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AKUFFO QUARDEINTERN (PEDIATRICS, TEMA GEN. HOSP)
Fluid and Electrolyte ManagementPhysiology of water homeostasisBody Fluid CompartmentsMaintenance Fluid RequirementsDe...
Physiology of Water HomeostasisTo understand that disorders of sodium balanceare related to conditions that alter extrace...
Physiology of Water HomeostasisOsmotic Shifts of water between body fluidcompartments is dependent on the soluteparticles...
Physiology of Water HomeostasisIn a steady state the osmolarity of bothintracellular and extracellular compartments willr...
Physiology of Water HomeostasisA complex set of homeostatic mechanisms areat play, which regulate water intake and watere...
Physiology of Water HomeostasisNon-osmotic stimuli will also cause AVP to bereleased. (atrium / large vessels in the ches...
Neonatal PhysiologyAt birth renal function is generally reduced,particularly in premature neonates.GFR increases progres...
Neonatal PhysiologyAVP has been measured in amniotic fluid andis present in fetal circulation by mid-gestation.At birth,...
Neonatal PhysiologyWhy a low urine concentrating ability inneonates?Decreased glomerular filtration rate (decreasedrenal...
Neonatal PhysiologyNeonates have increased non-urinary waterlosses (skin and respiratory) as a function ofweight/BSA, whi...
Body Fluid CompartmentsWater accounts for 60% of TBW in men and50% in women while infants have a higherproportion of wate...
Body Fluid CompartmentsWater is distributed between two maincompartments, the intracellular fluidcompartment (ICF) and ex...
Maintenance Fluid RequirementsMaintenance requirements are related tometabolic rate and affected by bodytemperature.Inse...
Maintenance Fluid RequirementsThe Holliday-Segar method remains thesimplest in approximating maintenance fluidrequirement...
Maintenance Fluid RequirementsTable 3Caloric, Water, and Basic Electrolyte Requirements Based on WeightSodium Chloride Pot...
Maintenance Fluid Requirements5% dextrose is provided to deliver 5 g ofcarbohydrate per 100 mL of solution or 50 g/LFor ...
Intravenous FluidsIntravenous fluids that are safe to administerparenterally based on their osmolalityEach solution is s...
Intravenous FluidsSolutions Used for Intravenous AdministrationOsmolality Sodium Potassium Chloride DextroseSolution mOsm/...
Dehydration and Fluid TherapyDehydration is significant depletion of bodywater and electrolytesDehydration usually due t...
Dehydration and Fluid TherapyAetiology and PathophysiologyIt results from increased fluid loss or adecrease intake or bot...
Dehydration and Fluid therapySymptoms and SignsThey vary based on the fluid deficit.Dehydration without hemodynamic chan...
Dehydration and Fluid TherapySeverity of DehydrationCharacteristicsInfants Mild – 1–5% Moderate – 6–9% Severe – >10%(=> 15...
Dehydration and Fluid TherapyTreatmentTreatment is best approached by consideringan estimated fluid deficit, ongoing los...
Dehydration and Fluid TherapyTreatmentChildren with evidence of circulatorycompromise – severe dehydration, should begiv...
Dehydration and Fluid TherapyResuscitationPatients with symptoms and signs ofhypoperfusion, should receive fluidresuscita...
Dehydration and Fluid TherapyMost importantly response of the patient toresuscitation determines the endpoint of fluidres...
Dehydration and Fluid TherapyDeficit ReplacementThe resuscitation phase should have reducedmoderate or severe dehydration...
Dehydration and Fluid TherapyOngoing lossesVolume of ongoing losses should be measureddirectly (eg. NG tube aspirates, ca...
Oral Rehydration TherapyOral Fluid Therapy is effective, safe,convenient and effective compared with IVtherapy.It should...
Oral Rehydration TherapyORS is effective in patients with dehydrationregardless of age, cause or type of electrolyteimbal...
Oral Rehydration TherapyAdministrationMild dehydration – 50ml/kg over 4hoursModerate dehydration – 100ml/kg over 4hours...
