1. Fluids and electrolytes Terry Irwin MD FRCS Consultant Colorectal Surgeon

2. What we will cover  Assessing fluid needs  How to prescribe fluids and electrolytes  Common electrolyte problems

3. Who has agreed this protocol Surgery Anaesthesia Nephrology Medicine

6. 60 to 70% water = 42 Litres 2/3 intracellular 1/3 extracellular 1/5 intravascular 4/5 interstitial

7. Fluid compartments ICF (mmol/l) ECF (mmol/l) Sodium (Na)10145 Potassium (K)1404 Calcium (Ca)33 Magnesium (Mg)502 Chloride (Cl)4110 Bicarbonate (HCO 3 )1025 Phosphate (PO 4 )752 Protein (g/dL)165

8. Fluid compartments ICF (mmol/l) ECF (mmol/l) Sodium (Na)10145 Potassium (K)1404 Calcium (Ca)33 Magnesium (Mg)502 Chloride (Cl)4110 Bicarbonate (HCO 3 )1025 Phosphate (PO 4 )752 Protein (g/dL)165

9. Distribution of infused fluids Interstitial fluidIntracellular fluidPlasma

10. Distribution of infused fluids Interstitial fluidIntracellular fluidPlasma Colloids

11. Distribution of infused fluids Interstitial fluidIntracellular fluidPlasma Colloids 0.9% NaCl

12. Distribution of infused fluids Colloids 0.9% NaCl 5% Dextrose Interstitial fluidIntracellular fluidPlasma

13. Why do we give fluids  Replace lost volume  Maintenance of daily requirements  Replace haemoglobin  Replace blood component  Diluent for drugs  Physical effect

14. Why do we give fluids  Replace lost volume  Maintenance of daily requirements  Replace haemoglobin  Replace blood component  Diluent for drugs  Physical effect

15. Daily prescriptions  Water  Sodium  Potassium

16. decide how much fluid to prescribe? How do you

17. Fluid volume prescription  Shock  Replacement of any existing deficit  Daily maintenance fluids  Allowance for predicted excess losses

24. Shock  Fluid bolus (usually 200 ml)  Rapid infusion, not increased rate  Repeat as necessary  Monitor immediate response

25. Maintenance prescription  Adults 30mls/kg/day  For children strictly by weight: – 100 mls/kg/day for 1st 10 kgs – 50 mls/kg/day for the 2nd 10 kgs – 20 mls/kg/day for the rest

26. Maximum 2.5 litres

27. Maximu m 2 litres

28. Sodium and Potassium

29. Sodium  2 mmols/kg/day  Up to a maximum of 150 mmol/day

30. Potassium  1 mmol/kg/day  Usually about 60 mmol per day  Infusion rate important maximum 10 mmol/hr maximum 40 mmol in any one bag of fluid

31. 3030 3030 ml /kg per day Maintenance fluid calculation

32. Can your patient drink ?

33. “Usual” daily fluid script ♀  1 L N Saline (150 mmols Na)  1 L 5% dextrose  60 mmol KCl

34. VolumeSolutionAdditivesRatePrescribed byAdministered 1 1 litreN Saline20 mmol KCl 84 ml/hrDr Joe Bloggs 2 1 litre5% Dextrose 40 mmol KCl 84 ml/hrDr Joe Bloggs 3 4 5

35. ....but what about  Oral intake  Enteral feeding  Paracetamol  IV antibiotics 3030 3030 ml /kg per day

36. If she is receiving  600 mls oral fluids per day  100 ml paracetamol IV 6 hourly

37. VolumeSolutionAdditivesRatePrescribed byAdministered 1 500 ml N Saline20 mmol KCl 42ml/hrDr Joe Bloggs 2 500 ml 5% Dextrose 40 mmol KCl 42ml/hrDr Joe Bloggs 3 4 5

38. VolumeSolutionAdditivesRatePrescribed byAdministered 1 500 ml N Saline20 mmol KCl 42ml/hrDr Joe Bloggs 2 500 ml 5% Dextrose 40 mmol KCl 42ml/hrDr Joe Bloggs 3 4 5 Plus: 400 ml Paracetamol 600 ml oral fluid Total: 2000 ml Plus: 400 ml Paracetamol 600 ml oral fluid Total: 2000 ml

39. Replacing the deficit

40.  Symptoms and signs  Fluid balance chart  Urinary output  Biochemistry results  Postural fall in blood pressure  Urine - osmolality (>300), ↓[Na] < 10

41. Estimating the deficit SeveritySymptoms and signs Mild (1 to 2 litres)Mild thirst, dry mouth, normal otherwise Moderate (2 to 4 litres)Thirsty, mild tachycardia, low urinary output, mildly disturbed electrolytes, orthostatic hypotension, slow capillary refill Severe (4 to 6 litres)Dry mucous membranes, pulse >100, low BP, severe oliguria, raised urea and creatinine, veins guttered, peripheries cool Very severe (>6 litres)Sunken eyes, leathery tongue, hypotension, tachycardia >120, anuria, grossly disturbed electrolytes

42. Replacing the deficit  Estimate the deficit  Choose the most appropriate fluid  Replace over 24 to 36 hours  Monitor response

43. Excess losses Ongoing losses

44. Excess losses  Gastric – Vomiting – NG aspiration  Bowel – Diarrhoea – Stoma output  Fistulae

45. Excess losses  Calculate estimated volume  Replace with same volume of appropriate fluid  Always within the next 24 hour period

46. What fluid should be used?

47. Replace with N Saline with potassium as required

48. Replace with Hartmann’s solution (if potassium OK)

49. Daily prescriptions  Shock  Deficit  Maintenance  Excessive losses

50. Daily prescriptions  Shock  Deficit  Maintenance  Excessive losses N Saline /colloid / blood products

51. Daily prescriptions  Shock  Deficit  Maintenance  Excessive losses N Saline /colloid / blood products N Saline or Hartmann’s

52. Daily prescriptions  Shock  Deficit  Maintenance  Excessive losses N Saline and 5% dextrose N Saline /colloid / blood products N Saline or Hartmann’s

53. Daily prescriptions  Shock  Deficit  Maintenance  Excessive losses N Saline and 5% dextrose N Saline /colloid / blood products N Saline or Hartmann’s

54. Common problems

55. RIFLE criteria Categor y GFR criteriaUrine output Risk Increased creatinine x1.5 or GFR decrease > 25% UO < 0.5ml/kg/h x 6 hr Injury Increased creatinine x2 or GFR decrease > 50% UO < 0.5ml/kg/h x 12 hr FailureIncrease creatinine x3 or GFR decrease > 75% UO < 0.3ml/kg/h x 24 hr or Anuria x 12 hrs LossPersistent ARF = complete loss of kidney function > 4 weeks End stage End Stage Kidney Disease (> 3 months)

57. Too much water, not too few buildings!

58.  Usually caused by XS prescription of water  GAIN guidelines available www.gain-ni.org

60. Hypokalaemia  Often under-prescription of potassium  May be due to excessive losses

61. Hyperkalaemia

62. Summary  Calculate don’t guess  30 ml fluid/kg/day (maximium 2 to 2.5 L)  2 mmol Na + /kg/day (up to 150mmol/day)  1 mmol K + /kg/day  Estimate and replace existing deficit  Replace predicted losses  Monitor response