Fluid & Electrolytes (Part 2) Flashcards
1
Q
Fluid Management Goal
A
Euvolemia
Maintain adequate:
Intravascular fluid volume
LV filling pressure
CO
SBP
Oxygen delivery to tissues
2
Q
Physical Exam
A
Skin turgor
Mucus membranes
Peripheral pulses
Resting heart rate and blood pressure
Orthostatic changes
Urine output
NPO Status
3
Q
Body Fluid Composition
A
approx. 55-60% water
2/3 Intracellular
1/3 Extracellular
4
Q
(Functional Compartments)
ICF
-body weight
-ions
A
ICF: 40% of your weight
~ 28 L (2/3 of body H20)
Primary Ions:
K+, Mg+2, PO4-2 & proteins
5
Q
controls constituents of ICF
A
Cell membranes & cellular metabolism
6
Q
Extracellular fluid
-body weight
-ions
A
The remaining 1/3 of body water
approx. 20% of body weight
Primarily a Na+, Cl- & NaHCO3 solution
7
Q
Interstitial Fluid (ISF)
A
surrounds cells
does not circulate
~ 80% of the ECF
8
Q
Plasma
A
ECF component of blood
~20% of ECF
9
Q
ECF is 80% ____ & 20% ___.
A
80% interstit.
20% plasma
10
Q
Examples of extracellular fluid
A
Interstitial Fluid (ISF) (80%)
Plasma (20%)
Transcellular fluid
11
Q
Transcellular fluid
A
are fluids that are outside of the normal compartments
12
Q
Transcellular fluids
examples
how many Liters?
A
CSF, digestive (gastric) juices, mucus, etc.
1 - 2 liters of fluid
13
Q
TBW
values for M, F , infants & obese
A
Total body water (TBW) varies with age, gender & body type
Males: 60%
Females: 50%
Infants: 80%
Obese adults & diabetics: less water per kg
14
Q
Basic constituent of the human body
A
water
15
Q
Laboratory Evaluation
Hypovolemia
A
Increasing Hct
Hypernatremia
Metabolic acidosis (severe hypovolemia)
Urine SG >1.010
Urine Na < 10 mEq/L
Urine osmolality > 450 mOsm/kg
BUN: creatinine ratio > 10:1
16
Q
Urine specific gravity assessment
A
17
Q
Signs of Hypovolemia
5%
10%
15-20%
A
18
Q
⭐️
Hypovolemia
A drop in BP does not occur in a patient that is already in the supine position until about __% of the blood volume is lost
A
30
19
Q
Intraop Urine output goals
A
0.5-1 ml/kg/hr
BURN pts:
1.5 ml/kg/hr
20
Q
Decrease in urine output generally does not occur until ___% of blood volume is lost
A
~20
21
Q
Signs of Hypervolemia
A
Pitting edema
Presacral edema
Later signs:
Tachycardia
Crackles
Wheezing
Pulmonary edema
22
Q
T/F
Chest X-ray is not a reliable assessment tool for hypervolemia.
A
False
23
Q
Electrolytes
ECF & ICF
A
ECF:
Major (+): Na, K, Ca
Major (-): Cl, Bicarb, Proteins
ICF:
Major (+): Na, K, Mag
Major (-): Cl, Bicarb, Proteins
*same major anions
*difference is in major cations
“this is Ma Mag”
“Kick out Ca”
24
Q
Most important electrolytes
A
Sodium, Potassium, and Calcium
25
affects resting membrane potential
K
26
determines threshold potential
Ca
27
Na fxn
resting potential
generate & propagate AP
28
Which ions affect excitability of nerve & muscle?
