Fluids & Electrolytes Flashcards
1
Q
ICF is _____of the human body, while ECF is ______
A
2/3
1/3
2
Q
The ECF compartment its composed of
A
80% interstitial fluid
20% plasma
3
Q
ICF compartment is rich in what electrolytes?
A
K+
Mg
Ca
Phos
Protein
4
Q
ECF compartment is rich ini what electrolytes?
A
Na
Cl
5
Q
Proteins & large molecules are prevented from free movement by
A
Vascular endothelial cell tight junctions
Endothelial glycocalyx layer
6
Q
The inflammatory state will increase the number of
A
Pores
7
Q
The inflammatory state will promote
A
Protein & macromolecule movement into the interstitial space, which can cause albumin to double (during surgery ~10% or more in sepsis ~20%)
8
Q
Characteristics of Static parameters
A
Read in real time
Less accurate
Vascular status can goo unrecognized
9
Q
Beta blockade can
A
Mask tachycardic response to hypovolemia
10
Q
CVP may be inadequate in determining..
A
Preload
Fluid Responsiveness
Pulmonary Edema Risk
11
Q
Inhalation anesthetics & surgical stress maay reduce
A
Urine output iin euvolemic patients
12
Q
Intraop oliguria, _______, does not
A
<0.5 ml/kg/hr
Predict AKI
13
Q
Mixed venous O2 saturation is intended to _________ & is proportional to________
A
Track global O2 delivery
Proportional to CO, tissue perfusion, & O2 delivery
14
Q
Mixed venous O2 saturation may
A
NOT reflect tissue perfusion changes when O2 consumption is variable (fever/sepsis)
15
Q
Characteristics of Dynamic parameters
A
More accurate
Preferred
Goal-directed
16
Q
Characteristics of respiratory variations
A
Variations in PPV, SVV, SBPV
Controlled mechanical ventilation
Vasomotor tone & cardiac function
17
Q
What is the normal variation with respirations?
A
<10-12%
18
Q
What does it mean in variations are Greater than 10-12%?
Less than?
A
Greater than means fluid responsiveness
Less than means vasopressor responsiveness
19
Q
What are the limitations to respiratory variations?
A
During spontaneous ventilation
Low TV/ High PEEP
Open thoracic surgery
Elevated intra-abdominal pressure
Tamponade
Arrhythmias
Right sided HF
Vasoactive infusions
20
Q
When do we use End-expiratory occlusion test?
A
Used in ventilated patients with arrhythmias, spontaneous ventilation or low TV
Ventilation is interrupted for 15sec
Assess for >5% increase in pulse pressure or pulse contour CO
21
Q
Fluid solution containing water-soluble electrolytes & low molecular weight molecules
A
Crystalloids
22
Q
Crystalloids are classified by
A
tonicity
23
Q
Isotonic & “balanced” crystalloids contain
A
Various levels of other electrolytes like K, Mg, & Cl
Contains organic anions (lactate, gluconate & acetate)
24
Q
Isotonic & Balanced Crystalloids are used to treat
A
ECF deficits
Administration of drugs & blood products
25
26
27
What are examples of isotonic/balanced crystalloids
0.9% NaCl
LR
Plasmalyte
Normosol-R
28
What is the strong ion difference?
Difference between completely dissociated cations & anions in the plasma
29
What is the normal SID?
~40mEq/L
30
Increased SID _____ the pH
Decreased SID _____the pH
Increased SID= Increased pH
Decreased SID= Decreased pH
31
What can happen with excessive 0.9% NS infusion?
Lactic Acidosis
Hyperchloremic Metabolic Acidosis
32
When Isotonic crystalloids are given, what percent remains intravascularly?
20-25% in the healthy patient
33
In healthy patients, volume of distribution approximates ________
Relative size of intravascular & interstitial compartments
33
Effective SID also takes into account
Bicarb & the anion equivalent of albumin & phosphate
34
When isotonic crystalloids are infused, what percent of the infused volume can be lost?
