Download - Fundamentals Fluid Electrolyte Balance
FUNDAMENTALS OF FUNDAMENTALS OF FLUID AND FLUID AND
ELECTROLYTE BALANCEELECTROLYTE BALANCE
FLUID REQUIREMENTSFLUID REQUIREMENTS
SourcesSources LossesLosses
WaterWater 1500 ml1500 ml UrineUrine 1500 ml1500 ml
FoodFood 800 ml800 ml StoolStool 200 ml200 ml
OxidationOxidation 300 ml300 ml SkinSkin 500 ml500 ml
Resp. TractResp. Tract 400 ml400 ml
TotalTotal 2600 ml2600 ml TotalTotal 2600 ml2600 ml
FLUID CONTENT OF THE BODYFLUID CONTENT OF THE BODY
Varies with age, sex, adipose tissueVaries with age, sex, adipose tissue Females 45-50% TBWFemales 45-50% TBW MalesMales 50-60% TBW 50-60% TBW Infants 77% TBWInfants 77% TBW
BODY FLUID COMPARTMENTSBODY FLUID COMPARTMENTS
RULE OF THIRDSRULE OF THIRDS1.1. Intracellular: 2/3 Intracellular: 2/3 (40% TBW)(40% TBW)
2.2. Extracellular: 1/3 Extracellular: 1/3 (20% (20% TBW)TBW)
a.a. Interstitial + Lymph: 2/3 (15% TBW)Interstitial + Lymph: 2/3 (15% TBW)
b.b. Intravascular: 1/3 (5% TBW)Intravascular: 1/3 (5% TBW)
Biomedical Importance of WaterBiomedical Importance of Water
Homeostasis (CES)Homeostasis (CES)• Water distributionWater distribution• PH maintenancePH maintenance• Maintain Electrolyte Concentration Maintain Electrolyte Concentration
Set of Fluid BalanceSet of Fluid Balance• Depletion (dehydration)Depletion (dehydration)• Intoxication (over-hydration) Intoxication (over-hydration) • Osmotic & non osmotic mechanismOsmotic & non osmotic mechanism
Water as ideal biologic solventWater as ideal biologic solvent
Tetrahedron structureTetrahedron structure Bipolar moleculeBipolar molecule Multiple energyMultiple energy Hydrogen bond determines Hydrogen bond determines
macromolecule structuremacromolecule structure The best nucleofilThe best nucleofil Minor DissociationMinor Dissociation Electrostatic interactionElectrostatic interaction Interaction with biomoleculeInteraction with biomolecule
ELECTROLYTES IN ELECTROLYTES IN BODY FLUID COMPARTMENTSBODY FLUID COMPARTMENTS
INTRACELLULARINTRACELLULAR EXTRACELLULAREXTRACELLULAR
POTASSIUMPOTASSIUM SODIUMSODIUM
MAGNESIUMMAGNESIUM CHLORIDECHLORIDE
PHOSPHOROUSPHOSPHOROUS BICARBONATEBICARBONATE
IV FLUID DISTRIBUTION IN IV FLUID DISTRIBUTION IN BODY COMPARTMENTSBODY COMPARTMENTS
ICFICF ECFECF
Dextrose 5% in Dextrose 5% in Water Water
1000 ml1000 ml
2/32/3
667 ml667 ml1/31/3
333 ml333 ml
Sodium Chloride Sodium Chloride 0.9% 1000 ml0.9% 1000 ml 1000 ml1000 ml
SOLUTESSOLUTES
Non-electrolytesNon-electrolytes• DextroseDextrose• UreaUrea• CreatinineCreatinine
ElectrolytesElectrolytes• AnionsAnions• CationsCations
MAINTENANCE vs. REPLACEMENTMAINTENANCE vs. REPLACEMENT
Maintenance:Maintenance:• Provide normal daily requirements:Provide normal daily requirements:
Water: 2.5 LWater: 2.5 L
Sodium ½ or ¼ NSSodium ½ or ¼ NS
KCl 40-60 meq/LKCl 40-60 meq/L Example:Example:
D5 ½ NS with KCL 20 meq/L running at D5 ½ NS with KCL 20 meq/L running at 100 ml/hr100 ml/hr
MAINTENANCE vs. REPLACEMENTMAINTENANCE vs. REPLACEMENT
Replacement:Replacement:• Replace abnormal losses with a fluid Replace abnormal losses with a fluid
and electrolytes similar to that which and electrolytes similar to that which was lost.was lost.