Sodium, Potassium, and Calcium
29
He didn't emphasize this chart much
30
Hypernatremia
cause
at risk population
Secondary to **lack of water**
At risk:
Debilitated and dehydrated
Extremes of age
Altered LOC
31
T/F
Hypernatremia is often d/t excessive sodium intake
False
Secondary to lack of water – not because of too much salt
32
HyperNa
S/S
S/S:
**Restlessness, lethargy, seizures** and death
-reflect rate of H20 movement from brain
-Ruptured cerebral veins, focal hemorrhage
(Coma = HypoNa)
33
Na NR
135 - 145 mEq/L
34
Most common cause of diabetes insipidus
Hypernatremia w/ normal total body sodium
results from medical intervention
35
diabetes insipidus
w/ normal total body sodium
↓↓↓ renal “concentrating-ability”
**↓ ADH secretion
renal tubules don't respond normally to circulating ADH (polyuria)**
polyuria
excessive pale urine
36
⭐️
HyperNa w/ low total body Na
Lost sodium & water
**Water loss > sodium loss**
Losses:
renal (osmotic diuresis)
or
extrarenal (diarrhea or sweat)
37
⭐️
HyperNa w/ increased total body sodium
Most commonly caused by the administration of large quantities of hypertonic Na+ solutions (3% NaCl or 7.5% NaHCO3)
Cushing's syndrome – too much ACTH
38
hypertonic Na+ solutions
3% NaCl or 7.5% NaHCO3
39
⭐️
Most commonly caused by the administration of large quantities of hypertonic Na+ solutions
HyperNa w/ increased total body Na
40
Cushing's syndrome = too much ___
ACTH
41
Hypernatremia > 145 mEq/L
S/S
Neuro:
Extreme Thirst
Progressive Weakness & Fatigue
**Intracranial bleeding (brain shrinks**→vessels pull/shear)
Disorientation, Hallucination, Irritability
CV:
**Hypovolemia**
Renal:
Oliguria
Renal Insufficiency
42
⭐️
Treatment of Hypernatremia
how fast can we correct it?
fluid deficits corrected over 48 - 72 hours:
hypotonic solution (D5W)
**MAX Na decrease: 0.5 - mEq/L/hour**
43
Rapid fluid deficit correction can result in
seizure, cerebral edema and coma
44
Elective surgery should be postponed until sodium level is ___ mEq/L and H2O deficits corrected
< 150
45
Hyponatremia
Associated conditions/diagnosis
alcoholism
liver failure
severe burns
malignant neoplasms
hemodialysis and sepsis
46
⭐️
Na
Neurologic symptoms occur below...
120 mEq/L
47
Hyponatremia is serum Na less than ___
< 135 mEq/L
48
Hyponatremia
S/S
Neurological:
Seizures → Coma
Cerebral edema
Agitation, Confusion, h/a
GI:
N/V → anorexia
Musculoskeletal: cramps and weakness
May not see when under GA!
49
Hyponatremia
Diagnosis is based on the assessment of:
serum osmolality
volume status
50
Osmolality & Osmolarity
Osmolality: osmoles of solute *per kilogram* of water (e.g., weight)
Osmola**r**ity: osmoles of solute *per lite**r*** of water (e.g. fluid)
51
Tonicity
Effect a solution has on cell volume
Hypertonic
Hypotonic
Isotonic
52
Osmosis is movement of ___
H20
53
Plasma Osmolarity
NR and equation
54
Plasma Osmolarity
Most important determinant
Na+
55
What increases plasma osmolarity?
Hyperglycemia or high BUN
56
⭐️
Normal Osmolality
280 – 295 mOsm/kg
57
H20 flows from compartment of low to high (osmolarity/osmolality) if the membrane between the compartments is permeable to H2O
osmolality
(a cell in relatively hyperosmolar solution: fluid moves out of cell → highly [ ] compartment to reach homeostasis →→ cell shrinks)
58
Osmolality
Reflects fluid shifts from ....
what happens to Na?
ICF → ECF
Decreased plasma sodium levels
59
Meds that can change normal plasma osmolality
amitriptyline
cyclophosphamides
Tegretol
morphine
60
Disease processes that can shift fluid from ICF → ECF
hypothyroidism,
glucocorticoid insufficiency
SIADH
61
SIADH
(inappropriate antidiuretic secretion)
clinical presentation
Clinically euvolemic & good renal fxn!
but
↑ urine osmolality (>200mOsm) WITH ↓ serum osmolality
Urine Na >20 mEq/L
62
Causes of SIADH
Dz & Rx
Pulmonary carcinoma
Brain metastases, other malignancies
CNS disorders
Idiopathic forms – esp old ppl
Meds:
antidepressants agents (SSRIs)
HCTZ
NSAIDs
Vincristine (chemo for leukemia & others)
Neuroleptic agents
Haldol (PONV; D2 receptor antag in CTZ)
Zyprexa (ADHD)
Vasopressin
Oxytocin
63
⭐️
SIADH Acute treatment starts @ Na levels of ____.
