What proportion of an adult male’s body is water?
2/3
How does the proportion of TBW in men compare to women and infants?
Women have less TBW, infants have more TBW
What proportion of water weight is intracellular (which cells) versus extracellular?
2/3 intracellular (mostly muscle) and 1/3 extracellular
What is the breakdown of the extracellular water?
2/3 interstitial, 1/3 plasma
Which compartment osmotic pressures are determined by protein?
Determines plasma / interstitial compartment osmotic pressures
Which osmotic pressures are determined by Na?
Intracellular / extracellular osmotic pressure
What is the MCC of volume overload?
Iatrogenic
What is the first sign of volume overload?
Weight gain
What molecule is released in significant amounts with cellular catabolism?
water
How many mEq/L of sodium is in NS?
154 mEq/L
How many mEq/L of sodium is in LR?
130 mEq/L
How many mEq/L of sodium is in plasmalyte?
140 mEq/L
what is the pH of plasmalyte?
7.4
How many mEq/L of potassium is in LR?
4 mEq/L
How many mEq/L of potassium is in plasmalyte?
5 mEq/L
How many mEq/L of potassium is in NS?
0 mEq/L
How many mEq/L of calcium is in NS?
0 mEq/L
How many mEq/L of calcium is in LR?
3 mEq/L
How many mEq/L of calcium is in plasmalyte?
0 mEq/L
How many mEq/L of Magnesium is in NS?
0 mEq/L
How many mEq/L of Magnesium is in LR?
0 mEq/L
How many mEq/L of Magnesium is in plasmalyte?
3 mEq/L
How many mEq/L of chloride is in NS?
154 mEq/L
How many mEq/L of chloride is in LR?
109 mEq/L
How many mEq/L of chloride is in plasmalyte?
98 mEq/L
How many mEq/L of lactate is in NS?
0 mEq/L
How many mEq/L of lactate is in LR?
28 mEq/L
How many mEq/L of lactate is in plasmalyte?
0 mEq/L
How many mEq/L of gluconate is in NS?
0 mEq/L
How many mEq/L of gluconate is in LR?
0 mEq/L
How many mEq/L of gluconate is in plasmalyte?
23 mEq/L
How many mEq/L of acetate is in NS?
0 mEq/L
How many mEq/L of acetate is in LR?
0 mEq/L
How many mEq/L of acetate is in plasmalyte?
27 mEq/L
What is the osmolarity in mOsm/L of NS?
308 mOsm/L
What is the osmolarity in mOsm/L of LR?
275 mOsm/L
What is the osmolarity in mOsm/L of plasmalyte?
294 mOsm/L
What is the pH of NS?
5.50
What is the pH of LR?
6.75
What percentage of insensible losses come from which organ system? (2)
75% skin, 25% respiratory
What fluid is lost through insensible losses?
pure water
Which crystalloid should be used intraop and 24 hours postop after major adult GI surgery?
LR
Which crystalloid should be used at > 24hours postop after major adult GI surgery and why?
D5 1/2NS + 20K. Dextrose stimulates insulin release, resulting in amino acid uptake and protein synthesis. Also prevents protein catabolism
How much glucose and calories are provided every 24 hours by D5-1/2NS + 20K @125cc/hr?
150g glucose / 525 kcal
How much fluid does the stomach produce per day?
1-2L / day
How much fluid does the biliary system produce per day?
500-1000cc/day
500-1000cc/day How much fluid does the pancreas produce per day?
500-1000cc/day
How much fluid does the duodenum produce per day?
500-1000cc/day
What is the normal K+ requirement in mEq/kg/day?
0.5-1.0 mEq/kg/day
What is the normal Na+ requirement in mEq/kg/day?
1-2mEq/kg/day
What is the [Na] in sweat
Hypotonic, [Na] = 35-65
What body fluid has the highest [K+] in the body?
Saliva
What electrolytes are in stomach fluid?
H+ and Cl-
What electrolytes are in bile?
bicarb
Which electrolytes are in small intestine secretions?
Bicarb, K+
Which electrolytes are in colonic secretions?
K+
Which crystalloid should you use to replace gastric losses?
D5-1/2NS + 20K
Which crystalloid should you use to replace pancreatic losses?
LR with bicarb
Which crystalloid should you use to replace biliary losses?
LR with bicarb
Which crystalloid should you use to replace small intestine losses?
LR with bicarb
Which crystalloid should you use to replace large intestine losses?