~50% cane lost in ~30min
35
Giving hypotonic crystalloids will
Reduce the osmolarity of the ECF, making the water redistribute to the intracellular compartment
35
Hypotonic crystalloid have a _____effective osmolality than the patient
Lower
36
Hypotonic crystalloids are used as
Maintenance fluids
Treat solute-free water deficits
Administration of drugs
37
What are examples of Hypotonic crystalloids
0.45%NaCl
5% Dextrose in water
Plasma-Lyte 56 (5% dex)
38
Hypertonic crystalloids have a _______ effective osmolality than the patient
Greater
39
Hypertonic crystalloids _______the osmolality of ECF
Increase osmolality of the ECF, which causes water to redistribute out of the intracellular compartment
40
Hypertonic crystalloids are used to target
A desired solute concentration
Promote fluid redistribution
41
Examples of hypertonic crystalloids
Dextrose 5% in NS
3-7.5% Saline
42
What should be kept in mind of the fasting period
Try to minimize it
42
What is the positive fluid balance goal?
1-2L at the end of surgery
43
Which resuscitation method is preferred?
Balanced
44
What is the risk of balanced salt administration?
Large volumes place the patient at risk for hyperlactatemiaa, metabolic alkalosis, & hypotonicity
45
Ca+ containing solutions risk
The formation of micro thrombi when they are administered with citrate-containing blood products
46
Colloids are
A fluid solution containing large molecular weight particles suspended in a crystalloid solution
47
How are colloids categorized?
Natural or Synthetic
48
What are examples of natural colloids?
Whole Blood
Plasma
Concentrated Albumin Solutions
49
What are examples of colloid synthetics/semi-synthetics?
Gelatins
Hydroxyethyl starch (HES) solutions
Dextrans
Polysaccharides
50
Albumin increases
Serum albumin & colloid osmotic pressure
51
Albumin is pasteurized to
Reduce the risk of viral transmission
52
Hydroxyethyl Starches are a
Variety of solutions with different concentrations, molecular weights & crystalloid carriers
53
HES solutions affects
Osmotic pressure, half life, & coagulation effects
54
What are the black box warnings of HES?
Critically ill/sepsis
Renal dysfunction or signs of renal injury after HES infusion
Open heart surgery w/CPB
Signs of coagulopathy after HES infusion
55
Dose of HES?
20-50ml/kg/day
56
What are the redistribution characteristics of HES?
Leaves the plasma
Temporary storage in the skin, liver, & kidneys
Trace amounts of HES detectable up to 6 months later
57
Adverse effects of HES
Decrease ion factor 8 & von Willebrand factor
Decreased PLT function
Impaired renal function (renal injury)
58
What happens once HES is really excreted?
Immediate glomerular filtration
Delayed filtration of large molecules
Hydrolysis in the plasma by alpha-amylase
Hydroxyethyl groups can slow the process
59
When are crystalloids used intraoperatively?
Routine
Replacement of senile & insensible losses
Replace blood loss
Optimize intravascular volume
60
What fluid can be used in renal patients?
NS
61
Which solution is typically avoided?
Dextrose containing solutions due to hyperglycemia risk
62
Colloids should be given in a ______ replacement
1:1
63
Colloids can be used to
Expand microvasacular volume with minimal capillary leakage iiii fluid responsive patients
64
When are colloids preferred?
In patients with fluid restrictions since it reduces the edema risks
65
What increases the risk of significant HOTN during induction?
Fasting
Bowel prep
Diuretics
Inflammatory disorders
Interstitial edema
Active hemorrhage
66
What surgical factor can lead to hypervolemia?
Excess crystalloid. colloid, or PRBC which dilutes coagulation factors leading to exacerbation of bleeding
67
What patient factors can lead to hypervolemia?
CHF with compensatory fluid retention
Renal insufficiency
68
General anesthesia can cause
Dose-dependent vasodilation, myocardial depression & HOTNN
69
Neuraxial anesthesia can cause
Sympathetic blockade with overload of IVF
70
What are the risk associated with fluid overload?
