Shock Flashcards
What is shock?
Inadequate oxygen to meet metabolic/tissue demands
Does shock mean hypotension?
No it can be normal, increased, or decreased
What shock is from an inadequate blood volume or oxygen carrying capacity?
Hypovolemic Shock
Hemorrhagic Shock
What shock is from inappropriate distribution of blood volume and flow?
Distributive Shock
What shock is from impaired cardiac contractility
Cardiogenic Shock
What shock is from obstructed blood flow?
Obstructive Shock
Main function of the cardiopulmonary system
deliver O2 to body tissues and remove metabolic by products of cellular metabolism (CO2)
When O2 is inadequate to meet tissue demand
Cells use anaerobic metabolism - to produce energy
= LACTIC ACID
Oxygen delivery to the tissues is dependent on…
Arterial O2 content (oxygen bound to hemoglobin plus dissolved O2)
Cardiac output (volume of blood pumped each minute)
Arteries vs veins
Arteries carry O2
Veins carry blood back through the vena cava to be reoxygenated
O2 may be normal despite hypoxemia due to what compensation
CO increasing
When hypoxemia is chronic what does hemoglobin concentration due
increases - polycythemia
Therefore increasing the O2 carrying capacity of the blood
CO =
SV X HR
CO
SV
HR
CO - (the volume of blood pumped by the heart in each minute)
SV - The amount of blood pumped by the left V with each contraction
HR - Number of times the ventricles contract per minute
Infants are more dependent on CO or HR?
very small SV - dependent on HR
Preload
Volume of blood present in the ventricle before contraction
Contractility
Strength of contractin
Afterload
Resistance against which the ventricle is ejecting
Inadequate preload is the most common cause of
hypovolemic shock
Inadequate contractility is the most common cause of
Cardiogenic Shock
Increased afterload can cause
cardiogenic shock
what is pulse pressrue
the distance between systolic and diastolic pressure
If SVR is low (as in sepsis) what happens to the pulse pressure
diastolic pressure decreases and pulse pressure widens
Compensated shock.
Maintain a systolic pressure
Compensated shock clinical symptoms
tachycardia (vasoconstriction) decreased UO (Retaining water) delayed cap refill (send blood to peripheral)
Pulses in compensated shock
Narrow pulse pressure (increase in diastolic)
In most types of shock what is hypotension
a late finding
what is hypotension in septic shock?
When SVR is decreased due to the mediators of sepsis - hypotension will be an early sign
(brisk cap refill, full pulses)
Hypotensive forumla
70 + (Age in years X 2)
How long can it take compensated shock to turn into hypotensive shock
Possibly hours
Hypotensive Shock to Cardiac arrest?
Possibly mintues