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Pediatric Fluid Management and Blood Product Therapy. ASA Fasting Guidelines. Clear liquids 2 hours Breast Milk 4 hours Infant Formula Neonates 4 hours Infants 6 hours Nonhuman Milk 6 hours Solids 8 hours. Clear Liquids.
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Pediatric Fluid Management and Blood Product Therapy
ASA Fasting Guidelines Clear liquids 2 hours Breast Milk 4 hours Infant Formula Neonates 4 hours Infants 6 hours Nonhuman Milk 6 hours Solids 8 hours
Clear Liquids • water, juice without pulp, carbonated • beverages, clear tea, black coffee • should not contain alcohol • type of liquid ingested important than • volume • infants < 5 mos 10 ml/kg • children and adults 15 ml/kg
Breast Milk • is NOT a clear liquid • does contain milk solids • cleared from the stomach more • quickly than nonhuman milk
ASA Fasting Guidelines • pre-op fast does not guarantee an empty stomach • timing of last fluid ingestion has little relation to volume of gastric contents at induction
ASA Fasting Guidelines • gastric fluid volume and pH are independent of duration fluid fast beyond 2 hours • main determinant: endogenous gastric secretion
ASA Fasting Guidelines • reduces the risk of pulmonary aspiration • offering clear liquids up to 2 hours before • induction • > reduces hunger and irritability • > preserves hydration • > risk of hypoglycemia
BODY FLUID COMPOSITION Compartments Total Body Water (TBW) = Intracellular Fluid ( ICF ) + Extracellular Fluid ( ECF ) • a)interstitial fluid ( ISF ) : no protein • b) plasma volume ( PV ) : with protein • * ISF and PV basically same electrolyte content
Body Fluid Composition INFANTCHILD ADULT Total Body Water 75 % 70 % 55-60 % ECF 40 % 30 % 20 % ICF 35 % 40 % 40 % Fat 16 % 23 % 30 %
PHYSIOLOGIC CONSIDERATIONS Developmental Factors CVS : • incomplete myocardial development • immature sympathetic innervation IMPLICATION: neonates and young infants are more sensitive to hypovolemia
PHYSIOLOGIC CONSIDERATIONS Developmental Factors RENAL: • immature renal function at birth GFR 25% of adult level at term adult level at age of 2 years concentrating capacity of newborn kidney term infant : max. 600-700 mOsm/kg adult:max. 1200 mOsm/kg
PHYSIOLOGIC CONSIDERATIONS Developmental Factors • free H2O clearance : excrete markedly dilute urine up to 50 mOsm / kg vs. 70-100 Osm/kg in adults Na reabsorption HCO3 /H exchange • urinary losses of K+ and Cl-
PHYSIOLOGIC CONSIDERATIONS Developmental Factors IMPLICATION: Newborn kidney has limited capacity to compensate for volume excess or volume depletion
PHYSIOLOGIC CONSIDERATIONS Developmental Factors HEPATIC : • limited hepatic glycogen stores > risk of hypoglycemia > provide 5%-10% dextrose in fluid maintenance > supplemental insulin for sustained hyperglycemia from dextrose
PHYSIOLOGIC CONSIDERATIONS Metabolic and Fluid Requirements metabolic rate O2 consumption neonates: 6-9 ml/kg/min adults: 3 ml/kg/min growth 120 kcal/kg/day
PHYSIOLOGIC CONSIDERATIONS Metabolic and Fluid Requirements fluid requirement > greater BSA to mass ratio in infants > other factors: radiant warmers fever illness injury thinner skin and lack of keratinization of stratum corneum in premature neonates
Compensatory Mechanisms 1) Temporary mechanism 2) Definitive mechanism
Compensatory Mechanisms Temporary Mechanism > activated to maintain normal BP and normal fluid volume a) endogenous vasopressors ADH, angiotensin II, catecholamines b) transcapillary refill: ISF PV (skin turgor) c) ADH : free H2O absorption caution : hyponatremia using hypotonic fluids
Compensatory Mechanisms Definitive Mechanism > through the kidneys > activation of renin - angiotensin - aldosterone (RAA) system > urine output and urine specific gravity
Maintenance Fluids • replaces water and electrolytes lost under ordinary conditions • Evaporative / insensible water loss (ISWL) • Urinary and stool losses • Growth
Maintenance Fluids 1) Evaporative or Insensible Water Loss (ISWL) • solute-free H2O losses from skin and lungs • 30-35 % of total maintenance volume • 1/3 of total maintenance requirement • affected by ambient humidity and temperature • minimum replacement : 60-100 ml/kg/day
Maintenance Fluids 2) Urinary Losses • 280-300 mOsm /kg of H2O specific gravity 1.008-1.015 • 2/3 of total maintenance fluids 3) Growth
Maintenance Fluids Hourly Maintenance Fluid Requirement 1) 4 - 2 -1 rule WEIGHT FLUID 0 - 10 kg 4 ml/kg/hr 10 - 20 kg 2 ml/kg/hr > 20 kg 1 ml/kg/hr * reliable up to body weight of 80 kg
Hourly Maintenance Fluid Requirement 2) Holliday and Segar WEIGHT FLUID/day 0 - 10 kg 100 ml / kg /day 10 - 20 kg 1000 + 50 ml/kg/day > 20 kg 1500 + 20 ml/kg/day * based on caloric requirement of hospitalized patients
Maintenance Fluids Hourly Maintenance Fluid Requirement 3) OH Method WEIGHT FLUID/hr 0 - 10 kg 4 ml / kg / hr 10 - 20 kg 20 + 2 ml/kg/hr > 20 kg 40 + 1ml /kg/hr
