Fluid, electrolytes and imbalances Flashcards
1
Q
What are common anions in the body
A
Cl- and HCO3-
2
Q
What are anions involved in? In which organs?
A
acid base regulation in the kidneys and lungs
3
Q
What would you adjust sodium and bicarb levels based on
A
serum pH
4
Q
What can the electrolytes tell you about a patient?
A
- volume status
- acid base status
- renal function
5
Q
What is osmolality measured in
A
mOsmol/L
6
Q
What is omolality
A
concentration of solutes per liter of solution (sodium, potassium, glucose, urea)
7
Q
What would increased serum osmolality suggest?
A
volume depletion and concentration of electrolytes
8
Q
what would decreased serum osmolality suggest?
A
volume overload and dilution of electrolytes
9
Q
What is normal intake/output of water in a normal adult
A
1600 in 1600 out
10
Q
What controls the H2O balance in the body
A
antidiuretic hormone
11
Q
Where is ADH secreted
A
posterior pituitary
12
Q
What causes dysnatremias
A
malfunction of the feedback mechanism within the kidneys
13
Q
What is third spacing
A
when there is a large volume of fluid from the intravascular compartment that shifts into an interstitial space
14
Q
When is third spacing seen
A
trauma, burns, sepsis, ascites, pleural effusion
15
Q
What are colloids? Where do they remain?
A
solutions that do not cross the cell membrane because they are too big so they remain in the intravascular compartment
16
Q
What are examples of colloid solutions
A
- albumin solutions
- hypertonic starch
- dextran
- gelatin
17
Q
What do colloid solutions do
A
expand the intravascular volume and draw fluid from the extravascular spaces via higher oncotic pressure
18
Q
What are crystalloids
A
solutions that contain small molecules that easily pass through cell membrane
19
Q
Where do crystalloid fluids increase fluid volume
A
both the intersitial and intravascular space
20
Q
What is an isotonic solution
A
has the same concentration of solutes in the blood so the cells content stays the same
21
Q
What are hypotonic solutions
A
has lower concentration of solutes so solution moves into cells causing them to swell
22
Q
What are hypertonic solutions
A
have a higher concentration of solutes so solutions pull fluid from the cells so they shrink
23
Q
What are the isotonic IV fluids
A
- normal saline
- lactated ringers
- ringers solution
- D5W
24
Q
Indications for giving normal saline
A
LOW INTRAVASCULAR VOLUME
- dehydration
- severe vomiting/diarrhea
- mild hyponatremia
- hemorrhage
- shock
- metabolic acidosis
25
What is the only IV fluid that can be given with blood products
normal saline
26
What to lactated ringer mimic?
the blood and plamsa concentration
27
What electrolytes are in lactated ringers
sodium, potassium, chloride, bicarb
28
When are lactated ringers indicated?
- diarrhea/vomiting
- drainage from fistula
- fluid loss due to burns
- metabolic acidosis
29
When should you not give lactated ringers? Why?
- liver disease (cant metabolize lactate)
- lactic acidosis (contains lactate)
- pH greater than 7.5
- caution with renal impairment (contains K)
30
What is the difference between ringers solutions and lactated ringers?
presence of lactate
31
When would you give ringers solution?
-contraindication to giving lactated ringers
lactic acidosis, liver disease
32
What effect does D5W have on blood products
hemolysis
33
What happens to D5W when it gets metabolized
becomes hypotonic-->fluid shifts into cells
34
Which solutions are considered hypotonic
- 2.5 dextrose
- 0.45 normal saline (half normal)
- 0.33/0.2 NaCl
35
When are hypotonic solutions indicated
-patients with conditions causing intracellular dehydration
hypernatremia, DKA, hyperosmolar hyperglycemia
36
When should you use cautions with hypotonic solutions
- dehydration
- hypotension/hypovolemia
- liver disease
- trauma
- burns
- increased risk for ICP
37
What are examples of hypertonic solutions
- 3/5% NaCl
| - concentrated dextrose >10%
38
What are the complications of giving hypertonic fluids
- fluid overload
| - pulmonary edema
39
When are hypertonic solutions indicated
- severe hyponatremia
| - dehydration
40
What do dysnatremias have to do with
hydration status more so than circulating sodium
41
When is hyponatremia considered severe
<120
42
What is hyponatremia classified as moderate
120-129
43
When is hyponatremia considered mild
130-134
44
What are some causes of hyponatremia
- heart failure
- cirrhosis
- renal failure
- aggressive IVFs
- hyperglycemia
- hypertonic mannitol administration
- SIADH
- chronic ETOH
- water intoxication
45
Cut off for acute hyponatremia
48 hours
46
Does acute or chronic hyponatremia have more complications
acute
47
What are the most important determinants of the onset of hyponatremia sx
degree of hyponatremia and how fast it develops
48
If Na+ falls below 125-130 what clinical signs will you see
nausea, malaise
49
If Na+ falls below 115-120 what clinical signs will you see
- HA
- lethargy
- obtunded/coma
- seizures
- respiratory arrest
- pulmonary edema
50
What can excess overcorrection cause in hyponatremic patients
osmotic demyelination syndrome
51
What are the parameters for correction of sodium levels
raise serum sodium concentration by 4-6 mEq/L in a 24 hr period
52
How do you correct a patient with an Na+ <130 and asymptomatic
30 mL bolus 3% saline and remeasure Na+ hourly
53
How do you correct a patients with Na+ <130 and symptomatic
100 mL bolus of 3% saline, if sx persist 2 more 100 mL bolus in 30 minute period
54
What is the most common cause of hypernatremia
volume depletion
55
Disease states that can cause hypernatremia
- diabetes insipidus
- primary hyperaldostteronism
- altered thirst mechanism (psych pts)
56
Signs and sx of hypernatremia
- AMS
- ataxia
- seizures
- hyperreflexia
- irritability
- lethargy
57
How do you manage a pt with hypernatremia
D5W 3-6 mL/kg/hr until Na+ <145
THEN
decrease infusion to 1 mL/kg/hr until 140
58
Why do we need potassium
cell metabolism
neurologic and cardiac electrical transmission
59
What are the main regulators of K+
kidney
60
What are the most common causes of hypokalemia
- diuretic therapy
- diarrhea/vomiting
- medications
- hypomagnesemia
- hyperaldosteronism
61
Signs and sx of hypokalemia
- muscle weakness/cramping
- respiratory muscle weakness
- palpitations
- ileus/constipation
- fatigue
62
What do the sings and sx of hypokalemia typically manifest
K+ less than 3.0
63
Hypokalemia on EKG
- flat T waves
- S T segment depression
- formation of U waves
64
Treatment of hypokalemia
- mild treated with oral KCL
| - severe and symptomatic IV drip no more than 10 mEq/hr
65
If ___ is low it must be replaced before K+ replacement. Why?