Reduced tissue perfusion r/t tissue edema
Impaired O2 exchange & respiratory dysfunction
GI edema, decreased motility, ileus, or ascites
Coagulopathy
71
What is a typical rate to infuse crystalloids, that supports fluid loss & metabolic rate?
3-5ml/kg/hr
72
What bolus should be given to help support respiratory variations >10-12%
250cc bolus crystalloid/colloid
73
The majority of Na is in the
ECF
74
What are the functions of Na?
Water movement/balance
Control of osmotic pressure
Osmolality & volum eof ECF
Nerve impulse conduction
Muscle contraction
75
Na excretion is stimulated by
parathyroid hormone & natriuretic peptides
76
Hyponatremia can be caused by
Hypervolemic causes (CHF & cirrhosis)
Hypovolemia causes (diarrhea, vomiting & diuretics)
Salt wasting (intracranial injury)
Euvolemic causes (adrenal insufficiency & polydipsia)
77
What are the symptoms of hyponatremia?
Cerebral edema
Confusion
Coma
N/V
Muscle cramps
78
Hypernatremia is caused by
Water loss
Nephrogenic/central diabetes insipidus
Excessive Na administration
79
Symptoms of hypernatremia
Signs of dehydration or fluid excess
Cellular death
AMS
Seizures
Coma
80
The majority of K+ is in
ICF
81
Function of K+
Cell membrane excitability (nerve, muscle & heart)
Kidney function
Endothelial-dependent vasodilator
Inhibits thrombus formation & PLT activation
Influences osmotic pressure
82
What hormones affect K+ secretion?
Aldosterone
Glucocorticoids
Catecholamines
Arginine vasopressin
83
Acidosis ______ K+ secretion
Decreases
84
Alkalosis ________ K+ secretion
Increases
85
Hypokalemia can be caused by
Diuretics
Beta Agonists
Insulin
Abx
Catecholamines
GI losses
86
Symptoms of hypokalemia
Skeletal muscle weakness
Muscle cramps
Rhabdomyolysis
Ileus
N/v
Abdominal distention
Dysrhythmias
87
What are the EKG characteristics with hypokalemia?
Hyperpolarization
Increased automaticity & excitability
T wave inversion
U wave
Tachyarrhythmias
Torsades
Afib
88
How do you treat hypokalemia?
K+ replacement PO/IV
10mEq/hr IV
20mEq/hr central line
89
K+ replacement in the setting of intracellular shifts
May cause hyperkalemia
90
Patients with diminished regulation of K+ like DM or renal failure have a
Higher risk of hyperkalemia
91
Hyperkalemia can be caused by
K+ redistribution or inhibition of secretion
Aldosterone antagonists
Beta antagonists
NSAIDs
Chemo
PRBC transfusion
92
Symptoms of hyperkalemia
Peaked T waves
QRS widens
Prolonged PR
Cardiac conduction blockade
Decreased automaticity
VF
Asystole
Paresthesias
Skeletal muscle weakness
93
How do you treat hyperkalemia?
Calcium IV ( not as fast)
Sodium bicarbonate 0.5-1mEq/kg IV
Insulin + glucose
Kayexalate
Beta agonists
Loops
94
Calcium IV will
rapidly repair adverse cardiac conduction & contractility effects
95
Sodium bicarbonate alkalinization will
shift K+ into the cells & promote secretion
96
Giving insulin + glucose when treating hyperkalemia can decrease serum K+ by
1.5-2.5 mEq/L
97
The majority of Mg is in
ICF (bone, muscle & soft tissue)
98
What are the functions of Mg?