Choice of Maintenance Fluids • Remains controversial • Hypotonic solution • D5 1/2 NS + 20 mEq KCl • D5 1/4 NS : may be a better choice in • neonates due to their limited ability • to handle Na + loads • Balanced salt solution
Guide for Maintenance Fluid Therapy Newborn Term Day 1 50-60 ml/kg/day D10 W Day 2 100 ml/kg/day D10 1/2 NS >Day 7 100-150 ml/kg/day D5-D10 1/4 NS Older Child 4-2-1 rule Holliday & Segar method
Daily Electrolyte Requirements Na 2-3 mEq /kg/day day 2-3 K 1-2 mEq /kg/day day 3-4 Cl 2-3 mEq /kg/day Ca 20-100 mg/kg/day day 1 * 1 mEq = 1 mmol
Glucose Requirements term and preterm infants : 5 - 6 mg/kg/min goal: maintain normoglycemia 40 - 120 mg/dl D10W 60-80 ml/kg/day >1kg infants D5W 100 ml/kg/day <1kg infants
Perioperative Fluid Management • 3 Phases • Maintenance Fluid Replacement • Replacement of Preop Deficit • Replacement of Ongoing Losses
Perioperative Fluid Management Maintenance Fluid Replacement 4 - 2 -1 rule WEIGHT FLUID 0 - 10 kg 4 ml/kg/hr + 10 - 20 kg 2 ml/kg/hr + > 20 kg 1 ml/kg/hr
Perioperative Fluid Management Preoperative Deficit DEHYDRATION MILD(1-5 %) history of vomiting or diarrhrea urine output (1st) MODERATE (6-10%) skin turgor sunken eyes and fontanelles weight loss dry mucous membranes lethargic
Perioperative Fluid Management Preoperative Deficit SEVERE (11-15%) cardiovascular instability BP mottled skin tachycardia anuria sensory changes 20% coma shock
Perioperative Fluid Management Preoperative Deficit Therapy Components: 1) dehydration severity Hx and PE electrolyte values serum tonicity 2) type of dehydration isotonic hypotonic hypertonic
Perioperative Fluid Management Preoperative Deficit Therapy 3) replacement of deficit • goal: restore CV, CNS and renal function • monitor adequacy based on response clinical condition urine output and urine specific gravity vital signs
Perioperative Fluid Management Estimated Preop Fluid Deficit number of fasting hrs x maintenance fluids infuse 1/2 on the first hr infuse 1/4 on the 2nd hr infuse 1/4 on the 3rd hr
Perioperative Fluid Management Choice of Fluids Isotonic Crystalloids • generally the most appropriate for preop and intraop deficits Hypotonic Fluids • can cause significant hyponatremia
Perioperative Fluid Management Lactated Ringers (LR) reasonable for maintenance fluids less expensive than other BSS provide Na and K avoid infusion with blood due to calcium content
Perioperative Fluid Management Normal Saline (NS) higher Na content (154) preferred in patients high risk for cerebral edema prolonged infusion can lead to : hypernatremia hyperchloremia metabolic acidosis
Perioperative Fluid Management Composition of IV Crystalloid Solution SOLUTION pH Osm Gluc Na K CL Lact Ca mg/dl mmol/L D5 5.0 253 500 -- -- -- -- -- LR 6.7 273 -- 130 4 109 28 3 D5 LR 5.3 527 500 130 4 109 28 3 D5 0.22% NSS 4.4 330 500 38.5 -- -- -- -- D5 0.45% NSS 4.2 407 500 77 -- 77 -- -- 0.9% NSS 5.7 308 -- 154 -- 154 -- -- Normosol R 7.4 295 -- 140 5 98 acetate 27 -- gluconate 23 Stoelting RK: Pharmacology and Physiology in Anesthetic Practice, ed 2, Philadelphia 1991, JB Lippincott
Perioperative Fluid Management Composition of Colloid Solutions Na Cl Osm 5% Albumin 145 100 330 mOsm/L Hespan 154 154 308 mOsm/L Hextend 143 124 307 mOsm/L
Perioperative Fluid Management Intraoperative Glucose Administration Effects : intraop hyperglycemia hyperosmolality osmotic diuresis worsen neurologic outcome during cerebral ischemia
Perioperative Fluid Management Intraoperative Glucose Administration Exceptions :patients at risk for hypoglycemia • neonates and young infants • debilitated patients with chronic illness • patients on parenteral nutrition • neonates of diabetic mothers • Beckwith-Wiedeman syndrome • nesidioblastosis
Perioperative Fluid ManagementIntraoperative Glucose Administration Existing infusions of dextrose-containing fluid may be continued at a reduced rate (50% of maintenance) to compensate the effect of surgical stress on glucose control
Perioperative Fluid Management Replacement of Ongoing Losses 1) Real Losses blood loss insensible losses urine output drainage from various sites 2) 3rd Space Loss trauma peritonitis burns upper GI drainage
Perioperative Fluid Management Replacement of Ongoing Losses Degree ofAdditional Fluid Tissue TraumaRequired Minimal Incision 3-5 cc/kg/hr Moderate Incision 5-10 cc/kg/hr with viscus exposure Large Incision 8-20 cc/kg/hr with bowel exposure
Perioperative Fluid Management Replacement of Ongoing Losses EBL Replacement • crystalloid (3:1 ratio) 3 cc / 1 cc blood lost • colloid solution (1:1 ratio) 1 cc / 1 cc blood lost • blood products (1:1 ratio) 1 cc / 1cc blood lost
Perioperative Fluid Management Replacement of Ongoing Losses Albumin • 25 % and 5% solutions • pooled from human donors • no ABO testing or blood filter required • remains expensive • in short supply