Fluids and electrolytes Flashcards
(166 cards)
1
Q
Name two hypotonic solutions
A
0.45% NaCl
D5W
2
Q
Name 3 isotonic solutions
A
NaCl 9%
LR
Plasmalyte A
3
Q
What is the tonicity of plasma?
A
285
4
Q
What are 3 isotonic colloids?
A
Albumin 5%
Voluven 6%
Hespan 6%
5
Q
which isotonic colloid has the highest osmalarity?
A
Hespan 6% (309)
6
Q
What is the osmalrity of NaCl 0.9%?
A
308
7
Q
What is the osmalrity of albumin
A
300
8
Q
What hypertonic solution has the highest osmalrity and what is the osmalarity?
A
NaCl 3%
1026
9
Q
Name hypertonic solutions
A
3% NS
D5 NS 0.9%
D5 NS 0.45%
D5 LR
10
Q
Name the hypertonic colloid
A
Dextran 10% 350
11
Q
Giving hypotonic fluid has what effect on extracellular fluid and intacellular fluid
A
Increases ECF
Increases ICF
Decreases plasma osmalarity
12
Q
A patient with an elevated ICP should never receive what type of IV fluid?
A
hypotonic
13
Q
D5W is osmotically active but is metabolized when administered. What byproducts does it produce and what is the clinical significance?
A
Breaks down into CO2 and water
Although initially active, the metabolism produces free water, making D5W hypOtonic
14
Q
How long to isotonic crystalloids stay in the plasma?
A
about 30 minutes
15
Q
The lactate in LR serves as a ___ and is converted to ___ by the liver
A
buffer; bicarbonate
16
Q
Which isotonic crystalloid is better for large volume resuscitation and why?
A
LR is the preferred choice for large volume; NS can lead to hyperchloremic metabolic acidosis
17
Q
Giving an isotonic solution ___ the ECF, but the ICF and plasma osmalarity _____
A
Increases; remains the same
18
Q
what crystalloid is typically avoided when diluting blood products? Why?
A
LR; due to calcium content (textbook answer/not clinically significant
19
Q
Isotonic solutions increase/decrease/remain the same for the following compartments:
ECF
ICF
Plasma volume
Plasma osmolarity
A
ECF: increases
ICF: same
Plasma volume: increase
Plasma osmolarity: same
20
Q
Hypertonic solutions increase/decrease/remain the same for the following compartments:
ECF
ICF
Plasma volume
Plasma osmolarity
A
ECF: increases
ICF: decreases
Plasma vol: increases
Plama osmolarity: increases
21
Q
What complication can occur if serum sodium rises too quickly while administering hypertonic solutions?
A
Central pontine myelinolysis
22
Q
What colloid is useful for reducing blood viscosity in microvascular surgery?
A
Dextran 40
23
Q
What is the replacement ratio for crystalloids vs. colloids?
A
Crystalloid 3:1
Colloid 1:1
24
Q
What colloid has anti-inflammatory properties
A
albumin
25
Which class of fluid expands the ECF and restores 3rd space loss?
crystalloids
26
How long do colloids expand the plasma volume?
3-6 hours
27
Will crystalloids or colloids cause less peripheral edema?
Colloids are associated with less peripheral edema
28
What colloid is associated with hypocalcemia
albumin.. binds Ca++
29
From highest to lowest, rank the following colloids based on their likelihood of causing coagulopathy. What is the max volume recommended to avoid this?
Hextend
Hetastarch
Dextran
Voluven
Dextran>Hetastarch>Hextend
**voluven is NOT associated with coagulopathy**
20ml/kg
30
What is the black box warning on synthetic colloids?
risk of renal injury
31
What colloid has the highest anaphylactic potential?
dextran
32
how long do crystalloids expand the plasma volume?
20-30 min
33
what fluid class (crystalloid/colloid) is more likely to dilute coagulation factors?
Crystalloids
34
What colloid is the *only* colloid derived from human blood products? Does it contain antibodies? Increased infection risk?
Albumin; No; No
35
what is the normal range for serum K+
3.5-5.5 mEq/L
36
Hypokalemia ____ membranes, while hyperkalemia _____ membranes
hyperpolarizes, depolarizes
37
What is responsible for maintaining the intracellular distribution of potassium?
Na/K/ATPase pump
38
what organ is the most important for regulating potassium homeostasis? n
Kidney
39
What is the most important ion in repolarization of neural tissue and muscle cells?
Potassium
40
a patient with hypoaldosteronism would be expected to have a ____ serum potassium
increased
41
A patient taking beta blockers could be at risk for ____ serum potassium
increased
42
A patient taking albuterol would be at risk for a ____ serum potassium
decreased
43
A patient with Zollinger-Ellison syndrome is at risk for a ____ serum potassium
decreased
44
Licorice can cause what pseudo syndrome and what electrolyte imbalance is it associated with?
