Shock Flashcards
shock definition
a syndrome due to impaired tissue perfusion resulting in cellular hypoxia and build up of toxic metabolites
pathophysiology of shock
a trigger decreases blood flow to organs, compensatory mechanisms initiate (HR increase, aldosterone released, vasoconstriction), metabolic acidosis occurs (lactic acid released r/t anaerobic metabolism), leading to organ failure if continues to progress
s/s of shock
tachycardia, tachypnea, hypotension, thready pulse, decreased peripheral pulses, cyanosis, neurological symptoms, decreased UOP and absent bowel sounds; neurogenic would have a slow bounding pulse and cardiogenic would have bradycardia
distributive shock (vasogenic)
severe peripheral vasodilation; technically enough blood in the vessels but it can’t be distributed properly - vessels are too dilated
cardiogenic shock
heart can’t consistently pump out enough blood to meet needs of the body; low CO with hypotension; caused by MI* (cardiomyopathic), arrhythmias (arrhythmogenic), or valve issues (mechanical)
hypovolemic shock
most common type; reduced intravascular volume which reduces CO; hemorrhagic (some source of bleeding) or non-hemorrhagic (diarrhea, excessive diuresis, third-spacing)
obstructive shock
causes outside of the heart that cause pump failure, often associated with poor R ventricular output; causes could be PE, pulmonary HTN, tension pneumothorax, pericardial tamponade, or cardiomyopathy
absolute hypotension
SBP less than 90 or MAP less than 65
relative hypotension
drop in SBP of 40 or more
initial stage
narrowing pulse pressure; decreasing CO, tissue perfusion, and aerobic metabolism; increase in anaerobic metabolism and lactic acid production
later changes with shock
DBP decreases then the SBP decreases
compensatory stage
body attempting to preserve vital organs; sympathetic nervous system response: hormonal, neurological, and chemical
hormonal compensation
renin-angiotensin and antidiuretic hormone release, and an intracellular fluid shift; goal to increase intravascular volume
sympathetic nervous system
releases epinephrine and norepinephrine –> vasoconstriction; increases HR, cardiac output, and bp
progressive stage
compensatory mechanisms beginning to fail, anaerobic metabolism continues, more lactic acid is produced
refractory stage
shock undetected or unresponsive to therapy; cells are dying r/t apoptosis and Na-K+ pumps fail; MODS; death
effects on heart
decreased coronary artery perfusion, SV, CO, and bp
effects on lungs
increased pulmonary capillary membrane permeability, decreased gas exchange –> hypoxia, possibly ARDS
effects on brain
decreased function r/t hypoxia, unconsiousness, further impairment of cardiac and respiratory function, impaired thermoregulation
effects on liver
glycogen stores are depleted by excess circulatory epinephrine, coagulation factors, metabolic acids are NOT detoxified by liver –> metabolic acidosis; recovers fairly well when blood flow is restored
effects on kidneys
AKI and decreased UOP
ABCDE assessment
airway, breathing, circulation, disability (alert/responsive), exposure (looking over physically)
additional assessments
capillary perfusion: skin color, temperature, moisture; JVD: distended w/ cardiogenic shock or pulmonary congestion; flattened w/ hypovolemic or distrubritive shock
ABGs
early: respiratory alkalosis r/t tachypnea; pt will fatigue and RR decreases –> CO2 buildup –> respiratory acidosis; anaerobic metabolism continues and metabolic acidosis worsens
CVP less than or equal to 4
hypovolemia or vasodilation