FLUID AND ELECTROLYTES A Practical Bedside Approach VICENTE V. TANSECO, JR., MD,FPCP, FPSN.
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Transcript of FLUID AND ELECTROLYTES A Practical Bedside Approach VICENTE V. TANSECO, JR., MD,FPCP, FPSN.
FLUID FLUID AND AND
ELECTROLYTESELECTROLYTESA Practical Bedside ApproachA Practical Bedside Approach
VICENTE V. TANSECO, JR., MD,FPCP, FPSNVICENTE V. TANSECO, JR., MD,FPCP, FPSN
F & E PARAMETERSF & E PARAMETERS
SALINE BALANCESALINE BALANCE
WATER BALANCEWATER BALANCE
POTASSIUM BALANCEPOTASSIUM BALANCE
HYDROGEN ION BALANCEHYDROGEN ION BALANCE
BASIC F&E PRINCIPLESBASIC F&E PRINCIPLES
60 % of BW is H2O60 % of BW is H2O
The major fluid compartments
1. ICF
2. ECF
a. Plasma -
b. Int. FC -
65 % BW55 % BW
70 % BW
80 % BW
20 % BW
5 % BW
15 % BW
- thin- obese
- infants
FLUID COMPARTMENTSFLUID COMPARTMENTS
STOMACH INTESTINES
BLOOD PLASMALUNGS KIDNEYS
INTERSTITIAL FLUID
INTRACELLULAR FLUID
SKIN5 % BODY WT.4 L
15 % BODY WT.
11 L
40 % BODY WT. 30 L
ELECTROLYTE COMPOSITIONELECTROLYTE COMPOSITION
BLOOD PLASMAINTERSTITIAL
FLUID
INTRACELLULARFLUID
EXTRACELLULAR FLUID
Mg++
Ca++
K+
Na+Na+
HCO3
Na+
ClCl
protein
Org. acid
SO4 K+
Ca++
Mg++ AG
K+
Mg ++
HCO3
HPO4=
SO4=
Protein
HCO3
BASIC F&E PRINCIPLESBASIC F&E PRINCIPLESNa+ is the major cation in the ECFNa+ is the major cation in the ECF
K+ is the major cation in the ICF 98-99%K+ is the major cation in the ICF 98-99%
only 1-2 % is extracellularonly 1-2 % is extracellular
All Fluid compartments are separated by a semi-All Fluid compartments are separated by a semi-permeable membranepermeable membrane
Water passes through the semi-permeable Water passes through the semi-permeable membranes but not solutes to maintain equal membranes but not solutes to maintain equal osmolality in all compartmentsosmolality in all compartments
BASIC F & E PRINCIPLESBASIC F & E PRINCIPLESSemi-permeable membrane
ECF ICF
Na+ Na+ K+
Na+ H2O
H2O Na+
K+ H2O
H2O Na+
Na+ K+ H2O
Na+ H2O
Na+ K+ H2O
H2O K+
Na+ K+ H2O
K+ Na+
H2O K+ H2O
K+ H2O
BASIC F&E PRINCIPLES BASIC F&E PRINCIPLES
ICFECF
Volume increase
Addition of Na+
K+ H2O
Na+
H2O Na+
Na+ H2O
K+ Na+
Na+ H2O
H2O K+
Na+ K+
K+ H2O K+
H2O K+
Na+
H2O K+
Na+ Na+
BASIC F&E PRINCIPLES BASIC F&E PRINCIPLES
ICFECF
Volume increase- negligible
Addition of H2O
Osmolality
Na+ H2OH2O Na+
Na+ K+
H2O Na+
K+ Na+
Na+ H2O
H2O K+ Na+
K+ H2O
K+ Na+
K+H2O K+ H2O
WATER BALANCEWATER BALANCEWATER DEFICIT
OSMOLALITY
OSMORECEPTORS
HYPOTHALAMUS PITUITARY
THIRST CENTER
ANTIDIURETIC HORMONE
COLLECTING TUBULE
WATER REABSORPTION
WATER INTAKE
FEEDBACK FEEDBACK
REMEMBER !REMEMBER !
