Cardiovascular Responses to Shock Flashcards
What is Shock?
An abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation
Adequate tissue perfusion and oxygenation is dependent on…
Adequate blood pressure and cardiac output
What causes Hypovolaemic Shock?
Loss of blood volume
What is the pathway of Hypovolaemic Shock?
Loss of blood volume Decreased blood volume Decreased venous return Decreased EDV Decreased SV Decreased CO and BP Inadequate tissue perfusion
What two types of Hypovoleamic Shock can occur?
Haemorrhagic
Non-haemorrhagic
What causes Cardiogenic Shock?
Severe damage to the heart’s pumping ability (e.g. MI)
What is the pathway of Cardiogenic Shock?
Decreased cardiac contractility
Decreased SV
Decreased CO and BP
Inadequate tissue perfusion
What causes Obstructive Shock?
Anything which interferes with the mechanisms e.g. Tension Pneumothorax Cardiac Tamponade Pulmonary Embolism Severe Aortic Stenosis
What is the pathway of Obstructive Shock (Tension Pneumothorax)
Increased intrathoracic pressure Decreased venous return Decreased EDV Decreased SV Decreased CO and BP Inadequate tissue perfusion
What causes Neurogenic Shock?
“Knocking off vasomotor tone”
Massive dilatation affecting blood flow in the system
e.g. Spinal Cord Injury
What is the pathway of Neurogenic Shock?
Loss of sympathetic tone
Massive venous and arterial vasodilatation
Decreased venous return and decreased TPR
Decreased CO and BP
Inadequate tissue perfusion
What causes Vasoactive Shock?
Massive dilatation affecting blood flow in the system due to release of vasoactive mediators e.g. Septic shock
Anaphylactic Shock
What is the pathway of Vasoactive Shock?
Release of vasoactive mediators
Massive venous and arterial vasodilatation (also increased capillary permeability)
Decreased venous return and decreased TPR
Decreased CO and BP
Inadequate tissue perfusion
How do you treat Shock?
High flow O2
Volume replacement
Cardiogenic = Inotropes
Tension Pneumothorax = Immediate chest drain
Anaphylactic Shock = Adrenaline
Septic Shock = Vasopressors
Causes of Hypovolaemic Shock
Haemorrhage, e.g. =
Surgery
Trauma
GI haemorrhage
Non-Haemorrhagic, e.g. =
Vomiting
Diarrhoea
Excess sweating