LR with K+
What ratio should you use to replace GI losses?
1:1 ratio (cc for cc)
What crystalloid should you use to resuscitate for dehydration?
NS
What is the minimal goal UOP? Should it be replaced?
0.5cc/kg/hr, no please do not replace
What is a normal serum concentration value for K+
3.5-5.0
How does hyperkalemia present on EKG?
Peaked T waves
What is the MC comorbidity with hyperkalemia
Renal failure
What are the four meds to treat hyperkalemia and what do they do?
Calcium gluconate (stabilizes cardiac membrane); sodium bicarb (alkalinity helps K go intracellular); 10U insulin (glucose + K into cells); 1 ampule D50 (prevents hyperglycemia); kayexelate (poo out K+)
What does calcium gluconate do to treat hyperkalemia?
Cardiac membrane stabilizer
What does sodium bicarb do treat hyperkalemia?
Causes alkalosis, then K enters the cell in exchange for H
What does the 10U insulin + 1 ampule D50 do for hyperkalemia
Insulin allows K to be driven into cells with glucose
What is the treatment for refractory hyperkalemia?
dialysis
What are the EKG findings in hypokalemia
T waves disappear
What is the MCC of hypokalemia?
overdiuresis
Which electrolyte do you usually have to replace in hypokalemia before you can correct K+?
Mg
What is the normal range for Na?
135-145
What is the MCC of hypernatremia?
dehydration
Name 3 symptoms of hypernatremia
Restlessness, irritablity, seizures
Which crystalloid do you use to correct hypernatremia?
D5W
Why do you need to correct hypernatremia slowly?
to prevent brain swelling
What is the MCC of hyponatremia?
fluid overload
Name 4 symptoms of hyponatremia
HA, N, V, seizures
How do you treat hyponatremia (first and second-line)
First-line: free water restriction; Second-line: diuretics
Why do you need to correct Na slowly?
To prevent central pontine myelinosis
What rate should you correct hyponatremia?
No more than 1meq/hr
How does hyperglycemia affect sodium measurements?
Hyperglycemia can cause pseudohyponatremia
How do you correct for hypergycemia causing pseudohyponatremia (formula)?
For each 100 increment of glucose above normal, add 2 points to Na value
How does SIADH affect Na concentrations?
Causes hyponatremia
What is the normal range for calcium?
8.5 – 10.0
What is the normal range for ionized calcium?
4.4-5.5
How high does Ca/iCa need to be to cause hypercalcemic symptoms?
Ca > 13 or iCa>6-7
What are the symptoms of hypercalcemia?
Lethargy
What is the MC malignant cause of hypercalcemia?
Breast CA
What is the MC benign cause of hypercalcemia?
Hyperparathyroidism
Which crystalloid is CI in hypercalcemia and why?
LR b/c it contains Ca2+
Which diuretic is contraindicated in hypercalcemia and why?
Thiazide diuretics b/c they cause Ca retention
What is the treatment for benign hypercalcemia?
NS @ 200-300cc/hr and Lasix
What is the treatment for malignant hypercalcemia (4)?
Mithramycin (antineoplastic drug), calcitonin, alendronic acid (bisphosphonate), dialysis
What are the Ca/iCa measurements for symptomatic hypocalcemia?
Ca < 8 or iCa <4
Name 5 S/Sx a/w hypocalcemia
Hyperreflexia; Chvostek’s sign (tapping on face produces twitching); Perioral tingling and numbness; Trousseau’s sign (carpopedal spasm); Prolonged QT interval
Which surgery can cause hypocalcemia postop?
parathyroidectomy
Which electrolyte may you have to replace prior to replacing Ca?
Mag
How do you adjust calcium for albumin levels?
For every 1g decrease in protein, add 0.8 to calcium
What are normal levels for magnesium
2.0 – 2.7
What are the symptoms of hypermagnesemia?
lethargy
What is the MC comorbidity a/w hypermagnesemia?
Renal failure patients taking Mg-containing products
What is the treatment for hypermagnesemia?
Calcium
Name three causes of hypomagnesemia
Massive diuresis; chronic TPN without mineral replacement; EtOH abuse
What are the S/Sx of hypomagnesemia (5)?
Hyperreflexia; Chvostek’s sign (tapping on face produces twitching); Perioral tingling and numbness; Trousseau’s sign (carpopedal spasm); Prolonged QT interval
How do you calculate anion gap?
Na – (HCO3 + Cl)
What is a normal anion gap?