TALK OF SALINETALK OF SALINE
THINK OF VOLUME
•TALK OF WATER
THINK OF OSMOLALITY
SALINE BALANCE ASSESSMENT:SALINE BALANCE ASSESSMENT:
HistoryHistory
PEPE
1. ECF Volume:1. ECF Volume:
-Orthostatic BP-Orthostatic BP
-CVP-CVP
-Urine Output-Urine Output
-Urine Sp. Gr.-Urine Sp. Gr.
-Hct. -Hct. (3 x Hb = Hct.)(3 x Hb = Hct.)
Blood Volume Blood Volume
2. Interstitial volume2. Interstitial volume
-skin turgor-skin turgor
-edema-edema
-crackles in the -crackles in the lungslungs
-mucosal dryness-mucosal dryness
SALINE
VOLUME
ESTIMATION OF SALINE DEFICITESTIMATION OF SALINE DEFICIT
WT LOSS SALINE CLINICALREPLACEMENT PRESENTATION
5 % 50 CC/Kg BW weak, ambulatory, good mental status
10 % 100 CC/Kg BW weaker, non-ambulatory,
slow mental status15 % 150 CC/Kg BW Obtunded, stuporous,
Coma, seizures
20 % 200 CC/Kg BW Not compatible with life
A SIMPLE ONE !A SIMPLE ONE !
1 Kg change in 1 Kg change in Body weightBody weight
•1 L change in isotonic saline or sodium balance
CORRECTION OF SALINE CORRECTION OF SALINE IMBALANCEIMBALANCE
MAKE THE MAKE THE DIAGNOSISDIAGNOSIS
COMPUTE FOR COMPUTE FOR DEFICIT OR DEFICIT OR EXCESSEXCESS
CORRECT 50 % CORRECT 50 % OF EXCESS OR OF EXCESS OR DEFICITDEFICIT
ESTIMATION OF WATER ESTIMATION OF WATER IMBALANCEIMBALANCE
H20 Deficit (L):H20 Deficit (L):=0.5(BW) (Na+/140)-1=0.5(BW) (Na+/140)-1
•100 mg% increase in Blood sugar, add 3 mEq to the serum Na+
•3 mEq change in Na+=1L change in H2O
•1 mEq dec in Na+ for every 4.6 g/l Inc in Lipids
CORRECTION OF WATER CORRECTION OF WATER IMBALANCEIMBALANCE
MAKE THE MAKE THE DIAGNOSISDIAGNOSIS
COMPUTE FOR COMPUTE FOR WATER EXCESS WATER EXCESS OR DEFICITOR DEFICIT
CORRECT 50 % CORRECT 50 % OF COMPUTED OF COMPUTED EXCESS OR EXCESS OR DEFICITDEFICIT
RENAL HANDLING OF K+RENAL HANDLING OF K+
K+ IS FREELY FILTEREDK+ IS FREELY FILTERED
90 % IS REABSORBED FROM 90 % IS REABSORBED FROM PROXIMAL TUBULEPROXIMAL TUBULE
SECRETION FROM THE DCT AND SECRETION FROM THE DCT AND CT IS THE PRIMARY MODULATOR CT IS THE PRIMARY MODULATOR OF K+ EXCRETIONOF K+ EXCRETION
FACTORS AFFECTING K+ FACTORS AFFECTING K+ EXCRETIONEXCRETION
ALDOSTERONEALDOSTERONE
Na + DELIVERY TO DISTAL TUBULESNa + DELIVERY TO DISTAL TUBULES
H + EXCRETION:H + EXCRETION:
- ALKALOSIS ---- K + - ALKALOSIS ---- K + EXCRETIONEXCRETION
- ACIDOSIS ----- K + - ACIDOSIS ----- K + EXCRETIONEXCRETION
URINE FLOWURINE FLOW
DIURETICSDIURETICS
MORE ABOUT K+MORE ABOUT K+
98 % OF K+ IS 98 % OF K+ IS INTRACELLULARINTRACELLULAR
SERUM K + SERUM K + CONCENTRATION CONCENTRATION GENERALLY GENERALLY REFLECTS TOTAL REFLECTS TOTAL BODY K+BODY K+
SERUM K + IS SERUM K + IS AFFECTED BY AFFECTED BY THE SERUM pHTHE SERUM pH
