Fluid Resuscitation Flashcards Preview

RB Y2 CLASP - Sepsis > Fluid Resuscitation > Flashcards

Flashcards in Fluid Resuscitation Deck (26):

define hypotension 

it is difficult to classify but generally

  • a BP <90/60 mmHg
  • >40 mmHg below normal


how does hypotension occur in sepsis 

  • bacteria produce toxins which stimulate the immune system to produce cytokines eg TNF alpha 
  • these increase NO production in vascular smooth muscle which causes vasodilation
  • fall in TPR, leads to a fall in BP = TPR x CO(=HR x SV)
  • endothelial dysfuntion and capillary leak leads to decreased intravascular volume  


NO production 

  • continuously produced by vascular endothelium from amino acid L-arginine through NOS enzyme 
  • potent vasodilator, short action
  • shear stress on vascular endothelium stimulates calcium release from vascular endothelial cells and activation of NOS 


consequences of hypotension 

  • Leads to hypoperfusion in tissues which causes hypoxia and organ dysfunction 
  • Hypoxia leads to anaerobic metabolism, which produces lactic acid as a byproduct

  • This causes a progressive metabolic acidosis with a raised anion gap, which leads to detrimental effects:


detrimental effects of metabolic acidosis 

  • exacerbates vasodilatation , reducing TPR further 
  • decreased myocardial contractility, reducing CO 
  • generalised impaired function of cells 


what does hypoperfusion cause in kidneys 

acute kidney injury 


immediate fluid management - sepsis 6

  • 500ml 0.9% saline STAT 
  • repeat boluses of fluid as required 


signs of hypovolaemia 

  • Cool peripheries (though may be warm)
  • Clammy
  • Dry mucous membranes
  • Decreased JVP
  • Tachycardia
  • Hypotension, postural drop is evident first
  • Skin turgor
  • Mottling of skin
  • Poor urine output


monitoring of fluid 

  • HR, BP, RR
  • Sepsis 6: serum lactate and urine output


what is the normal serum lactate level 

<1.8 mmol/L


what does elevated lactate suggest 

  • tissue hypoperfusion/hypoxia - anaerobic metabolism 
  • in the context of sepsis, suggests severe illness or organ dysfunction as a result of tissue hypoperfusion 


how is urine output best monitored

  • urinary catheter - more accurate and can give hourly volumes 
  • also option of recording urine volume 


normal urine output 

should be at least 0.5ml/kg/hr

(heavier patients produce more)

anything less than this is oliguria 


what does oliguria indicate in sepsis 

renal hypoperfusion 


crystalloid fluids 

  • eg 0.9% NaCl and Hartmanns solution 
  • cheap and widely available 


Hartmanns solution 

a crystalloid that contains additional electrolyes 

generally only used for surgical procedures 


colloids fluids 

  • eg Gelofusin 
  • theoretically, should maintain oncontic pressure, however this does not translate in practice  
  • expensive 


which fluids carry a small risk of anaphylaxis 

colloids and albumin (colloids>)



  • a natural colloid that maintains oncotic pressure 
  • derived from donated blood samples
  • there is a small risk of infection - HepC


where is albumin made 



blood as a fluid 

  • the most physiological colloid 
  • increases oxygen carrying capacity 
  • scarce resource


what is there a risk of with blood fluid replacement 

  • there is a risk of transfusion reaction - type II hypersensitivity 
  • Anti-blood group Ab bind to the surface of circulating donor RBCs
  • There is an overwhelming systemic inflammatory response, which can occur after only 1ml of blood has been transfused


what should never be used in fluid resuscitation 

dextrose 5% - exits the intravascular space took quickly to do any good 


how much fluid do most patients require to restore euvolaemia 

  • 2l 
  • if in doubt, always give too much rather than too little 


how can overload oedema be managed 

  • loop diuretic eg IV furosemide 
  • inhibit NaCl transporter in the Loop of Henle, decreasing blood volume 


further management of a patient who is still hypotensive despite optimized fluid resuscitation/euvolaemia restored 

  • inotropic support/vasoconstrictors eg nor/adrenaline 
  • cause vasoconstriction ± increased myocardial contractility 
  • adminstered through a central venous catheter in HDU/ICU