20 Shock Flashcards
Shock
pathogenesis
- imbalance bw O2 supply + O2 requirement at the cellular level
- shock represents a diverse group of life-threatening conditions
- common factor among all types of shock HYPOPERFUSION + impaired cellular O2 utilization
inadequate cellular oxygenation may result from…
1 decreased CO
2 maldistribution of BF
3 reduced blood oxygen content
Shock
types
1 Cardiogenic
2 Obstructive
3 Hypovolemic
4 Distributive
Cardiogenic Shock
inadequate CO despite sufficient vascular volume
Obstructive Shock
circulatory blockage (like a large pulmonary embolus or cardiac tamponade)
Hypovolemic Shock
loss of blood volume as a result of hemorrhage or excessive loss of extracellular fluids
Distributive Shock
greatly expanded vascular space bc of inappropriate vasodilation
lack of oxygen causes…
reperfusion injury
Types of Distributive Shock
- characterized by excessive vasodilation + peripheral pooling of blood
- –CO inadequate due to reduced preload
1 Anaphylactic Shock
2 Neurogenic Shock
3 Septic Shock
Anaphylactic SHock
- Type I Hypersensitivity
- mast cells release HISTAMINE resulting in severe hypotension
Histamine
vasodilatory mediators
Neurogenic Shock
loss of sympathetic activation of arteriolar smooth muscles
Septic Shock
severe systemic inflammatory response to infection
-NO + kinin
Shock
complications
- shock states results in reduced/inadequate cellular oxygen consumption
- -may affect all organs + systems of body
- complications are INFLAMMATORY
- inflammation triggered by hypoxic injury to cells, by antigen or endotoxin
Acute Respiratory Distress Syndrome [ARDS]
- commonly assoc w Septic Shock
- dvlpt of refractory hypoxia, decr pulmonary compliance, + radiographic evidence of pulmonary edema
- neutrophils release proteolytic enzymes, produce oxygen-free radicals, + secrete inflammatory chem that makes pulmonary capillaries leaky
primary cause of death in ARDS
multiple organ failure
-NOT severe hypoxemia
exudate
a mass of cells and fluid that has seeped out of blood vessels or an organ, especially in inflammation
Neutrophils role in ARDS
1 release proteolytic enzymes,
2 produce oxygen-free radicals,
3 secrete inflammatory chem that makes pulmonary capillaries leaky
Neutrophils effects in ARDS
1 exudate leaks into interstitial spaced + alveoli of lung
—interfered w pulmonary gas xchange
2 inflammation may also damage type II pneumocytes which normally produce surfactants
Disseminated Intravascular Coagulation [DIC]
- usually in septic shock
- immune activation of clotting cascade
- microcirculation obstruction leads to ischemic tissue damage
- widespread clot formation (consumes platelets + clotting factors)
DIC clinical manifestations
low platelet + fibrinogen levels
high D-dimer
Acute Renal Failure
-kidneys undergo long periods of hypoperfusion
-vasoconstriction causes decr flomerular BF
»reduced hydrostatic P + filtration rt
-Acute Tubular Necrosis
-may need dialysis
Acute Tubular Necrosis [ATN]
assoc w decreased urinary excretion of waste products (creatinine + urea)
-assoc w acute renal failure
Multiple Organ Dysfunction Syndrome [MODS]
-when 2 or more systems are affected
-initiated by overactive + destructive immune mechanisms
-cytokines affect endothelium, recruit neutrophils, + activate inflammation in vascular beds
»» leads to tissue destruction + organ dysfunction
most common cause of secondary MODS
sepsis + septic shock
Stenosis
failure of the valve to open completely in result of extra pressure work for the heart
Regugitation
insufficiency
- inability of a valve to completely close
- results in extra volume work for the heart
Mitral Valve Stenosis
chronic pulmonary HTN
- RIGHT VENTRICLE HTN
- right sided HTN
Shock - Clinical Manifestations
Heart, Circulatory, + Lungs
INCR: heart rt, resp rt,
DECR: pulse pressure, hypotension (SBP<90), capillary refill, constrict of slanchnic vessel
Shock - Clinical Manifestations
hormonal + kidney
RELEASE: ADH (brain),
Aldosterone + Cortisol (kidney)
decr urine output, incr specific gravity
Shock - Clinical Manifestations
s/s
cool clammy bluish/gray color
thirst, restlessness, dilated pupils
