Transcript 005_Fluid And Electr..

Fluid & Electrolytes
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Esraa S. Al Tawil, Msc. Pharm, BCPS, BCNSP
Nutrition Support Specialized Residency
SICU/ TPN Clinical Pharmacist
King Saud University Medical City
April 2015
Learning Objectives
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Identify the compartments where water is distributed in the body
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Describe the physiologic functions of sodium, potassium, magnesium,
phosphate, and calcium
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Differentiate hypovolemic, euvolemic, and hypervolemic hypotonic
hyponatremia
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Identify common etiologies of sodium, potassium, magnesium,
phosphorus, and calcium disorders
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Recognize signs and symptoms associated with electrolyte imbalances
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Recommend appropriate management for electrolyte disorders
Body Fluid
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The percentage of water to body weight
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Human embryo: 97%
 A newborn infant: 70-80%
 Pediatrics and adults: 60%
 Male: 60%
 Female: 50%
FYI
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Adapted from The Science and Practice of Nutrition Support, 2001
Fluid Compartments
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1) Intracellular Fluid: 40%
2) Extracellular Fluid: 20%
a) Intravascular
b) Interstitial fluid
 70-kg man, Total Body Water (TBW): 42 L
 Intracellular fluid represents 28 L (40 % of TBW)
 Extracellular fluid represents 14 L (20% of TBW)
 Plasma:
3.5 L
(5% of TBW)
 Interstitial: 10.5 L (15% of TBW)
Fluid Compartments
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Normal Fluid Intake: 70 kg man: 2500 ml
Liquid: 1200-1500 ml
Food: 1000 ml
Oxidation of food: 300 ml
Normal Fluid Output: 1400-2500ml/day
Skin: 500 ml
Lungs: 500 ml
Urine: 1400 ml
Feces: 100 ml
Fluid Requirements
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Method I
Weight: Preterm
130-150 ml/kg/day
Term
130-150 ml/kg/day
2.5-10 kg 100 ml/kg/day
>10-20 kg 1000 ml + 50 ml/kg for every kg >10 kg up to 20 kg
> 20 kg (age < 50 years) 1500 ml + 20 ml/kg for every kg > 20 kg
(age > 50 years) 1500 ml + 15 ml/kg for every kg > 20 kg
Method II
Body surface area: 1500 ml/m2
Method III
Age:
35 ml/kg/day (Adults)
30 ml/kg/day (Elderly adults)
40 ml/kg/day (Pediatrics)
Fluid Requirements
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Factors need to increase fluid
 Fever
 Excessive sweating
 Excessive losses e.g. vomiting, diarrhea, fistula, chest tube
 Radiant warmers
Factors need to decrease fluid
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Congestive heart failure
Renal failure
Liver Failure
Pulmonary disease
Elderly patients
FYI
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ELECTROLYTES
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SODIUM
CALCIUM
PHOSPHATE
POTASSIUM
MAGNESIUM
FYI
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Adapted from Clinician’s Pocket Reference, 2007
Sodium
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An extracellular cation
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Serves as a serum osmolality and acid base balance regulator
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Serves as a transmembrane electric potential for neuromuscular functioning
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The kidneys are the primary organs for controlling body sodium and water
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Serum concentration is between 135-145 mmol/l (135-145 mEq/L)
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Serum osmolality (mOsm/l) = 2 x serum Na + BUN + Glucose
2.8
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Hyponatremia
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• Defined as a serum sodium concentration is less than 135 mmol/l
• The most common electrolyte imbalance in hospitalized patients
• Signs & Symptoms
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Nausea, vomiting
Muscle twitches, irritability, seizure
Hyporeflexia, mental changes, lethargy, confusion, and coma
Seizures and coma may occur with sodium level <125 mmol/l
Hyponatramia
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 Isotonic (Pseudohyponatrmia, Factitious):
i.e. Hyperproteinemia, Hyperlipidemia
