Critical care Flashcards
What is shock?
a critical condition that is brought on by a sudden drop in blood flow through the body. The circulatory system fails to maintain adequate blood flow, sharply curtailing the delivery of oxygen and nutrients to vital organs.
Signs of shock?
Skin: pale, cold, sweaty, vasoconstricted
Pulse: weak + rapid (Often in AF if septic)
Pulse pressure reduced
Urine output reduced
Confusion, weakness, collapse
Coma then death
Causes of hypovolaemic shock? (pre-load) the liquid
Loss of blood: acute GI bleeding, trauma, peri/post operative, splenic rupture (cause = EBV in glandular fever)
Loss of fluid: dehydration, burns, pancreatitis (into 3rd space lesions)
Causes of cardiogenic shock? (preload) the pump
Cardiac tamponade - muscle ok but compressed from fluid in pericardial sac
Tension pneumothorax (lung collapses from increasing air vol in pleural space, increases pressure on lung and thus pulmonary arteries, heart works harder to pump)
PE (RV failure)
Acute MI (muscle failure)
Fluid overload on pre-existing poor L but ESPECIALLY R ventricular function
Myocarditis (viral, eclampsia, toxin)
Causes of septic shock?
Vasoactive endotoxins causing pathological dilation of arterioles
Causes of anaphylactic shock?
Mast cells degranulate, release IgE
Vasodilation by inflammatory mediators deluging into circulation -> haemodynamic collapse
Commonly caused by: latex, antibiotics
Causes of neurogenic shock
Pathological dilation of arterioles as damage of sympathetic outflow from spinal cord
Afterload shock? the pipes
Septic, anaphylactic, neurogenic
Signs of anaphylaxis?
Intense allergic reaction
causes haemodynamic collapse
Breathlessness and wheeze
Skin and mucosal urticaria, erythema and angio-oedema
Causes of shock from rhythm disturbance?
Ventricular tachycardias
-> shock, DC cardioversion, oxygen, get vascular access
AF w/ low degree of block (results in rapid ventricular rate)
Complete heart block
AF in valve disease where loss of atrial kick (ie atrial filling is 30%) of ventricle causes it to fail
Why do shocked people look grey and sweaty?
Reduction in ventricular filling leads to fall in BP, decreased pressure on baroreceptors (in aortic arch and carotid sinus), increased peripheral and splanchnic vasoconstriction (due to catecholamines, ADH, angiotensin II and renin - also thus causing reduced urine output, thirst)
Maintaining perfusion to brain and myocardium
Treatment of shock?
Oxygen delivery
Fluids - but only increase systolic BP to 100 (risk of clot embolising esp. in GI bleed)
Establish cause of shock and give specifics
Chronotropic (increase rate of heart), ionotropics drugs (increase contractility of heart), vasodilative -give vasopressors to vasoconstrict
Septic: IV abx broad spec
Anaphylaxis: IM adrenaline
Where can you lose blood into?
Abdomen, thoracic cavity, pelvis, into femurs, out of body
What is sepsis?
Life threatening organ dysfunction due to dysregulated host response often due to infection
What is septic shock?
Sepsis + hypovolaemia unresponsive to fluids
