Developments in Fluid Management

1. Developments in Fluid Management Dr Kerry Gunn Division of Anaesthesiology 3rd Feb 2006

2. The principle of fluid therapy is to maintain tissue perfusion

3. Escalating fluid management • Plasmalyte • Colloid • Blood • Clotting factors • Inotropes

4. A colloid has protein like massA crystalloid is just an ionic solution

6. Plasmalyte • Crystalloid • First line fluid • Use in expanding intravascular space (ECF) • Ratio 3:1 to loss • Isotonic

7. Gelatins • Colloid • Effective volume expander • Moderate intravascular life • Some anaphylaxis • Ratio 2:1 to loss • MW 40,000 Daltons

8. Crystalloids and colloids

9. Persistence of fluids in circulation

10. Albumin 4% (SPPS) • Raises oncotic pressure • Cochrane analysis • Higher mortality than using crystalloids • Since refuted (SAFE 2004) • Useful for hypoalbuminaemia • Use limited • liver and renal disease, Burns

11. The Crystalloid-Colloid debate

12. What are the differences? • NaCl give you hyperchloraemic acidosis • Less volume required by colloid • Coagulopathy • Less weight gain • Renal dysfunction

13. How to you know • Which to use? • When to transition? • Does using one product vs another change outcome? • What is the quatity of the research?

14. Emergency Resuscitation • How much? • What Fluid? • Which Endpoints?

15. Exsanguination 72 of 78 deaths had isolated or combined injuries of the liver

16. Pick a Trauma Hospital • 5645 trauma admissions / yr (2000) • 501 patients received 5219 units RBCs (8%) • 322 patients received 1-10 units • 147 patients received >10 units (31%) • These 147 patients received • 3693 units RBC (71% ) • 3564 units FFP (69%) • 928 units platelets (88%) • 62% RBCs given in first 24 hrs of admission Como &Dutton Transfusion 2004;44: 809-14

17. Como &Dutton Transfusion 2004;44: 809-14

18. Predictors of death • Red cell transfusion >4,000 mls • Total blood transfusion >5,000 mls • OR fluid transfusion >12,000 mls • Estimated blood loss >5,000 mls • Transfusion rates >12 mls/min • pH <7.2 • Temp <34oC • HCO3 <15 mmol/l

19. Classic Starting Response • Start with 2 large IVs • Run in 2 litres of Crystalloid • Isotonic fluid • Normal Saline (? Hyperchloraemic acidosis) • Plasmalyte • Reassess • Is the patient actively bleeding? • Is the trauma blunt or penetrating? • Do they have a head injury?

20. Refining the answer • If going to surgery • Enough fluid to maintain consciousness • Recordable BP, pulse • Do not delay definitive care • If decreased Level of consciousness • Maintain systolic BP >90 mmHg

21. Refining further • Colloids give quicker response, with less volume BUT no proven benefit. • Hypertonic saline may have advantages in head injury (controversial) • Give BLOOD for active bleeding +++

23. 21 pigs Bleed to MAP of 20 mmHg (~50% bv) Vasopressin 0.4 mg/kg Fluid resus with colloid and crystalloid Vasopressin resuscitated pigs

24. Give volume to fill R ventricle…just In damage control this still may be a considerable amount

25. Blood • Give early in active bleeding • Discuss before giving in stable patients • Risks may outweigh benefits in fit patients

26. Does RBC Transfusion work? • Patients in ICU, Canada: RCCT; n=838 • A: (n=418) Maintain Hb 70 - 90 g/L • B: (n=420) Maintain Hb > 90g/L • Outcomes • 30 day Mortality • Multiple organ dysfunction score • LOS in ICU and hospital, blood use

27. 30 day mortality Results

28. Basic Rules • In otherwise stable patients • Hb in the 70-100 g/L range • Almost no need to transfuse to over 100g/L • Transfuse to remove signs and symptoms • Shortness of breath • Tachycardia • Chest pain • Higher threshold with co-morbidities

29. To transfuse or not to transfuse?That is the question

30. 0 Expert Endpoints • Maintain INR <1.5 • Maintain platelet count >50,000 x 109 • Maintain fibrinogen >1.0 mg/L • Maintain Hb >7 g/L • Fibrinolysis present • Management uncertain • Await surgical control

31. Refining the answer • Serial measurements • Assess volume status with Hb results • Ensure bleeding not occurring • Frusemide only in patients with overload issues.

32. Use Plasmalyte or colloids to restore perfusion • Hypotension • Tachycardia • Oliguria • Cool peripheries • Known blood loss

33. Beware the “increasing the rate” • 150 ml/hr to 200 ml/hr gives 50 ml/hr extra per hour • What if the patient is 1 litre down on intravascular volume?

34. Suggested intravascular volume replacement • Plasmalyte 1000ml over 30 min then reassess • Gelofusine 500 ml over 15 mins then reassess • Don’t simply increase rate slightly • No place for Dextrose Saline

35. Modify your fluid management with the changing patient needs

36. Intravascular volume replacement The best estimate of the volume required is the patients response After therapy started observe • vital signs • urine output (> 0.5mls/kg/hr) • central venous pressure

37. Assessment of intravascular depletion • 5% thirst, dry mucous membranes, UO 1-2 ml/kg/hr • 10% tachycardia, oliguria, UO 0.5-1 ml/kg/hr • 15%-20% tachycardia, hypotension, severe oliguria, UO < 0.5 ml/kg/hr (1-2 L deficit)

38. Maintenance Fluids

39. Dextrose saline • Supplies daily Na+ • Hypotonic • Iso-osmolar • Need to add isotonic solution for losses • K+ • BEWARE HYPONATRAEMIA

40. Post operative hyponatraemia • Patients continue to loose Na+ • Losses thru vomit, third space, bleeding • Patients retain water • Stress response (ADH release) • Beware in elderly, long term fasting • Monitor, and limit IV dextrose • Never give detrose to neuro cases

41. Do elective surgical patients need pre-op fluids? • Usually not • Drink water till two hours pre-op • Resuscitated intra-op • Exceptions • Bowel preps • Acutes and hypovolaemic patients • Long fasting times

42. Not too hot and not too cold

49. Therapeutic endpoints • Goal • normal haemodynamic parameters • normal electrolyte concentration • Method • replace normal maintenance requirements • ongoing losses and deficits • Studies suggest too little post op fluid given

50. Post op hypovolaemia • Many patients remain hypovolaemic postoperatively • Correcting this may reduce post op stay • Patients with co morbidities should be monitoried closely, not left hypovolaemic