Pseudo-Conn's syndrome; hypokalemia
45
What 3 drugs are named that can impair potassium excretion
NSAIDS
Spironolactone
Triamterene
46
hyperventilation will have what effect on serum potassium?
Decrease
47
cramps, weakness, paralysis are all associated with ____.
hypokalemia
48
Hyperkalemia presents as
cardiac rhythm issues
49
a serum potassium of 5.5-6.5 you would expect to see what EKG finding?
Peaked T-waves
50
a serum potassium of 6.5-7.5 you would expect to see what EKG finding?
P wave flattening, PR prolonged,
51
a serum potassium of 7-8 you would expect to see what EKG finding?
QRS prolongation
52
a serum potassium >8.5 you would expect to see what EKG finding?
Sine wave -> Vfib
53
What findings would you expect to find on an EKG for a patient who is hypokalemic
PR prolonged
QT interval prolonged
Flattened T wave
U wave
54
What is the most common electrolyte imbalance in clinical practice?
hypokalemia
55
What percentage of K+ is stored inside cells
98%
56
Treating hypokalemia with supplementation is potentially fatal with what etiology?
Intracellular redistribution
* insulin
* hyperventilation
* HCO3-
* Beta agonist
* Hypokalemic periodic paralysis
57
what is the treatment for hyperkalemia
* Membrane stabilization: Ca++
* Redistributon: Insulin and D50, hyperventilation
HCO3-, Beta 2 agonist
* Elimination: K+ wasting diuretics, Kayexelate, dialysis
58
Max rate for Potassium through an IV in mEq/hr
Max rate for Potassium through a central line in mEq/hr:
IV: 10 mEq/hr
CVL: 20mEq/hr
59
what should happen prior to treating hyperkalemia
confirm lab specimen was not hemolyzed (make sure it's not pseudohyperkalemia)
60
The movement of a **substance** from an area of high concentration to an area of low concentration with a fully permeable membrane
diffusion
61
The movement of **water** across a semipermeable membrane. Water movement driven by solute concentration and moves from high concentration to low concentration
osmosis
62
When there is a semipermeable membrane what structure helps move solutes across the membrane?
Carrier proteins
63
what types of membranes seperate the bodies compartments?
Semipermeable membranes
64
The pressure of a solution against a semipermeable membrane that prevents water form diffusing across that membrane
Osmotic pressure
65
66
What does **not** effect osmotic pressure in regards to osmotically active particles in solution
molecular weights
67
Osmalarity units
osmoles per liter of **solution**
mOsm/L of **total solution**
68
Osmolality units
Osmoles per Kg of **solvent**
mOsm/kg of H20
69
What is the most important determinant of plasma osmalarity
Na+
70
What is the formula for plasma osmalarity?
Osmolarity= 2 [Na+] +(Glu/18) + (BUN/2.8)
71
Hyperglycemia and hyperuremia have what effect on plasma osmalrity?
Increased
72
Rank the following fluids (1-4) from highest to lowest osmolarity
* Albumin 5%
* D5+ NaCl 0.45
* D5W
* NaCl 3%
1. NaCl 3%
2. D5 + NaCl 0.45%
3. Albumin 5%
4. D5W
73
Hyponatremia correction with 3% NS should be carefully titrated to not increase serum sodium by more than ____ mEq/L/Hr
1-2 mEq/L/hr
74
Rapid correction of hypOnatremia can cause
central pontine myelinolysis
75
Rapid treatment of hypERnatremia can cause fluid shift from ____ to ____ and can produce what complication
ECF to ICF
Cerebral edema
76
List 5 ways that potassium is eliminated in the GI tract
1. Vomiting/diarrhea
2. Nasogastric suctioning
3. Zollinger-Ellison syndrome
4. Jejunoileal bypass
5. Kayexelate
77
A patients preoperative serum sodium is 130 mEq/L what should you do?
a. Replace the sodium
b. Do nothing.. procede as normal
c. Delay the surgery
C. Delay surgery
78
What is the most abundant extracellular cation?
Sodium
79
Normal serum sodium
135-145
80
What is the most important ion during the depolarization of neural tissue and muscle cells?
Na+
81
Name 3 things that regulate sodium homeostasis
1. GFR
2. RAAS
3. Antinatretic peptides (BNP)
82
Causes of hyponatremia associated with a decreased TOTAL Na+ content
Diuretics
salt wasting disease
hypoaldosteronism
83
Causes of hyponatremia associated with a normal total body Na+ content
SIADH
hypothyroidism
water intoxication
perioperative stress
84
Causes of hyponatremia associated with an increased total body Na+ content
CHF
Cirrhosis
85
A patient is experiencing N/V and malaise. They have a diagnosis of hyponatremia. What would you expect the serum sodium to be?
