Chapter 3 - Shock Flashcards
What is shock
An abnormality of the circulatory system that results in inadequate organ perfusion and tissue oxygenation
What are examples of obstructive shock
Tension pneumothorax - reduce venous return
Cardiac tamponade- inhibits cardiac contractility and reduces cardiac output
Neurogenic shock caused
Extensive injury to upper thoracic or cervical spinal cord - loss of sympathetic tone and vasodilation
Does brain injury cause shock
Only when brain stem is involved
What is the first step in managing shock
Recognising it
What are the types of shock
Hypovolaemic / haemorrhagic Neurogenic Cardiogenic Obstructive Septic
What is the most common cause of shock in trauma patients?
Haemorrhage
What is the most effective way of restoring adequate cardiac output
By locating and stopping the source of bleeding
What are signs of cardiac tamponade
Tachycardia, muffled heart sounds, dilated engorged neck veins, hypotension, insufficient response to fluid therapy
Signs of tension pneumothorax
Distended neck veins, hypotension, absent breath sounds, hyperresonant percussion, acute respiratory distress, subcutaneous emphysema, tracheal shift
what is the classic presentation of neurogenic shock
hypotension without tachycardia or cutaenous vasoconstriction
name the causes of non-haemorrhagic shock
cardiogenic, neurogenic, cardiac tamponade and tension pneumothorax, septic shock
what is the estimated circulatory blood volume for a 70kg person
usually 7% of body weight, roughly 5L
tell me about class 1 heamorrhage
less than 15% blood volume loss
not ususally tachycardia or hypotension
does not usually require replacement or transfusion
will be restored in 24h
tell me about class 2 haemorrhage
15-30% blood volume loss
clinically tachycardia, tachypnoea and decreased pulse pressure (due to increased SVR)
anxiety, fear, hostility
20-30ml/hour UO
crystalliod infusions, may need transfusion
