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PEDIATRIC PERIOPERATIVE FLUID THERAPY Evangeline Ko-Villa, MD, DPBA Clinical Associate Professor UP-PGH Department of Anesthesiology.

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Presentation on theme: "PEDIATRIC PERIOPERATIVE FLUID THERAPY Evangeline Ko-Villa, MD, DPBA Clinical Associate Professor UP-PGH Department of Anesthesiology."— Presentation transcript:

1 PEDIATRIC PERIOPERATIVE FLUID THERAPY Evangeline Ko-Villa, MD, DPBA Clinical Associate Professor UP-PGH Department of Anesthesiology

2 Objectives Review relevant physiological considerations in the pediatric population Review relevant physiological considerations in the pediatric population Review how to evaluate intravascular volume Review how to evaluate intravascular volume Discuss the different types of IV fluids Discuss the different types of IV fluids Discuss regimens for perioperative fluid and blood replacement therapy Discuss regimens for perioperative fluid and blood replacement therapy

3 Body Fluid Compartments TOTAL BODY WATER (60%) EXTRACELLULAR FLUID (1/3 TBW) INTRACELLULAR FLUID (2/3 TBW) INTERSTITIAL FLUID (3/4 ECF) PLASMA (1/4 ECF) TRANSCELLULAR FLUID Accurate for children 6 months of age and older

4 Body Fluid Compartments B o d y C o m p o s i t i o n (%)

5 Body Fluid Compartments ICF – 2/3 TBW ICF – 2/3 TBW The proportion of ECF is much greater to that of the ICF in the preterm infants. The proportion of ECF is much greater to that of the ICF in the preterm infants. Upon birth, there is gradual shift from the ECF to the ICF Upon birth, there is gradual shift from the ECF to the ICF

6 Blood Volumes Preterm 100 ml/kg Preterm 100 ml/kg Term 90 ml/kg Term 90 ml/kg Infant 80 ml/kg Infant 80 ml/kg School Age 75 ml/kg School Age 75 ml/kg Adult 70 ml/kg Adult 70 ml/kg Source: A Practice of Anesthesia for Infants and Children by Cote 4 th ed

7 Renal System Features of a fetal kidney: low RBF, low GFR Reasons behind these features: 1. low systemic arterial pressure 2. high renal vascular resistance 3. low permeability of glomerular capillaries 4. small size and number of glomeruli

8 Renal System 1 st 3 -4 days of life: 1 st 3 -4 days of life: circulatory changes RBF and GFR circulatory changes RBF and GFR 1 month of age: kidneys are 60% mature. This is sufficient to handle almost any contingency. 1 month of age: kidneys are 60% mature. This is sufficient to handle almost any contingency. 2 yrs: complete maturation of renal function 2 yrs: complete maturation of renal function

9 Renal System Immature tubular cells cannot completely reabsorb Na + under the stimulus of aldosterone Neonate continue to excrete Na + in the urine despite the presence of a severe Na + defect Implication: obligate sodium loser

10 Renal System: Concentrating Capacity Limited in the neonate Limited in the neonate Max urine osmolality is only ½ of adult levels (700-800 meq/L vs 1300 – 1400 meq/L) Max urine osmolality is only ½ of adult levels (700-800 meq/L vs 1300 – 1400 meq/L) Contributory factors: Contributory factors: low circulating ADH levels low circulating ADH levels renal responsiveness to ADH renal responsiveness to ADH tonicity in the medulary insterstitium tonicity in the medulary insterstitium Implication: Increases free water losses during excretion of a solute loss excretion of a solute loss

11 Renal System: Diluting Capacity A water-loaded infant can excrete dilute urine with osmolality as low as 50 mOsm/kg. A water-loaded infant can excrete dilute urine with osmolality as low as 50 mOsm/kg. The diluting capacity becomes mature by 3 to 5 weeks of postnatal life. The diluting capacity becomes mature by 3 to 5 weeks of postnatal life.

