Fluid management in Pediatrics

Quick review on fluid management

1. Fluid management in special circumstances Presented by: Dr. Jyoti Jha Department of Pediatrics

2. Composition of Body Fluids Total body water: TBW = Intracellular fluid + Extracellular fluid TBW as a percentage of body weight varies with age.

3. FLUID COMPARTMENTS

4. Oncotic pressure  is a form of  osmotic pressure  exerted by proteins either in the blood plasma or interstitial fluid.  Hydrostatic pressure  is a force generated by the pressure  of fluid on the capillary walls either by the blood plasma or interstitial fluid.

5. 1. Hypoalbumiemia : Low albumin=Decreased oncotic pressure of intravascular compartment = edema 2. Heart failure: Impaired pumping = Expansion of intravascular volume= Increase venous hydrostatic pressure= Fluid moves from intravascular to interstitial space.

6. ELECTROLYTE COMPOSITION

7. TERMINOLOGY Osmolarity  is number of  osmotically  active particles  per  one  litre Osmolality is number of  osmotically  active particles  per  one  Kg Tonicity  refers to osmolality of a solution relative  to  plasma Normal   285- 295 mosm /kg

8. OSMOLALITY T he concentration of a solution expressed as the total number of solute particles per kilogram Plasma osmolality = 285-295 mOsm /kg Formula: Osmolality =2x( Na ) + glucose/ 18 + BUN / 2 . 8

9. TONICITY

10. COMMON IV FLUIDS 5 % Dextrose (D5) 10 % Dextrose (D10) Normal Saline (NS) Ringer Lactate (RL) 5% Dextrose Normal Saline  (DNS) 5% Dextrose ½ Normal Saline  (½ DNS) Isolyte  P 3% Saline (Hypertonic Saline)

11. Isotonic fluid Hypotonic fluid Hypertonic fluid Omsolality = body fluid osolality Omsolality < body fluid osolality Osmolality > Body fluid osmolality Example : Normal saline Ringer lactate 5% dextrose Half Normal saline 3% Normal saline DNS 10% Dextrose

12. Normal Saline ( 0.9% w/v) Each 100 ml contains: Sodium chloride 0.9 g Each litre contains: Sodium = 154 mmol Chloride = 154 mmol Osmolality = 308

13. Ringer Lactate Each 100 ml contains Lactic acid = 0.24 ml Equivalent to Sodium lactate = 0.32 g Sodium chloride = 0.6 g Potassium chloride = 0.04 g Calcium chloride = 0.027 g Each litre contains : Sodium = 131 mosm Potassium = 5 mosm Calcium = 2 mosm Bicarbonate = 29 mosm Chloride = 111 mosm Osmolality = 273 mosm

14. DNS Each 100 ml = Dextrose anhydrous = 5 g Sodium chloride = 0.9 g Electrolytes / litre Sodium = 154 mosm Chloride = 154 mosm

15. Mainteance therapy Maintenance intravenous fluids are used in a child who cannot be fed enterally G OALS OF MAINTENANCE FLUIDS: Prevent dehydration Prevent electrolyte disturbance Prevent ketoacidosis Prevent protein degradation

16. calculation                           HOLIDAY  SEGAR FORMULA For one day: Upto  10 kg BW: 100ml/kg  11-20  kg BW:  1000+  50 ml /kg for  each  1 kg >  10kg >  20Kg  BW:  1500+  20 ml/kg for  each   kg > 20 kg  Hourly:   Upto  10 kg BW: 4ml/kg/hr.  11-20  kg BW:  40   ml/ hr +  2  ml/kg/ hr x ( wt – 10 kg) >  20Kg   BW: 60ml/ hr + 1 ml/kg/ hr x ( wt -20)

17. M AINTENANCE W ATER Crucial component of maintenance fluid therapy. Maintenance water = Measurable loss of water 65% (Urine 60%, stools 5%) + Insensible of water 35% (skin & lungs)

