Fluids, Electrolytes, and Goal-Directed Therapy Flashcards
(240 cards)
1
Q
ICV represents
A
2/3 of TBW
1
Q
ECV represents
A
1/3 of TBW
2
Q
perioperative fluid mamangment involves:
A
- maintaining intravascular volume
- augmenting CO
- maintaining tissue perfusion
- promoting oxygen delivery
- correcting and maintaining electrolyte balance
- enhancing the microcirculatory flow
- facilitating the delivery of nutrients
- clearance of metabolic waste
2
Q
TBW in an average adult represents
A
60% of lean body mass
3
Q
primary cation and anion in the ECV
A
sodium, chloride
4
Q
primary cation and anion in the ICV
A
potassium, phosphate
5
Q
resting membrane gradient for these electrolytes is maintained by the
A
Na and K ATPase
6
Q
cell membrane is permeable to
A
water
as a result of the ICV and the ECV maintain a state of osmotic equilibrium
7
Q
daily fluid volume required to maintain TBW homeostasis
A
25-35 mL/kg per day or 2-3 L/day
8
Q
ECV is further divided into
A
intravascular compartment
interstitial compartment
9
Q
interstitial compartment represents
A
3/4 of the ECV
10
Q
intravascular compartment represents
A
1/4 of the ECV
10
Q
ECV is also composed of a small amount of
A
transcellular fluid:
- CSF
- GI secretions
- intraocular fluid
- synovial fluid
11
Q
Transcellular fluids are anatomically __ from the fluid dynamics that impact the remaining ECV, therefore they are considered ___
A
isolated; nonfunctional
12
Q
Capillary hydrostatic pressure (Pc)
A
is the intravascular blood pressure, driven by the force of the CO impacted by the vascular tone
13
Q
Interstitial fluid pressure (Pif)
A
is the hydrostatic pressure of the interstitial space
14
Q
Pif of most tissues is slightly __ ; this is thought to be d/t the contraction of __ vessels in the interstitum
A
negative; lymphatic
15
Q
what has a slightly positive Pif?
A
rigid or encapsulated tissues of the kidneys, brain, bone marrow, and skeletal muscle
16
Q
plasma oncotic pressire (πp)
A
is the osmotic force of collodial proteins of the vasular space
17
Q
interstitial oncotic pressure (πif)
A
is the osmotic force of the colloidal proteins within the interstitial space
18
Q
what protein is the primary determinant of both capillary and interstitial oncotic pressures?
A
albumin
19
Q
Increase in Pc and πif favor
A
filtration of fluid into the interstitial space
20
Q
increase in Pif and πp favor
A
absorption of fluid into the intravascular space
21
Q
Increased Kf favors
A
filtration
22
A sigma of 0 indicates
that the endothelium is freely permeable to the substance
23
a sigma of 1 indicates
that the endothelium si completely impermeable to the substance
24
positive net filtration favors fluid exudation into
the tissues
25
net filtration tends to be slightly __ at the arterial end of capillaries and slightly __ at the venous end
positive; negative
26
overall balance of filtration pressures within capillaries of the entire body is slightly
positive
27
at what rate is the intravascular volume being filtered into the interstitial space ?
2 mL/min
28
volume is returned to the intravascular space via the
lymphatic system
29
glycocalyx
is a gel layer on the luminal surface of the vascular endothelium that plays an important role in:
- transcapillary fluid exchange
- microcirculatory flow
- blood component rheology
- plasma oncotic pressure
- signal transduction
- immune modulation
- vascular tone
30
glycocalyx diameter
0.1 to 0.2 micrometers
31
glycocalyx is composed of a matric of
glycoproteins, polysaccharides, and hyaluronic acid
32
dynamic barrier ionically repels __ charged polar compounds in addition to __ __
negatively; blood componenets
33
binding to circulating plasma albumin, the glycocalyx also helps preserve __ __ __ and __ capillary permeability to water
capillary oncotic pressure; decrease
this is known as the double barrier effect
34
the glycocalyx is thought to contain ___ ___ whose binding sites are enclosed in the matrix, helping prevent leukocyte adhesion
inflammatory mediators
35
other functions of the glycocalyx
- scavenging of free radicals
- binding and activation of anticoagulation factors
- signal transduction that helps regulate local vasoactive responses to mechanical stress
36
normal daily alterations in TBW are regulated by
RAAS (renin-angiotensin-aldosterone system)
ADH (antidiuretic hormone)
ANP (atrial natriuretic peptide)
37
what is one of the primary determinants of serum osmolarity and water transport?
