What does shock result in?
- Inadequate oxygenation at the cellular level
2.inadequate removal of toxic metabolic by products which is prolonged leads to generalized impairment of cellular funciton and cellular death
Shock vs Hypotenison
Shock
-inadequate tissue perfusion
-cells not getting enough O2 and not clearing waste
-lead to cell dysfunction -> organ failure -> death if not treated
Hypotension
-low blood pressure
-tells you the pressure not weather the tissues are getting enough oxygen
What are the three principal sources of energy for cells?
1.carbohydrates
2. Proteins
3. Lipids
Carbohydrates
-most of the time cells use carbs in the ore of glucose
-when glucose is metabolized by the cells energy is stored in the form of ATP
What are the two process for the metabolism of glucose
1.inefficent, occurs in the absence of oxygen.
I.e anaerobic environment. Glycolysis and lactic acid is a byproduct
2.presence of oxygen aerobic. Known as the kerbs citric acid cycle and the electron transport chain ATP and CO2 are the by procuts
What happens to the cells in shock?
1.Cells need oxygen to make energy (cells use oxygen to make ATP)
2.in shock -> poor perfusion (not enough oxygen cells with to anaerobic metabolism)
3.Anaerobic metabolism causes problems (less energy produces, toxic products like lactic acid build up, the cells can’t maintain homeostasis )
4. Lysosomes rupture (cell starts digesting itself becasue energy is low)
5.cell membrane becomes incompetent (cell membrane cant conrol what enters and exits and can’t maintain elecotlyes)
6. Damage spreads (toxic enzymes and by products damage nearby cells, organ dysfunction
7. If not reversed -> irreversible shock
Hypovolemic Shock
Not enough circulating fluid blood or water -> not enough preload -> heart can’t pump enough out
Hemorrhagic hypovolemic shock
-blood loss
-internal bleeding or external
non hemorrhagic hypovolemic shock
Fluid loss
-GI loss
-renal loss
-burns or heatillness
Mechanical / obstructive shock
-volume might be okay, and the heart might be okay but something is physically blocking blood flow or filling
Causes
-tension pneumo
-cardiac tamponade
-PE
-disection aorta
Cardiogenic shock
Pump failure
-low CO even if volume is okay
Caues
-MI contusion
-arrhythmias
Neurogenic shock
The fight or flight vasoconstriction is blocked -> vessel dilate -> blood pools in the periphery -> low venous return
Causes
-spinal shock
-severe head injury
-overdose
Septic & anaphylactic shock
Chemicals in blood casue
-vasodialiton (pipes to wide)
-capillary leak (fluid leaves bloodstream into tissues)
Septic shock
-triggered by infection -> inflammatory mediators
Anaphylactic shock
-triggered by allergen -> massiv mediator relase
Addisons disease
-not enough cortisol/ aldosterone -> poor vascular tone + fluid / elecotlyes
Myxedema coma
Sever hypothyroidism
-very slow metabolic > low heart function, low temp, altered LOC
Tension pneumo
-raised intrathoracic pressure impedes venous return
-mediastinum shift. This is what impairs the blood flow to the lungs and to LV
-mechanical obstructive shock
Cardiac tamponade
-impaired diastolic filing since fluid/ blood in the pericardium compresses the heart
Example of mechanical/ obstructive shock
Dissecting aortic Anerusym
-obstruct blood flow distal to the LV and reuslt in hypopefusion and hypoxia
**mechanical obstructive shock
What is the importance physical finding of mechanical shock and caridogenic shock
Distended neck veins indicating raised central venous pressure
Septic shock
-Release of endotoxins by microorganisms (usualy gram negative) into bloodstream
-decreased vascular resistance, peripheral pooling of blood and capillary leak with fluid extravascuation (presure is to low to push blood to vital organs)
-decreased blood to organs
-common in elderly with diabetic and cancer
What causes RV infarction?
-often form proximal RCA occlusion
-RCA supplies:
-SA node
-AV node
-RV
-inferior LV
What goes wrong physiologically ?
-right ventricle cannot pump blood into the lungs
-LV gets no preload
-CO falls
-Hypotenison develop -> caridogenic shock