<10-15
Name 8 causes of high anion gap acidosis
MUDPILES: methanol, uremia, DKA, paraldehydes, isoniazid, lactic acidosis, ethylene glycol, salicylates
What are two causes of normal anion gap acidosis
Loss of Na/HCO3- (ileostomies, small bowel fistulas)
What is the treatment of metabolic acidosis?
Treat underlying cause; keep pH > 7.20 with bicarb b/c acidosis can affect myocardial contractility
What is the MCC of metabolic alkalosis?
Contraction alkalosis (activation of RAA system causes angiotensin II to increase bicarb reabsorption and aldosterone causes increased H+ secretion)
What metabolic disturbance is caused by NG suction?
Hypochloremic, hypokalemic, metabolic alkalosis with paradoxical aciduria
What causes the hypochloremia and alkalosis a/w NG suction?
Loss of Cl- and H+ from the stomach
What causes the hypokalemia a/w NG suction?
Loss of water causes kidney to reabsorb Na in exchange for K+ (Na/K ATPase) causing loss of K+
What causes the paradoxical aciduria a/w NG suction?
Na/H exchanger is activated to reabsorb water and K, causes release of H+ and paradoxical aciduria
What is the treatment for the metabolic derangements a/w NG suction?
NS helps treat the Cl- deficit
what are the pH, CO2, and HCO3 derangements seen with respiratory acidosis?
low pH < 7.4, elevated CO2 > 40, elevated HCO3 > 24
what are the pH, CO2, and HCO3 derangements seen with respiratory alkalosis?
elevated pH > 7.4; low CO2 < 40; low bicarb < 24
what are the pH, CO2, and HCO3 derangements seen with metabolic acidosis?
low pH < 7.4; low CO2 < 40; low bicarb < 24
what are the pH, CO2, and HCO3 derangements seen with metabolic alkalosis?
elevated pH > 7.4; elevated CO2 > 40; elevated bicarb > 24
Define respiratory compensation for acid/base balance
CO2 regulation for acidosis/alkalosis
How much time does respiratory compensation take?
Minutes
Define renal compensation for acid/base balance
HCO3- regulation for acidosis / alkalosis
How much time does renal compensation take?
Hours to days
What is the best test for azotemia?
Fractional excretion of sodium
What is the formula for FeNa?
[(Urine Na*Plasma Cr) / (Urine Cr*Plasma Na)]
What percent of renal mass may be damaged before you see elevated BUN and Cr?
70%
What is the FeNa value for prerenal disease?
< 1%
What is the urine Na for prerenal disease?
< 20
What is the BUN/Cr ratio for prerenal disease?
> 20
What is the Urine osmolality for prerenal disease?
>500 mOsm
What is the best way to prevent contrast-induced renal damage?
Prehydration is the best, bicarb and N-acetylcysteine
What does myoglobin convert to in an acidic environment?
Ferrihemate in an acidic environment
What happens to renal cells when exposed to myoglobin
Myoglobin becomes ferrihemate, toxic to renal cells
How do you treat myoglobinemia and prevent renal damage?
Alaklanize urine
Define tumor lysis syndrome and what chemicals are released
Metabolic abnormalities that occur as a complication of cancer treatment, when tumor cells lyse and release their contents into the bloodstream. Releases purines, pyrimidines leading to increased PO4, increased uric acid, and decreased Ca
What are the renal effects of tumor lysis syndrome?
Increased BUN / Cr from renal damage
What are the cardiac effects of tumor lysis syndrome?
EKG changes
What are the five treatments for tumor lysis syndrome
Hydration is the best treatment; Rasburicase, allopurinol, diuretics, alkalanization of urine
What is the MOA of rasburicase
Converts uric acid to inactive metabolite allantoin
What is the MOA of allopurinol
Reduces uric acid production
What is the conjugation reaction of vitamin D in the skin
UV sunlight converts 7 dehydrocholesterol to cholecalciferol
What two reactions occur after conjugation of vitamin D in the skin?
Liver for 25-OH and then kidney for 1-OH to create active form of Vitamin D
What does the active form of vitamin D do?
Increases calcium-binding protein leading to increased intestinal calcium absorption
What happens to the vitamin D balance and Ca balance in the body with CRF?
Reduced active vitamin D b/c reduced 1-OH hydroxylation
Why does anemia result from CRF?
Reduced erythropoeitin
What is the function of transferrin?
Transporter of iron
What is ferritin?
Storage form of iron