sodium
38
RAAS is an important regular of __ homeostasis
sodium
39
what detects hypotension in the RAAS?
- intracardiac
- renal afferent arteriole barorecpetos
40
juxtaglomerular cells of the kidney release
the enzyme renin
41
interaction of circulating renin with the precursor __ causes the cleaving of __ to the active substance __
angiotensinogen; angiotensinogen; angiotensin I
42
angiotensin I exerts local
vasoconstrictor activity
43
primary role of angiotensin I
is as a precursor for the more potent angiotensin II
44
this change occurs in the __ as a result of ACE acting as a catalyst for the conversion of angiotensin I to II
lungs
45
angiotensin II directly stimulates what to reabsorb sodium and water?
renal tubules
45
angiontensin II is a potent
vasoconstrictor
46
angiotensin II causes the __ __ to release aldosterone , which further stimulates Na and water retention by the kidneys
adrenal cortex
47
secretion of ADH contributes to an increase in
urine concentration and osmolarity
47
the ADH pathway functions primarily to regulate
water balance
48
Posterior pituitary gland releases __ which causes __ channels within the kidney to transiently reabsorb large quantities of __
ADH; aquaporin; water
49
ADH also plays a role in preserving blood pressure by
acting as a potent arterial vasoconstrictor
50
stretch receptors in the cardiac __ walls stimulate the release of __ from cardiac myocytes as a result of increased preload or hypervolemic state
atrial; ANP
51
the release of ANP stimulates
the kidney to release Na and water, thus reducing circulating blood volume and offloading the heart
52
ANP also produces __ responses in the afferent and efferent renal arterioles to __ the GFR, and it inhibits the release of __ & __
vasoactive; increase; renin; ADH
53
during periods of decreased preload, atrial receptors __ the release of ANP
inhibit
54
crystalloid infusions are preferable for resuscitation of
dehydration conditions
55
dehydration examples
- prolonged fasting states
- active GI losses
- polyuria
- hypermetabolic conditions
56
crystalloids are preferred for their lack of __ potential, ease of metabolism, and __ clearence
allergenic; renal
57
isotonic crystalloids are distributed evenly throughout the __ space, their ability to __ plasma volume is transient
extracellular; expand
58
crystalloids favor filtration approx ___ into the interstitial space
75%-80%
59
what is the most common crystalloid solution administered worldwide?