125-129
86
A patient with hyponatremia and a serum sodium in the ____ range may have no signs or only very mild signs
130-135
87
A serum sodium of ____ (range) is associated with headache, lethargy, and altered LOC
115-124
88
A serum sodium of 115 or less is associated with
* Seizures
* Coma
* Cerebral edema
* Respiratory arrest
89
Causes of hypernatremia with a decreased total body Na+ content
Osmotic diuresis
N/V
Adrenal insufficiency
90
Causes of hypernatremia with a normal total body Na+ content
DI
Renal failure
Diuretics
91
Causes of hypernatremia with an increased total body Na+ content
hyperaldosteronism
increased Na+ intake (3% NS)
92
What symptoms are associated with a serum osmolality of 350-375
* headache
* agitation
* confusion
93
What symptoms are associated with a serum osmolality of 376-400
* weakness
* tremors
* ataxia
94
What symptoms are associated with a serum osmolality of 401-430
* hyperreflexia
* muscle twitching
95
What symptoms are associated with a serum osmolality of 431or more
* seizure
* coma
* death
96
What is the plasma volume of a 70kg male
3L
97
In a 70kg male water represents about ____ % total body weight which is equal to ____ L
60% ; 42L
98
what two compartments can can total body water be divided into? What percentages of total body weight do these represent?
Intracellular volume 40%
Extracellular volume 20%
99
What are the major ions associated with intracellular volume
K+, Mg2+, PO4 -2 ,
100
what are the major ions associated with extracellular volume
Na+, Ca2+, Cl-
101
Extracellular volume can further be divided into 2 compartments. What are these two compartments, and what percentage of total body weight do they represent
Interstitial fluid 16%
Plasma 4%
102
What is the difference in TBW % in neonates compared to adults
Neonates have a higher TBW% by weight
103
What special populations have a lower TBW % by weight
Obese, females, and the elderly
104
what are the starling forces that move fluid FROM the capillary TO the interstitial space
Pc = capillary hydrostatic pressure (pushes fluid out)
πif = interstitial oncotic pressure (pulls fluid out of capillary)
105
What forces move fluid move fluid from the interstitial space into the capillary
Pif= interstitial hydrostatic pressure (pushes fluid into the capillary)
πc= capillary oncotic pressure (pulls fluid into the capillary)
106
What is the equation for the net filtration pressure
Net filtration pressure= (Pc - Pif) - (πc - πif)
107
NFP > 0 = ?
filtration (fluid exits capillary)
108
NFP < 0 = ?
Reabsorption (fluid is pulled into the capillary)
109
Are erythrocytes considered part of the extracellular compartment or intracellular compartment?
Intracellular compartment
110
110
Blood volume is the sum of what two volume %s
Plasma volume 60%
Blood cell volume 40%
111
Define hematocrit
The fraction of blood volume (plasma + blood cell volume) that is occupied by erythrocytes
112
What can increase Hct
increased number of RBCs
decreased plasma volume
113
what factors can decrease Hct
decreased RBC (anemia)
incrased plasma (hypervolemia/hemodilution)
114
Interstitial fluid is a gel that is made up of fluid and
proteoglycan filaments
115
There is greatest risk of chylothorax during a ____ internal jugular cannulation
Left
116
Where do the thoracic ducts join the venous circulation?
At the juncture of the subclavian vein and internal jugular
117
The thoracic duct is larger on which side?
left
118
How does the lymphatic system create negative pressure
Lymph is moved forward with a vessel network linked by one way valves
119
what is the function of the lymphatic system
To remove fluid, protein, bacteria, and debris that has entered the interstitium
120
Calcium is responsible for what phase of the cardiac myocyte action potential
Phase 2 (plateau phase)
121
Acidosis causes what change in ionized calcium and why?
Increased iCa2+
Acidosis increases H+ ions, which bind to albumin and displace Ca2+. Albumin is a Ca2+ reservoir
122
Calcium is what factor in the coagulation pathway?
Factor 4
123
Normal plasma calcium (total)
* 8.5-10.5 mg/dL
* 4.5-5.5 mEq/L
* 2.12-2.62 mmol/dL
124
Normal ionized calcium
* 4.65-5.28 mg/dL
* 2.2-2.6 mEq/dL
* 1.16-1.32 mmol/dL
125
# Calcium distribution
% ionized
% bound to albumin
% bound with an anion
* 50% ionized
* 40% bound to albumin
* 10% bound to anion
126
What is the most abundant electrolyte in the body?
