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8/10/2019 Fluid and Electrolytes (Introduction) and Sodium Imbalance
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Fluid and electrolyte management are
paramountto the care of the surgical patient.
Changes in both fluid volume and electrolyte
composition occur preoperatively,
intraoperative, and post operatively, as wellas in response to trauma and sepsis.
Fluid and Electrolytes in Surgical PatientsIntroduction (1)
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Fluid and Electrolytes BalanceNormal Anatomy and Physiology
Total Body Water (60% body weight)Lesser in
obesity(Adipose tissues
less water)
ExtracellularFluid(20%b
ody
weight) Active
NA
Pump
Fluid and Electrolytes in Surgical PatientsIntroduction (2)
Micropores
allow
escape and
returning of
ALBUMIN
(5%/hr)
Sodium and
potassiumto maintain
electrical
neutrality
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Fluid and Electrolytes in Surgical PatientsIntroduction (3)
External fluid and electrolyte balance between body and its
environment is defined by intake of fluid & electrolytes with
the output from kidney, GI tracts, skin and lungs (insensible
loss).
Modified and may not be the same, if there are excessive
loss due to diseases, changes in climate and etc.
Intake (in ml) Output (in ml)
Water from beverages 1200 Urine 1500
Water from solid food 1000 Insensible losses from skin and
lungs
900
Metabolic water from oxidation 300 Faeces 100
2500 2500
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Fluid and Electrolytes in Surgical PatientsIntroduction (4)
Normal Maintenance Requirement
Calculated approximately from an estimation of insensible
(lungs, skin) and obligatory losses.
Typical daily maintenance fluid regimen consists 5% dextrose witheither Hartmannsor normal salineto a volume of 2 liters.
Replacement fluids required to correct pre-existing deficienciesand supplemental fluids required to compensate for anticipatedadditional intestinal or other loses.
Water 25 -35 ml /kg/day
Sodium 0.91.2 mmol/kg/day
Potassium 1 mmol/kg/day
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Fluid and Electrolytes in Surgical PatientsIntroduction (5)
Solution NA K Ca Cl Lactate Colloid
Hartmanns 131 5 2 111 29
Normal Saline(0.9% NaCl) 154 154
Dextrose Saline(4% Dextrose in 0.18% saline)
30 30
Gelofusine 150 150 Gelatin
in 4 %
Haemcael 145 5.1 < 1 145 Polygelin(75g/L)
Hetastarch Hydroxyethyl starch
(6%)
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
INTRODUCTION
Defined as a serum sodium concentration lower than135 mmol/L.
It can result from a particular laboratory technique or fromimproper blood collection, excessively high water intake, or,most commonly, an inability of the kidneys to excrete freewater.
Causes by
(a) Sodium depletion
(b) Sodium dilution
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
CAUSE 1 : SODIUM DEPLETION1. Decrease intake
(a) Low Na diet(b) Enteral feeds
2. Increase loss(a) Gastrointestinal Losses like vomiting, prolonged NGT
suctioning, and diarrhea(b) Renal Losses due to diuretics and primary renal disease
3. Dehydration (loss fluids and loss electrolytes)
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
CAUSE 2 : SODIUM DILUTION
1. Due to excess extracellular water
(a) Intentional: excessive oral intake
(b) Iatrogenic: Intravenous
2. Drugs like antipsychotics, Tricyclic antidepressants andAngiotensin-converting enzyme inhibitors
3. Hyperosmolar like Mannitol and Hyperglycemia
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Establishing Type of Hyponatremia
BP, JVP, Skin Turgor
DecreasesBP, JVP, Skin Turgor
Increases
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
Clinical Presentation
CNS symptom show when Na
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
Management
Calculate the deficit of Na by the formula below:
Na+deficit (mEq) = (140 Naserum) x 0.6 x Kg
Correct sodium to above 120 mEq/dl
NaCl + 40 mEq/L KCl
3% Saline
serial electrolytes
be prepared to handle seizures
Replace potassium
Cl should correct itself
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
Treatment Strategies
Hypovolemic Hyponatremia
expand intravascular volume
0.9% NS or 3% Hypertonic Saline
Hypervolemic Hyponatremia
water restriction
treat medical condition
hemodialysis
Euvolemic Hyponatremia SIADH
restrict fluid: 7-10 ml/kg/d
demeclocycline antagonizes vasopressin
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Sodium Hyponatremia
Central Pontine Myelinosis
Results from overcorrection of sodium
Acute correction limit 25 mEq /day Chronic correction limit 10 mEq/day
In hyponatremia, brain adjust their osmolytes to fall, then
they will absorb free water from surrounding.
If too rapid correction, causes ECF to be hypertonic, free waterwill then move out from cells, brain appear to shrink.
Manifest as paralysis, dysphagia, dysarthria
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Hypernatremia
Hypernatremia
High level of sodium
Due to increase sodiumor decrease in water
Plasma sodium more
than 145 mEq/L
Water moves from ICFto ECF
Cell dehydrates/shrink
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Hypernatremia
Hypernatremia
Volume Status
Normal
Nonrenal water loss
Skin
Gastrointestinal
Renal water loss
Renal disease
Diabetes insipidus
High
Iatrogenic sodium
administration
Mineralocorticoid excess
Aldosteronism
Cushings disease
Congenital adrenal
hyperplasia
Low
Nonrenal water loss
Skin
Gastrointestinal losses
Renal water losses
Diabetes insipidus
Adrenal failure
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Hypernatremia
Presentation
Thirst
Neurologic symptoms like confusion,neuromuscular excitability, seizures, coma
due to osmotic shift of water out of brain cells
(brain cell shrinkage)
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Hypernatremia
Diagnosis
Clinically and measuring of serum Na
Determine underlying disorders
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Fluid and Electrolytes in Surgical PatientsElectrolytes Imbalance: Hypernatremia
Treatment
Normal saline in hypovolemic patients
Hypotonic fluid (D/w 5%, D/W 5% in or normal saline,
or entral water)
The formula used to estimate the amount of water
required to correct hypernatremia:
140Water deficit (L)= Serum sodium - 140 TBW