0.9% NS
59
high chloride load contributes to
- acid-base imbalances
- hyperchloremic metabolic acidosis
60
normal physiologic concentration of Na and Cl is
Na is much higher than Cl
60
NS is roughly equal concentrations of
Na and Cl
61
hyperchloremia has a substantial impact on
renal function
62
increased Na load introduced by large volumes of NS shown to cause
increased salt and water retention, hemodilution, and interstitial edema well into the postop period
63
NS in modern anesthesia can be given in __ volumes to __ patients
small; neurosurgical
64
NS is the preferred fluid for patients at risk for
cerebral edema
65
NS may also be indicated in fluid management of patients with
anuria and ESRD who cannot excrete K content of a more balanced crystalloid solution
| B/c NS does not contain K, avoid worsening hyperK, safe choice
## Footnote
LR contains K thats why its no good for ESRD pt's
66
Hypertonic solutions (3% or greater) are sometimes used in low dose infusions in
trauma and head injury paitents
| help w/ ICP improve CPP, osmotic effect: draw H2O out of braincells
## Footnote
volume-expanding effect, help CO, antiinflammatory effects, preservation fo cerebral blood flow
67
hypertonic solutions promote
volume expansion that mobilizes intracellular and interstitial fluids into the intravascular space
68
risks for hypertonic solutions
- vascular irritation
- sudden and pronounced fluid shift into the intravascular space
- potential for dehydration of neural cells leading to osmotic demyelination syndrome
69
LR contains
sodium lactate as a bicarb substrate or buffering agent
69
LR is not recommended for
- large volume administration in diabetic patients b/c byproducts of hepatic metabolism of lactate can result in gluconeogenesis
| lactate is metabolized into bicarb in the liver --> metabloic alkalosis
70
T/F NS is more effective as a resuscitative fluid administration than LR for preserving intravascular volume
FALSE
71
LR is mildly __ and may cause transient serum hypo-osmolarlity and associated ___ __
| osmolarity=meausre of the concentration of solute particles ina solution
hypotonic; cerebral edema
72
LR is contraindicated in patients with
TBI or other neurovascular insults
73
LR contains __ and is contraindicated in infusions with citrated (preservative used in blood products) d/t the risk of coagulation
calcium
| citrate binds with calcium, risk for calcium chelation
## Footnote
preventing coagulation and preserving the viability of blood products
74
plasmalyte-A, Normosol-R, Isolyte S
most isotonic of the balanced solutions
75
what does plasmalyte use as alkalinizing buffers?
- sodium gluconate
- sodium acetate
76
colloids are suspensions of __-molecular weight molecules in __ solutions
high; electrolyte
77
colloids produce
intravascular volume expansion by directly increasing πp and interacting with the endothelial glycocalyx to decrease transcapillary permeability
78
colloids are effective for their plasma volume __, and are often used perioperativley for their __-__ effects compared to crystalloids
expansion; fluid-sparring
79
what is the only naturally occurring colloid solution available?
albumin
80
how are colloid infusions classified?
- molecular weight
- concentration
- half-life
81
what is the oldest artificial colloid?
Dextran
81
dextrans characteristics
- high-molecular-weight (40-70 kDa)
- derived from bacterial metabolism of sucrose
- first manufactured in 1940's
- markedly hyperosmolar
- 1/2 life of 6-12 hours
82
Dextrans associated with a variety of coagulopathic effects d/t
- Von Willebrand factor
- activation of plasminogen
- inerference with platetlet agreggation
83
Dextrans cause
acute RF
indirect hyperosmotic RI and direct RT damage as a result of accumulation
84
dextrans may also adhere to the surface of __ & __ and interefere with cross matching of bood products
platelets & RBCs
85
T/F Dextrans are still used in clinical practice
False
d/t the propensity to cause acute RF, and induce anaphylaxis, and coagulopathy
86
Genlatins are __ colloids derived form __ __
synthetic; bovine components
87
Gelatins characteristics
- molecular weight of 30-35 kDa
- shorter half-life 2-4 hours
- limited duration of plasma expansion
88
Gelatins risks
- interfere with platelet function
- cause nephrotoxicity
- high propensity of causing anaphylaxis
89
Use of gelatins in clinical practice is
cautioned
90
HES (hyroxylethyl starches) can cause allergic reactions in people who are allergic to
potatoes, maize, sorghum, and other components
91
Hydroxyethyl starches (HES) are __ macromolecules derived from __ __
synthetic; starchy plants
92
how does HES provide prolonged volume expansion?
high C2/C6 ratio indicated HES will be difficult to metabolize
93
where is HES widely used?