OSMOLALITYOSMOLALITY
Definition: Concentration of particles (osmotically Definition: Concentration of particles (osmotically active) in solution. It is usually expressed in active) in solution. It is usually expressed in millosmoles of solute per kg of solution.millosmoles of solute per kg of solution.
Osmolality is independant of valence.Osmolality is independant of valence. Osmolality (mOsm/Kg) of dilute solutions Osmolality (mOsm/Kg) of dilute solutions
approximate osmolarity (mOsm/L)approximate osmolarity (mOsm/L) Plasma: 280-300 mOsm/KgPlasma: 280-300 mOsm/Kg Same in all body compartmentsSame in all body compartments Water distribution Water distribution
Normal Laboratory ValuesNormal Laboratory Values
SodiumSodium 135-145 meq/L135-145 meq/LPotassium Potassium 3.5-5.0 meq/L3.5-5.0 meq/LChlorideChloride 95-105 meq/L95-105 meq/LBicarbonateBicarbonate 22-28 meq/L22-28 meq/LCalciumCalcium 9-11 mg/dL9-11 mg/dLPhosphatePhosphate 3.2-4.3 mg/dL3.2-4.3 mg/dLGlucoseGlucose 70-110 mg/dL70-110 mg/dLBUNBUN 8-18 mg/dL8-18 mg/dLCreatinineCreatinine 0.6-1.2 mg/dL0.6-1.2 mg/dLOsmolality (P)Osmolality (P) 280-295 mOsm/kg280-295 mOsm/kgOsmolality (U)Osmolality (U) 50-1200 mOsm/kg50-1200 mOsm/kg
ELECTROLYE DISORDERSELECTROLYE DISORDERSSODIUMSODIUM
JO is a 58 year-old male with cirrhosis of JO is a 58 year-old male with cirrhosis of the liver due to ethanol abuse. Physical the liver due to ethanol abuse. Physical examination reveal ascites. examination reveal ascites.
Baseline lab is as follows:Baseline lab is as follows:
Na 128, K 3.8, Cl 95, CO2 24Na 128, K 3.8, Cl 95, CO2 24
JO is to be started on TPN, Should we JO is to be started on TPN, Should we request additional sodium to correct his request additional sodium to correct his hyponatremia?hyponatremia?
ELECTROLYE DISORDERSELECTROLYE DISORDERSSODIUMSODIUM
Primary extracellular cationPrimary extracellular cation HyponatremiaHyponatremia
1.1. Excess of TB waterExcess of TB water
2.2. Decrease in TB sodiumDecrease in TB sodium
a.a. Isotonic hyponatremia (factitious)Isotonic hyponatremia (factitious)
b.b. Hypertonic hyponatremia (dilutional)Hypertonic hyponatremia (dilutional)
ELECTROLYTE DISORDERSELECTROLYTE DISORDERSHypotonic HyponatremiaHypotonic Hyponatremia
Increased ECVIncreased ECV Decreased ECVDecreased ECV Normal ECVNormal ECV
Edematous statesEdematous states Hypovolemic statesHypovolemic states SIADHSIADH
CHFCHF
CirrhosisCirrhosis
Renal dzRenal dz
Diuretic inducedDiuretic induced
GI lossesGI lossesSydrome of Sydrome of inappropriate inappropriate antidiuretic hormoneantidiuretic hormone
Excess of TB Na and Excess of TB Na and waterwater
Depletion of water Depletion of water and Naand Na
Excess of water: Excess of water: dilutionaldilutional
Treatment:Treatment:
DiureticsDiuretics
Water & Na restrictionWater & Na restriction
CHF- cardiac CHF- cardiac glycosidesglycosides
Water and Na Water and Na replacementreplacement
Fluid restrictionFluid restriction
Furosemide and NSFurosemide and NS
Chronic: DeclomycinChronic: Declomycin
ELECTROLYE DISORDERSELECTROLYE DISORDERSSODIUMSODIUM
JO is a 58 year-old male with cirrhosis of the JO is a 58 year-old male with cirrhosis of the liver due to ethanol abuse. Physical liver due to ethanol abuse. Physical examination reveal ascites. examination reveal ascites. Baseline lab is as follows:Baseline lab is as follows:Na 128, K 3.8, Cl 95, CO2 24Na 128, K 3.8, Cl 95, CO2 24JO is to be started on TPN, Should we request JO is to be started on TPN, Should we request additional sodium to correct his hyponatremia?additional sodium to correct his hyponatremia?
