# CHAPTER 09- FLUIDS AND ELECTROLYTES.txt

The flashcards below were created by user scottmreis on FreezingBlue Flashcards.

1. What % of the total body weight is water?
• 1) Roughly 2/3 of total body weight is water (men)
• 2) infants have a little more body water
• 3) Women have a little less
2. What percentages are in which compartments?
• 1) 2/3 of water weight is intracellular (mostly muscle
• 2) 1/3 of water is extracellular
• 1- 2/3 of extracellular water is interstitial
• 2- 1/3 of extracellular water is plasma
3. What determines plasma/interstial compartment osmotic pressures?
Proteins determine plasma/interstitial compartment osmotic pressures
4. What determines intracellular/extracellular osmotic pressure?
Na determines intracellular/extracellular osmotic pressure
• 1) most comon cause is iatrogenic
• 2) first sign is weight gain
6. What cellular process can release a significant amount of H20
cellular catabolism
7. 0.9% normal saline:
Na 154 and Cl 154
8. Lactate Ringer's solution:
• 1) LR; ionic composition of plasma:
• 2)
• Na-130
• K-4
• Ca- 2.7
• Cl- 109
• Bicarb- 28
9. Formula for plasma osmolarity:
(2 x Na)+(glucose/18)+(BUN/2.8)

Normal= 280-295
10. Estimates of volume replacement:
• 1) 4cc/kg/h for 1st 10kg
• 2) 2cc/kg/h for 2nd 10kg
• 3) 1cc/kg/hr for each kg after that
• 4) best indicator of adequate volume replacement is urine output
11. What is the fluid loss in open abdominal operations:
During open abdominal operations, fluid loss is 0.5-1.0L/h unless there are measurable blood losses
12. At what point do you need to replace blood loss?
usually do not have to replace blood loss unless it is >500cc
13. Insensible fluid losses:
• 1) 10cc/kg/day
• 1- 75% skin
• 2- 25% respiratory
• 3- pure water
14. IV replacement after major adult gastrointestinal surgery:
• 1) during operation and 1st 24 hours, use LR
• 2) After 24 hours, switch to D5 1/2 NS with 20mEq K
• 1- 5% dextrose will stimulate insulin release, resulting in amino acid uptake and protein synthesis (also prevents protein catabolism)
• 2- D5 1/2NS @ 125/h provides 150g glucose per day (525kcal/day)
15. GI fluid secretion:
• Stomach: 1-2L/day
• Biliary System: 500-1,000 ml/day
• Pancreas: 500-1,000 ml/day
• Duodenum: 500-1,000 ml/day
16. Normal K+ requirement:
Normal Na+ requirement:
• Normal K+ requirement: 0.5-1 mEq/kg/day
• Normal Na+ requirement: 1-2 mEq/kg/day
17. Electrolyte losses:
Sweat-
Saliva-
Stomach-
Pancreas-
Bile-
Small Intestine-
Large Intestine-
• Sweat- hypotonic
• Saliva- K+ (highest concentration of K+ in the body)
• Stomach- H+ and Cl-
• Pancreas: HCO3-
• Bile- HCO3-
• Small Intestine- HCO3-, K+
• Large Intestine- K+
18. What do you replace gastric losses with?
Gastric losses- replacement is D5 1/2NS with 20mg K+
19. What do you replace pancreatic/biliary/small intestine losses with?
replacement is LR with HCO3-
20. What do you replace Large intestine (diarrhea) losses with?
replacement is LR with K+
21. How is volume of GI losses replaced?
GI losses- should generally be replaced cc/cc
22. What should urine output be kept at?
Urine output- should be kept at least 0.5cc/kg/h; should not be replaced, usually a sign of normal postoperative diuresis
23. Potassium:
1) Normal: 3.5-5

• 2) Hyperkalemia- peaked T waves initial finding on EKG
• 1- calcium gluconate (membrane stabilizer for the heart)
• 2- sodium bicarbonate (causes alkalosis, K enters cell in exchange for H)
• 3- 10U insulin and 1 ampule of 50% dextrose (K driven into cells along with glucose)
• 4- kayexalate
• 5- dialysis if refractory
• 3) Hypokalemia- T waves disappear
• 1- may need to replace Mg+ before you can correct K+
24. Sodium:
1) Normal: 135-145

• 2) Hypernatremia- restlessness, irritability, ataxia, seizures
• 3) Correct with D5 water slowly to avoid brain swelling
• 4) Total free water deficit =
• 0.6 x patient's weight (kg) x [(Na+/140)-1]
• 5) Water Requirement:
• [desired change in Na+ over 1 day x TBW]/
• [desired Na+ after giving the water requirement]
• 1- TBW (total body water)= 0.6 x patient's weight (kg)
• 2- Change Na more than 0.7mEq/h (16mEq/day for below)
• 3- for the equation above, if the Na was 165 for a 70kg man: (16x42)/149= 4.5L

