Patho & Pathophis Shock 1 Flashcards
What is shock?
Shock is the inadequate (hypoperfusion) of o2 & nutrients to tissues to maintain metabolic needs. Eventually leading to hypoxia & cell death
What is catabolic & Anabolic metabolism
Catabolic - breaking down molecules e.g. fat, carbohydrates & protein to smaller units of energy
Anabolic - building molecules (like protein) from smaller units
What are the 3 components that essential to avoid shock
- Ventilation
- Oxygenation
- Perfusion
What are the 2 types of ventilation?
What is known as dead space
The volume of air that is inhaled that does NOT take part in gas exchange. This occurs when it either remains in the conducting airways or reaches alveoli that are not/poorly perfused
How does ventilation occur
The diaphragm contracts forcing the thoracic cavity down creating a low pressure system in the lungs. The opposite happens on exhalation
What factors affect gas exchange?
What maintains perfusion
Pumping action of heart
Blood vessels
Blood volume
How do you work out Cardiac output & MAP (BP)
Cardiac output = stroke volume x heart rate
BP = cardiac output x peripheral vascular resistance (PVR)
What BP regulation mechanisms are there to regulate BP
Neural: fast acting, Involving either sympathetic or parasympathetic systems
Hormonal: slower acting but LONGER lasting
Sympathetic response
Stronger/faster heart beat
Dilates vessels to improve blood flow to muscles
Constricts blood vessels supplying nonessential organs e.g. skin
How does the body detect blood pressure
Baroreceptors - in the aortic arch respond to stretch of vessel walls (pressure)
Chemoreceptors - monitor 02 &CO2 located on carotid and aortic bodies
What is the neural Sympathetic response
This involves the release of Epinephrine & norepinephrine activating alpha & beta adrenergic receptors
What affects does epinephrine have to the different receptors
What is the hormonal sympathetic response
Hypothalamus releases corticotropin stimulating the pituitary gland to release adrenocorticotropin hormone (ACTH)
ACTH stimulates the adrenal glands to release cortisol.
Cortisol elevates blood sugar levels and stimulates renal sodium water retention
What does increased Renin stimulate
It leads to increased Angiotensin II in the blood
What affect does Angiotensin II have
It causes vasoconstriction leading to increase in TPR
It also triggers the adrenal cortex to secrete Aldosterone which increases Na+ reabsorption and H20 absorption resulting in more blood volume and a higher blood pressure
How to the Osmoreceptors in the Hypothalamus regulate blood volume
They detect water concentration, then they stimulate the POSTERIOR PITUITARY to release ADH Antidiuretic Hormone.
This affects similar to Aldosterone by increasing the water absorption in the nephrons in the kidneys therefore increasing blood volume
Which is is more effective for producing ATP Aerobic or Anaerobic
Aerobic
Why does Anaerobic Metabolism cause damage
You become acidotic
Enzyme denaturing
Lack of O2 being able be carried
Lack of ATP (lack of energy available to muscle and nerve conduction)
Ride of interstitial oedema (causing blood to become more thick)
Anerobic respiration summarized
What are the 3 different stages of shock
What can dsiruptive shock be broken into
Septic
Neurogenic
Anaphylactic
What is distributive shock Characterised as
Loss of blood vessel tone or vasodilation
Hypovolaemic shock
Occurs where there is loss of 15-20% of circulating volume
Could be a loss of whole blood e.g. bleed
Los of plasma from burns
Or a loss of 3rd space fluid this is where fluid shifts from the vascular compartment to interstitial space
how much blood can be lost with fractures
Summary of Hypovolaemic shock
What is the Deadly trauma Triad
This is the correlation between hypothermia and negative outcomes for hypovolemia.
Acute fatal hemorrhagic shock is categorized by
Acidosis - occurs due to hypo-perfusion & continued anaerobic respiration
Hypothermia - Blood = heat and less blood means less energy production
Coagulopathy - occurs with continued depletion of blood volume
results in circulatory failure & death
Cardiogenic Shock
This is where the heart is unable to sufficiently pump out the amount of blood necessary for adequate perfusion
How do you diagnose cardiogenic shock
What is obstructive shock
This is due to a mechanical obstruction of blood through the central circulation.
This causes a increase in heart pressure due to impaired function commonly on right side.
What are some causes of obstructive shock
Pulmonary embolism
Dissecting aortic aneurysm
Pneumothroax
Haemothorax
Atrial myxoma (tumour)
Abdominal eviceration into thoratic cavity (ruptured hemidiaphram)
Summary of obstructive shock
How does adrenaline/epinephrine cure anaphylaxis
Triggers the sympathetic nervous system which inhibits the action of the mast cells that slow down the release of histamine
