Shock Flashcards
What percentage of peple diagnosed with shock will die?
50%
What is shock - in basic terms?
hypoperfusion of vital organs
(brain, kidneys, lungs, gut)
it’s NOT just low BP
What is the pathophysiology of shock ultimately all about?
oxygen consumption is greater than delivered oxygen
What do tissues have to do when there’s a lack of oxygen? What lab marker is associated with this?
switch to anaerobic metabolism, with lactic acid as a marker of the severity of oxygen supply and demand impalance
What is the autonomic response to anaerobic metabolism?
increase sympathetics: arterial vasoconstriction, increase HR and contractility initially, venous constriction, release of catecholamines and cortisol, release of ADH to conserve water and sodium
What are the typical 5 lab findings in shock?
hyperkalemia hyponatremia metabolic acidosis hyperglycemia (glycogenolysis for autotransfusion) lactic acidosis (anerobic glycolisis)
What is the continuum of shock?
progression from general concern to systemic inflammatory response syndrome to multi-organ dysfunction syndrome and death
What are the criteria for systemic inflammatory response syndrome/
at least two of:
- temp less than 36 C or over 38 C
- pulse over 90 (tachycardia)
- respirations over 20 (tachypneic)
- pCO2 less than 32 mmHg
- WBC less than 4000 or over 12,000 (or 10% bands)
What’s an easy way to think about SIRS?
can be thought of as a septic-like disorder in the absence of infection
What does SIRS progress to?
multiorgan dysfunction syndrome (MODS)
What’s the first stage of shock characterized by?
increased volume requirements mild respiratory alkalosis oliguria hyperglycemia increased insulin requirement
What is the second stage characterized by?
tachypneic
hypocapcnic
hypoxemic
moderate liver dysfunction and possible hematologic abnormalities
What is the third stage characterized by?
azotemia (high nitrogen products in blood like urea and creatinine)
acid=base disturbances
significant coag abnormalities
What is stage four characterized by?
vasopressor dependence
oliguric/anuric
ischemic colitis
lactic acidosis
What are the classic exam findings in shock?
hypotension
cool, clammy skin
altered mental status
urine output less than 20 cc/hf
What are the two best things to monitor in a patient in shock?
level of alertness
urine output
What is the shock index?
heart rate divided by systolic pressure
normal is 0.5 to 0.7; over 1 has significantly increased mortality
Do we use swan ganz catheters in shock?
we used to all the time - find the capillary wedge pressure to reflect left ventricular pressure
but use of the catheters has been associated with an increased mortality, so we don’t use them much any more
What are the four major categories of shock?
cardiogenic (heart fails)
Extracardiac (utflow obstruction - like PE)
Distributive/Dissociative (increased area for blood to disperse to)
Hypovolemia (lack of fluid)
Three of the four categories of shock are issues with O2 delivery. Which one is related to O2 consumpition?
distributive/dissociative
What are some examples of extracardiac shock causes?
PE
tamponade
constrictive pericarditis
pulmonary hypertension
What are some examples of hypovolemic shock causes?
blood loss
profuse diarrhea, vomiting, diuretics or sweating leading to dehydration
burns
3rd spacing - ascites (not enough fluid in the CV system)
What are some examples of cardiogenic shock?
MI - if over 40% myocardial damage
acute valve damage - mitral regurgitation or VSD
arrhythmia (too fast or slow)
out-flow obstruction like aortic stenosis or hypertrophic cardiomyopathy
What are some examples of distributive shock causes?
sepsis (endotoxin from gram negs, exotosin from gram pos) anaphylaxis spinal cord injury cyanide carbon monoxide
