A FEW THOUGHTS ABOUT FLUIDS IN KIDS

1. A FEW THOUGHTS ABOUT FLUIDS IN KIDS William Primack, MD UNC Kidney Center Chapel Hill NC USA August 21, 2006

2. HOMEOSTASIS The living organism does not really exist in the milieu exteriour (the atmosphere it breathes, salt or fresh water if that is its element) but in the liquid milieu interior formed by the circulating organic liquid which surrounds and bathes all the tissue elements, this is the lymph or plasma, the liquid part of the blood which in the higher animals is diffused through the tissues and forms the ensemble of the intercellular liquids which is the basis of all local nutrition and the common factor of all elementary exchanges. The stability of the milieu interior is the primary condition for the freedom and independence of existence, the mechanism which allows of this is that which ensures in the milieu interior the maintenance of all the conditions necessary to the life of the elements. Claude Bernard

4. Body spaces

5. Body spaces by age

6. Maintenance fluids • Holliday M and Segar W • Pediatrics 1957;19:824 • 100 kcal~100ml • Their data led to the 100:50:20 protocol for the AVERAGE hospital patient

7. Maintenance fluids • Holliday M and Segar W • Pediatrics 1957;19:824 • 100 kcal~100ml • Their data led to the 100:50:20 protocol for the AVERAGE hospital patient • We never admit any kids like that!!!

8. MAINTENANCE FLUIDSWhat makes up 100 ml/kg

9. MAINTENANCE FLUIDSAbnormal losses

10. Maintenance fluidsAdjustments to 100:50:20 rule • Increase maintenance fluids • By 12 % for each degree C of fever • Insensible losses from 45 to 50-60 ml/100cal for hyperventilation • Decrease maintenance fluids • Insensible losses from 45 to 0-15 ml/100cal for high humidity (= ventilator)

11. Maintenance fluids • Unless you know what you are replacing and why, using maintenance plus (e.g. 1 ½ x maintenance) is illogical

12. Maintenance fluidsAn alternative approach • Based on body surface area • Use estimated insensible losses and replace all other fluid losses based on volume and content • Recalculate as often as needed q6h-q24h • Probably more accurate for PICU type patients

13. BODY SURFACE AREA • BSA (M2) of average proportioned • Newborn=0.25 • 10 kg infant = 0.5 • 30 kg child = 1.0 • 70 kg adult = 1.73 • If average proportioned 3-30 kg • BSA=(wt + 4)/30

14. MAINTENANCE FLUIDSDaily water requirement

15. Continuing losses • NO MATTER WHICH SYSTEM YOU USE • It is essential to regularly reassess child for continuing losses. • Regularly reevaluate effectiveness of your fluid prescription and modify it p.r.n. • May need to recheck labs more than q.d. • Reweigh more than q.d. if appropriate

16. Contents of abnormal lossesmeq/liter

17. Comparison of Electrolyte Composition of Diarrhea Caused by Different Organisms Molla et al. J Pediatr 1981; 98: 835

18. MAINTENANCE FLUIDSFluids based on BSA

19. Case 1 • 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours • On exam decreased turgor, dry mouth, BP 90/60, wt= 9 kg. • Labs Na=140, K=4, HCO3=17, BUN=30, creatinine=0.4. • Receives 10-20 ml/kg bolus and makes some urine

20. Isotonic dehydration

21. Isotonic dehydrationcorrection

22. Isotonic dehydrationcorrection ½ in first 8 hrs, remainder over 16 hours Reassess for and replace continuing losses

23. Case 2 • 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 24 hours • Given ‘clear fluids’. • On exam decreased turgor, dry mouth, BP 80/50, wt= 9 kg. • Labs Na=125, K=4, HCO3=15, BUN=40, creatinine=0.4. • Receives 10-20 ml/kg bolus and makes some urine

25. Hypotonic dehydration

26. Hypotonic dehydrationcorrection

27. Hypotonic dehydrationcorrection (Desired Na – measured Na) X TBW (135 – 125) meq/l X .6 l/kg = 6 meq/kg Thus deficit= 60 meq Na

28. Hypotonic dehydrationcorrection ½ in first 8 hrs, remainder over 16 hours Reassess for and replace continuing losses

29. Case 3 • 1 y.o., 10 kg, child develops vomiting for 12 hours and then diarrhea for 48 hours • Continues to drink cow’s milk • On exam nl to ‘woody’ turgor, moist mouth, BP 90/50, wt= 9 kg. • Labs Na=170, K=4, HCO3=18, BUN=25, creatinine=0.4. • Receives 10-20 ml/kg bolus and makes some urine

30. Hypertonic dehydration

31. Hypertonic dehydrationcorrection Lower maintenance water requirement as high ADH will decrease UO

32. Hypertonic dehydration initial day correction Target is to drop Na by 10 meq/day. Lower maintenance requirement as high ADH will decrease UO Reassess for and replace continuing losses

33. Hypertonic dehydrationcorrection • Lower maintanence requirment as high ADH will decease UO • Goal is to decrese Na by 10 meq/day (Desired Na – measured Na) X TBW (165 – 175) meq/l X .6 l/kg = 6 meq/kg Thus sodium surplus= 60 meq Na

35. 600 500 400 300 200 100 Pre-perfusion Perfusion with electrolytes and 61 mM galactose Perfusion with electrolytes and 56 mM fructose Perfusion with electrolytes and 58 mM glucose Perfusion with electrolytes only MEAN NET STOOL OUTPUT RATE (ml/hr) Post-perfusion 1 2 3 4 5 6 7 8 9 Comparison of Effect of Glucose on Net Stool Rate with Galactose and Fructose in Perfusions Delivered Uniformly throughout Most of the Small Intestine via Multilumen Tube 12-HOUR PERIODS Adapted from Hirschhorn N et al. N Engl J Med 1968; 176

36. Na-glucose co-transport Intestinal brush border Duggan C JAMA 2004;291:2628

37. Outcome of Oral Treatment of 216 Patients with Rotavirus *Requiring unscheduled treatment intravenously. Percentages are given in parentheses. Taylor PR et al. Arch Dis Child 1980; 55(5):376-379

38. ORAL vs IV REHYDRATION IN MODERATE DEHYDRATION Spandorfer et al.Pediatrics 115 (2): 295. (2005)

39. ORS • 30-50 ml/kg over 3-4 hours of ORS • If vomiting give in sips (Pedialyte pops) • May also add 5-10 ml/kg per diarrheal stool for ongoing losses • Expect increased stool content • After rehydration, CHO rich foods • Continue nursing

40. ORS and other ‘clear liquids’