European union
94
first-generation HES are associated with
- dose-dependent coagulopathy b/c of hemodilution and binding of clotting factors
- interference of platelet adhesion
- inhibition of fibrin polymerization
- alterations in plasma viscosity
95
HES can also accumulate for form interstitial colloid deposits in subcutaneous and other organ tissue than can lead to severe..
pruritus
nephrotoxicity
96
FDA issued a black box warning for
HES in 2013 to notify for public risks of renal injury and increased mortality
97
the PRAC and EMA issued a sudden recommendation to fully suspend all
HES solutions in jan 2018
98
albumin is a
fractionated blood product produced from pooled human plasma
molecular weight of 65-69 kDa
99
small volumes of __ provide __ degree of intravascular resuscitation as compared to equal or greater volumes of crystalloid
albumin; greater
99
albumin is __ treated to __ pathogens and eliminate the risk of dx transmission
heat; inactivate
100
T/F Albumin preparation is significantly more costly than crystalloid solutions
true
101
T/F Albumin does not carry a risk for anaphylaxis
false
102
albumin is a carrier for a # of protein-bound ionic substances including:
- drugs and their metabolites
- electrolytes
- enzymes
- hormones
103
T/F albumin has a negative electrostatic charge
true
104
Donnan effect
albumin molecules bind ions, which increase plasma osmolarity and intravascular volume
105
stimulation of osmotic and autonomic afferent nerves in the area of surgical incision triggers the activation of
hypothalamic-pituitary axis (HPA)
106
the hypothalamus releases __ which then elicits the creation and release of cortisol from the __ __
ACTH; adrenal cortex
107
cortisol stimulates
protein catabolism, hepatic gluconeogenesis, and glycogenolysis, and increased hepatic production and release of plasma proteins
108
hyperglycemia is a major risk factor for damage or destruction of the
endothelial glycocalyx
109
hyperglycemia also contributes too
- impaired wound healing
- contributes to osmotic diuresis
- interferes with immune response
110
sympathetic stimulation in combination with hyperosmolar conditions triggers the release of
ADH
111
most beneficial effect of cortisol
the anti-inflammatory effect it exerts by inhibiting the production, release, and vascular aggregation of inflammatory mediators
111
"third space" was introduced in the 1960's as
a nonfunctional component of the ECV
112
EBL ratio of crystalloid to blood
3:1
113
evidence demonstrates that actual observed ratio is less than
2:1
114
4-2-1 calculation
0-10kg: 4mL/kg/hr
11-20kg: 2mL/kg/hr (for the first 10kg x4, next 10kg x2)
> 20kg: 1mL/kg/hr (for the first 10kgx4, next 10kgx2, everything after that x1)
115
estimated fluids deficit
estimated fluid deficit = maintenance requirment x fasting hrs
116
superficial trauma (orofacial)
1-2 mL/kg/hr
117
minimal trauma (herniorrhaphy)
2-4 mL/kg/hr
118
moderate trauma (major nonabdominal surgery or laparoscopic abd surgery)
4-6 mL/kg/hr
119
severe trauma (major open abd surgery)
6-8 mL/kg/hr
119
consequences of under resucitation
- hypovolemia
- decreased microvascular perfusion leading to decreased O2 delivery
- reduced tissue perfusion
- end-organ complications
- PONV
- renal dysfunction
- myocardial ischemia
- hemoconcentration leading to increased blood viscosity, thrombotic events
120
consequence of overresuscitation
- vascular overload, acute CHF
- microvascular congestion leading to decreased oxygen delivery
- endothelial glycocalyx disruption
- decreased tissue oxygenation
- altered coags and potential hemorrhage
- hemodilution leading to anemia, thrombocytopenia, altered viscosity
- decreased gut motility
- increased infection rates
- decreased organ perfusion
- increased EVLWI? and prolonged post-op MV
- increased incidence of VAP
- hepatic congestion and dysfunction
- abd compartment syndrome
121
aim of GDFT is
utilize individualized hemodynamic endpoints to support oxygen transport balance by minimizing O2 demands and optimizing CO, tissue oxygenation, capillary and macrovascular flow, oxygen, nutrient delivery, and end-organ perfusion