 Hypertonic: i.e. Hyperglycemia
For each 100mg/dl (5.6 mmol/l) increase in blood
glucose, the serum sodium will be decreased by 1.6
mEq/L (1.6 mmol/l)
 Hypotonic: represents
hyponatremia
the most common of
Hypotonic Hyponatremia
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a) Hypotonic Hyponatremia
Hyponatremia associated with Low Total Body Sodium
(Hypovolemic hyponatremia)
Etiology
 GI losses: Vomiting, diarrhea
 Medication: Diuretics
 Intravascular fluid loss: Burns, peritonitis
 Hypoaldosteronism, Addison disease
 Patient treated with diuretics who receiving sodium-free
solution
Hypotonic Hyponatremia
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Signs and Symptoms
 Decreased BP from lying to standing position
 Increased heart rate
 Decrease skin turgor
Hypotonic Hyponatremia
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Management
 D5% NS or NS
 Life–Threatening (Seizures, coma): 3% or 5% NS
 Total volume of NaCl (3% or 5%) needed=Mmol of Sodium (3% or 5%) –patient sodium level
(F x Patient weight) +1
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3% Sodium Chloride: 513 mmol/l 5% Sodium Chloride: 855 mmol/l
*Factor: 0.6: Children and men < 70 years old
0.5: Men
> 70 years old and women < 70 years old
0.45: Women > 70 years old
X= Should not more than 12 mmol/l/24 hrs ( Prefer < 10 mmol/l/24hrs)
Example; If patient's Na level 120 mmo/l. The target correction
for serum sodium in 24 hrs is 130 mmol/l
Infusion rate: 0.5 mmol/kg/hr (Asymptomatic)
1-2 mmol/kg/hr (Symptomatic)
** 3% or 5% hypertonic saline for patient who has central line only except
if patient experiences symptoms
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 Volume of 3% saline (L/ 24 hours)=
target change PNa (mmol/L/24 hours) X TBW /513
 We should not exceed
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10 mmol/L in the 1st 24 hours
20 mmol/L in the 1st 48 hours
 E.g. 70 kg man Pna=105 mmol/L ; TBW=42
 Needed Na= 10 X 42 = 420 mmol
 420/513  0.82L /24 hours of 3% NS or 34 ml/hr
Isovolemic Hyponatremia
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 Hyponatremia associated with Normal Total Body Sodium as a result of water
excretion impairment without changing in sodium excretion
Etiology
 Hypoadernalism
 Hypothyroidism
 SIADH
 Water intoxication
Management
 Restrict fluids (1000-1500ml/day)
 Demeclocycline can be used in chronic SIADH
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Inhibit vasopressin-mediated water reabsorption
Hypervolemic Hyponatremia
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Hyponatremia associated with High Total Body Sodium: as a result of
increased in total body sodium with a larger increase in the total body water
Etiology
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Congestive heart failure
Cirrhosis
Chronic renal failure
Nephrotic syndrome
Management
 Correct underlying cause
 Fluid restrictions
 Furosemide
Hypernatraemia
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 Hypernatremia (serum sodium > 147 mmol/1) is most often the
result of a reduced water intake or water loss rather than excessive
sodium intake
Hypernatremia classifications:
a) Isovolemic Hypernatremia (Free water loss): Diabetes insipidus
b) Hypovolemic Hypernatremia (Water and sodium loss): Diuretics, osmotic
diuresis due to glucosuria, mannitol
c) Hypervolemic Hypernatremia (Addition of hypertonic solution): Hypertonic
dialysis, hypertonic saline, adrenal hyper-function
Hypernatraemia
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Signs and Symptoms:
 Dry mucous membrane, decreased skin turgor, thirst
 Irritability, hyperreflexia, restlessness, ataxia
 Seizure and coma may occur if serum sodium level > 160 mmol/l
Hypernatraemia
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Management
 Monitor fluid input and output
 Hypovolemic Hypernatremia (Orthostatic hypotension)
Determine whether the patient is volume depleted: if so, rehydrate with NS until
hypovolemia improves then change to 1/2 NS
 Calculate fluid deficit
D5% ½ NS or oral water
Hypernatraemia
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 Euvolemic/Isovolemic (No orthostatic hypotension)
Calculate free water deficit
Water deficit (L): Pt weight x F x (Patient sodium level ) -1
Target Na level
*F: 0.6: Children and men < 70 years old
0.5: Men > 70 years old and women < 70 years old
0.45: Women > 70 years old
Give free water as D5W, one half of the volume on the first
24 hrs, and the full volume in 48 hrs.