18. Insensible water loss Source of water loss Insensible loss - Lungs   and Skin= 35% Sensible  water loss Urine –  60% Stool  – 5  % CALCULATION Insensible  water loss 400 ml/M2 BSA Or 1/3 maintenance 30ml/kg in infancy 20ml/kg in children 10ml/kg in adults

19. INTRAVENOUS SOLUTION Normal saline (NS) and Ringer lactate (LR) are isotonic solutions The usual choices for maintenance fluid therapy in children are half-normal saline (1/2 NS) and NS. These solutions are available with 5% dextrose (D5) or without dextrose. A normal plasma osmolality is 285-295 mOsm /kg . Infusing an intravenous solution peripherally with a much lower osmolality can cause water to move into red blood cells, leading to hemolysis. Thus, 0.2NS (osmolality = 68) should not be administered peripherally, but D5 0.2NS (osmolality = 346) or D5 1/2 NS + 20 mEq /L KCl (osmolality = 472) can be administered.

20. Hypotonic fluids increase the risk of hyponatremia 0.2NS is no longer recommended as a standard maintenance fluid and its use is restricted at many hospitals.

21. Glucose in maintenance fluid Maintenance fluids usually contain D5 It provides 17 calories/ 100 mL and nearly 20% of the daily caloric needs This level is enough to prevent ketone production and helps minimize protein degradation If prolonged , receives inadequate calories and will lose 0.5-1% of weight each day.

22. SELECTION OF MAINTENANCE FLUIDS nonosmotic ADH production D51/2NS + 20 mEq /L KCl is recommended in the child who is NPO. Children with volume depletion, baseline hyponatremia , or at risk for nonosmotic ADH production (lung infections such as bronchiolitis or pneumonia; central nervous system infection) should receive D5 NS + 20 mEq /L KCl .

23. Surgical patients T ypically receive isotonic fluids (NS, LR) during surgery and in the recovery room for 6-8 hr postoperatively the rate is typically approximately two-thirds of the calculated maintenance rate , with dextrose added if clinically indicated. Subsequent maintenance fluids should be D5 NS or LR, with addition of 10-20 mEq /L of KCl based on the serum potassium and the clinical setting . Electrolytes should be measured at least daily in all children receiving more than 50% of maintenance fluids intravenously unless the child is receiving prolonged intravenous fluids (TPN).

24. M ONITORING W HILE ADMINISTERING F LUIDS * electrolytes and glucose 4-6 hours after commencing, and then according to results and the clinical situation but at least daily. particular attention to the serum sodium on measures of electrolytes. If <135mmol/L (or falling significantly on repeat measures) If >145mmol/L (or rising significantly on repeat measures) Children on iv fluids should have a fluid balance chart documenting input, ongoing losses and urine output. *Royale Children’s Hospital Melbourne Guidelines

25. Child should be weighed prior to the commencement of therapy, and daily afterwards. Children with ongoing dehydration/ ongoing losses may need 6 hourly weights to assess hydration status All children on IV fluids should have serum electrolytes and glucose checked before commencing the infusion (typically when the IV is placed) and again within 24 hours if IV therapy is to continue. *Royale Children’s Hospital Melbourne Guidelines

26. Adjustment in maintenance water and electrolytes

27. Clinical condition that modify normal water and electrolyte Factor Alteration Fever (persistent) 10-15% increase for every 1C/1.8F increase in temperature above 38C/100.4F Hyperventilation 10-60 ml/kg (per 100 kcal) Sweating 10-60 ml/kg Humidified ventilation Reduce GI and Renal loss Monitor and adjust

28. Replacement fluid The gastrointestinal (GI) tract is potentially a source of considerable water loss. GI water losses are accompanied by electrolytes and thus may cause disturbances in intravascular volume and electrolyte concentrations . GI losses are often associated with loss of potassium, leading to hypokalemia . Because of the high bicarbonate concentration in stool, children with diarrhea usually have a metabolic acidosis, which may be accentuated if volume depletion causes hypoperfusion and a concurrent lactic acidosis. Emesis or losses from an NG tube can cause a metabolic alkalosis

29. It is impossible to predict the losses for the next 24 hr ; better to replace excessive GI losses as they occur. The child should receive an appropriate maintenance fluid that does not consider the GI losses. The losses should then be replaced after they occur, with use of a solution with a similar electrolyte concentration as the GI fluid . The losses are usually replaced every 1-6 hr , depending on the rate of loss, with very rapid losses being replaced more frequently.

30. Diarrhea is a common cause of fluid loss in children. It can cause dehydration and electrolyte disorders Average composition of Diarrheal stools (except cholera) Na 55 mEq /l K 25 mEq /l Bicarbonate 15 mEq /l Approach to Replacement of Ongoing Losses D5 1/2 NS + 30 mEq /l sodium bicarbonate + 20 mEq /l KCl Replace stools ml/ml every 1 to 6 hrs

31. R EPLACEMENT F LUIDS Replacement fluid for Emesis or Nasogastric losses* Average composition of Gastric Fluid Na 60 mEq/l K 10 mEq/l Chloride 90 mEq/l Approach to Replacement of Ongoing Losses NS + 10 mEq/l KCl Replace Output ml/ml every 1 to 6 hrs *Nelsons Text book of pediatrics 19 th edition

32. R EPLACEMENT F LUIDS Replacement fluid for Altered Renal Output* Oligouria / Anuria Place patient on insensible fluids (25 to 40% of maintenance ) with D51/2NS Replace Urine output ml/ml by D5 half NS +/- KCL Polyuria Re p lace ment of insensible fluids (25 to 40% of maintenance ) with D5 ½ NS +/- KCL Measure urine electrolytes Replace Urine output ml/ml with solution based on measured urine electrolytes *Nelsons Text book of pediatrics 19 th edition

33. Deficit therapy Dehydration, most often caused by gastroenteritis, is a common problem in children

34. CALCULATION OF THE FLUID DEFICIT Determining the fluid deficit necessitates : clinical determination of the percentage of dehydration and multiplication of this percentage by the patient’s weight; a child who weighs 10 kg and is 10% dehydrated has a fluid deficit of 1 L.

35. APPROACH TO SEVERE DEHYDRATION The child with dehydration needs acute intervention to ensure that there is adequate tissue perfusion Resuscitation phase: Requires rapid restoration of the circulating intravascular volume and treatment of shock with an isotonic solution, such as normal saline (NS) or Ringer lactate (LR ). The child is given a fluid bolus, usually 20 mL/kg of the isotonic fluid, over approximately 20 min. The child with severe dehydration may require multiple fluid boluses and may need to receive the boluses as fast as possible. In a child with a known or probable metabolic alkalosis (the child with isolated vomiting), LR should not be used because the lactate would worsen the alkalosis.

36. The initial resuscitation and rehydration phase is complete when the child has an adequate intravascular volume. Typically, the child shows clinical improvement, including a lower heart rate, normalization of blood pressure, improved perfusion, better urine output, and a more alert affect .

37. MONITORING AND ADJUSTING THERAPY

38.  IDEAL CONCENTRATION OF  sodium IN   IVF? Below  10 kg BW:       D5  ¼ NS + 20  mmol /L of  KCl Above 11 kg BW:       D5  1/2 NS + 20  mmol /L of  KCl Ref : Nelson text book of pediatrics.  18 th  edition P.310

39. Clinical conditions and fluid management

40. Hyponatremic dehydration: The pathogenesis of hyponatremic dehydration usually involves a combination of sodium and water loss and water retention to compensate for the volume depletion. G oal : correction of intravascular volume depletion with isotonic fluid (NS or LR). Avoid correcting the serum sodium concentration by >12 mEq /L/24 hr or >18 mEq /L/48 hr. An overly rapid (>12 mEq /L over the first 24 hr ) or overcorrection in the serum sodium concentration (>135 mEq /L) is associated with an increased risk of central pontine myelinolysis Patients with neurologic symptoms (seizures) need acute infusion of hypertonic (3%) saline to increase the serum sodium concentration rapidly.