12 Cardiovascular System relatively low contractile mass/gram of cardiac tissue limited ability to myocardial contractility in ventricular compliance extremely limited ability to stroke volume Implication: need to HR to cardiac output

13 Cardiovascular System cardiac Ca 2+ stores are due to immaturity of sacroplasmic reticulum dependent of exogenous Ca 2+ cardiac Ca 2+ stores are due to immaturity of sacroplasmic reticulum dependent of exogenous Ca 2+Implication: Neonatal heart is vulnerable to myocardial Neonatal heart is vulnerable to myocardial dysfunction in the presence of citrate-induced hypocalcemia

14 Hematologic System Neonates have higher baseline Hb values (14 – 20 g/dl) Neonates have higher baseline Hb values (14 – 20 g/dl) They have a higher percentage of fetal Hb They have a higher percentage of fetal Hb At birth, vitamin K dependent factors are at 20 – 60% of adult levels At birth, vitamin K dependent factors are at 20 – 60% of adult levels

15 Neonatal Fluid Management At birth: ECF is greater than ICF At birth: ECF is greater than ICF A few days after birth: A few days after birth: ECF contraction and wt loss due to ANP induced diuresis 2° to pulmonary blood flow & stretch of left atrial receptors ECF contraction and wt loss due to ANP induced diuresis 2° to pulmonary blood flow & stretch of left atrial receptors This is followed by water and Na requirements to match those of the growing infant This is followed by water and Na requirements to match those of the growing infant Implication: Fluids should be restricted until the postnatal weight loss has occurred.

16 Neonatal Fluid Management If a baby requires IV fluids from birth, they shld be given 10% dextrose in the following volumes If a baby requires IV fluids from birth, they shld be given 10% dextrose in the following volumes Day 160 ml/kg/dayDay 4150 Day 290Day 5150 Day 3120 Na + 3 mmol/kg/day & K + 2 mmol/kg/day shld be added after the postnatal diuresis or if Na + drops Na + 3 mmol/kg/day & K + 2 mmol/kg/day shld be added after the postnatal diuresis or if Na + drops A premature neonate may require an additional 30 ml/kg/day and additional Na + A premature neonate may require an additional 30 ml/kg/day and additional Na +

17 Neonatal Fluid Management Fluid requirements are titrated to the: Fluid requirements are titrated to the: patients changing weight patients changing weight urine output serum sodium

18 Evaluation of Intravascular Volume Physical Examination Physical Examination Laboratory Exam Laboratory Exam Hemodynamic Measurements Hemodynamic Measurements

19 Clinical and laboratory assessment of the severity of dehydration in children Signs and Symptoms Mild Dehydration Moderate Dehydration Severe Dehydration Wt loss (%) 51015 Fluid deficit (ml/kg) 50100150 Vital Signs PulseNormal, weak greatly, feeble BPNormal Normal to low, orthostatic RespirationNormalDeep Deep & rapid

20 Clinical and laboratory assessment of the severity of dehydration in children Signs and Symptoms Mild Dehydration Moderate Dehydration Severe Dehydration BehaviorNormalIrritable Hyperirritable to lethargic ThirstSlightModerateIntense Skin turgor NormalDecreased Greatly Greatly Ant. fontanelle NormalSunken Markedly depressed Urine flow (ml/kg/hr) <2<1<0.5 Urine SG 1.020 1.020 – 1.030 >1.030

21 Choice of fluids Crystalloids Crystalloids Colloids Colloids Blood products Blood products Whole blood pRBC FFP Platelets

22 Crystalloids sterile aqueous solutions which may contain glucose, various electrolytes, organic salts and nonionic compounds sterile aqueous solutions which may contain glucose, various electrolytes, organic salts and nonionic compounds rapidly equilibrates with ECF rapidly equilibrates with ECF

23 Composition of Crystalloids FluidOsmolaritypHNaKClGlucose 0.9% NaCl 3086.015401540 LR2736.513041560 D5WD5WD5WD5W2524.500050 D 5 LR 5255.0130415650 D 5 NR 5475.214050

24 Crystalloid Solutions 2 ways of classification 2 ways of classification a. based on use a. based on use b. based on tonicity b. based on tonicity

25 Crystalloid Solutions: Based on Use Maintenance-type solutions Maintenance-type solutions water loss water loss hypotonic solutions hypotonic solutions Replacement-type solutions Replacement-type solutions water and electrolyte losses water and electrolyte losses isotonic electrolyte solutions isotonic electrolyte solutions Fluids for special purposes Fluids for special purposes