 Diabetes Insipidus (DI)
 Central DI ( Responsive to desmopressin): DDAVP 10 mcg intranasaly, QD
 Nephrogenic DI (Unresponsive to desmopressin): Thiazide diuretics and salt
restriction. Amiloride for lithium induced nephrogenic DI
Hypernatraemia
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Hypervolemic Hypernatremia
 Avoid medication containing sodium
 D5W along with furosemide
 Dialysis if there is renal impairment
Potassium
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 Potassium is the most abundant cation in the body
 Total body potassium is about 3000 to 4000 mEq:
 Ninety eight percent is found in the intracellular space
 Only 2% is present in the extracellular fluid
 The rate –limiting step for potassium into the cells is the Na K
ATPs pump
 Serum concentration is between 3.5-5 mmol/l (3.5-5 mEq/L)
Potassium
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Functions
 Cellular metabolism
 Carbohydrate and protein synthesis
 Regulation of enzymatic reactions
 Regulation of muscle and nerve excitability
 Plays a role in controlling of intracellular volume
 Excretion:
80%: the kidneys
15%: feces
5%: sweat
Hypokalemia
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 Defined as a serum potassium concentration less than 3.5 mmol/l
Etiology
 Inadequate supplementations
 Intracellular shifting: Metabolic alkalosis (each 0.1 increase in PH lowers
serum K+ 0.5-1 mmol/l), administration of dextrose,
insulin, B2-adrenergic agonists, TPN
 Increased losses: vomiting, diarrhea, NG drainage, laxative abuse,
intestinal fistulas
 Medications: Amphotericin B, diuretics, corticosteroids
 Diseases: Hyperaldosteronism, cushing’s syndrome
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Hypokalemia
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Signs and Symptoms
 Myalgias, skeletal muscle weakness, cramps, ileus
 Hypotension, arrhythmias, heart block
 ECG changes (PR prolongation, QRS widening with severe hypokalemia)
 Death secondary to cardiac and respiratory muscle paralysis
Hypokalemia
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Management
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Correct underlying cause
A 24-hour urine for K+ may be helpful if the diagnosis is unclear
Treat hypomagnesemia if presents
Mild hypokalemia: Oral potassium supplement by potassium-rich food & tablets
Moderate-Severe hypokalemia: IV potassium
FYI
Guidelines for Intravenous Potassium Replacement in
Adults and Pediatrics
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Serum Potassium
IV Loading
Infusion rate
Concentration of
IV loading
(Adults & Pediatrics)
---------------------------------------------------------------------------------------------------------------------------------------K > 2.5 mmol/l
Adults
Measure Sr. K
Central line
<10 mmol/hr
at least every 24 hrs
< 20 mmo/100 ml
Pediatrics
Peripheral line
< 0.5 mmol/kg/hr
< 10 mmo/100 ml
(up to 10 mmolhr )
K < 2.5 mmol/l
Adults
With/ without ECG >20 mmol//hr
abnormalities or
Pediatrics
myopathy
< 1 mmol/kg/hr
(up to 20 mmol/hr)
Monitoring
Parameters
ECG monitoring with all
doses exceeding
10 mmol/hr in adults
or 0.5 mmol/kg/hr
in pediatrics
Monitor K level 2-4 hrs after
the end of infusion, then
at least every 24 hrs
Central line
< 40 mmo/100 ml
Peripheral line
< 10 mmo/100 ml
Hyperkalemia
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Defined as a serum potassium concentration greater than 5 mmol/l
Etiology
 Excessive supplementation
 Extracellular shifting: Metabolic acidosis (each 0.1 decrease in PH elevates serum
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K+ 0.5-1 mmol/l
Decreased output: Acute or chronic renal failure
Medications: Potassium sparing diuretics, ACEI, NSAID, B2–adrenergic antagonist
Others: Addison’s disease, Hemolysis, Rhabdomyolysis, muscle crash injury, Tumor
lysis syndrome, burns
Pseudohyperkalemia: Leukocytosis, thrombocytosis, prolonged
