Shock Flashcards
Examples of obstructive shock
Tamponade
Tension pneumothorax
Neurogenic shock mechanism
Loss of sympathetic input
Peripheral vasodilation(low BP)
Low HR
Most common cause of shock in trauma patients
Haemorrhage
Cardiac output def
Volume of blood pumped/min
CO=HR*SV
Stroke volume def
amount of blood leaving heart per beat
Factors affecting stroke volume
Pre-load
contractility
After-load
Role of vasopressors in haemorrhagic shock
Contra-indicated as a first-line as worsen tissue perfusion
Earliest signs of shock
Increased HR
Cutaneous vasoconstriction
Tachycardia threshold through ages
Infant: >160 bpm
Pre-school: >140bpm
School - puberty: >120
Adults: >100
Change in pulse pressure with haemorrhagic shock
Results in narrowed pulse pressure
Effect of haemorrhagic shock on Hb and HCT
Massive blood loss may only produce a slight decrease in initial haematocrit or haemoglobin
Causes of cardiogenic shock
Blunt injury
Tamponade
Air embolus
MI
Beck’s triad of cardiac tamponade
Muffled heart sounds
Raised JVP
Low BP
Cause of neurogenic shock
Isolated INTRACRANIAL injuries do NOT cause shock
So look for elsewhere including brainstem, thoracic and cervical spine
Relationship between body weight and circulatory blood volume in an adult
7%
In a 70kg man, 5L of circulatory volume