Exam 1 - States of Shock Flashcards
What is the classic definition for shock? (2)
hypotension as either an SBP <90 mmHg or a decrease in 40 mmHg from baseline
What is the formula for mean arterial pressure?
MAP = 1/3 SBP + 2/3 DBP
List factors affecting MAP? (2)
cardiac output, vascular resistance
List factors affecting cardiac output? (2)
heart rate, stroke volume
List factors affecting stroke volume? (3)
preload, afterload, contractility
What is the goal MAP? HR? Lactate?
MAP >65 mmHg; HR = <100 bpm; lactate <2 mmol/L
What is the goal venous blood gas for pulmonary artery catheters? Central venous catheters?
PA = >60%; CVC = >65%
List the shock states? (4)
hypovolemic, distributive, cardiogenic, obstructive
Define hypovolemic shock and list its causes?
inappropriately low and sudden loss of intravascular volume; hemorrhage, GI losses, severe dehydration, third spacing, burns
Match the clinical parameters associated with physical variables? (4)
preload = PCWP, pump function = CO, afterload = SVR, tissue perfusion = mixed venous oxygen saturation (SVO2)
Explain the changes during hypovolemic shock? (4)
decreased preload, decreased pump function, increased afterload, decreased tissue perfusion
What are treatments for hypovolemic shock? (3)
surgical hemostasis, replace blood (PRBCs, anticoagulation reversal), fluids (IV crystalloids, albumin)
Define cardiogenic shock and list its causes?
failure of left ventricle to deliver blood due to impaired stroke volume or heart rate; MI, arrhythmias, HF, valve diseases, dilated cardiomyopathy
Explain the changes during cardiogenic shock? (4)
increased preload, decreased pump function, increased afterload, decreased tissue perfusion
What are treatments for cardiogenic shock? (3)
revascularization for MI (CABG), correct arrhythmias, left ventricular assist devices (LVADs) and ECMO
Define distributive shock and list its causes?
characterized by pronounced vasodilation (vasodilatory shock); sepsis, anaphylaxis, neurogenic, myxedema coma, adrenal/hepatic insufficiency
Explain the changes during distributive shock? (4)
decreased preload, variable pump function, decreased afterload, variable tissue perfusion
Define obstructive shock and list its causes?
results from critical decrease in LV stroke volume or increase in LV outflow obstruction; PE, severe pulmonary HTN, tension pneumothorax, pericardial tamponade
What are treatments for obstructive shock? (2)
needle decompression, fluid drainage
Explain the changes during obstructive shock? (4)
increased preload, decreased pump function, increased afterload, decreased tissue perfusion
What is the treatment for fluid therapy in shock therapy?
IV crystalloids 30 mL/kg over 15-30 min, then by 10 mL/kg boluses (if cardiogenic 100-200 mL boluses)
What is the MOA of norepinephrine?
alpha adrenergic agonist (increases MAP via peripheral vasoconstriction)
What is the MOA of epinephrine?
alpha and beta adrenergic agonist
What are other important points regarding epinephrine? (2)
may increase aerobic lactate production, useful for anaphylactic shock
What are AEs of epinephrine?
tachycardia, arrhythmias, cardiac ischemia, peripheral vasoconstriction, reduced renal blood flow, hyperglycemia, and hypokalemia
Explain dopamine’s dose-dependent pharmacologic properties?
<5 mcg/kg/min = vasodilatory, 5-10 = beta-1 adrenergic effects (increased HR), >10 = alpha-1 adrenergic effects (vasoconstriction)
What are AEs of dopamine?
tachycardia, arrhythmogenesis, peripheral vasoconstriction (high doses)
What types of patients is dopamine most effective in?
those with hypotension and depressed cardiac function
What is the MOA of phenylephrine?
alpha-1 adrenergic agonist
Which types of patients is phenylephrine most effective in?
those with high cardiac output and low blood pressure
What are AEs of phenylephrine?
vasoconstriction, bradycardia, myocardial ischemia
Which types of patients is dobutamine most effective in?
those with cardiac output or SVO2/SCVO2 goals that have not been achieved with previous vasopressor therapy
Which types of patients is vasopressin most effective in?
those with septic shock
Which types of patients is angiotensin II (Giapreza) most effective in?
those with septic shock (or other distributive shocks)
What is an AE of angiotensin II (Giapreza)?
thromboembolism