tourniquet time
Hyperkalemia
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Signs & Symptoms
 Nausea, muscle twitching
 Cardiac rhythm disturbances, hypotension, bradycardia, and cardiac arrest in
severe hyperkalemia
 Symptomatic hyperkalemia may occur if serum potassium concentration rises
above 6 mmol/l
Hyperkalemia
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Management
 Correct underlying cause
 Monitor patient with ECG if symptoms present, discontinue all K supplements
 Ca Chloride (a heart protective); no effect on serum potassium level
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Infant and pediatrics 10-20 mg/kg
Adult 2-4 mg/kg (10 % solution)
May be repeated every 10 minutes if necessary until
cardiovascular symptoms resolve
Hyperkalemia
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Management
 Sodium polystyrene (Kayexalate): enhances colonic excretion of potassium
Adults:
Orally: 15 gm/kg/day 1-4 times per day
Rectally retention enema: 30-50 gm every 6 hours
Pediatrics: Orally: 1 gm/kg/dose up to 4 times per day
Rectally retention enema: 1 gm/kg/dose every
2-6 hours
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Insulin/dextrose (promote cellular uptake of potassium):
10 units of regular insulin in 50 ml of 50% of dextrose
 Consider dialysis in case of severe hyperkalemia
Magnesium
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 The average body contains 2000 mEq with the following
distribution: 50% in bone, 45% in intercellular fluid, and 5% in
the extracellular fluid
 Normal serum total Mg+2: 1.4-2 mEq/L (0.7-1 mmol/l)
 In case decline in serum magnesium, PTH will be stimulated to
increase magnesium level by increasing its release from bone and
its renal re-absorption
Magnesium
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Functions
 Activates enzymatic systems
 Involves in neurological function
 DNA replication & transcription; mRNA translation
 Maintenance of Na/K ATPase pump
 Regulates vascular smooth muscle tone
Hypomagnesemia
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Defined as a serum magnesium below 0.7 mmol/l
Etiology
 Inadequate supplementations
 Intracellular shifting
 Increased losses: vomiting, diarrhea, prolonged NG suction,
intestinal fistulas, laxative abuse
 Electrolyte disturbances: Hypokalemia, hypocalcemia,
hypophosphatemia
 Medications: Diuretics, amphotericin B, cisplatin, carboplatin,
foscarnet, cyclosporine, aminoglycoside
 Others: Hyperthyroidism, hyperaldosteronism
Hypomagnesemia
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Signs & Symptoms
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Nausea
Vomiting
Muscle weakness
Lethargy
Drowsiness
psychosis
Tremor
Tetany
hyperactive reflexes
 Severe Hypomagnesemia: Seizures, ECG abnormalities
(prolonged QT interval: increased risk of arrythmias)
Hypomagnesemia
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Management
 Correct underlying cause
 Magnesium supplement: Oral for mild and asymptomatic hypomagnesemia: High oral doses
can cause diarrhea
 IV for moderate-severe hypomagnesemia
 Moderate: 1gm over 1 hour, can be repeated if necessary
 IV infusion rate> 8 mEq/hour (4 mmol/hr) exceed the renal threshold and the most
of dose will be eliminated faster
 Severe (Tetany or Seizures): Monitor patient with ECG. Administer 2 gm
magnesium sulfate over 10-20 minutes. Follow with IV infusion 5-6 gm over 12-24
hrs
 Magnesium level can be checked after the end of infusion by 2 hours
Hypermagnesemia
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 Defined as a serum magnesium concentration greater than 1mmol/l
Etiology
 Excess magnesium intake
 Decreased losses: renal failure
 Taking medications in rich with magnesium: antacids, laxative
Hypermagnesemia
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Signs and Symptoms
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Nausea