JO’s is in an edematous state. He has an excess of JO’s is in an edematous state. He has an excess of TB water and sodium. The appropriate TB water and sodium. The appropriate treatment is water and sodium restriction. He treatment is water and sodium restriction. He should also receive diuretic treatment. The should also receive diuretic treatment. The drug of choice is Aldactone (spironolactone), an drug of choice is Aldactone (spironolactone), an aldosterone antagonist. aldosterone antagonist.
ELECTROLYE DISORDERSELECTROLYE DISORDERSModel for Distribution and Elimination of Model for Distribution and Elimination of
Intracellular IonsIntracellular Ions
K Phos Mg
ICF ECF
Intake
GI (stool)Losses
RenalLosses
StomachIntestine
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Primary intacellular cationPrimary intacellular cation Hypokalemia: CausesHypokalemia: Causes
1.1. Decreased dietary intakeDecreased dietary intake
2.2. RedistributionRedistribution InsulinInsulin
Metabolic Alkalosis Metabolic Alkalosis
DehydrationDehydration
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Metabolic Alkalosis and HypokalemiaMetabolic Alkalosis and Hypokalemia
Intracellular Fluid
H+
ExtracellularFluidK+
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Primary intacellular cationPrimary intacellular cation Hypokalemia: CausesHypokalemia: Causes
3.3. Increased Urinary or GI LossesIncreased Urinary or GI Losses DiureticsDiuretics
NG SuctionNG Suction
DiarrheaDiarrhea
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hypokalemia: CausesHypokalemia: Causes
3.3. Increased Urinary or GI LossesIncreased Urinary or GI Losses NG SuctionNG Suction
DiarrheaDiarrhea
DrugsDrugs
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Drugs which may cause hypokalemiaDrugs which may cause hypokalemia
Urinary wasting: aminoglycosides, Urinary wasting: aminoglycosides, amphotericin B, corticosteroids, diuretics, amphotericin B, corticosteroids, diuretics, levodopa, nifedipine, penicillins, rifampinlevodopa, nifedipine, penicillins, rifampin
Gastrointestinal losses: laxativesGastrointestinal losses: laxatives
Redistribution: Beta-2 agonists, lithiumRedistribution: Beta-2 agonists, lithium
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hypokalemia: Treatment/Estimation of Hypokalemia: Treatment/Estimation of DeficitDeficit
If serum K > 3meq/L: If serum K > 3meq/L:
100-200 meq required per each change in 100-200 meq required per each change in serum K of 1 meq/Lserum K of 1 meq/L
If serum K < 3 meq/L:If serum K < 3 meq/L:
200-400 meq required per each change in 200-400 meq required per each change in serum K of 1 meq/Lserum K of 1 meq/L
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hypokalemia: Estimation of DeficitHypokalemia: Estimation of Deficit
If serum K > 3meq/L: If serum K > 3meq/L:
100-200 meq required per each change in serum K of 1 meq/L100-200 meq required per each change in serum K of 1 meq/L
If serum K < 3 meq/L:If serum K < 3 meq/L:
200-400 meq required per each change in serum K of 1 meq/L200-400 meq required per each change in serum K of 1 meq/L
Example: Serum K = 2.5 How much K is required to correct serum K to Example: Serum K = 2.5 How much K is required to correct serum K to 4.0?4.0?