<110 (SEVERE hypoNa)
64
SIADH Acute treatment
interventions
(Na <110)
IV Lasix – diuresis
NS with 20–40 mEq/L KCL
65
⭐️
Can we use 3% NS for Acute SIADH? Why or why not?
Rare
replacement MUST be done slowly, over days
risk: central **pontine myelinolysis** (demyelinate brain's white matter)
↓
quadraplegia
66
SIADH (Chronic treatment)
-Water restriction ~1000 ml QD
-**Declomycin** – mechanism unknown
-Urea
-PO Salt tablets
-**Vasopressin receptor antagonists:
Conivaptan, Vaprisol, Tolvaptan, Samsca
-Lithuim**
67
HypoNa in HYPERtonic state
pt has high osmolality (>295 mOsm /kg)
Hypervolemia caused by:
Mannitol excess
Glycerol Treatment
Nephrotic Syndrome
CHF
Cirrhosis
Treatment:
Salt/water restriction or diuretics
68
HypoNa in a Hypotonic state
-osmolality
-causes
Low serum osmolality (<280 mOsm/kg)
**assess volume status**
hypovolemia may be due to:
-GI losses
-Renal losses + excess water ingestion
-Diuretics
-ketonuria
-3rd Spacing
-adrenal insufficiency
-N & V
69
⭐️
Hyponatremia
How fast do we correct it?
Not too fast!
Pontine myelinolysis risk permanent damage!
70
Pontine myelinolysis
S/S
Balance problems
Confusion/delirium/∆s in consciousness
dysphagia
Hallucinations
speech changes/poor enunciation
Tremors
weakness face, arms, or legs; usually B/L
Acute progressive quadriplegia
71
HypoNa Tx
symptomatic: consider 3% NaCl
sodium 1-2 mEq/L/hr x 2H →0.5 mEq /L/hr
asymptomatic: sodium 0.5 mEq/L/hr
Max in 24 hr: 10 mEq TOTAL rise
Max in 48 hr: 18 mEq TOTAL rise
72
HypoNa Tx
MAX rise in Na over 24 & 48 H
Max in 24 hr: 10 mEq TOTAL rise
Max in 48 hr: 18 mEq TOTAL rise
73
Potassium
NR
3.0 – 5.5 mEq
74
Hyperkalemia results in altered distribution of ___ between...
K
intra- & extracellular sites
75
HyperK
Adverse effects are d/t...
to acute ↑ in serum concentration
76
HyperK
Most detrimental effect occurs in....
What do we see?
cardiac conduction system
Prolonged PR interval
Widening QRS complex
Peaked T wave
77
Hyperkalemia is serum K greater than....
5.5
78
HyperK
causes & S/S
79
Treatment of Hyperkalemia
-NaHCO3 (~50 mEq) ↑cell uptake of K+ w/in 15 minutes (Note: cannot be used alone)
-Beta agonists
-Glucose 30-50 gm + Insulin 10 units (can take up to 1 hour)
-Hyperventilation
-dialysis
-Ca (cont on another card)
80
Treatment of Hyperkalemia
Ca
protect 🩷 from hyperK (1 amp = 1 gm CaCl)
↓ excitability & threshold potential
500-1000 mg IV: antag 🩷 effects; rapid but short-lived
⚠️Ca potentiates digoxin toxicity
81
Ca potentiates ____ toxicity
Digoxin
82
Hyperkalemia
Tx algorithm
83
HyperK vs HypoK
ECG changes
HYPER:
Prolonged PR interval
Widening QRS complex
Peaked T wave
HYPO:
Flattened T waves and presence of U wave
84
How does pH affect K?
(indirectly proportional relationship)
0.1 change in arterial pH = 0.6 meq change plasma K+
Acidosis:
-high Plasma K in relation to total body stores
-K depletion d/t urinary or GI losses: plasma concentration may be normal or reduced
85
The bajillion causes of hypoK
86
Treatment of Hypokalemia
PO KCL 60-80 mEq/day (sour tummy common)
IV:
Peripheral: MAX 8 mEq/hr (vein irritation)
Central: 10-20 mEq/hr
87
What K values do we need to proceed with surgery?
greater than 3-3.5mEq/L
88
(hypo/hyper)kalemia causes increased sensitivity to NMBs. So we should decrease the dose by ___%
hypoK
25-50%
89
Ca NR
8.5-10.5 mg/dl
90
Hypocalcemia
is a/w...
hypoparathyroid
pancreatitis
renal failure
decreased albumin
91
HypoCa
affects on muscle
Skeletal muscle spasm **including laryngospasm**
↓ 🩷 contractility
⚠️ Avoid Hyperventilation
pH 0.1 increase (alkalosis) = 0.16 mg/dL decrease ionized Ca
92
What should we avoid with hypoCa?
