Shock! Flashcards
Three important components of shock treatment:
1) optimization of volume status
2) optimization of oxygen demand
3) support of the circulation
Define shock:
maldistribution of blood flow causing an imbalance between oxygen delivery and demand, leading to tissue hypoxia
DOz (O2 delivery) =
CO (HR x SV) x CaO2
-arterial O2 content
As preload increases, active tension_______.
increases
also, ventricular contraction increases and SV
tension depends on the _________ of the heart.
inotropic state
Barorecptors detect changes in _____. Cardiopulmonary mechanical baroreceptors detect changes in _______.
Blood pressure
central blood volume
What are the five types of shock?
1) cardiogenic
2) hypovolemic
3) distributive
4) obstructive
5) neurogenic
Etiologies of Cardiogenic Shock:
(when the pump fails!)
-MI, cardiomyopathy, myocarditis, arrhythmia, valve malfunction
Etiologies of Hypovolemic Shock
(the tank is empty - intravascular volume loss)
-significant hemorrhage or severe hypovolemia (diarrhea, vomiting, dehydration)
Etiologies of Distributive Shock
(the pipes are leaky)
-sepsis (absolute hypovolemia and cardiac depression), anaphylaxis, liver cirrhosis, pancreatitis
Etiologies of Obstructive Shock
(problem filling the pump)
-cardiac tamponade, PE, tension pneumothorax
Etiologies of Neurogenic Shock
loss of vascular tone due to abnl sympathetics (type of distrib shock)
-spinal cord injury, deep general anesthesia, reflux response to deep pain
Which types of shock have significant decreases in CO?
those that correlate with a pump dysfunction: cardiogenic and obstructive
What type of shock has a significant decrease in central venous pressure (CVP, or IVC or PCWP)?
hypovolemic, has a decreased preload!
What type of shock has a significantly decreased SVR (systemic vascular resistance)?
distributive, has a decreased afterload
If a pt. is cold, pale, clammy and has mottled skin associated with delayed cap refill, what type of shock are you thinking?
a low CO state, so cardiogenic or obstructive or hypovolemic
What imaging method provides a noninvasive, real-time assessment of the causes of circulatory dysfunction?
Ultrasound!
-especially the focused echo
Rapid Ultrasound in SHock (RUSH) protocol:
1) evaluate the heart (LV + RV size and fx)
2) assess the intravascular volume (fluid responsiveness)
3) evaluate the pipes (m aa + vv)
Importance of lactate levels:
in low-flow states –> tissue hypoxia –> anaerobic metabolism –> increased lactate production
-also, increased glycolysis and decreased clearance (LF)
Importance of SVO2 levels:
assesses the balance between O2 demand and supply. It will be decreased in those w/ low-flow states or anemia, but high-nl in those w/ distributive shock.
The goal of resuscitation is to:
restore early and adequate O2 delivery.
It should be started while investigation of the cause is ongoing. Don’t wait!
Fluid therapy in shock:
-intended to improve preload, SV and CO, but need to predict if the pt. will be fluid-responsive or not
Medications used in shock:
B1 agonists (increases HR and contractility)
a-agonists (vasoconstriction)
ex) norepinephrine
inotropes to increase contractility
Why should we mechanically ventilate?
-reduces the work of breathing and O2 demand of respiratory muscles, more O2 for other organs