Step 1Step 1
To increase from 2.5 to 3.0: 200-400 meq X 0.5=100-200meqTo increase from 2.5 to 3.0: 200-400 meq X 0.5=100-200meq
Step 2Step 2
To increase from 3.0 to 4.0: 100-200 meq X 1.0=100-200meqToTo increase from 3.0 to 4.0: 100-200 meq X 1.0=100-200meqTo
Total=200-400meqTotal=200-400meq
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUM POTASSIUM
Hypokalemia: TreatmentHypokalemia: Treatment
Serum KSerum K Max Max Infusion Infusion RateRate
Max.Max.
Conc.Conc.Max. Dose Max. Dose 24 hrs24 hrs
> 2.5meq/L> 2.5meq/L 10 meq/hr10 meq/hr 40 meq/L40 meq/L 200 meq200 meq
<2meq/L<2meq/L 40 meq/hr40 meq/hr 80 meq/L80 meq/L 400 meq400 meq
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Mrs D. is a 62 year-old female who is having an Mrs D. is a 62 year-old female who is having an acute exacerbation of Crohn’s disease. She acute exacerbation of Crohn’s disease. She complains to you of severe and frequent complains to you of severe and frequent diarrhea over the last four days. She diarrhea over the last four days. She experiences dizziness when she stands. Your experiences dizziness when she stands. Your physical examination reveals dry mucous physical examination reveals dry mucous membranes. In the supine position her membranes. In the supine position her BP=110/65 and in the upright position her BP=110/65 and in the upright position her BP=90/45 and her pulse=140. Your lab values BP=90/45 and her pulse=140. Your lab values are as follows:are as follows:
Na 132, K 2.9, Cl 92, CONa 132, K 2.9, Cl 92, CO22 31, 31, BUN 25, Cr 1.0BUN 25, Cr 1.0
Discuss Mrs. D’s fluid and electrolyte problems.Discuss Mrs. D’s fluid and electrolyte problems.
ELECTROLYE DISORDERSELECTROLYE DISORDERSCase Study: HypokalemiaCase Study: Hypokalemia
Mrs D. is a 62 year-old female who is having an acute exacerbation of Mrs D. is a 62 year-old female who is having an acute exacerbation of Crohn’s disease. She complains to you of severe and frequent Crohn’s disease. She complains to you of severe and frequent diarrhea over the last four days. She experiences dizziness when diarrhea over the last four days. She experiences dizziness when she stands. Your physical examination reveals dry mucous she stands. Your physical examination reveals dry mucous membranes. In the supine position her BP=110/65 and in the membranes. In the supine position her BP=110/65 and in the upright position her BP=90/45 and her pulse=140. Your lab upright position her BP=90/45 and her pulse=140. Your lab values are as follows:values are as follows:
Na 132, K 2.9, Cl 92, CONa 132, K 2.9, Cl 92, CO22 31, 31, BUN 25, Cr 1.0BUN 25, Cr 1.0Mrs D’s has extracellular volume depletion due to prolonged diarrhea. Mrs D’s has extracellular volume depletion due to prolonged diarrhea.