26 Crystalloid Solutions: Based on Tonicity Balanced salt solutions Balanced salt solutions electrolyte composition similar to ECF electrolyte composition similar to ECF Hypotonic with respect to Na Hypotonic with respect to Na FluidOsmpHNaKOther LR2736.51304 Lactate = 28 Normosol2957.41405 Mg =3, acetate = 27, gluconate = 23 Plasmalyte298.55.51405 HCO 3 = 50

27 Crystalloid Solutions: Based on Tonicity Normal Saline Normal Saline isotonic (6.0) and isoosmotic (308) isotonic (6.0) and isoosmotic (308) contains no buffers or electrolytes contains no buffers or electrolytes large volume: large volume: dilutional hyperchloremic acidosis dilutional hyperchloremic acidosis

28 Crystalloid Solutions: Based on Tonicity Hypertonic Salt Solutions Hypertonic Salt Solutions Na conc n range from 250 – 1200 meq/L Na conc n range from 250 – 1200 meq/L Rapid volume expansion after infusion of small amounts (e.g. 250 mL) Rapid volume expansion after infusion of small amounts (e.g. 250 mL) t½: similar to isotonic saline t½: similar to isotonic saline may cause hemolysis at point of injection may cause hemolysis at point of injection

29 Glucose containing solutions Glucosegiven intravenouslyis rapidly metabolized, leaving free water behind distributes across all compartments rapidly

30 Crystalloids Advantages Advantages Inexpensive Inexpensive Very low incidence of adverse reactions Very low incidence of adverse reactions Disadvantages Disadvantages Short lived hemodynamic improvement (intravascular t½: 20 – 30 mins.) Short lived hemodynamic improvement (intravascular t½: 20 – 30 mins.) Peripheral/pulmonary edema Peripheral/pulmonary edema

31 Final Word on Crystalloids What is the best crystalloid? What is the best crystalloid? Isotonic crystalloids are preferred over hypotonic crystalloids Isotonic crystalloids are preferred over hypotonic crystalloids

32 Do we have to routinely give glucose containing solutions? Routine dextrose administration is no longer advised for otherwise healthy children receiving anesthesia. Routine dextrose administration is no longer advised for otherwise healthy children receiving anesthesia. There is a growing consensus to selectively administer intraoperative dextrose only in pts at greatest risk for hypoglycemia and in such situations to consider the use of fluids with lower dextrose concentrations (1% or 2.5%) There is a growing consensus to selectively administer intraoperative dextrose only in pts at greatest risk for hypoglycemia and in such situations to consider the use of fluids with lower dextrose concentrations (1% or 2.5%)

33 Colloids contains high MW substances - proteins, large glucose polymers contains high MW substances - proteins, large glucose polymers maintain plasma oncotic pressure maintain plasma oncotic pressure intravascular t½: 3 – 6 hrs. intravascular t½: 3 – 6 hrs.

34 Colloids: Classification Natural Protein Colloid Natural Protein Colloid Albumin or Plasma Protein fraction Albumin or Plasma Protein fraction Synthetic Protein Colloids Synthetic Protein Colloids Hetastarch Hetastarch Dextrans Dextrans Gelatins Gelatins

35 Albumin Colloid gold standard Colloid gold standard Derived from human pool plasma heated to 60 C for 10 hrs ultrafiltration Derived from human pool plasma heated to 60 C for 10 hrs ultrafiltration MW: 69 kDa MW: 69 kDa Available as: 5% and 25% Available as: 5% and 25% Albumin 5% osmotically equivalent to an equal volume of plasma Albumin 5% osmotically equivalent to an equal volume of plasma

36 Albumin Use with caution in patients with Use with caution in patients with increased intravascular permeability increased intravascular permeability (e.g. critically ill, sepsis, trauma, burn) (e.g. critically ill, sepsis, trauma, burn)

37 Albumin: Side Effect Rare Rare Might still have weak anticoagulation effects through platelet aggregation inhibition or heparin-like effects on antithrombin III Might still have weak anticoagulation effects through platelet aggregation inhibition or heparin-like effects on antithrombin III These effects are thought to be clinically insignificant if volume replacement with albumin is kept below 25% of the patients blood volume.