⚠️ Avoid Hyperventilation
pH 0.1 increase (alkalosis) = 0.16 mg/dL decrease ionized Ca
93
Hypocalcemia
EKG changes
Mild: broad-based tall peaking T waves
Severe: extremely wide QRS, low R wave, no p waves, tall peaking T waves
94
Hypocalcemia
S/S
HTN before hypovolemia (usually)
Anorexia, N/V
Weakness, muscle aches, tingling lips
Muscle spasms of the throat (laryngospasm)
Polyuria
Ataxia
Irritability, lethargy, or confusion
Seizures, Coma → Death
*Trousseau's Sign: BP cuff = carpopedal spasm
*Chvosteks's Sign: tap facial CN; edge of mouth spasms
95
Trousseau's & Chvostek's sign are a/w
HypoCa
96
Treatment of Hypocalcemia
Symptomatic = *true medical emergency*
Rule of 10’s:
10mL 10% calcium gluconate/Cl over 10 mins
↓
drip: elemental calcium 0.3-2 mg/kg/hr
serial *ionized* Ca
Check magnesium and consider giving magnesium 1 gm
97
Which is a/w necrosis?
Ca gluconate
CaCl
CaCl
(Ca gluconate is better for periph IV)
98
When correcting hypoCa, what other electrolyte should we gve?
Check magnesium
consider magnesium 1 gm
99
Hypercalcemia
ranges
Serum Ca+ > 10.5
ionized >5.6 mg/dL
100
HyperCa
causes
Hyperparathyroidism
Malignancy - bone
Renal Failure
Thiazide Diuretics
Excess Ca+ supplements
101
HyperCa
S/S
HTN
Dysrhythmias →CHB
**Shortened QT**
Sedation
Polyuria
Anorexia
Pancreatitis
102
Treatment of Hypercalcemia
1) Rehydrate w/ NS
2) brisk diuresis (200-300 ml/hr)
*loop diuretic to ↑Ca excretion
3) serial ionized calcium
Avoid acidosis may further elevate calcium levels
103
How does pH affect Ca?
Acidosis can further elevate Ca
104
Magnesium
NR
1.7 – 2.2
105
Low Magnesium
causes
Alcoholism
Chronic diarrhea
polyuria
sweating
Hyperaldosteronism
Malnutrition
Malabsorption syndromes (celiac, IBS)
meds:
diuretics
aminoglycoside antibiotics
chemotherapy
106
Symptoms: Hypomagnesemia
Abnormal eye movements (nystagmus)
Seizure
Fatigue
Muscle spasms or cramps
Muscle weakness
Numbness
Dysrhythmias
107
Treatment of Hypomagnesemia
IV mag sulfate 1-2 G *slowly* over 60 minutes
-**Assess for concomitant hypoK or hypoCa**
-Monitor EKG for arrhythmias
(Identical to hypokalemia: Flattened T waves and presence of U wave)
108
HypoMg shows the same EKG abnormalities as ....
hypoK
Flattened T waves and presence of U wave
109
Hypomag is often accompanied by which other 'lyte imbalances?
hypoK or hypoCa
110
Hypermagnesemia
S/S
**Flushing**
Nausea & vomiting
Drowsiness
Weakness
**Loss of patellar reflex, decreased DTRs
Respiratory depression**
Cardiac arrest
Coma
111
Treatment of Hypermagnesemia
Stop all sources of magnesium
-**IV Ca 1G** (temporarily antagonize most effects)
-**Loop diuretic + rehydration D1/2 NS** (enhances excretion)
-Monitor for vasodilation and negative inotropic effects
-Decrease dosages of NDMB by 25-50%
112
Hypermag
anesthesia considerations
Decrease dosages of **N**DMB by 25-50%
(hypoK: decrease NMB dose 25-50%)
113
Hypervolemia
What would we see in a CXR?
What labs should we draw?
Kerly B lines: **Increased** pulmonary & interstitial markings
Diffuse alveolar infiltrates
Labs: blood & UA