The ECVD is supported by her physical assessment and postural The ECVD is supported by her physical assessment and postural hypotension and her BUN/Cr is > 20:1. The diarrhea has resulted hypotension and her BUN/Cr is > 20:1. The diarrhea has resulted in a loss of fluid and sodium chloride. Some potassium was lost in a loss of fluid and sodium chloride. Some potassium was lost directly in the stools, but the main cause of her hypokalemia is directly in the stools, but the main cause of her hypokalemia is her ECVD which has induced a metabolic alkalosis (contraction her ECVD which has induced a metabolic alkalosis (contraction alkalosis.) The alkalosis contributed to her hypokalemia by two alkalosis.) The alkalosis contributed to her hypokalemia by two mechanisms. Some potassium has moved to the intracellular mechanisms. Some potassium has moved to the intracellular compartment but much of it has been lost in the urine where compartment but much of it has been lost in the urine where potassium wasting occurs secondary to chloride deficit. potassium wasting occurs secondary to chloride deficit. Administration of Normal Saline with Potassium Chloride will Administration of Normal Saline with Potassium Chloride will correct her fluid and electrolyte problems (and alkalosis.)correct her fluid and electrolyte problems (and alkalosis.)
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hyperkalemia: CausesHyperkalemia: Causes
1.1. Decreased Renal ExcretionDecreased Renal Excretion CRF and ARFCRF and ARF
Drug induced: Drug induced:
K-sparing diuretics (spironolactone, K-sparing diuretics (spironolactone, triamterine, amiloride)triamterine, amiloride)
Angiotensin converting enzyme inhibitorsAngiotensin converting enzyme inhibitors
NSAIDSNSAIDS
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hyperkalemia: CausesHyperkalemia: Causes2.2. RedistributionRedistribution
Trauma, burnsTrauma, burns AcidosisAcidosis Hyperosmolar states Hyperosmolar states
3.3. Increased intakeIncreased intake Salt substitutesSalt substitutes Blood transfusionsBlood transfusions K salts of antibioticsK salts of antibiotics
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Metabolic Acidosis and HyperkalemiaMetabolic Acidosis and Hyperkalemia
Intracellular Fluid
K+
ExtracellularFluidH+
ELECTROLYE DISORDERSELECTROLYE DISORDERSPOTASSIUMPOTASSIUM
Hyperkalemia: TreatmentHyperkalemia: Treatment1.1. Potassium AntagonistPotassium Antagonist
Calcium ChlorideCalcium Chloride
2.2. RedistributionRedistributiona.a. Insulin + dextroseInsulin + dextroseb.b. Sodium bicarbonateSodium bicarbonate
3.3. Cationic binding resinsCationic binding resinsKayexalate (polystyrene sulfonate)Kayexalate (polystyrene sulfonate)
4.4. Renal Elimination/dialysisRenal Elimination/dialysis
ELECTROLYE DISORDERSELECTROLYE DISORDERSMAGNESIUMMAGNESIUM
Hypomagnesemia: CausesHypomagnesemia: Causes1.1. Decreased IntakeDecreased Intake
MalnutritionMalnutrition AlcoholismAlcoholism
2.2. Decreased AbsorptionDecreased Absorption3.3. Increased LossesIncreased Losses
GI lossesGI losses Renal lossesRenal losses
ELECTROLYE DISORDERSELECTROLYE DISORDERSMAGNESIUMMAGNESIUM
Drug Induced HypomagnesemiaDrug Induced Hypomagnesemia
1.1. GI LossesGI Losses LaxativesLaxatives
2.2. Renal LossesRenal Losses Diuretics, cisplatin, aminoglycosides, Diuretics, cisplatin, aminoglycosides,
amphotericin Bamphotericin B
ELECTROLYE DISORDERSELECTROLYE DISORDERSMAGNESIUMMAGNESIUM
Hypomagnesemia: TreatmentHypomagnesemia: Treatment
1.1. IV Magnesium SulfateIV Magnesium Sulfate Replace over several daysReplace over several days
Renal threshold for reabsorption of MgRenal threshold for reabsorption of Mg
1 mEq/kg on day 11 mEq/kg on day 1
0.5 mEq/kg on days x 3-5 days0.5 mEq/kg on days x 3-5 days
2.2. Oral replacementOral replacement MylantaMylanta
