Shock Flashcards
What is it?
State of generalised cellular hypoperfusion leading to inadequate cellular oxygenation to meet metabolic
Warm Ischaemia Time
What is it - the amount of time that an organ remains at body temperature after its blood supply has been stopped/reduced
Heart, Brain, Lungs - 4-6 minutes
Kidneys, liver, Gi tract - 45-90 minutes
Muscle, bone, skin - 4-6 hours
How does Hypovolaemia relate to Impaired Metabolism?
The pt is losing blood volume, loss of volume means fewer RBCs circulating through the capillary beds to deliver oxygen to the cells. the lack of oxygen impairs metabolism.
Consequences of Decreased ATP
K+ and Lactic acid - low pH results of cellular enzymes that auto digest cells. Cellular death, organ failure result
Na+ and H2O enter the cell - cellular oedema, further loss of blood volume
What the Pt looks like:
- ATP produces heat therefore pt without ATP can’t produce/regulate heat
- Happens even in mild temps
Hypovolaemic Shock
Shock caused by haemorrhage is the most common cause of shock in trauma pt.
Assume haemorrhagic shock until proven otherwise
Measure of an Effective Pump (CO)
- CO = SV x HR
- Decrease in SV which less blood volume
Adequate Perfusion
- CO is a factor for maintaining BP
- Adequate BP is required perfusion
- BP = CO x SVR
The 5 Types of Shock
- Distributive - Broken gas hose
- Neurogenic - Gas pump electricity gone bad
- Obstructive - Gas blockage
- Cardiogenic - Gas pump not working
- Hypovolaemic - Not enough gas
Causes of Distributive Shock
Causes; global vasodilation - anaphylaxis, sepsis, adrenal crisis, neurogenic
The Different Presentations of Distributive:
Septic - increased CO, HR and decreased BP, sats
Neurogenic - decreased CO, HR, BP, sats
Anaphylactic - increased HR and decreased CO, BP, sats
- Will give a similar presentation to hypovolaemic shock, the ‘pipes’ that flow are very wide, decreasing the pressure
Causes of Neurogenic Shock
dmg to spinal cord above T5
How does Neurogenic Shock work?
- This dmg causes the distraction of the sympathetic NS meaning the continual stimulation of vasodilation
- The body then can’t adequately fill the ‘container’ by the normal amount of blood in the vascular system
Signs and Symptoms of Neurogenic Shock
- Warm, dry skin
- Normal skin colour, especially below the spinal injury
- Bradycardia
- Hypotension
Causes of Obstructive Shock
reduced return to heart due to blockage - tension pneumothorax, pulmonary embolism (PE) and cardiac tamponade
How does Obstructive Shock work?
- Reduced venous return means less blood to organs and tissue, reducing perfusion
- The compensation for this is increased HR, resps and reducing BP
Causes of Cardiogenic Shock
insult to the heart - MI, ACS, cardiomyopathy, myocarditis, drug toxicity, contusion
→ Blood will be directed to central, vital organs. Therefore the heart and O2 demand increasing HR and resps
Intrinsic Causes of Cardiogenic Shock
- Blunt cardiac trauma leading to muscle dmg and/or dysrhythmias
- Valve disruption
Extrinsic Causes of Cardiogenic Shock
- Pericardial tamponade
- Tension pneumothorax
Causes of Hypovolaemic Shock
dehydration, D&V, GI bleed, trauma
How does Hypovolaemic Shock work?
- Loss of circulating volume RBCs therefore reduces capacity of O2 carrying cells
- Reduces CO
- Reduces BP and reduces oxygenation
- The body tries to compensate for this by increasing the HR and resp rate
Signs of Shock (B)
- Hypoxia and acidosis stimulate the respiratory centre
- 20-30 breaths per minute is moderate
- > 30 more severe
- ‘Air hunger’ - pt may not tolerate mask on face as it will distress them ‘getting air’ - turn on O2 before putting it on
Things to Look for in C
- Levels of consciousness
- Haemorrhage
- HR
- Skin colour and temp
- CRT
- BP
Signs of Shock in D
– Decreased cerebral perfusion will mean altered LOC
- Assume altered LOC is due to shock and treat as such
- DONT FORGET to rule out TBI before giving fluids
MSK Considerations
- Major or multiple fractures can lead to significant blood loss therefore hypovolaemic shock
- Of most concern are pelvic and femur fractures
- Tibia/Fibia - 10-20% of blood volume
- Femur - 20-40% of blood volume
- Pelvis - 100% blood volume
4 Qs of Shock Managment
- What is causing the shock?
- What type of shock is it and what is its care?
- Where can this pt get this care?
- What can be done now before reaching defninitive care?
The Lethal Triad
→Metabolic Acidosis → Hypothermia → Coagulopathy→
- Severe bleeds reduced oxygen deliver, leading to hypothermia
- Meaning, coagulopathy is reduced as its harder to clot at lower temps, increasing bleeding times
- In the absence of blood with O2 and nutrients, metabolic acidosis starts, damaging organs which reduces myocardial performance, decrease CO/oxygen delivery even more
A decrease in pH by 0.4 can reduce enzyme activity that activated clotting by more than 70%