POTASSIUM BALANCEPOTASSIUM BALANCE
Acidosis Acidosis K+ is highK+ is high
Alkalosis Alkalosis K + is lowK + is low
H+
ECF ICF
H+
K+ H+
K+ H+
H+
K+ K+
K+ H+
H+ K+
K+
K+ H+
H+
K+ K+
H+ K+
K+ H+
H+
EFFECT OF pH CHANGEEFFECT OF pH CHANGE
FOR EVERY 0.1 FOR EVERY 0.1 pH CHANGEpH CHANGE
15 % CHANGE IN 15 % CHANGE IN SERUM K + SERUM K + LEVELLEVEL
POTASSIUM ASSESSMENT:POTASSIUM ASSESSMENT:
HistoryHistory
Physical examinationPhysical examination
Laboratory:Laboratory:– Serum Potassium level Serum Potassium level
(n.v.= 3.5-4.5)(n.v.= 3.5-4.5)– EKG:EKG:– H+; pHH+; pH
POTASSIUM DEPLETIONPOTASSIUM DEPLETION
Muscle weakness, fatigue due to Muscle weakness, fatigue due to hyperpolarization of cell hyperpolarization of cell membranes potential of cells & membranes potential of cells & nervesnerves
Low serum K+ (< 3.8 mEq/L)Low serum K+ (< 3.8 mEq/L)
EKG changes: flat inverted T EKG changes: flat inverted T waves, prolonged QT interval, waves, prolonged QT interval, prominent U wavesprominent U waves
ESTIMATION OF K + DEFICITESTIMATION OF K + DEFICIT
A drop of K+ from 4 to 3 A drop of K+ from 4 to 3
100-200 mEq deficit100-200 mEq deficit
Below 3 mEq/L 1 mEq/L drop in K Below 3 mEq/L 1 mEq/L drop in K ++
200-400 mEq deficit200-400 mEq deficit
At 1.5 mEq/L serum K +At 1.5 mEq/L serum K +
400-800 mEq deficit400-800 mEq deficit
A SIMPLE METHODA SIMPLE METHOD
For every 1 For every 1 mEq/L change in mEq/L change in serum K+serum K+
Equivalent 100-Equivalent 100-150 mEq/L 150 mEq/L change in total change in total body K+body K+
GUIDE TO K + DEFICIT GUIDE TO K + DEFICIT CORRECTIONCORRECTION
Oral therapy is desirableOral therapy is desirable
For intravenous correction:For intravenous correction:
- If K+ > 2.5 mEq/L and no EKG changes- If K+ > 2.5 mEq/L and no EKG changes
rate < 10 mEq/HR & conc. Not > rate < 10 mEq/HR & conc. Not > than 30 mEq/L of IVFthan 30 mEq/L of IVF
- If K+ < 2 mEq/L w/ EKG changes- If K+ < 2 mEq/L w/ EKG changes
40 mEq/HR & conc. Up to 60 40 mEq/HR & conc. Up to 60 mEq/LmEq/L
TREATMENT OF HYPER K+TREATMENT OF HYPER K+Calcium Gluconate - 5-10 ml of 10% solnCalcium Gluconate - 5-10 ml of 10% solnNaHCO3 - 45 mEq iv push (5 min)NaHCO3 - 45 mEq iv push (5 min)
- 1 L D10W + 90 mEq NaHCO3, 1st - 1 L D10W + 90 mEq NaHCO3, 1st 300 cc in 30 min, the rest 300 cc in 30 min, the rest
in 2-3 HRs.in 2-3 HRs.Glucose-Insulin (4 gm:1 Unit)Glucose-Insulin (4 gm:1 Unit)
- 300 cc D20W + 15 U RI- 300 cc D20W + 15 U RI - 50 cc D50W + 6 U RI- 50 cc D50W + 6 U RI
Cation Exchange Resin: 1 mEq/gm of resinCation Exchange Resin: 1 mEq/gm of resinDialysisDialysis
HYDROGEN ION BALANCEHYDROGEN ION BALANCEANION GAPANION GAP