ELECTROLYE DISORDERSELECTROLYE DISORDERSMAGNESIUMMAGNESIUM
Hypermagnesemia: CausesHypermagnesemia: Causes1.1. Exogenous ingestionExogenous ingestion
2.2. Impaired renal excretionImpaired renal excretion
Treatment: Eliminate exogenous Treatment: Eliminate exogenous source of Mgsource of Mg
ELECTROLYE DISORDERSELECTROLYE DISORDERSPHOSPHOROUSPHOSPHOROUS
Hypophosphatmeia: CausesHypophosphatmeia: Causes1.1. Impaired absorptionImpaired absorption
Aluminum or calcium bindingAluminum or calcium binding
2.2. RedistributionRedistribution Respiratory alkalosisRespiratory alkalosis
Glucose + insulinGlucose + insulin
3.3. Increased ExcretionIncreased Excretion
ELECTROLYE DISORDERSELECTROLYE DISORDERSPHOSPHOROUSPHOSPHOROUS
Hyperphosphatmeia: CausesHyperphosphatmeia: Causes1.1. Renal impairmentRenal impairment
2.2. Increased intakeIncreased intake
TreatmentTreatment Phosphate binders: Alternagel, Phosphate binders: Alternagel,
Amphojel, Calcium SupplimentsAmphojel, Calcium Suppliments
ELECTROLYE DISORDERSELECTROLYE DISORDERSPHOSPHOROUSPHOSPHOROUS
M.T. is a 55 year-old female with a history of M.T. is a 55 year-old female with a history of chronic renal failure who is admitted to the SICU chronic renal failure who is admitted to the SICU following a motor vehicle accident. She is following a motor vehicle accident. She is started on a TPN solution with minimal K, no Mg started on a TPN solution with minimal K, no Mg and no Phos. She also receives Mylanta II 30 ml and no Phos. She also receives Mylanta II 30 ml per NG tube every four hours. Although her per NG tube every four hours. Although her basline labs were normal on day six her labs are basline labs were normal on day six her labs are as follows:as follows:
K 4.3, Mg 2.6, Phos 1.6K 4.3, Mg 2.6, Phos 1.6
1.1. What role did the antacid play in her electrolyte What role did the antacid play in her electrolyte abnormalities?abnormalities?
2.2. What role did the TPN play?What role did the TPN play?
ELECTROLYE DISORDERSELECTROLYE DISORDERSPHOSPHOROUSPHOSPHOROUS
M.T. is a 55 year-old female with a history of chronic renal failure M.T. is a 55 year-old female with a history of chronic renal failure who is admitted to the SICU following a motor vehicle accident. who is admitted to the SICU following a motor vehicle accident. She is started on a TPN solution with minimal K, no Mg and no She is started on a TPN solution with minimal K, no Mg and no Phos. She also receives Mylanta II 30 ml per NG tube every four Phos. She also receives Mylanta II 30 ml per NG tube every four hours. Although her basline labs were normal on day six her labs hours. Although her basline labs were normal on day six her labs are as follows:are as follows:
K 4.3, Mg 2.6, Phos 1.6K 4.3, Mg 2.6, Phos 1.6
M.T’s K is normal, but she has hypermagnesemia and M.T’s K is normal, but she has hypermagnesemia and hypophosphatemia. The antacid contributed to both of these hypophosphatemia. The antacid contributed to both of these abnormalities. It provided a significant source of Mg this patient abnormalities. It provided a significant source of Mg this patient with impaired excretion. Also the aluminum in the antacid acted a with impaired excretion. Also the aluminum in the antacid acted a phosphate binder contributing to the hypophosphatemia.phosphate binder contributing to the hypophosphatemia.
The TPN could have contributed to the hypophosphatemia by The TPN could have contributed to the hypophosphatemia by inducing an intracellular shift of phosphate (refeeding.) The inducing an intracellular shift of phosphate (refeeding.) The potassium probably remained normal because some was being potassium probably remained normal because some was being provided. Mg was being provided enterally. provided. Mg was being provided enterally.