Vomiting
Hypotension
Bradycardia
Decreased deep-tendon reflexes
Decreased serum calcium
Respiratory paralysis
ECG abnormalities (increased PR and QRS interval) and asystole in
severe cases of hypermagnesemia
Hypermagnesemia
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Management
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Correct the underlying cause
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Stop magnesium–containing medication
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Protect heart if patient is symptomatic: 10 ml of 10% calcium gluconate
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Fluid: NS or 1/2 NS with furosemide
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Hemodialysis may be necessary in severe cases
Phosphate
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A major intracellular anion
 Total body phosphorus ~ 700 to 1000 mg
 Bone, skeletal muscle, and the ECF hold 85%, 9%, and less
than 1%, respectively
 The higher phosphate levels in children and the elderly reflect a
higher bone turnover
Functions
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The essential element in cell membrane structures
Regulation of intercellular metabolism carbohydrate, protein,
and fats synthesis
A major component of phospholipid membrane, RNAs,
nicotinamide diphosphate, cyclic adenine and guanine
nucleotide
Formation of high energy bonds in ATP production
A component of 2,3 DPG for the release of oxygen from
hemoglobin to tissues
A regulator in glycolysis and hydroxylation of cholecalciferol
Hypophosphatemia
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 Defined as a serum phosphate concentration less than 0.7 mmol/l
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Etiology
Decreased phosphate or vitamin D intake
Intracellular shifting: dextrose infusion, insulin, TPN
Medications e.g. aluminum & calcium containing antacids, loop diuretics,
foscarnet
Respiratory or metabolic alkalosis
Hypercalcemia, hypokalemia, hypomagnesemia, alcohol abuse
Others: Refeeding syndrome, severe burns, management of DKA
Hypophosphatemia
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Signs and Symptoms
 Muscle weakness and pain
 Tenderness
 Neurological irritability
 Confusion
 Severe hypophosphatemia: rhabdomyolysis, hemolysis, platelet
dysfunctions, and cardiac and respiratory failures
Hypophosphatemia
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Management
 Oral Phosphate: Asymptomatic with mild hypophosphatemia
 IV Phosphate: for moderate-severe hypophosphatemia
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Na Phosphate is preferred over K Phosphate if sodium level is normal
Na Phosphate (4 mmol Na/ml- Phosphate 3 mmol/ml)
K Phosphate (4.4 mmol K/ml- Phosphate 3 mmol/ml)
Use normal saline as IVF if there is no contraindication
Infuse phosphate over 3 hours for adults and 4-6 hours for pediatrics: too rapid
replacement can lead to hypocalcemic tetany
 Check level after the end of infusion by 2 hours
Hyperphosphatemia
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Defined as a serum phosphate concentration greater than 1.45 mmol/l
Etiology
 Increased intake of vitamin D or phosphate products
 Metabolic acidosis
 Renal failure
 Tumor lysis syndrome post chemotherapy or radiation
 Rhabdomyolysis
 Hyperthyroidism, hypoparathyroidism, acromegaly
Hyperphosphatemia
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Signs & Symptoms
 Tetany
 Renal osteodystrophy
 Ca-PO-4 complex deposition in soft tissue
Hyperphosphatemia
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Management
 Correct underlying cause
 Restrict Phosphate intake
 Oral phosphate binder: e.g. Aluminum hydroxide,
Magnesium hydroxide, Calcium Carbonate
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Severe cases: Acetazolamide 15 mg/kg q 4 hours
Insulin and glucose infusion
