M1: Fluids & Electrolytes Flashcards
TBW: 60%
Water
Four compartments of Human body
Water, Protein, Fat & Bone ash
Example of transcellular
CSF, Synovial & Ocular
Total Body Water: of TBW
50-70%
Total Body Water: young adult male
60%
Total Body Water: young adult female
50%
Total Body Water: decrease with
Aging
Total Body Water: increase with
Newborn
Total Body Water: three functional compartments
Plasma, Interstitial fluid & Intracellular volume
ECF is composed
Plasma & Interstitial Fluid
Major cation in the ECF
Na
Major cation in the ICF
K
Major anion in the ECF
Chloride
Major anion in the ICF
Phosphate & Proteins
Plasma volume 5%, interstitial 15%.
ECF
Total number of osmotically active particles
Osmotic pressure
Serum Osmolality by giving value of
Na, Glucose & Ures
Normal exchange of F&E
Water exchange & Salt gain and losses
Normal individual water consumed
2-2.5 L
H20 Losses: stool
250cc
H20 Losses: urine
800-1500cc
H20 Losses: insensible
600cc
Irreversible brain damage. Hypoxic Encephalopathy.
6minutes
Classification of body fluid changes
Volume, Concentration & Composition
Classic for Volume Excess. Distenden neck veins, Increase CVP & Murmur.
CHF
Normal Atrial pressure
8-15mmHg
Increase in BUN & Crea
Azotemia
Daily salt intake
50-90 mEq
Salt gain & losses is maintained by
Kidney
Baroreceptors found in the
Carotid
Osmoreceptors found in the
Kidney
Most common fluid disorder in a surgical patient. Most common ECF loss GI fluids
Volume deficit
Iatrogenic, renal insufficiency, cirrhosis and CHF
Volume excess
Common CNS manifestation in Hyponatremia
Seizure & coma
For every 100mg/dL increment in plasma glucose above normal, the plasma sodium decreased by 1
Check glucose for hyponatremia
Common cause of hypernatremia
Iatrogenic sodium administration
Whether high or low sodium this manifestation will occur
Seizure
Electrolyte composition
Potassium, Calcium, Phosphorus & Magnesium
Excessive K intake. Increased release of K from cells. Impaired K excretion by kidneys. Seen in high voltage electrical burn.
Hyperkalemia
Needed for depolarization
Potassium
When severely dehydrated you become
Acidotic
Frequent drug offender that causes hypokalemia
Furosemide
Usual manifestation of Hypokalemia in NMS
Weakness & Paralysis
Contained in bone matrix. Protein bound 40%, completed to phosphate plus anion 10%.
Calcium
Normal calcium level
8.5-10.5 mEq/L
Bony mets, primary hyperparathyroidism & secretion of parathyroid hormone related protein.
Hypercalcemia
Looks like catatonia
Hypercalcemia
Below 8.5mEq/L. Etiology is pancreatitis, severe soft tissue infections, renal Failure & etc.
Hypocalcemia
Adjust total serum calcium down by _______ for every 1g/dL decrease in albumin.
0.8mg/dL
Decreased urinary excretion, increased intake and endogenous immobilization.
Hyperphosphatemia
Decreased intake. Intracellular shift. Increased excretion.
Hypophosphatemia
50% incorporated in bone. Excreted in feces & urine. Kidneys conserve this. Essential for proper functioning if enzyme system.
Magnesium
Severe renal insufficiency. Parallel changes in K excretion. Excess antacid intake.
Hypermagnesemia
Water constitutes how many percent of TBW
50-60%
TBW water for male
60%
TBW water for female
50%
TBW adjusted downward approximately 10-20% for
Obese individual
TBW adjusted upward by 10% for
Malnourished individuals
Is the largest fluid compartment in the body and makes up approximately 40% of TBW
Intracellular fluid
Extracellular fluid is composed of
Plasma & Interstitial fluid
Percentage of ECF
20%
Percentage of plasma
5%
Percentage of Interstitial fluid
15%
Most common cation present in ICF
Potassium
Most common cation present in ECF
Sodium
Virtually absent in intracellular fluid and is present only in small amounts in ECF.
Calcium
Principal determinants of osmolality
Sodium, Glucose & Urea
Formula & conversion for serum osmolality
SO= 2 sodium + (Glucose/18) + (Urea/2.8)
A patient develop a high output fistula following abdominal surgery, the fluid is sent for evaluation with the ff results Na 135, K 5 & Cl 70. What is the source of the fistula.
Pancreas
Diagnosis for a patient with normovolemic hyponatremia
SIADH
Can be seen with an excess of solute relative to free water, such as with untreated hyperglycemia or mannitol administration.
Hyponatremia
Exerts an osmotic force in the extracellular compartment, causing a shift of water from intra to extracellular compartments.
Glucose
For every 100mg/dL increment in plasma glucose above normal, the plasma sodium should decrease by
1.6 mEq/L
Results from either loss of free water or a gain of sodium in excess water
Hypernatremia
Hypervoleomic hypernatremia is usually caused by
Iatrogenic administration of sodium containing fluids
Excess sodium bicarbonate & mineralocorticoid is seen in patients with
Cushing’s sydrome & Congenital adrenal hyperplasia
Can contribute to hyperkalemia in patients renal insufficiency
NSAIDS
Causes decrease deep tendon reflexes
Hypokalemia
Causes increase deep tendon reflexes
Hypomagnesemia & Hypocalcemia
In hyperkalemia, first ECG change seen in most patients.
