Flashcards in Shock Deck (82)
What is shock?
Inadequate oxygen delivery to meet metabolic demands resulting in global tissue hypo perfusion and metabolic acidosis.
Can shock occur with normal blood pressure?
What happens to oxygen delivery during shock?
inadequate systemic O2 delivery activates autonomic responses to maintain systemic oxygen delivery.
Where does blood flow go during shock?
redirects tot he heart, kidneys and brain. Other beds are restricted.
explain the pathway from pain to shock
pain-> hemorrhage ->cortical perception of traumatic injury -> hormone and inflammatory mediators are released -> sympathetic nervous system releases catecholamines (NE, epi, dopamine, cortisol) -> vasoconstriction, increases in HR and increase CO -> RAAS ->decreased O2 delivery
What are 5 cellular responses to decreased systemic O2 delivery?
ATP depletion- ion pump dysfunction
-hydrolysis of cell membranes and cell death
- individual cells take up fluid
-depletion of intravascular fluid
- cell edema occludes adjacent capillaries
What is no reflow phenomenon?
prevents reversal of ischemia even with restoration of adequate macro-circulation
What is the bodies intrinsic goal during shock?
To maintain cerebral and cardiac perfusion.
What mediators do ischemic cells produce?
-inflammatory factors (prostacyclin, thromboxane, prostaglandins, leukotrienes, endothelin, etc.)
What happens when the these mediators are released?
systemic metabolic lactic acidosis that overcomes the body's compensatory mechanisms.
What is global tissue hypoxia?
endothelial inflammation and disruption. Inability of O2 delivery to meet demands.
When global tissue hypoxia (GTH) ensues, what is the result?
lactic acidosis, cardiovascular insufficiency, increased metabolic demands.
What happens to the central nervous system during GTH?
triggers a neuroendocrine response. Regional glucose uptake in the brain changes, reflexes and cortical activity are depressed (referable with mild hypo perfusion).
Failure to recover neurological function is a sign of poor prognosis.
What happens to the kidneys and adrenal glands during GTH?
Maintain GFR by selective vasoconstriction and concentration of blood flow in medulla and deep cortical area.
Prolonged hypotension -> decreased cellular energy -> inability to concentrate urine -> patchy cell death -> tubular necrosis -> renal failure
What happened to the heart during GTH?
cardiac function is well preserved in the late stages. Lactate, free radicals, and other humoral factors act as negative inotropes and, in a bleeding patient, may produce cardiac dysfunction as the terminal event in the shock spiral.
Trauma patient with cardiac disease....
Fixed stroke volume inhibits the body's inability to increase blood flow in response to hypovolemia and anemia.
Tachycardia is the only option.
Shock in the elderly may therefor be rapidly progressive and not respond predictably to fluid administration.
What happens to the lung in GTH?
filter for the inflammatory by-products of the ischemic body. Immune complex and cellular factors accumulate in pulmonary capillaries.
Explain at the cellular level whats happening with the lungs?
Neutrophil and platelet aggregation, increased capillary permeability, destruction of lung architecture, ARDS, (the lung is the sentinel organ for the development of multi organ system failure in a traumatic patient)
Does pure hemorrhage, in the absence of hypoperfusion, produce pulmonary dysfunction?
Is traumatic shock more than just a hemodynamic disorder?
What happens to the gut during GTH?
One of the earliest organs affected by hypoperfusion. May be the prime trigger for MOSF. Intense vasoconstriction occurs early and frequently leads to "no reflow" phenomenon. Intestinal cell death -> breakdown in the barrier function in the gut -> increased translocation of bacteria to the liver and lung -> potentiation of ARDS.
What happens to the liver during GTH?
complex microcirculation; potential for repercussion injury during recovery from shock. Hepatic cells are metabolically active and contribute to the ischemic inflammatory response and to irregularities in blood glucose. Absence of liver after shock is almost always lethal.
What happens to skeletal muscle during GTH?
Not metabolically active during shock; tolerates ischemia well. Skeletal muscle mass -> of lactic acid and free radicals.
sustained ischemia ->increased intracellular Na and free water -> further depletion of intravascular and interstitial fluid.
What is Multiorgan dysfunction syndrome
progression of physiologic effects as shock ensues. cardiac depression, reap distress, renal failure, and DIC.
Result is end organ failure.
Symptoms of shock
pallor, diaphoresis, hypotension, tachycardia, prolonged cap refill, diminished urine output, narrowed pulse pressure
diagnosis of shock
physical exam (VS, mental status, skin color, temp, pulses)
labs (cbc, chemistries, lactate, coags, cultures, ABG)
further studies that should be performed
CT of head, lumbar puncture, wound cultures, acute and series, and/pelvis CT or US, cortisol level, fibrinogen, FDPs, d-dimer
what historical questions do you ask for the pt in shock
recent illness, fever, chest pain, SOB, and pain, commodities, medications, toxins/ingestions, recent hospitalizations or surgeries, baseline mental status.
physical exam for a pt in shock
vitals, CNS (mental status), skin (color, temp, rashes, sores), CV (JVD, heart sounds), reap (lung sounds, RR, o2 sats, ABG), GI (and pain, rigidity, guarding, rebound), renal (urine output)