Shock Flashcards
what are the different types of shock?
distributive
obstructive
hypovolaemic
cardiogenic
what is shock?
life-threatening disorder of circulatory system
resulting in inadequate organ perfusion and tissue hypoxia, causing metabolic disturbances and irreversible organ damage
shock index - calculation
pulse rate/systolic BP
normal shock index
0.4-0.7
shock index when shock is present
> 1
causes of hypovolaemic shock
haemorrhage
non-haemorrhagic fluid loss
haemorrhage causes
postpartum
upper GI bleed
blunt/penetrating trauma
non-haemorrhagic fluid loss
diarrhoea vomiting increased insensible fluid loss - burns third space fluid loss renal fluid loss
clinical features of hypovolaemic shock
hypotension tachycardia weak pulse cold, clammy, pale extremities slow capillary refill decrease preload decreased cardiac output increased afterload increased total peripheral resistance increased systemic vascular resistance decreased mixed venous oxygen saturation
treatment of hypovolaemic shock
fluid resuscitation
management of haemorrhage
possibly blood transfusion
causes of cardiogenic shock
arrhythmias MI valve defects heart failure cardiomyopathy myocarditis drugs blunt cardiac trauma
clinical features of cardiogenic shock
hypotension tachycardia weak pulse cold, clammy, pale extremities slow capillary refill increased/decreased preload decreased cardiac output increased afterload increased total peripheral resistance increased systemic vascular resistance decreased mixed venous oxygen saturation
treatment for cardiogenic shock
diuretics
inotropic therapy
causes of obstructive shock
cardiac tamponade PE tension pneumothorax constrictive pericarditis restrictive cardiomyopathy large systemic emboli aortic dissection aortic stenosis
clinical features of obstructive shock
hypotension tachycardia weak pulse cold, clammy, pale extremities slow capillary refill increased/decreased preload decreased cardiac output increased afterload/total peripheral resistance increased SVR decreased mixed venous oxygen saturation
treatment for obstructive shock
decompression
what are the types of distributive shock?
septic
anaphylactic
neurogenic
causes of septic shock
infection
bacteraemia
clinical features of septic shock
flushed dry, warm skin tachycardia hypotension fever decreased preload increased cardiac output decreased afterload/total peripheral resistance decreased systemic vascular resistance increased mixed venous oxygen saturation
treatment of sepsis
fluid resuscitation
vasopressors
broad-spectrum empirical antibiotic therapy
causes of anaphylactic shock
drug reactions
insect stings/bites
food allergies
clinical features of anaphylaxis
flushed dry, warm skin tachycardia hypotension itchy skin hives bronchospasm laryngeal oedema swelling of tongue uvula angioedema decreased preload increased cardiac output decreased afterload/total peripheral resistance decreased systemic vascular resistance increased mixed venous oxygen saturation
treatment for anaphylaxis
fluid resuscitation vasopressors adrenaline antihistamines glucocorticoids
causes of neurogenic shock
spinal cord injury
traumatic brain injury
cerebral haemorrhage
clinical features of neurogenic shock
flushed dry, warm skin bradycardia hypotension neurological deficits decreased preload decreased cardiac output decreased afterload/ total peripheral resistance decreased systemic vascular resistance decreased mixed venous oxygen saturation
treatment for neurogenic shock
fluid resuscitation
vasopressors
atropine for bradycardia
diagnosis of shock
assess HR, BP and oxygen sats measure CVP - central venous catheter catheterise bladder to monitor urine output renal function tests ABG clotting parameters LFTs electrolytes
Renal function tests for shock
blood urea nitrogen is raised
creatinine
shock electrolytes
sodium
potassium
calcium
shock ABG
lactic acidosis
shock LFTs
hyperbilirubinaemia
increased AST/ALT
what is the end stage of shock?
DIC
disseminated intravascular coagulation
what are the stages of shock?
preshock
shock
end organ dysfunction
pre shock
non progressive phase
activation of compensatory neurohumoral reflexes to maintain vital organ perfusion
clinical features of pre-shock
peripheral vasoconstriction
cold, clammy extremities
increased capillary refill time
decreased capillary hydrostatic pressure - increased absorption of interstitial fluids into intravascular space to maintain BP
tachycardia - absent in neurogenic shock
no peripheral vasoconstriction in distributive shock
oligouria
shock
progressive phase
clinical features of shock
worsening hypotension
hypoperfusion of peripheral tissues
generalised hypoxia
anaerobic metabolism in underperfused organs
lactic acidosis
worsening tachypnoea
precapillary dilation and postcapillary constriction of vessels
pooling and stasis of blood in capillary bed
decreased CO
formation of microthrombi in capillaries
DIC
hypoxic injury
acidosis
cerebral hypoperfusion = altered mental status
end organ dysfunction
irreversible phase
decompensation
irreversible tissue damage
clinical features of end organ dysfunction
cerebral hypoxia autonomic dysfunction myocardial ischaemia - ACS decreasec CO widespread cell necrosis bowel ischaemia
widespread cell necrosis
release of lysozymal enzymes further tissue injury worsening of shock activation of immune system release of cytokines DIC further tissue damage
DIC
blood clots form in small blood vessels
ischaemia of organs
organ failure
clotting uses up clotting factors and platelets so there is excessive bleeding
clotting activated throughout the body
inhibition of clotting control mechanisms
clotting and bleeding together
signs/symptoms of DIC
blood in stool/urine headaches - brain bleeds bruises petechiae wound/surgical sites bleeding mucosal bleeding organ dysfunction blackening of skin - ischaemia chest pain haemoptysis difficulty breathing heart attack symptoms stroke symptoms
how to manage shock?
warm
lay flat
peripheral IV line using large calibre catheter
intraosseous route if IV unavailable
oxygen therapy
ventilation
monitoring of HR, BP, CRT, RR, urine output and presence of skin mottling
target oxygen sats
94-98% unless hypercapnic/ type II respiratory failure = 88-92%
treating cardiogenic shock
wide bore cannula crystalloid fluids reassess haemodynamic status examine for fluid overload vasopressor if hypotension or continued hypoperfusion despite fluids
crystalloid fluid resuscitation
0.9% saline or hartmann’s solution
200-250ml over <15 mins bolus
target MAP
65mmHg if cause of shock is unknown
treatment for fluid overload/ pulmonary oedema?
loop diuretic
IV furosemide
or vasodilator if systolic BP is over 90mmHg
vasopressor
causes vasoconstriction
e.g. noradrenaline, metaraminol, dopamine, vasopressin, adrenaline, inotrope - dobutamine if there is impaired cardiac function/CO
treatment for haemorrhagic shock
major haemorrhage protocol blood products reverse anticoagulation IV tranexamic acid in trauma fluid resus hypovolaemic shock = blood products
blood products for haemorrhagic shock
RBCs
fresh frozen plasma - FFP
1:1 ratio in trauma or 1:2 in non-trauma
platelets
cryoprecipitate or fibrinogen concentrate if low fibrinogen
target haemoglobin in haemorrhagic shock
7-9g/dL or 70-90g/L
What does tranexamic acid do?
clot formation
antifibrinolytic
how to treat obstructive/ distributive/ non-haemorrhagic shock?
crystalloid fluid resus reassess haemodynamic status examine for fluid overload vasoactive drug - vasopressor/ inotrope arterial line and central venous catheter