122
GDFT protocols begin with a baseline assessment of target __ measures followed by the administration of a __ volume fluid bolus
hemodynamic; small (200-250)
123
basis of the frank-starling mechanism is the relationship between
LVEDP and myocardial contractility (SV)
124
the FS is highly effective until
the point at which the sarcomere cannot generate additional force
further increases in preload after this threshold will generate no further increases in SV
125
limitations of dynamic measures
- SV (spontaneous ventilation)
- small TV
- open chest
- sustained arrhythmias
- PEEP
- right heart dysfunction
126
ERAS means
enhanced recovery after surgery
127
ERAS was initially developed for
colon surgery
128
primary cellular injury can
impair O2 and nutrient delivery to vital organs resulting from local and global perfusion changes
129
secondary cellular injury
process caused by the stress response associated with surgery that results in the release of local inflammatory mediators or hormones
130
combination of primary and secondary cellular injury result in
delayed wound healing and gut dysfunction and may lead to postsurgical complications
131
two fundamental elements that affect postsurgical outcomes are attributed to
fluid therapy and effective pain managment
132
BBB has limited permeability
to ionic solutes
132
normal values
CO
CI
EVLWI (extravascular lung water index)
FTc (corrected flow time)
GEDI (global end diastolic index)
change in peak pressure
PPV/ change in pulse pressure
PVI (plethysmography variability index)
ScvO2 (central venous O2 saturation)
SPV (systolic pressure variation)
SV/SVI
SVR/SVRI
Svo2 (mixed venous O2 saturation)
SVV
4-8 L/min
2.5-4 L/min/m^2
3-7 mL/kg
330-360 ms
680-800 mL/m^2
> 12% predicts preload responsiveness
> 13% predicts preload responsiveness
> 14% predicts preload responsiveness
normal value 70% (blood in the SVC)
> 14% predicts preload responsiveness
SV: 60-100 mL/beat, SVI: 33-47 mL/m^2/beat
SVR: 800-1200 dynes-sec/cm-5/m^2 SVRI: 1970-2390
60-80% (blood in PA measured by PAC)
> 13% predicts preload responsiveness
133
changes in water concentration are largely d/t
sodium
134
limited permeability in the BBB prevents the equilibration of __ active ionic solutes between ECV & ICV
osmotically
135
most important osmotically active substance influencing the water content of the brain tissues?
sodium
136
sodium imbalances reflect an impaired
concentration between water and Na
137
hyponatremia
the intracellular environment is hyperosmolar compared to the ECV leading to an influx of water into the ICV
138
most significant consequences of hyponatremia is
cerebral edema
139
whos at an increased risk of brain damage resulting from hyponatremia?
menstruating women
believed that progesterone and estrogen inhibit the efficiency of Na-K-ATPase pump
female sex hormones may facilitate the movement of water into the brain through the mediation of ADH
140
what is the most common electrolyte abnormality in hospitalized patients?
hyponatremia
141
development of hypervolemic hyponatremia in patients with ___ & ___ is assoicated with an increased risk of death
CHF; cirrhosis
bonus polycystic kidney dx
142
rapid correction of hyponatremia particularly in patients with chronic hyponatremia can result in
- seizures
- spastic quadriparesis
- coma d/t osmotic demyelination
143
vasopressin receptor antagonists are available to treat
hypervolemic or euvolemic hyponatremia
medications antagonize arginine vasopressin by inhibition of renal V1a, V1RA, V2, & V3RA receptors. result in increased free water excretion by the kidneys
144
initial treatment of hyponatremia usually includes
fluid restriction & diuresis
145
myelinolysis
Central pontine myelinolysis
can lead to disorders of the upper neurons, spastic quadriparesis, pseudobulbar palsy, mental disorders, death
146
serum Na concentrations should be increased no more than ___ mEq/L per hour
1 to 2
146
whos at risk for myelinolysis ?