Oral Rehydration TherapyVomiting is not a contraindication to oralrehydration. Small frequent volumes should begiven. (e....
CONCLUSION
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Fluid and-electrolytes-2010

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fluid and electrolyte therapy

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Fluid and-electrolytes-2010

  1. 1. AKUFFO QUARDEINTERN (PEDIATRICS, TEMA GEN. HOSP)
  2. 2. Fluid and Electrolyte ManagementPhysiology of water homeostasisBody Fluid CompartmentsMaintenance Fluid RequirementsDehydration and Fluid therapyOral Rehydration TherapyPractical Examples
  3. 3. Physiology of Water HomeostasisTo understand that disorders of sodium balanceare related to conditions that alter extracellularfluid volumeTo recognize clinical signs and symptoms ofthe different forms of dehydration.To appreciate that the management ofhypernatremic dehydration differs from that ofisonatremic/hyponatremic dehydration.
  4. 4. Physiology of Water HomeostasisOsmotic Shifts of water between body fluidcompartments is dependent on the soluteparticles within individual body compartments.Effective osmolarity of body fluid compartmentsis contributed to by unique properties of the cellmembranes ( difference in permeability to waterand solutes)The difference in concentration of impermeableparticles across cell membranes determinesthe osmotic movement of water. (effectiveosmolarity)
  5. 5. Physiology of Water HomeostasisIn a steady state the osmolarity of bothintracellular and extracellular compartments willremain the same. (approx. 300MOsm)There is a delicate interaction betweenosmolality and water balance.(movement of water in the initial phase ofcompensation for osmolar changes, is to resetosmolarity either at a higher level or lower level.i.e. Osmolarity of both intracellular andextracellular fluids should remain the same
  6. 6. Physiology of Water HomeostasisA complex set of homeostatic mechanisms areat play, which regulate water intake and waterexcretion.The hypothalamus and surrounding braincontrol the sense of thirst and the productionand release of arginine vasopressin (AVP), theantidiuretic hormone (ADH)It is the osmolality of plasma and extracellularfluid which is “sensed” by osmoreceptors in theanteromedial hypothalamus.
  7. 7. Physiology of Water HomeostasisNon-osmotic stimuli will also cause AVP to bereleased. (atrium / large vessels in the chest)A reduction in “effective circulating volume”[blood loss, hemorrhage, ECF volume depletion(dehydration, diuretics, etc.), nephroticsyndrome, cirrhosis, congestive heartfailure/low cardiac output]
  8. 8. Neonatal PhysiologyAt birth renal function is generally reduced,particularly in premature neonates.GFR increases progressively during gestationparticularly in the third trimester. By 1 to 2years, GFR, Urea clearance and maximumtubular clearances would have reached adultlevels.
  9. 9. Neonatal PhysiologyAVP has been measured in amniotic fluid andis present in fetal circulation by mid-gestation.At birth, vasopressin levels are high butdecrease into “normal” ranges within 1–2 daysIn neonates, AVP responds to the same stimulias older children and adults. However, theability to concentrate urine to the maximumachieved by older children or adults does notoccur.
  10. 10. Neonatal PhysiologyWhy a low urine concentrating ability inneonates?Decreased glomerular filtration rate (decreasedrenal blood flow)reduced epithelial cell function in the loop ofHenle and collecting ductreduced AVP receptor number and affinityreduced water channel number or presence onthe cell surface
  11. 11. Neonatal PhysiologyNeonates have increased non-urinary waterlosses (skin and respiratory) as a function ofweight/BSA, which are greater compared toolder children and adults.The net effect is that neonates are at greaterrisk of dehydration either due to inadequatewater provision or to high osmolar loadsRisk of volume overload (hyponatremia/hypo-osmolality) if fluids are given too rapidly
  12. 12. Body Fluid CompartmentsWater accounts for 60% of TBW in men and50% in women while infants have a higherproportion of water, 70–80% (due to the lowerproportion of muscle in comparison to adipose)The higher proportion of TBW to whole bodyweight in younger children is mainly due to thelarger ECF volume when compared to adults.disproportionate weight of brain, skin, and theinterstitium in younger children contributes tothe variability in the ECF volume.
