Shock Flashcards
What is shock?
acute condition of inadequate blood flow = catastrophic fall in arterial BP = circulatory shock
describe the characteristics of hypovolaemic shock
reduced blood vol, haemorrhage = poor venous return, CO
falls, arterial pressure falls, detected by baroreceptors, peripheral vasoconstriction impairs tissue perfusion = hypoxia = multi system failure
describe the characteristics of cardiogenic shock
pump failure = ventricle cannot empty properly e.g MI damage to LV, arrhythmias = too slow to maintain BP, central venous pressure = raised/normal = backflow, dramatic drop in arterial pressure = coronary arteries poorly perfused = exacerbates
describe the characteristics of mechanical shock
obstructive = ventricle cannot fill properly e.g. Cardiac tamponade, pulmonary embolism from DVT occludes pulmonary artery
describe the characteristics of anaphylactic shock
Histamine = profound peripheral vasodilation = lowers TPR, CO increased but cant overcome vasodilation – give adrenaline to vasoconstrict via alpha-1 adrenoceptors
describe the characteristics of septic (‘toxic’) shock
profound peripheral vasodilation = lowers TPR, endotoxins = vasodilation, serious life-threatening = persisting hypotension despite fluid resuscitation
Describe general features of management of the various types of shock
fluid to raise BP, adrenaline to cause vasoconstriction, blood transfusion if blood has been lost
Define pulseless electrical activity
Electrical activity with no mechanical activity
Define asystole
Loss and electrical and mechanical activity
Define ventricular fibrillation
Uncoordinated electrical activity
Define cardiac arrest
Unresponsiveness associated with lack of pulse
What does defibrillation do to the electrical nature of the heart?
Electric current delivered to the heart = depolarises all cells = puts them into refractory period = allows coordinated electrical activity to start