hyponatremic greater than 48 hrs, orthotopic liver tx, hx of alcohol abuse
147
symptomatic patients can infuse
3% saline at a rate of 1 to 2 mL/kg/hr
148
what is the usual cause of hypernatremia
impaired water itnake
149
If the hypernatremia is acute, water deficits can be replaced relatively __ with __ solution
rapidly; hypotonic
150
if chronic hypernatremia is accompanied by volume __, the volume disorder is corrected first with __ __
depletion; isotonic crstalloids
151
once the circulating volume is restored, __ solutions are used to correct the water deficit
hypotonic
152
plasma Na should be decreased by __ to __ mEq per hour until to the patient is clinically stable
1 to 2
153
__ within these compartments are in large part responsible for the resting membrane potential
K
154
Homeostasis is maintained by absorption of K from
- GI tract
- renal excretion
- reabsorption into the peritubular capillary network
155
renal regulation of K is dependent on
- the concentration gradient between the distal tubules and collecting duct relative to the peritubular capillary network
- the distal convoluted tubular flow rate and Na concentration
- aldosterone concentration
- changes in pH
156
aldosterone has a potent effect on __ levels
K
157
hyperkalemia causes adrenal cortical synthesis and the release of
aldosterone
which promotes potassium excretion from the distal renal tubules
158
hypokalemia is defined as
less than 3.5
159
redistribution of K from the ECV to the ICV can lead to
hypokalemia
160
hypokalemia can result from
GI losses, renal loss, intracellular shift, increased nonrenal losses, endocrinopathies, and poor intake
161
what is the most common electrolyte abnormality to come across in clinical practice?
hpokalemia
162
what promotes the movement of K into the ICV
B-adrenergic stimulation, insulin, and alkalosis
163
hypokalemia is __ times more likely to occur with patients on thiazide diuretics & __ as high for men than woman
11; twice
164
symptoms of mild hypokalemia
- palpitations
- skeletal muscle weakness
- muscle pain
165
symptoms of K < 2.5
- paresthesia
- depressed deep tendon reflexes
- fasciculations
- muscle weakness
- altered level of consciousness
166
patients with CHF & ischemia, hypokalemia increases the potential for
dysrhhythmias
167
common cardiac dysrhythmias present with hypokalemia are
- first-degree heart block
- second-degree heart block
- a-fib
- vfib
- asystole
168
ECG abnormalities with hypokalemia include
- ST depression
- flattened T-wave
- the presence of U wave
169
What's the fastest K can be given? and why?
40mEq per hour if levels are less than 2.0
170
maximum rate of 10-20mEq is recommended to avoid in
iatrogenic hyperkalemia? i think the book meant hypokalemia
171
IV K can be replaced with __ because __ makes it difficult for the kidney to conserve K
chloride; hypochloremia
172
hyperkalemia is defined as serum K
< 5
occurs less commonly compared to hypokalemia if renal causes are excluded
173
what meds increase ECV K
- beta blockers
- ACEIs
- ARBs
173
causes of hyperkalemia
- impaired renal excretion
- high intake of K
- shift of K from the ICV to the ECV
174
hyperkalemia can lead to increased __ production and apoptosis
LA
175
decreasing angiotensin, ___/___ can cause hyponatremia and hyperkalemia
ACEIs/ARBs
176
what is laboratory artifact?
pseudohyperkalemia
177
pseudohyperkalemia results from
hemolysis of the blood sample, leukocytosis, thrombosis, prolonged fist clenching during blood drawing
178
treatment of hyperkalemia accomplishes 3 physiologic effects
1.) stabilization of the cardiac membrane
2.) driving K from ECV to ICV
3.) removal of K from the body
179
treatment of hyperkalemia
10 units of regular insulin
1 ampule of D50
a complication can be hypoglycemia
180
what percent of calcium is found in the bones as hydroxyapitate ?
99%
181
remaining 1% of calcium exists in
the plasma and body cells
182
calcium as a second messenger is critical for functions of
muscle contractions, release of hormones, and neuotransmitters
183
calcium plays an important role in
blood coagulation, muscle function (myocardial contractility)
184
calcium in the ECV is found in 3 distinct fractions
- 50% is ionized Ca and is the physiologically active portion
- 10% of Ca is bound to anions
- 40% bound to plasma proteins primarily albumin
185
total of circulating Ca within the blood is
9.0 to 10.5 mg/dL
186
serum Ca levels are maintained by the release of inhibition of
PTH but also by vitamin D and calcitonin
187
causes of hypocalcemia
hyperventilation and massive rapid transusion
| hypervent causes respalkalosis, decr conc of ionized Ca by incr bind alb
187
hyperventilation leads to __ pH, which facilitates __ protein binding of calcium, thus __ serum ionized Ca
increased; increased; decreasing
188
citrate is a
preservative added to pRBCs
189
citrate chelates or binds to calcium, __ serum Ca available for physiological reactions
decreasing
190
massive rapid blood transfusions can cause acute
hypocalcemia
191
treatment of hypocalcemia involves the infusion of
Ca salts
cause signif venous irritation and tissue necrosis as compared to Ca gluconate
192
Ca gluconate preparation
10 mL of 10% Ca gluconate over 10 mins followed by an infusion of 0.3 - 2 mg/kg per hour
193
second most common cause?
