Shock Flashcards
SHOCK (MCH is in shock)
is defined as a syndrome characterized by decreased tissue perfusion , resulting in cellular, metabolic and hemodynamic instability.
All shock results in ineffective tissue perfusion and acute circulatory failure
Shock is initiated by a Drop in MAP (mean arterial Pressure) - how to calculate MAP?
Leads to impaired tissue perfusion
MAP = SBP + 2(DBP)/3
how does shock start?
Shock begins with an inciting event:
focus of infection: abscess, UTI
Injury: gun shot wound, burn…
This event produces a systemic circulatory abnormality that may progress through several stages :
SVR - Systemic Vascular Resistance - SVR is the same as afterload
(sever the afterload)
The resistance that the left ventricle must pump against to eject bld. (Afterload)
Afterload (after the force) (same as SVR)
Force Left ventricle pumps against to eject blood into body. (SVR)
Preload- when does it start?
Filling pressure of left ventricle Amount of blood in left ventricle at the end of diastole
Left ventricular end diastolic pressure (pre - end in the lungs)
= Preload = pressure in the lungs or in the right side of the heart
Chronotrope med (rate chron news)
Affects heart RATE
Inotrope med (I NO I contract)
Affects contractility of heart
Stroke Volume- normal amount- (stroke it for 60 min)
Amt of blood ejected from ventricle with each contraction (60—130ml)
Sympathetic Receptors: (the alpha is not sympathetic)
alpha, beta 1 and beta 2
Alpha
(the alpha is smooth and constricts)
(vascular smooth muscle) Vasoconstriction
beta 1
(beta take care of my one heart)
(1 heart) (Cardiac tissue)
beta 2 (2 lungs) - and drug ex? YOU know this
(2 lungs)
Relaxes vascular smooth muscle, vasodilation of lung tissue = bronchodilators (albuterol)
PCWP or PAWP: (Swanz Ganz Catheter)
(P for preload)
Pulmonary cap wedge pressure = Left ventricular end diastolic pressure
Same as preload pressure in the lungs or in the right side of the heart
normal 5-12 mm Hg
SVO2/ScvO2 measurements - used for what? (just think O2)
Used to monitor adequacy of tissue oxygenation
CVP and PA catheters can have SVO2/ScvO2 sensors
MAP:
Mean Arterial Pressure
Normal 70-90.
MAP= SBP + 2(DBP) /3
CO Cardiac Output - equation
SV X HR = CO
60-130ml X HR
Example: 80 bpm X 100ml = 8L/min
Response to Shock - first a drop in what?
Initially there is a drop in the MAP
Shock may develop rapidly or gradually depending on the severity of the insult
Compensatory Stage of Shock (major organs)
Compensatory measures kick in to maintain perfusion to vital organs
Brain
Heart
lungs
Compensatory Stage of Shock - which nervous system?
Inhibition of Baroreceptor activity:
Stretch receptors in aorta/carotid sinus respond to ↓ MAP and stimulates the vasomotor center of medulla.
This causes activation of the Sympathetic Nervous System
Sympathetic Nervous System stimulation - cause release of what? and stimulates what?
(epi is sympathetic)
Causes release of the catecholamines:
Epinepherine
Norephinepherine
These stimulate
alpha-adrenergic
beta-adrenergic receptors.
Alpha-adrenergic receptors (alpha constricts bc he needs more blood in his brain and heart)
Cause selective peripheral vasoconstriction
↑ Blood flow to the brain and heart
↓ Blood flow to the kidneys, GI, muscles and skin
Beta-adrenergic receptors - Beta 1
(beta get your 1 HR up)
Beta 1 = ↑ HR, ↑ contractility
Increases CO = ↑ BP