• 4) Hyponatremia- headaches, delirium, seizures, nausea,vomiting
• 1- Na deficit= 0.6 x (weight in kg) x (140-Na)
• 2- Water restriction is the first treatment of hyponatremia, then diuresis, then NaCl replacement
• 3- Correct Na slowly to avoid central pontine myelinosis (no more than 1mEq/h)
• 4- Hyperglycemia can cause pseudohyponatremia- for each 100 increment of glucose over normal, add 2 points to the Na value
• 5- SIADH results in hyponatremia
25. Calcium
• 1) Normal: 8.5-10; Normal ionized Ca- 4.4-5.5
• 2) Hypercalcemia (Ca usually >13 or ionized >6-7)- causes lethargic state
• 1- breast Ca most common malignant cause
• 2- no lactate ringer's (contains Ca2+)
• 3- no thiazide diurectics (these retain Ca2+)
• 4- Tx: NS at 200-300cc/h, Lasix
• 1- for malignant disease- mithramycin, calcitonin, aledronic acid, dialysis

• 3) Hypocalcemia (Ca usually <8 or ionized Ca <4)- 1- hyperreflexia
• 2- Chvostek's sign (tapping on face produces twitching)
• 3- perioral tingling and numbness
• 4- Trousseau's sign (carpopedial spasm)
• 5- prolonged QT interval
• 4) may need to correct Mg before being able to correct Ca
• 5) Protein adjustment for calcium- for every 1g decrease in protein, add 0.8 to Ca
26. Magnesium:
• 1) Normal: 2.0-2.7
• 2) Hypermagnesemia- causes lethargic state; burn, trauma, and renal dialysis patients.
• 1- Tx: calcium
• 3) Hypomagnesemia- signs similar to hypocalcemia
27. Metabolic Acidosis: (following slides):
28. Anion gap:
Anion gap = Na - (HCO3 + Cl)

Normal <10-15
29. Anion gap acidosis:
"MUDPILES"

• Methanol
• Uremia
• Diabetic ketoacidosis
• Paraldehydes
• Isoniazide
• Lactic acidosis
• Ethylene glycol
• Salicylates
30. Normal gap acidosis:
1) usually due to loss of Na/HCO3- (ileostomies, small bowel fistulas)
31. Treatment of metabolic acidosis:
• 1) keep pH > 7.2 with bicarbonate
• 2) Severely decreased pH can affect myocardial contractility
32. Metabolic alkalosis:
• 1) usually a contraction alkalosis
• 2) Nasogastric suction- results in hypochloremic, hypokalemic, metabolic alkalosis, and paradoxical aciduria
• 3) Loss of Cl- and H ion from stomach secondary to nasogastric tube (hypochloremia and alkalosis)
• 4) Loss of water causes kidney to reabsorb Na in exachange for K (Na/K ATPase), thus losing K+ (hypokalemia)
• 5) Na/H exchanger activated in an effort to reabsorb water along with K/H exchanger in an effort to reabsorb K--> results in paradoxical aciduria
33. Acid-Base Balance:
• Respiratory acidosis:
• pH: low
• CO2: high
• HCO3: high

• Respiratory alkalosis:
• pH: high
• CO2: low
• HCO3: low

• Metabolic acidosis:
• pH: low
• CO2: low
• HCO3: low

• Metabolic alkalosis:
• pH: high
• CO2: high
• HCO3: high
34. Henderson-Hesselbach equation:
pH= pK + log [HCO3-]/[CO2]

Ratio of base to acid (HCO3- to CO2) of 20:1 = pH of 7.4
35. Acute renal failure:
FeNa = (urine Na/Cr) / (plasma Na/Cr) = best test for azotemia

• Prerenal:
• 1- FeNa <1%
• 2- urine Na<20
• 3) BUN/Cr ratio >20
• 4- Urine osmolality >500mOsm

70% of renal mass must be damaged before theres an increase in BUN + Cr
36. Contrast dyes-
1) volume expansion best prevents renal damage: HCO3- and N-acetylcysteine gtt
37. Myoglobin
• 1) converted to ferrihemate in acidic environment, which is toxic to renal cells
• 2) Tx: alkalinize urine
38. Tumor lysis syndrome:
• 1) release of purines and pyrimidines leads to increased PO4 and uric acid, decreased Ca
• 2) Can result in:
• 1- increased BUN and Cr
• 2- EKG changes
• 3) Tx:
• 1- hydration
• 2- diuretics
• 3- allopurinol (decreased uric acid production)
• 4- alkalinization of urine
39. Vitamin D
• cholecalciferol
• 2) made in skin (UV sunlight) from 7-dehydrocholesterol
• 3) goes to liver for (25-OH), then kidney for (1-OH). This creates active form of vitamin D
• 4) active form of vitamin D- increases calcium-binding protein, leading to increased intestinal calcium absorption
40. Chronic renal failure:
• 1) decreased active vitamin D (decreased 1-OH hydroxylation)--> decreases Ca reabsorption from gut (decreased Ca-binding protein)
• 2) Anemia- from low erythropoietin
41. See image on pg 42: Multiple effects of increased angiotensin II release in response to the stimulus of decreased extracellular volume
42. Transferrin:
transporter of iron
43. Ferritin
storage form of iron
 Author: scottmreis ID: 126424 Card Set: CHAPTER 09- FLUIDS AND ELECTROLYTES.txt Updated: 2012-01-07 22:58:05 Tags: ABSITE Folders: Description: ABSITE Show Answers: