Shock Flashcards
Inadequate organ perfusion and delivery of nutrients necessary for normal tissue and cell function. May be irreversible at first but becomes life-threatening if not treated quickly
Shock
Causes of hypovolemic shock
Hemorrhage [hemorrhagic = most common cause]
Dehydration
Burns
[ex: GI bleeding, pelvic bleeding, hemorrhagic pancreatitis, AVM; non-hemmorrhagic causes are vomiting, diarrhea, burns, heat stroke; DKA leads to renal losses, hypoaldosteronism, adrenal insufficiency, third space loss, systemic inflammation]
Physiologic parameters used to define preload and afterload while discussing shock
Preload = PCWP
Afterload = SVR
4 types of shock
Hypovolemic
Cardiogenic
Obstructive
Distributive
Types of shock characterized by cold and clammy skin vs. warm and dry skin
Cold, clammy skin = hypovolemic, cardiogenic, or obstructive shock
Warm, dry skin = distributive shock
Describe changes in PCWP (preload), CO, and SVR (afterload) in pt with hypovolemic shock
PCWP markedly decreased
CO decreased
SVR increased
General tx for hypovolemic shock
IV fluids
General causes of cardiogenic shock
Acute MI
HF
Valvular dysfunction
Arrhythmia
Describe changes in PCWP (preload), CO, and SVR (afterload) in pt with cardiogenic shock
PCWP increased
CO markedly decreased
SVR increased
[same as obstructive shock]
General tx for cardiogenic shock
Inotropes
Diuresis
General causes of obstructive shock
Cardiac tamponade
Pulmonary embolism
[other examples include SVC syndrome, constrictive pericarditis, severe HTN]
Describe changes in PCWP (preload), CO, and SVR (afterload) in pt with obstructive shock
PCWP increased
CO markedly decreased
SVR increased
[same as cardiogenic shock]
General tx for obstructive shock
Relieve obstruction
General causes of distributive shock
Sepsis
Anaphylaxis
CNS injury
Describe changes in PCWP (preload), CO, and SVR (afterload) in pt with distributive shock
PCWP decreased
CO increased [unless CNS injury, then may be decreased]
SVR markedly decreased
Tx for distributive shock
IV fluids first, then at pressors as needed (epinephrine first choice)
______ levels are a reflection of tissue hypoxia
Lactate
[higher lactate = higher mortality]
Most common cause of noncardiogenic shock
Distributive shock
Describe changes in PCWP (preload), CO, and SVR (afterload) in pt with anaphylactic shock
PCWP normal at first, decreases later
CO may be decreased or increased
SVR decreased
Classifications of cardiogenic shock
Cardiomyopathic — MI, severe RVMI, stunned myocardium, severe septic shock (depressed EF), myocarditis, cardiomyopathy
Arrhythmogenic — afib, re-entrant tachycardia, vtach, vfib
Mechanical — severe AI or MR; acute valvular rupture, critical AS, VSD, ruptured ventricle wall aneurysm, atrial myxoma
Clinical signs of cardiogenic shock
Decreased BP Decreased UO Mental status changes Cool, mottled extremities Distended neck veins Pulmonary edema
Most common cause of cardiogenic shock
LV failure d/t AMI
Average time to develop cardiogenic shock after a STEMI
7-10 hours
Cardiogenic shock due to LAD often associated with ____ wall STEMI
Cardiogenic shock associated with inferior wall STEMI often associated with _____ complications
Anterior; mechanical
Mechanical support treatment that can be given in severe cardiogenic shock
IABD — decreased afterload deflates during systole; inflates during diastole — coronary perfusion use for mechanical complication (M, VSD)
LVAD — bridge for transplant; tandem heart/impella
ECMO — when O2 is severely impaired
First choice pressor agent in cardiogenic shock d/t STEMI
Norepi — alpha1, B1, B2 agonist (pressor and inotropic)
[second option is dopamine - B1 agonist, or phenylephrine - peripheral alpha agonist]
Inotropes used to tx cardiogenic shock
Dobutamine - B1 agonist; peripehral alpha1 and B2 agonist; can vasodilate; used with NE
Milrinone — PDE inhibitor; prevents degradation of cAMP to increase HR, increase SV, increase CO
Classifications of obstructive shock
Pulmonary vascular = hemodynamically significant, PE, severe pulmonary HTN, severe or acute obstruction of pulmonary or tricuspid valve
Mechanical = tension pneumothorax (trauma, ventilator induced, iatrogenic), pericardial tamponade, constrictive pericarditis, restrictive cardiomyopathy
Presentation of tension pneumothorax
SOB, unilateral pleuritic CP and decreased breath sounds, neck vein distention
Tracheal deviation AWAY from affected side
Virchow triad of hemodynamically significant PE
Endothelial injury
Stress
Hypercoagulability
Most common EKG finding in PE
Tachycardia
Imaging strategy for visualization of thrombi in pulmonary arteries; preferred over ventilation/perfusion lung (V/Q)
CT pulmonary angiography (CTPA)