Peaked T waves
Postoperative patient with a potassium of 2.9 is given 1mEq/kg replacement show the serum K to be 3.0. Give dx.
Hypomagnesemia
Will change serum potassium
Alkalosis
Measurement of total calcium levels. Adjust total serum calcium down by __________ for every 1g/dL decrease in labumin.
0.8mg/dL
Formula for serum calcium albumin computation (2.0 albumin & 6.6 calcium)
0.8 x 2 = 1.6 + 6.6 = 8.2
Caused by intracellular shift of phosphate in association with respiratory alkalosis, insulin therapy & refeeding syndrome.
Acute Hypophosphatemia
Occurs when excess calories are given to a starved person. Potentially lethal condition that occur with rapid and excessive feeding of patients with severe underlying malnutrition.
Refeeding syndrome
Associated with hyperkalemia & hyperphosphatemia
Rhabdomyolysis
Hypomagnesemia clinically resembles with
Hypocalcemia
Is essential for proper function of many enzyme systems. Depletion is characterized by neuromuscular and CNS system.
Magnesium ion
A patient presents obtunded to the ER with ff labs Na 130 Cl 105 K 3.2 HCO3 15. What is the most likely diagnosis?
GI losses
Formula of Anion Gap
AG= (Na) - (Cl+HCO3)
Best choice to replace isotonic(serum) fluid loss. Best approximates serum electrolytes and would be the fluid of choice to replace isotonic serum fluid loss.
Lactated ringer
First treatment administered to a patient with a potassium level of 6.3 and flattened P waves on either ECG
Insulin & Glucose
Potassium can be removed from the body using a cation exchange resin such as this that binds potassium in exchange for sodium
Kayexalate
Approximate IV rate maintenance fluids for a 50kg patient would be
90 mL/hr
Water constitutes how many percent of TBW
50-60%
TBW water for male
60%
TBW water for female
50%
TBW adjusted downward approximately 10-20% for
Obese individual
TBW adjusted upward by 10% for
Malnourished individuals
Is the largest fluid compartment in the body and makes up approximately 40% of TBW
Intracellular fluid
Extracellular fluid is composed of
Plasma & Interstitial fluid
Percentage of ECF
20%
Percentage of plasma
5%
Percentage of Interstitial fluid
15%
Most common cation present in ICF
Potassium
Most common cation present in ECF
Sodium
Virtually absent in intracellular fluid and is present only in small amounts in ECF.
Calcium
Principal determinants of osmolality
Sodium, Glucose & Urea
Formula & conversion for serum osmolality
SO= 2 sodium + (Glucose/18) + (Urea/2.8)
A patient develop a high output fistula following abdominal surgery, the fluid is sent for evaluation with the ff results Na 135, K 5 & Cl 70. What is the source of the fistula.
Pancreas
Diagnosis for a patient with normovolemic hyponatremia
SIADH
Can be seen with an excess of solute relative to free water, such as with untreated hyperglycemia or mannitol administration.
Hyponatremia
Exerts an osmotic force in the extracellular compartment, causing a shift of water from intra to extracellular compartments.
Glucose
For every 100mg/dL increment in plasma glucose above normal, the plasma sodium should decrease by
1.6 mEq/L
Results from either loss of free water or a gain of sodium in excess water
Hypernatremia
Hypervoleomic hypernatremia is usually caused by
Iatrogenic administration of sodium containing fluids
Excess sodium bicarbonate & mineralocorticoid is seen in patients with
Cushing’s sydrome & Congenital adrenal hyperplasia
Can contribute to hyperkalemia in patients renal insufficiency
NSAIDS
Causes decrease deep tendon reflexes
Hypokalemia
Causes increase deep tendon reflexes
Hypomagnesemia & Hypocalcemia
In hyperkalemia, first ECG change seen in most patients.
Peaked T waves
Postoperative patient with a potassium of 2.9 is given 1mEq/kg replacement show the serum K to be 3.0. Give dx.
Hypomagnesemia
Will change serum potassium
Alkalosis
Measurement of total calcium levels. Adjust total serum calcium down by __________ for every 1g/dL decrease in labumin.
0.8mg/dL
Formula for serum calcium albumin computation (2.0 albumin & 6.6 calcium)
0.8 x 2 = 1.6 + 6.6 = 8.2
Caused by intracellular shift of phosphate in association with respiratory alkalosis, insulin therapy & refeeding syndrome.
Acute Hypophosphatemia
Occurs when excess calories are given to a starved person. Potentially lethal condition that occur with rapid and excessive feeding of patients with severe underlying malnutrition.
Refeeding syndrome
Associated with hyperkalemia & hyperphosphatemia
Rhabdomyolysis
Hypomagnesemia clinically resembles with
Hypocalcemia
Is essential for proper function of many enzyme systems. Depletion is characterized by neuromuscular and CNS system.
Magnesium ion
A patient presents obtunded to the ER with ff labs Na 130 Cl 105 K 3.2 HCO3 15. What is the most likely diagnosis?
GI losses
Formula of Anion Gap
AG= (Na) - (Cl+HCO3)
Best choice to replace isotonic(serum) fluid loss. Best approximates serum electrolytes and would be the fluid of choice to replace isotonic serum fluid loss.
Lactated ringer
First treatment administered to a patient with a potassium level of 6.3 and flattened P waves on either ECG
Insulin & Glucose
Potassium can be removed from the body using a cation exchange resin such as this that binds potassium in exchange for sodium
Kayexalate
Approximate IV rate maintenance fluids for a 50kg patient would be
90 mL/hr