Dialysis
Calcium
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Total body calcium 1000 gm
It found mainly in bone (99.5%) and
only 0.5% in the ECF
Extracellular calcium exists in the
three forms:
Complex bound (6%), Protein bound
(40%), and ionized or free fraction (54%)
Calcium concentration is closely regulated
by a complex interaction among PTH,
serum phosphate, vitamin D system, and
target organs
 A therapeutic range (2.1-2.6 mmol/l = (8.510.5mg/dl)
Functions
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 Propagation of neuromuscular activity
 Regulation of endocrine functions
 Blood coagulation
 Metabolism of bone and tooth
Hypocalcemia
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Defined as a total serum calcium concentration less than 2.1 mmol/l
Etiology
 Poor intake
 Vitamin D deficiency
 Medications: Glucocorticoids, loop diuretics, phosphate salts,
plicamycin, foscarnet
 Hypoalbuminemia, hypoparathyroidism
 Hypomagensemia, hyperphosphatemia
 Continuous renal replacement therapy (CRRT)
 Renal failure
 Pancreatitis
Hypocalcemia
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Signs and Symptoms
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Finger numbness
Paresthesia
Tingling
Burning of extremities
Fatigue
Depression
Memory loss
Hallucinations
Muscle spasms
In severe hypocalcemia: tetany, seizures, hypotension, bradycardia,
arrhythmias, and coagulopathy
Hypocalcemia
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Management
Common Correction Formula
 Corrected Ca level=[ (4-Albumin level g/dl X 0.8 mg/dl]+ Ca uncorrected
 Corrected Ca level =[ (40 -Albumin level g/l X 0.02 gm/l]+ Ca uncorrected
Don't use in Critically Ill patients (Overpredicts)
The symptoms are generally appeared when the serum ionized calcium
concentration drops below 0.7 mmol/l which usually corresponds to a total Ca
concentration of 1.8-1.875 mmol/l
 Asymptomatic
Oral calcium Carbonate
Vitamin D replacement
 Symptomatic
IV calcium gluconate
Hypercalcemia
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Defined as a total serum calcium concentration greater than 2.6
mmol/l
Etiology
 Malignancy
 Primary Hyperparathyroidism
 Primary adrenal insufficiency
 Paget’s disease
 Excessive vitamin D or calcium
 Sarcoidosis
 Excessive PO or IV intake
 Medications: Tamoxifen, thiazide diuretics, estrogen, progesterone, lithium
FYI
Spectrum of Hypercalcemia
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Normal
Mild
Moderate Crisis
Total serum
Calcium (mmol/l)
2-2.6
2.6-<3
3-<3.5
3.5-4
Ionized
Calcium (mmol/l)
1-<1.4
1.4-<2
2-<2.5
2.5-3
Hypercalcemia
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Signs and Symptoms
 GI complaints: Nausea, vomiting, abdominal pain
 Severe hypercalcemia: The symptoms are generally appeared
when the serum ionized calcium concentration ≥ 1.5 mmol/l or
serum calcium concentration above 3 mmol/l
 Neuromuscular system: confusion, lethargy, psychosis, depression, coma
 Kidney system: nephrolithiasis, chronic interstitial nephritis, and renal
tubular acidosis
Hypercalcemia
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Management
 Correct underlying condition
 Encourage patient mobilization
 Intravenous NS with furosemide (correct more cases)
 Calcitonin: IM, SC 4 units/kg, may increase to 8 units/kg Q12 hours to
a maximum of Q6hrs
 Plicamycin: 25mcg/kg IV over 2-3 hours (use as last resort; very potent)
Hypercalcemia
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Management
 Severe hypercalcemia: Biphosphonates (Pamidronate, etidronate,
zoledronic acid)
Pamidronate: 60-90 mg, as a single dose and given as a slow infusion over
2-24 hours
Etidronate: 7.5 mg/kg/day as an infusion over 2 hrs x 3 days
 Glucocorticosteroid: Prednisone 40-60 mg/day for 10 days (vitamin D
intoxication, sarcoidosis)
 Dialysis in severe cases
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Questions?