Protein synthesis
Nucleic acid stability
Neuromuscular function
Muscle relaxation
Antiarrhythmic
Vasodilation
Stabilization of BBB
Limits cerebral edema
Decreases anesthetic requirements
99
Hypomagnesemia is caused by
diet
GI malabsorption
Renal losses
Citrate binding in massive transfusions
100
Symptoms of hypomagnesemia
Prolonged PR & QT
Diminished T wave
Torsades
Arrhythmias
Weakness
Tetany
Fasciculations
Convulsions
N/V
101
Hypermagnesemia is caused by
Excessive administration
102
Symptoms of hypermagnesemia
QRS widens
Conduction blockade
Asystole
HOTN
Respiratory depression
Muscle paralysis
Diminished reflexes
Narcosis
103
How to treat hypermagnesemia
Calcium glutinate 10-15mg/kg IV
Diuretics or dialysis
104
What is preeclampsia
A pregnancy disorder of HHTN, proteinuria & liver dysfunction
105
We give Mg to treat preeclampsia, since its MOA is to cause
Systemic, vertebral & uterine vasodilation
Increase concentration of endogenous vasodilators
Attenuate endogenous vasoconstrictors
106
What is the recommended dose of Mg in the treatment of preeclampsia?
4g loading dose + 1g/hr IV (24hrs)
107
What happens when Mg crosses the placenta?
Will have neonatal lethargy
HOTN
Respiratory depression
108
What arrhythmias can Mg treat?
Polymorphic wide complex tachycardias
Long QT syndrome
Digoxin induced tachyaarrhythmias
109
Mg is used during CPB/CABG since
It may help decrease post-op Afib
110
Mg is effective in being an analgesia due to
Antinociceptive affects & NMDA antagonism
111
Mg is helpful in treating asthma by being a
Bronchodilator via inhibition of calcium, histamine, & ACh
IV Mg may improve bronchodilation when other therapies fail
112
Mg can help treat Pheochhromocytoma (tumor w/ excess catecholamine) by
Causing arterial smooth muscle relaxation
Reducing catecholamine release
113
Plasma ionization of calcium depends on pH...
Acidosis increases
Alkalosis decreases
114
Calcium may shift storage sites
In low albumin states
115
Functions of Ca+
Musculoskeletal strength & contraction
Neuromuscular transmission
Cardiac muscle contractility, relaxation & rhythm
Vascular motor tone
Coagulation
Intracellular signaling
116
Ca+ involvement in homeostasis
Endocrine control through Vet D, parathyroid hormone & calcitonin
Regulates intestinal absorption, renal reabsorption & bone turnover
117
Hypocalcemia is caused by
Decreased albumin & Vit D
Hypoparathyroid
Pancreatitis
Chronic renal failure
Citrate binding
118
How to treat hypocalcemia
Calcium chloride (27mg)
Calcium Gluconate (9mg)
118
Symptoms of hypocalcemia
Neuromuscular excitation (twitching, spasms, paresthesia & tetany)
Seizures
Dysrhythmias
119
How should Ca+ chloride be administered?
Central line or it can cause extravasation, leading to subcutaneous irritation, necrosis or sloughing
120
Avoid rapid IVP administration of
Ca+
121
Dose of Ca+ treatment?
0.5-2g
122
Hypercalcemia is caused by
Hyperparathyroid
Parathyroid adenoma
Malignancies
Excess in dietary
Meds
123
Symptoms of hypercalemia
GI smooth muscle relaxation (N/V & constipation)
Decreased neuromuscular transmission (lethargy & hypotonia)
Polyuria
Dehydration
Renal Stones
Shortened QT
124
How is hypercalcemia treated?
Goal is to promote renal calcium excretion
IVF
Loops
Corticosteroids
Biophosphonates
Calcitonin
Gallium nitrate
Mithramycin
Hemodialysis
125
The majority of Phosphate is
Intracellular (bone & soft tissues)
126
What are the functions of phosphate?
Energy metabolism
Intracellular signaling (cAMP)
Immune system regulation
Coagulation cascade regulation
Buffer for acid base balance
127
Phosphate play a role in homeostasis by influencing
Vit D
Parathyroid hormone (GI absorption)
Renal reabsorption
Bone storage
128
Hypophosphatemia permits an
Increase in serum calcium
129
Hypophosphatemia decreases
ATP & 2,3 DPG in erythrocytes, which decreases the release of O2
130
Hypophosphatemia will cause
Skeletal muscle weakness & hypoventilation
CNS dysfunction
Peripheral neuropathy