  13. 13. Body Fluid CompartmentsWater is distributed between two maincompartments, the intracellular fluidcompartment (ICF) and extracellular fluidcompartment (ECF)The intracellular compartment makes upapproximately 2/3 of the TBW. The ECFconstitutes 1/3 of the TBW composed ofplasma and interstitial fluid
  14. 14. Maintenance Fluid RequirementsMaintenance requirements are related tometabolic rate and affected by bodytemperature.Insensible losses account for about half ofmaintenance requirements.Volume must rarely be exactly determined, butgenerally should aim to provide an amount ofwater that does not require the kidney tosignificantly concentrate or dilute the urine.
  15. 15. Maintenance Fluid RequirementsThe Holliday-Segar method remains thesimplest in approximating maintenance fluidrequirements.It is based on caloric requirement each day andthe amount of fluid needed based on caloricexpenditure.
  16. 16. Maintenance Fluid RequirementsTable 3Caloric, Water, and Basic Electrolyte Requirements Based on WeightSodium Chloride PotassiummEq/100 mEq/100 mEq/100Body weight (kg) Calories Water mL H2 O mL H2 O mL H2 O3–10 kg 100/kg 100/kg 3 2 211–20 kg 50/kg 1000 mL + 3 2 250 mL/kg foreach kg above>20 kg 20/kg 1500 mL + 3 2 220 mL/kg foreach kg above20
  17. 17. Maintenance Fluid Requirements5% dextrose is provided to deliver 5 g ofcarbohydrate per 100 mL of solution or 50 g/LFor a limited period of time (generally under 5–7 days) this amount of carbohydrate will besufficient to prevent protein breakdown.If it is anticipated that there will be a need forprolonged parenteral therapy, a higher dextrosesolution will be required.
  18. 18. Intravenous FluidsIntravenous fluids that are safe to administerparenterally based on their osmolalityEach solution is selected based on the clinicalstatus of the patient. Solutions without dextrose(0.45% isotonic saline) or without electrolytes5% dextrose in water are only administeredunder special clinical situations.
  19. 19. Intravenous FluidsSolutions Used for Intravenous AdministrationOsmolality Sodium Potassium Chloride DextroseSolution mOsm/L mEq/L Eq/L mEq/L mOsm/L0.9% Isotonic saline 308 154 154(normal saline)0.45% Isotonic saline 154 77 77∗(1/2 Normal)5% Dextrose in Water 2785% Dextrose + 0.33% 378 50 50 278isotonic saline5% Dextrose + 0.45% 432 77 77 278isotonic saline∗ The lowest intravenous solution that can be used safely is 0.45% isotonic saline with anosmolality of 154 mOsm/L or approximately 50% of plasma. Any solution with an osmolalityunder this value will result in cell breakdown with a large potassium load to the extracellularspace resulting in severe hyperkalemia leading to cardiac arrhythmias and possibly death.
  20. 20. Dehydration and Fluid TherapyDehydration is significant depletion of bodywater and electrolytesDehydration usually due to gastroenteritisremains a major cause of morbidity andmortality in infants and young childrenworldwhile.Infants are particularly susceptible on accountof their greater baseline fluid requirementsand higher evaporative losses. (High surfacearea) and their inablity to communicate thirst.
