L21: Shock Flashcards
What is shock
Clinical syndrome (collection of symptoms and signs) that arise from different pathophysiology that result in inadequate perfusion of tissue oxygenation due to an imbalance between oxygen deliver and oxygen demand
What is tissue perfusion dependent on
Mean arterial pressure
What is mean arterial pressure dependent on
Systemic vascular resistance
Cardiac output
What is cardiac output dependent on
Stroke volume
Heart rate
What is stroke volume dependent on
Pre load
Contactility
Afterload
What are the categories of shock
Cardiogenic
Obstructive
Distributive
Hypovolaemic
What is cardiogenic shock
Ventricular pump failure e.g mi or acute valve dysfunction, when stroke volume decreases, cardiac output decreases so mean aterial blood pressure decreases
What is obstructive shock
This is impaired ventricular filling or obstruction to the outflow tract due to pe or cardiac tamponade
What is distributive shock
Reduced systemic vascular restiance (vasdodilation) with normal cardiac function e,g due to sepsis
What is hypovolaemic shock
Loss of circualtinf volume with normal cardiac function e.g gi bleed, burns and diarrhoea
When the body is in shock how does the body compensate
- Increase cardiac output: stimulates sns to increase heart rate and stroke volume and systemic vascular resistance:
- Redistribution of blood to vital organs by vasoconstriction and release adh and renin to reduce urine production
- Increased oxygen delivery to the cell: bronchodilation, increased respiration
What is the emergency asessment for shock
ABCDE assessment/approach
What is dextrose fluid made of
Glucose dissolved in water
What happens when dextrose is given to someone
Glucose is taken up by cells and this leaves water behind so its distributed in the body water
What is saline made of
Sodium and chloride dissolved in water
What happens in the body when saline is given
Saline distributes to the interstitital fluid and plasma by 3:1 ratio
Where will hartmanns most end up
In the extracellular space
What are the 2 categories of flid
Cystalloid
Colloid
What is cystalloid
Small molecules dissolved in water e.g saline, dextrose and hartmanss
What is colloid
Large molculesin isotonic fluid
How do colloid fluids act
Counteract the hydrostatic pressure by exerting a osmotic pressure in the blood causing the fluid to remain within the vascular system
It increases the intravascular volume
When are cystalloid fluids used
Replacement of fluid e,g septic shock
To meet daily requirements
Special circumstances: traumatic brain injury, metabolic acidosis to renal failure
What are the 4 main groups of blood
O
A
B
Ab
What is a o group blood
Has no antigens has anti a and anti b antibodies in the plasma
What is blood group a
Has a antigens and anti b antibodies in the plasma
What is b blood group
Has b antigen and anti a antibodies in plasma
What is ab blood group
Has a and b antigens and no antibodies in the plasma
When we give blood where does it stay in the body
Intravascular space
In fluid resusitation what do we do
Give fluid first to correct the physiology and give cystalloids (500mls over than 15 minutes)
