Fluids in ICU. JMO teaching 5th July 2016

Transcription

1 Fluids in ICU JMO teaching 5th July 2016

2 Objectives Physiology of fluid infusion History of fluid resuscitation Physiology of fluid resuscitation Types of resuscitation fluid The ideal resuscitation fluid Fluid overload and how to avoid it

3 Physiology of fluid infusion What are the effects of rapid infusion of a litre of 5% dextrose into a patient?

4 Physiology of fluid infusion What are the effects of rapid infusion of a litre of 0.9% saline (Normal saline) into a patient?

5 Physiology of fluid infusion What are the effects of rapid infusion of a litre of 5% normal serum albumin solution into a patient?

6 Physiology of fluid infusion Which of the 3 infusions would be excreted the quickest and why?

7 History of fluid resuscitation 1832 = Robert Lewis administered Saline injections into the vines vs cholera pandemic the quantity necessary to be infected will probably be found to depend upon the quantity of serum lost; the object being to place the patient in nearly his ordinary state as to the quantity of blood circulating in the vessels

8 History of fluid resuscitation Sidney Ringer ( ) developed solution 1884 Alexis Hartmann ( ) modified solution by addition of lactate 1941 => blood fractionation => development of Albumin used at Pearl Harbour same year

9 Physiology of fluid resuscitation Target = restore intravascular volume NB: in concert & equilibrium with cardiac output Forget the microcirculation at your peril!

10 Physiology of fluid resuscitation Glycocalyx increasingly recognised to be essential to normal capillary membrane permeability Destruction by inflammation, sepsis, surgery etc

11 Types of resuscitation fluid Colloids Albumin HES (10%, 6%) Synthetic starch Crystalloids 0.9% saline Hartman s / CSL Plasmalyte NB: huge variation in global use of these solutions

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13 Ideal resuscitation fluid Predictable response Sustained increase in intravascular volume Truely balanced vs ECF Metabolised and exerted without accumulation No adverse metabolic or systemic effects Cheap NB: this does not exists currently

14 Albumin Reference colloid solution Fractionation blood => heat treated Advantages: Safe Not as much coagulopathy / renal failure as other colloids Disadvantages: Expensive (not so much in Australia) Limited availability in low/middle income countries Short shelf life (~1yr)

15 Albumin 1998 Cochrane meta-analysis, 24 trials,1419 patients, albumin vs N/S in hypovolaemia, burns and hypovolaemia => increased mortality (6% increase in absolute risk of death) SAFE trial (NEJM, 2004): MRCT, n = 6997, vs 28 day mortality, powered for 3% absolute reduction in mortality 4% albumin safe compared to normal saline Post hoc analysis = TBI and major trauma had worse outcomes with albumin and patients with septic shock tended to better with albumin. Martin (CCM, 2005) = pts hypoproteinaemic with ARDS given albumin + frusemide vs frusemide alone => improved oxygenation & CVS stability

16 Albumin An approach Use in Spontaneous bacterial peritonitis Early resuscitation of ICU patients esp sepsis (further studies pending) ARDS in patients with low albumin with frusemide NOT to be used in TBI??? To correct hypoalbuminaemia (<20)

17 0.9% NaCl Isotonic Not that normal Adverse effects Hyperchloraemic metabolic acidosis (strong ion difference = 0) Immune and renal dysfunction

18 0.9% NaCl vs HES CHEST (NEJM 2012): MRCT, 7000 pts, no significant difference in mortality at 90 days HES => pruritus and 21% relative increase in RRT

19 Plasmalyte solution Not truely balanced Recommended first line in surgery, DKA, burns,? trauma Single centre trials indicate significant decrease in rate of major complications, infections, CRRT, transfusions Adverse effects Metabolic alkalosis Hyperlactaemia Hypotonic (low Na+) Micro thrombi (Ca2+ with citrate containing blood transfusions) Large RCT about to start

20 Fluid administration How do you decide to administer a fluid bolus? What measures do you use to predict fluid responsiveness?

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23 Fluid administration What are the adverse effects of excessive fluid administration?

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26 Recommendations

27 Recommendations

28 Thank you Myburgh JA, Mythen MG. Resuscitation Fluids. N Engl J Med Sep 26;369(13): Ogbu OC, Murphy DJ, Martin GS. How to avoid fluid overload. Curr Opin Crit Care Aug; 21(4): CICM part II exams The physiology viva Kerry Brandis (2003)