PROTEINS
SODIUM
POTASSIUM
HCO3
CHLORIDE
ANION GAP
(Sodium + Potassium)-(Bicarbonate+Chloride)=+10
ANION GAPANION GAP
NORMAL
EXTRACELLULAR FLUID
Mg++
Ca++
K+
Na+Cl
protein
Org. acid
SO4
HCO3
UREMIA
Mg++
Ca++
K+
Na+Cl
protein
Org. acid
SO4
HCO3
DIABETIC K-A
Mg++
Ca++
K+
Na+Cl
protein
Org. acid
SO4
HCO3
PO4
AG
PO4
AG KETONESAG
PO4
HYDROGEN ION BALANCEHYDROGEN ION BALANCE
NORMAL NORMAL VALUESVALUES
-pH : 7.35-7.45-pH : 7.35-7.45
-pCO2: 40 torr-pCO2: 40 torr
-HCO3: 24 mEq/L-HCO3: 24 mEq/L
SIMPLE A/B PROBLEMSSIMPLE A/B PROBLEMS
– Check for pH:Check for pH:
High - High - ALKALOSISALKALOSIS
Low - Low - ACIDOSISACIDOSIS– Check for pCO2:Check for pCO2:
(OR) (OR) Opposite-Opposite-RESPIRATORYRESPIRATORY
(SM) Same- (SM) Same- METABOLICMETABOLIC
HYDROGEN ION BALANCEHYDROGEN ION BALANCE
MIXED ACID-BASE PROBLEMS:MIXED ACID-BASE PROBLEMS:– If pH is NORMAL:If pH is NORMAL:
No Acid-Base problemNo Acid-Base problem
Chronic Respiratory AlkalosisChronic Respiratory Alkalosis
Mixed Acid-Base ProblemMixed Acid-Base Problem– If Anion Gap is High - If Anion Gap is High - METABOLIC ACIDOSISMETABOLIC ACIDOSIS
RULESRULES
HCO3 w/ in pCO2 = 1 mEq/l of HCO3 w/ in pCO2 = 1 mEq/l of HCO3 for each 10 Torr in pCO2> HCO3 for each 10 Torr in pCO2> 4040
HCO3 w/ an acute in pCO2 = 2 HCO3 w/ an acute in pCO2 = 2 mEq/ of HCO3 for each 10 Torr in mEq/ of HCO3 for each 10 Torr in pCO2 below 40pCO2 below 40
HCO3 w/ chronic in pCO2 = 4 HCO3 w/ chronic in pCO2 = 4 mEq/L of HCO3 for each 10 Torr mEq/L of HCO3 for each 10 Torr in pCO2 above 40in pCO2 above 40
HYDROGEN ION BALANCEHYDROGEN ION BALANCE
HistoryHistory
PEPE
LaboratoryLaboratory–pCO2; pH; HCO3-;pCO2; pH; HCO3-;
CORRECTION OF H + CORRECTION OF H + IMBALANCEIMBALANCE
Base deficit or excess =Base deficit or excess =
change in actual HCO3 X BW X change in actual HCO3 X BW X 0.20.2
22
F&E THERAPEUTIC PLANF&E THERAPEUTIC PLANBASIC ALLOWANCE: LOSS H20 Na+ Cl- K+ urine 1500 50 90 40 S&I 1000 0 0 0
TOTAL 2500 50 90 40
CORRECTIONAL ALLOWANCE:
Water Sodium K+ H+
TOTAL
NA K H CL HCO3SWEAT 50 5 55GASTRICSECRETIONS
40 10 90 140PANCREATICFLUID
135 5 50 90BILE 135 5 105 35SMALL INT.FLUID
130 10 115 25DIARRHEALFLUID
50 35 40 45
ELECTROLYTE CONCENTRATIONS IN DIFFERENTBODY FLUIDS IN Meq/L
PRACTICAL PEARLSPRACTICAL PEARLS
SALINE BALANCE = VOLUMESALINE BALANCE = VOLUME
H2O BALANCE = SERUM SODIUMH2O BALANCE = SERUM SODIUM
NEVER USE D5W TO CHALLENGE NEVER USE D5W TO CHALLENGE VOLUMEVOLUME
NEVER GIVE K+ TO OLIGURIC PTS.NEVER GIVE K+ TO OLIGURIC PTS.VOMITING - D5NSSVOMITING - D5NSSDIARRHEA - D5LRSDIARRHEA - D5LRSCORRECT ONLY 50 % OF DEFICIT/EXCESSCORRECT ONLY 50 % OF DEFICIT/EXCESS