shock and resus Flashcards
What is shock
Condition of inadequate perfusion to sustain normal organ function
Name and describe each of the 5 classes of shock
Hypovolaemic - loss of circulating volume =
What are the clinical features of hypovolaemia?
Based on degree of shock:
- Pulse rate increase
- Blood pressure normal until around 1/3 blood is lost due to compensatory mechanisms and then decrease.
- Pulse pressure is normal or increased in mild blood loss but then decreases
- Increase in resp rate
- Decrease in urine output
- Anxiety due to fight or flight and eventually confusion and lethargy
Why do young people decrease rapidly when they have hypovolaemic shock?
Because they do really well at compensating until they don’t
What are the 4 compensatory mechanisms involved in hypovolaemic shock?
Baroreceptors - stretch sensitive,
What is the Frank-Starling curve
A reflection of the heart’s inotropic state and is generated by the isolated muscle preparation before being extrapolated to the heart itself
What happens when fluid is given in hypovolaemia
In hypervolaemia, patients are extremely fluid responsive therefore any fluid given has a big effect on the frank starling curve
What are some clinical signs of cardiogenic shock?
Hypotension/shock, fatigue and syncope due to poor forward flow
Pulmonary oedema, elevated JVP and hepatic congestion due to backpressure.
What is inotropy?
A measure of the contractile state of the myocardium for any given preload
How is positive inotropy achieved? (physiologically and pharmacologically)
The sympathetic nervous system
Beta and dopaminergic stimulation (positive inotropes) (Dobutamine/adrenaline, Dopamine/dopexamine
What are the three main causes of obstructive shock
Pulmonary embolism, Cardiac tamponade, Tension pneumothorax
Outline the treatment for each of the three main causes of obstructive shock
PE - Anticoag +/- thrombolysis
Tamponade - Pericardial drainage
Tension Pneumothorax - decompression and chest drainage
What is distributive shock often also known as
Vasodilatory/warm shock
What are the three main types of distributive shock?
Septic - bacterial endotoxin mediated capillary dysfunction
Anaphylactic - Mast cells release of histaminergic vasodilators
Neurogenic - Loss of thoracic sympathetic outflow following spinal injury
What are the 2 shockable and non-shockable cardiac arrest rhythms
Shockable - Ventricular fibrillation and pulseless ventricular tachycardia
Non-shockable - Pulseless electrical activity and asystole