  21. 21. Dehydration and Fluid TherapyAetiology and PathophysiologyIt results from increased fluid loss or adecrease intake or bothFluid is always lost with accompanyingelectrolytes, in varying concentrations.Common causes include (gastroenteritis, DKA,burns, 3rdspace losses eg. I/O)
  22. 22. Dehydration and Fluid therapySymptoms and SignsThey vary based on the fluid deficit.Dehydration without hemodynamic changesrepresents mild dehydration (5% body weightor 3% bw in adolescents)Tachycardia represents moderate dehydration.(10% body weight or 6% bw in adolescents)Hypotension with impaired perfusion meanssevere dehydration. (15% body weight ininfants or 9% in adolescents)
  23. 23. Dehydration and Fluid TherapySeverity of DehydrationCharacteristicsInfants Mild – 1–5% Moderate – 6–9% Severe – >10%(=> 15% =shock)Older Children Mild – 1–3% Moderate – 3–6% Severe – >6% (=>9% = shockPulse Full, normal Rapid Rapid, weakSystolic BP Normal Normal, Low Very LowUrine output Decreased Decreased Oliguria(<1 mL/kg/h)Buccal mucosa Slightly dry Dry ParchedAnt fontanel Normal Sunken Markedly sunkenEyes Normal Sunken Markedly sunkenSkin turgor/capillary refill Normal Decreased MarkedlydecreasedCool, mottling,Skin Normal Acrocyanosis
  24. 24. Dehydration and Fluid TherapyTreatmentTreatment is best approached by consideringan estimated fluid deficit, ongoing losses andmaintenance requirementsThe volume, composition and rate of infusion ofreplacement fluids differs for each.Most importantly, monitoring the vital signs,clinical appearance and urine output, serves asan appropriate guide.
  25. 25. Dehydration and Fluid TherapyTreatmentChildren with evidence of circulatorycompromise – severe dehydration, should begiven IVFs in the initial resuscitationThose unable or unwilling to drink or havingrepetitive vomiting should receive fluids IV,through an NG tube or by administeringrepeated small amounts orally.
  26. 26. Dehydration and Fluid TherapyResuscitationPatients with symptoms and signs ofhypoperfusion, should receive fluidresuscitation with boluses of isotonic fluid (e.g.0.9% Saline or Lactated Ringers)Resuscitation phase should reduce moderateor severe dehydration to a deficit less than 8%body weight.20ml/kg (2% body weight) is given IV over 20-30 minutes.
  27. 27. Dehydration and Fluid TherapyMost importantly response of the patient toresuscitation determines the endpoint of fluidresuscitation.This includes (Restoration of tissue perfusionand BP and return of increased heart ratetoward normal)
  28. 28. Dehydration and Fluid TherapyDeficit ReplacementThe resuscitation phase should have reducedmoderate or severe dehydration to a deficit of /about 8%.The remaining deficit can be replaced byproviding 10ml/kg (1% body weight) per hourover the next 8hours.Deficits in total body potassium is usuallybegan after urine output has improved (restoredtissue perfusion) . 2-3mEq/24hrs
  29. 29. Dehydration and Fluid TherapyOngoing lossesVolume of ongoing losses should be measureddirectly (eg. NG tube aspirates, catheter ,stools) or estimated e.g. 10ml/kg per diarrhealstool.
  30. 30. Oral Rehydration TherapyOral Fluid Therapy is effective, safe,convenient and effective compared with IVtherapy.It should be used for children with mild tomoderate dehydration who are accepting fluidsorally.Contraindications to ORT is incessant copiousvomiting, surgical abdomen, I/O.Soda, juice and fizzy drinks generally have toolittle sodium and too much carbs.
  31. 31. Oral Rehydration TherapyORS is effective in patients with dehydrationregardless of age, cause or type of electrolyteimbalance. [in the presence of unimpaired renalfunction]If ORS is unavailable, a sodium/glucosesolution can be used.SSS are prepared by adding 1tbsp of sugar to½ tsp of salt in 1L of water. Though lesseffective, it can be used for treating diarrhea.
  32. 32. Oral Rehydration TherapyAdministrationMild dehydration – 50ml/kg over 4hoursModerate dehydration – 100ml/kg over 4hours10ml/kg for each diarrheal stool (up to a max of240mls)Patient should be reassessed after 4hours.N.B – Patients with cholera may require manygallons of fluid per day
  33. 33. Oral Rehydration TherapyVomiting is not a contraindication to oralrehydration. Small frequent volumes should begiven. (e.g 5ml every 5mins and increasedgradually as tolerated)Importance of encouraging oral feeds.
  34. 34. CONCLUSION

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