skin
What is neurogenic shock and what type of shock is it?
interruption in the transmission of autonomic activity which results in vasodilation and peripheral pooling of blood
What are the two types of distributive shock?
anaphylactic shock
neurogenic shock
What are examples of obstructive shock?
cardiac tamponade massive pulmonary emboli tension pneumothorax pericardial disease increase in PVR from PE or pulm HTN cardiac tumor obstructive valvular disease
What is the treatment for shock?
treat the cause
Do all forms of shock need volume?
No
What are anesthetic implications for shock?
- anesthetize patient (recall occurs most often during times of hypotension and shock)
- keep patient warm
- keep normal pH