calcium
127
The main reservoir for calcium is
bone
128
Calcium antagonizes what electrolyte at the NMJ
Magnesium
129
List the important functions of Calcium in the body
Second messenger systems, neurotransmitter release, muscular contraction
130
Increased parathyroid hormone will cause what change in serum Ca2+ concentration
Increased serum calcium
131
An elevated serum calcium level will result in what feedback mechanism
Thyroid gland will release calcitonin and osteoclast activity will be inhibited. Kidneys will reduce calcium reabsorption and calcium levels in blood will decrease
132
A decreased serum calcium level will cause what feedback mechanism
parathyroid hormone will be released from parathyroid gland. Osteoclasts release Ca2+ from bone. Ca2+ will be reabsorbed from the kidneys. Ca2+ reabsorbed in the small intestine via vitamin D synthesis. Final result= increased serum Ca2+
133
Chvostek and Trousseau sign are both indicative of what electrolyte imbalance
hypocalcemia < 8.5mg/dL
134
Hypocalcemia EKG findings
Long QTi
135
Hypercalcemia EKG findings
QTi shortened
136
Causes of hypocalcemia
* Hypoparathyroidism
* Vit D deficiency
* Renal osteodystrophy
* Pancreatitis
* sepsis
137
Causes of hypercalcemia >10.5 mg/dL
* hyperparathyroidism
* Cancer
* Thyrotoxicosis
* Thiazide diuretics
* immobilization
138
What presenting symptoms would you expect to see with hypercalcemia
* Nausea
* abdominal pain
* hypertension
* psychosis
* mental status changes/seizures
139
What presenting symptoms would you expect to see with hypocalcemia
* Skeletal muscle cramps
* Nerve irritability->parastesia tetany
* laryngospasm
* mental status changes -> seizures
* Chvostek sign
* Trousseau sign
140
How do you treat hypercalcemia and hypocalcemia?
hyper: 0.9% NaCl and loop diuretics
Hypo: Calcium and Vitamin D
141
How to test for Chvostek sign and what findings are positive
Tap on angle of the jaw (facial nerve and masseter muscle)
positive -> facial contraction on the ipsilateral side
142
How to test for Trousseau sign and what indicates postive test
BP cuff inflated above SBP on upper extremitity for 3 min --> muscle spasms of hand and forearm = positive
143
Loss of deep tendon reflexes is most likely a sign of what electrolyte imbalance?
hypermagnesemia
144
Normal plasma magnesium
| mg/dL and mEq/L
1.7-2.4 mg/dL
1.5-2.1 mEq/L
145
What percentage of magnesium is in the ECF
1%
146
The majority of magnesium in the body is found where?
Intracellular: Muscle and bone
147
Magnesium antagonizes ____ at the neuromouscular junction,etc.
Calcium
148
Magnesium is required for ____ synthesis
DNA
149
Where is the majority of magnesium reabsorbed
renal tubules
150
Describe the management of pre-E with magnesium
4g Load IV over 10-15 min followed by 1g/hr for 24 hours
151
Neonates are at risk for respiratory depression, hypotension, and hypotensive if mother's magnesium infusion is longer than
a. 24hrs
b.36 hrs
c. 72 hrs
d. 48 hrs
48hrs
152
Magnesium clinical uses (4)
1. Pre-E
2. opioid sparing technique (NMDA receptor antagonism)
3. acute bronchospasm
4. Cardiac rhythm disturbances (torsades)
153
Causes of hypomagnesemia (5)
* poor intake
* alcohol abuse
* diuretics
* critical illness
* common with hypokalemia
154
Causes of hypermagnesemia
excessive administration
renal failure
adrenal insufficiency
155
EKG findings for hypomagnesemia
Must be very low*
Long QT
156
Ekg for elevated mag
very high -> heart block
157
Treatment for hypermagnesemia
Calcium chloride/gluconate
158
hypomagnesemia treatment
mag supplementation
159
A patient with a Mg of 5-7 mg/dL or 4.2-5.8 mEq/L would likely show what clinical symptoms?
* Diminished DTR
* Lethargy/drowsiness
* Flushing
* N/V
160
A patient with a Mg of 7-12 mg/dL or 5.8-10 mEq/L would likely show what clinical symptoms?
* Loss of DTR
* hypotension
* EKG changes
* Somnolence
161
A patient with a Mg of > 12 mg/dL or > 10 mEq/L would likely show what clinical symptoms?
* Respiratory depression
* apnea
* complete heart block
* cardiac arrest
* coma
* paralysis
162
A patient with a Mg <1.2 or <1 mEq/L would likely show what clinical symptoms?
* Tetany
* seizures
* dysrhythmias
163
A patient with a Mg of 1.2-1.8 mg/dL or 1- 1.5 mEq/L would likely show what clinical symptoms?
* Neuromuscular irritability
* hypokalemia
* hypocalcemia
164
What commonly used anesthetic drugs can hypermagnesemia potentiate?
Succinylcholine and nondepolarizing neuromuscular blockers
165