malignancy
193
hypercalcemia results usually from
movement of ca from bone to the ECV
which exceeds the kidney to excrete the Ca
194
what accounts for more than 1/2 of the cases of hypercalcemia?
primary hyperparathyroidism
195
treatment of hypercalcemia involves
volume expansion with NS, increase renal excretion of Ca
addition of a loop diuretic
196
also been used to treat hypercalcemia
- bisphosphonates
- mithramycin
- calcitonin
- glucocorticoids
- phosphate salts
197
HD is an acute treatment to rapidly lower
serum Ca
198
Mag is the __ most abundant intracellular cation
second
199
what percent of Mag is stored in muscle and bone?
within the cells?
and within the serum?
40-60%
30%
1%
200
importance of mag in its role as a cofactor in
- enzymatic reactions (involving energy metabolism)
- protein synthesis
- neuromuscular excitability
- function of the Na-K-ATPase pump
201
regulation of Mag occurs where?
intestines and kindeys
202
hypomagnesemia increases cardiovascular death in men and women by what percentage?
8% & 16%
203
hypomagnesemia has an __ effect on the Na-K-ATPase pump resulting in __ ICV of K
inhibitory; decreased
204
IV infusion of mag can relieve severe __ , and it can decrease __ __
bronchospasm; postoperative pain
204
hypo magnesium causes
increased renal or GI losses or poor mag intake and/or medications
205
ECG changes seen with hypomagnesemia
- flat T waves
- presence of U waves
- prolonged QT interval
- widened QRS complexes
- atrial and ventricular arrhythmias
206
treatment of hypomagnesemia
IV 1 to 2 g of mag sulfate over 5 mins followed by 1 to 2 g per hour
207
hypermagnesemia is the most commonly the result of
iatrogenic causes
208
hypermagnesemia can result from
- treatment of preeclampsia
- preterm labor
- ischemic heart dx
- cardiac dysrhythmias
209
symptoms of hypermagnesemia
depression of the peripheral and central NS, hypotension, QRS segment widening, PR & QT segment prolongation, heart block, and cardiac arrest
210
magnesium potentiates the action of
NDMR
211
treatment of hypermagnesemia
- d/c mag
- in urgent situations (brady, heart block, resp depression) calcium chloride should be used as an antagonist
212
majority of phosphate is located in
bone 85%
213
small amount of phosphate is located in
plasma, phospholipids, phosphate esters, inorganic phosphate (which is the ionized form)
214
intracellular phosphate has numerous metabolic effects such as
component of ATP, and 2,3 -diphosphoglycerate, also acts as a buffer in the regulation of acid/base imbalance
215
the concentration of phosphate in plasma in inversley proportional to
calcium
216
hypophosphatemia is defined as
< 2.0 mg/dL
217
hypophosphatemia causes
increased renal excretion & intestinal malabsorption
218
resp alkalosis can also cause low phosphate levels how?
accelerated use of ATP by cells
219
hypophosphatemia decreased 2-3-DPG is in RBC's causing what shift in ODC
leftward
220
hyperphosphatemia is defined as
greater than 4.7 mg/dL
221
majority of phosphate exists within the ECV, and cellular __ is a leading cause
destruction (exp. metastatic dx)
222
increase phosphate levels cause __ CA levels
decreased
so symptoms are synonymous with hypocalcemia
