Shock Flashcards
What is shock?
An abnormality of the circulatory system resulting in inadequate tissue perfusion and oxygenation
How does shock lead to cellular failure?
Inadequate tissue perfusion causes inadequate tissue oxygenation
Tissues must try and function via anaerobic respiration, but this leads to the build up of metabolic waste products
This results in cellular failure
What is hypovolemic shock?
Loss of blood volume
How does a loss in blood volume result in shock?
Decreased blood volume
Decreased venous return
Reduced end diastolic volume
Reduced stroke volume
Therefore, cardiac output is reduced and blood pressure is low
This results in inadequate tissue perfusion
What is cardiogenic shock?
Sustained hypotension caused by decreased cardiac contractility
What might cause obstructive shock?
Cardiac tamponade
Tension pneumothorax
Pulmonary embolism
Severe aortic stenosis
How does obstruction e.g. tension pneumothorax result in shock?
Tension pneumothorax causes increased intrathoracic pressure
This restricts venous return to the heart
Therefore, EDV and stroke volume are reduced
Cardiac output decreases and lowered blood pressure results in inadequate perfusion of tissues
What might cause neurogenic shock?
Spinal cord injury, resulting in loss of sympathetic tone
How does loss of sympathetic tone cause shock?
Massive venous and arteriolar dilatation occurs
TPR and venous return decreased
SV decreased, so CO decreased
What is the treatment of shock?
ABCDE
Oxygen
Volume replacement
What treatment should be given in anaphylactic shock?
Adrenaline
What treatment should be given in cardiogenic shock?
Inotropes
Up until which point can compensatory mechanisms maintain blood pressure?
<30% of blood loss