magnesium, it plays a big role in regulation of the Na+K+ATPase pump
66
What is the most common complication seen in renal disease
hyperkalemia
67
What medications can cause hyperkalemia
- ACE inhibitors
- ARBs
- aldosterone antagonists
68
Clinical manifestations of hyperkalemia
- muscle weakness/paralysis
- parasthesias
- cardiac conduction abnormalities
69
Hyperkalemia on EKG
- tall or peaked T waves
- widened/bizarre QRS
- flat P wave
70
Treatment of hyperkalemia
- IV calcium gluconate or chloride (FIRST)
- IV hypertonic glucose w/ regular insulin
- IV diuretic
- dialysis
- Kayexalate
71
What are factors that can influence serum calcium concentration
- PTH
- vitamine D
- calcium ion
- phosphate
72
Common causes of hypocalcemia
- parathyroid disease
- thyroid disease
- thyroid or parathyroid ectomy
- chronic renal failure
- vitamin D deficiency
73
What can cause pseudohypocalcemia? Why?
hypoalbuminemia because Ca+ is bound to albumin in serum
74
What are the symptoms of hypocalcemia
- parasthesias
- hyperreflexia
- tetany
- muscle cramps/spasm
- seizures
75
Classic physical exam findings for hypocalcemia
- Chvostek sign (facial spasm)
| - Trousseau's sign (hand spasm)
76
Hypocalcemia on EKG
prolonged QT
77
Treatment of hypocalcemia
| mild and severe
-oral Ca+ if asymptomatic
If severe
-IV calcium gluconate 1-2 g over 20 mins followed by Ca+ infusion of 0.5-1.5 mg/kg/hr
78
What are the most common causes of hypercalcemia
- hyerparathyroid
| - bone malignancy (multiple myeloma)
79
Signs and sx of hypercalcemia
- bone pain
- muscle weakness
- nephrolithiasis
- lethargy
- confusion
- constipation
- fatigue
- depression
- nausea
80
Treatment of hypercalcemia
- volume expansion with isotonic saline
- salmon calcitonin w/ bisphosphenate
- zoledronic acid
81
What are magnesium levels regulated by
- intestinal absorption
| - renal excreption
82
Causes of hypomagnesemia
- chronic ETOH
- reduced intestinal absorption
- increased renal excretion
- excessive GI loss
- starvation/refeeding syndrome
83
Signs and sx of hypomagnesemia
- lethargy
- confusion
- tremors/convulsions
- hyperrflexia
- parathesisas
- cardiac arrhythmias
84
Hypomagnesemia on EKG
- widened QRS
| - ST segments prolongation and depression
85
Treatment of hypomagnesemia. Mild and severe
- mild: oral replacement with magnesium salts
| - severe: 1-2 g of IV mag sulfate
86
What can oral magnesium salts cause
osmotic diarrhea
87
When is hypermagnesemia seen
- renal failure patients
- supratherapeutic replacement
- antacid abuse
88
Signs and sx of hypermagnesemia
- decreased deep tendon reflexes
- bradycardia
- hypotension
- flaccid paralysis
- cardiac arrest
- nausea/headache
- hypocalcemis
89
Hypemagnesemia on EKG
- tall T's
- widened QRS
- irregular conduction
- escape beats
90
Treatment of hypermagnesemia
- dietary restriction
- elimination of mag containing meds
- saline + loop diuretics
- dialysis
91
When is BUN increased? Decreased?
Increased: high protein diet, decrease in GFR, CHF
Decreased: liver disease, SIADH
92
Is BUN or creatinine a better indication of kidney function? Why?
Creatinine because it is excreted only by the kidney
93
Normal serum pH
7.35-7.45
94
What levels classify respiratory acidosis
pH <7.35 and PaCO2>45 mmHg
95
Treatment for respiratory acidosis
improve ventilation
96
What classifies respiratory alkalosis
pH >7.45 and PaCO2 <35mm Hg
97
What causes respiratory alkalosis? Treatment?
d/t hyperinflation
Tx depends on underlying cause
98
What classifies metabolic acidosis
pH <7.35 and HCO3 22 mEq/L
99
What causes metabolic acidosis? Tx?
d/t gain of acid of loss of base (excessive GI loss)
Tx by correcting the metabolic defect
100
What classifies metabolic alkalosis
pH >7.45 and HCO3 >26 mEq/L
101
What causes metabolic alkalosis? Tx?
d/t loss of acid and gain of base (vomiting, gastric suction)
Tx by correcting metabolic defect