38 Final word on Albumin Data supporting the continued use of albumin for general fluid resuscitation in children are lacking and in children with traumatic brain injury, it may actually be harmful. Its utility may exist in specific subgroups such as neonates and patients undergoing cardiac surgery.

39 Hetastarch modified natural polysaccharides modified natural polysaccharides Amylopectin Hetastarch

40 Hetastarch Described in terms of: Described in terms of: 1. Concentration 2. Average mean MW 3. Molar substitution 4. C 2 :C 6 ratio

41 Hetastarch: Concentration Definition – grams in 100 ml Definition – grams in 100 ml Available as: 3%, 6% and 10% Available as: 3%, 6% and 10%

42 Hetastarch: average mean MW 1. Low- <70 kDa 2. Medium - 130 – 270 kDa 3. High- >450 kDa higher MW longer volume effect greater side effect greater side effect

43 Hetastarch: Molar Substitution Definition: CH 3 CH 2 OH : glucose units Low (0.4 – 0.5) Low (0.4 – 0.5) High (0.62 – 0.7) High (0.62 – 0.7) higher MS longer volume effect greater side effect greater side effect

44 Hetastarch: C 2 :C 6 ratio Hydroxyethyl group attached at C 2 hinder breakdown Hydroxyethyl group attached at C 2 hinder breakdown C 2 :C 6 Higher ratio of C 2 :C 6 in slower enzymatic degradation and prolonged action without increasing side effects.

45 HES Solutions Properties and Availability HES 450/0.7 HES 670/0.7 HES 130/0.4 HES 70/0.5 Trade Name Hespan® Hextend ® Voluven ® AvailabilityEurope/USUSEurope/USUS Conc n 6666 Volume effect (h) 5 – 6 2 – 3 1 – 2 MW45067013070 MS0.70.750.40.5 C2:C6 ratio 4:14:19:14:1

46 HES: Unwanted Side Effects Hypocoagulable effect Hypocoagulable effect - seems to interfere with the function of vWF, factor VIII - seems to interfere with the function of vWF, factor VIII and platelets and platelets Renal toxicity Renal toxicity - induce renal tubular cell swelling & create hyperviscous - induce renal tubular cell swelling & create hyperviscous urine urine Pruritus Pruritus - accumulation on HES molecules under the skin - accumulation on HES molecules under the skin

47 Voluven Pediatric dose: mean dose of 16 + 9 ml/kg Pediatric dose: mean dose of 16 + 9 ml/kg Contraindication: Contraindication: known hypersensitivity to HES known hypersensitivity to HES CHF or pulmonary edema CHF or pulmonary edema renal failure with oliguria not related to hypovolemia renal failure with oliguria not related to hypovolemia pts receiving dialysis treatment pts receiving dialysis treatment severe hyperNa + or hyperCl + severe hyperNa + or hyperCl + intracranial bleeding intracranial bleeding

48 Final word on Hetastarch There are still limited clinical trials in children. There are still limited clinical trials in children. It appears that the new generation HES are much safer in comparison to the older generation HES. It appears that the new generation HES are much safer in comparison to the older generation HES.

49 Gelatins polypeptides produced by degradation of bovine collagen polypeptides produced by degradation of bovine collagen ave MW: 30,000 – 35,000 kDa ave MW: 30,000 – 35,000 kDa requires repeated infusions requires repeated infusions no dose limitation no dose limitation

50 Gelofusine: Pharmaceuticals Characteristics Concentration4% Na154 Cl120 pH7.4 Volume effect 100% Duration of vol expansion 4 hrs

51 Final word on Gelofusine It has less anaphylactoid and coagulation effect in comparison to HES. It has less anaphylactoid and coagulation effect in comparison to HES. The data supporting use of gelatin in children are limited. The data supporting use of gelatin in children are limited.

