Haemorrhage and shock Flashcards
Define circulatory shock
The cardiovascular system is unable to provide adequate substrate for aerobic cellular respiration
What are the clinical signs of shock?
Skin is pale, cold, sweaty and vasoconstricted
Pulse is weak and rapid, pulse pressure reduced, MAP may be maintained
Urine output reduced, confusion, weakness, collapse, coma
Define hypovolaemic shock
Low volume of blood due to blood/fluid loss
Define cardiogenic shock and name some causes
Heart does not pump
Cardiac tamponade, PE, acute MI, fluid overload, myocarditis
When would septic shock occur?
When sepsis is complicated by persistent hypotension unresponsive to fluid resuscitation
Important to administer antibiotics ASAP
State the stages of septic shock over time
Microbial load > toxic burden > inflammatory response > cellular dysfunction/tissue injury
When does anaphylactic shock occur?
Intense allergic reaction
Massive release of histamine and other vasoactive mediators causing haemodynamic collapse
Accompanied by breathlessness and wheeze
Which organ systems are at risk during shock?
Kidneys - acute tubular necrosis
Lung - ARDS
Heart - myocardial ischaemia and infarction
Brain - confusion, irritability, coma
What are the extra pulmonary and pulmonary causes of ARDS?
Extra-pulmonary - shock, head injury, drug reaction, sepsis
Pulmonary - pneumonia, chemical pneumonitis, smoke inhalation, near drowning
What therapies should be used to manage shock?
Ensure adequate oxygen delivery (100% O2)
Replace fluid to maintain organ perfusion
Establish cause of shock and give specific therapies
What are the effects of shock?
Fall in BP (can be maintained until shock advanced)
Tachycardia
Peripheral and splanchnic vasoconstriction - preserve perfusion of myocardium and brain
Reduced urine output
Thirst
What investigation is good for determining shock?
Capillary refill time