41. Hypernatremia S odium concentration >145 mEq /L, sometimes defined as >150 mEq /L. should not be corrected rapidly. Goal: is to decrease the serum sodium by <12 mEq /L every 24 hr , a rate of 0.5 mEq /L/hr. In hypernatremic dehydration, the first priority is restoration of intravascular volume with isotonic fluid Normal saline is preferable to lactated Ringer solution because the lower sodium concentration of the latter can cause the serum sodium to decrease too rapidly, especially if multiple fluid boluses are given.

42. Determinants of the rate of decrease of sodium concentration The sodium concentration of the deficit replacement fluid, the rate of fluid administration, and the presence of continued water losses. F ormula for calculating the water deficit : Water deficit = Body weightx 0.6 (1-45) / current sodium This calculation is equivalent to 3-4 mL of water per kg for each 1 mEq that the current sodium level exceeds 145 mEq . The utility of such formulas has never been proven in clinical practice.

43. HYPERNATREMIC DEHYDRATION

44. Acute watery diarrhoea 1. Assessment of dehydration 2. In case of severe signs of dehydration best iv fluid is Ringer lactate. Age First give Then give <12 months 30ml/kg in one hour 70 ml/kg in 5 hours 12 months – 5 years 30ml/kg in 30 min 70 ml/kg in 21/2 hours Repeat again if the radial pulse is still very weak or not detectable

45. Diabetes ketoacidosis

46. Shock

47. Acute renal failure Fluid challenge to differentiate pre-renal from intrinsic renal failure. For intrinsic renal failure failure maintenance fluid is reduced to insensible loss Plus urine output In oliguric renal failure no electrolyte should be added to the fluid.

48. Congestive cardiac failure They are in state of fluid overload Daily maintenance should be reduced to two third value Fluid of choice for 10 kg child = N/5 D5 with 2 ml KCL per 100 ml fluid @ 70ml/kg

49. Intestinal obstruction NG aspirate should be replaced with N/2 or N/3 saline with added potassium NS or RL can be used

50. Burn Fluid resuscitation should begin soon after the injury has occurred Parkland formula: 4 mL lactated Ringer solution/kg/% BSA burned Half of the fluid is given over the 1st 8 hr , calculated from the time of onset of injury; the remaining fluid is given at an even rate over the next 16 hr . The rate of infusion is adjusted according to the patient’s response to therapy. Pulse and blood pressure should return to normal, and an adequate urine output (>1 mL/kg/ hr in children; 0.5-1.0 mL/ kg/ hr in adolescents) should be accomplished by varying the IV infusion rate.

51. Vital signs, acid–base balance, and mental status reflect the adequacy of resuscitation. Because of interstitial edema and sequestration of fluid in muscle cells, patients may gain up to 20% over baseline ( preburn ) body weight. Patients with burns of 30% of BSA require a large venous access (central venous line) to deliver the fluid required over the critical 1st 24 hr . Patients with burns of >60% of BSA may require a central venous catheter In addition to fluid resuscitation, children should receive standard maintenance fluids

52. Fluid Maintenance During Surgery and Anesthesia Patients who are unconscious and immobile have lost venous pump mechanisms and have peripheral venous pooling. Volume expansion is most commonly provided by isotonic salt-containing solutions (normal saline, lactated Ringer solution ). Autonomic responses may be increased as part of the surgical stress response, with vasoconstriction and intravascular volume contraction caused by diuresis, intravascular volume loss from hemorrhage, evaporation (insensible loss, increased during surgery), and third space (interstitial space) fluid losses resulting from the inflammatory response. Abnormalities in the distribution of renal blood flow and secretion of antidiuretic hormone further complicate the regulation of intravascular volume.

53. ELECTROLYTE CONCENTRATION OF STOCK SOLUTION  FOR EVERY ONE ML IV Preparations - One ml Electrolyte content 3% saline 8.4% Sodium bicarbonate Potassium chloride 10% Calcium gluconate 0.5mEq of sodium 1 mEq of Na and HCO3 2 mEq of potassium 9.3 mg of Elemental ca

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