52 Colloids Advantages Advantages Smaller infused volume Smaller infused volume Prolonged increase in plasma volume Prolonged increase in plasma volume Minimal peripheral edema Minimal peripheral edema Disadvantages Disadvantages Expensive Coagulopathy Pulmonary edema Anaphylactoid reactions

53 Perioperative Fluid Therapy Vol of fluid = maintenance fluid requirement + deficit + loss + deficit + loss

54 Estimating Maintenance Fluid Requirements 0 – 10 kg 4 ml/kg/hr 0 – 10 kg 4 ml/kg/hr 11 – 20 kg Add 2 ml/kg/hr 11 – 20 kg Add 2 ml/kg/hr > 20 kg Add 1 ml/kg/hr > 20 kg Add 1 ml/kg/hr

55 Preexisting Deficits Overnight fasting Overnight fasting Preoperative bleeding Preoperative bleeding Vomiting Vomiting Diuresis Diuresis Diarrhea Diarrhea Other insensible losses Other insensible losses

56 Surgical Fluid Losses Blood loss Blood loss Third space loss Third space loss Evaporation Evaporation

57 Redistribution and Evaporative Surgical Fluid Losses Redistribution and Evaporative Surgical Fluid Losses DEGREE OF TISSUE TRAUMA ADDL FLUID REQUIREMENT DEGREE OF TISSUE TRAUMA ADDL FLUID REQUIREMENT Minimal 0 - 2 ml/kg/hr Minimal 0 - 2 ml/kg/hr Moderate 2 - 4 ml/kg/hr Moderate 2 - 4 ml/kg/hr Severe 4 - 8 ml/kg/hr Severe 4 - 8 ml/kg/hr

58 Blood Product Transfusion What? What? When? When? How much? How much?

59 Transfusion: pRBC MABL of 10-20 % EBV MABL of 10-20 % EBV MABL = EBV (pt initial Hct – lowest acceptable Hct) MABL = EBV (pt initial Hct – lowest acceptable Hct) pt initial Hct pt initial Hct Hb: 7- 10 g/dl Hb: 7- 10 g/dl Hct: 21-30 % Hct: 21-30 % Higher target Hct for certain pts Higher target Hct for certain pts

60 Blood Volumes Preterm 100 ml/kg Preterm 100 ml/kg Term 90 ml/kg Term 90 ml/kg Infant 80 ml/kg Infant 80 ml/kg School Age 75 ml/kg School Age 75 ml/kg Adult 70 ml/kg Adult 70 ml/kg Source: A Practice of Anesthesia for Infants and Children by Cote 4 th ed

61 Problem A 10 yr old 25 kg girl is scheduled to undergo closure of A 10 yr old 25 kg girl is scheduled to undergo closure of colostomy. Her baseline Hct is 36% and lowest acceptable Hct is 21%. What is her MABL? MABL = 1750 x (36 – 21) 36 36 = 730 ml = 730 ml

62 Problem In the same pt, if the blood loss exceeded the MABL by 150 ml and the target Hct is 30%, how much pRBC will you give? In the same pt, if the blood loss exceeded the MABL by 150 ml and the target Hct is 30%, how much pRBC will you give? Vol of pRBC = (vol of blood to replace) (target Hct) Vol of pRBC = (vol of blood to replace) (target Hct) Hct of blood product Hct of blood product = (150) (0.3) = (150) (0.3) 0.7 0.7 = 64.28 65 ml = 64.28 65 ml Short cut: 0.5 ml of pRBC for every ml of blood loss Short cut: 0.5 ml of pRBC for every ml of blood loss beyond the MABL if target Hct is 0.3 beyond the MABL if target Hct is 0.3

63 Transfusion: FFP Indication: Indication: treatment of isolated factor deficiencies, treatment of isolated factor deficiencies, reversal of warfarin therapy, reversal of warfarin therapy, correction of liver disease associated coagulopathy correction of liver disease associated coagulopathy Initial therapeutic dose: 10–15 mL/kg Initial therapeutic dose: 10–15 mL/kg Goal: 30% of the normal coagulation factor Goal: 30% of the normal coagulation factor concentration concentration

64 Transfusion: Platelets Indication: Indication: pts with thrombocytopenia or dysfunctional platelets in the presence of bleeding pts with thrombocytopenia or dysfunctional platelets in the presence of bleeding Transfusion threshold: Transfusion threshold: Plt counts less than 50,000 x 10 9 /L Plt counts less than 50,000 x 10 9 /L

65 THANK YOU


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