Fluids, electrolytes, & acid-base 3 Flashcards
Sodium osmolarity of 350-375 mEq/L can cause
headache
agitation
confusion
Sodium osmolarity of 376-400 mEq/L can cause
weakness
tremors
ataxia
Sodium osmolarity of 401-430 mEq/L can cause
hyperreflexia
muscle twitching
Sodium osmolarity of >430 mEq/L can cause
seizures
coma
death
Which statements represent the BEST understanding of the physiologic role of calcium? (Select 2).
a. Calcium is factor 6 in the coagulation cascade
b. albumin administration can cause hypocalcemia
c. it is responsible for phase 1 of the cardiac myocyte action potential
d. acidosis increases ionized calcium
b. albumin administration can cause hypocalcemia
d. acidosis increases ionized calcium
Normal plasma calcium is
8.5-10.5 mg/dL or 4.5-5.5 mEq/L
Normal ionized calcium is
4.65-5.28 mg/dL or 2.2-2.6 mEq/L
Parathyroid hormone ___________ serum calcium and calcitonin ___________- serum calcium
raises; lowers
Calcium plays a crucial role in ________ of the cardiac muscle cell action potential
phase 2
Important functions of calcium include
second messenger systems, neurotransmitter release, and muscular contraction (skeletal, cardiac vascular, bronchial, etc.)
The primary treatment for hypercalcemia includes
IV hydration (0.9% NaCl) & a loop diuretic (furosemide)
Calcium antagonizes the effects of _________ at the neuromuscular junction
magnesium
Calcium is factor ___ in the coagulation pathway.
4
Acidosis _________ionized calcium
increases
Alkalosis ___________- ionized calcium
decreases
What is the Chvostek sign?
tapping on the angle of the jaw–> facial contraction on the ipsilateral side
What is the Trousseau sign?
an upper extremity BP cuff is inflated above SBP for three minutes, decreased blood flow accentuates neuromuscular irritability–> muscle spasms of the hand and forearm
Etiology of hypocalcemia includes
hypoparathyroidism
vitamin D deficiency
pancreatitis
sepsis
renal osteodystrophy
Presentation of hypocalcemia includes
skeletal muscle cramps
nerve irritability
laryngospasm
mental status changes–> seizures
Chvostek sign
Trosseau sign
What are the EKG findings of hypocalcemia
long QT interval
What are the reasons for hypercalcemia?
hyperparathyroidism
cancer
thyrotoxicosis
thiazide diuretics
immobilization
What is the presentation of hypercalcemia?
nausea
abdominal pain
hypertension
psychosis
mental status changes–> seizures
What is the EKG findings of hypercalcemia?
short QT interval
Loss of deep tendon reflexes is MOST likely a consequence of:
a. hypomagnesemia
b. hypermagnesemia
c. hypocalcemia
d. hypercalcemis
b. hypermagnesemia
Normal plasma magnesium (total) is
1.7-2.4 mg/dL or 1.5-3 mEq/L
Magnesium antagonizes the effects of
calcium
Clinical uses of magnesium include
pre-eclampsia
opioid-sparing technique
acute bronchospasm
cardiac rhythm disturbances (symptomatic PVCs or torsades de points)
Magnesium is required for normal ___________ function
cardiac
What is the loading dose and dose of magnesium for pre-clampsia?
4 g load over 10-15 minutes then 1 g/hr for 24 hours
Administration of magnesium for >48 hours increases the risk of
neonatal respiratory depression, hypotension, and lethargy
Reasons for hypomagnesemia include
poor intake
alcohol abuse
diuretics
critical illness
common with hypokalemia
Reasons for hypermagenesemia include
excessive administration
renal failure
adrenal insufficiency
EKG findings of hypermagnesemia include
heart block
EKG findings of hypomagnesemia include
long QT
At a magnesium level of <1.2 mg/dL, you will see
tetany
seizures
dysrhythmias
At a magnesium level of 1.2-1.8 mg/dL, you will see
neuromuscular irritability
hypokalemia
hypocalcemia
At a magnesium level of 2.5-5 mg/dL, you will see
typically no symptoms
At a magnesium level of 5-7 mg/dL, you will see
lethargy, drowsiness, flushing, N/V, diminished deep tendon reflexes
At a magnesium level of 7-12 mg/dL, you will see
loss of deep tendon reflexes, hypotension, EKG changes, somnolence
At a magnesium level of >12 mg/dL, you will see
respiratory depression–> apnea, complete heart block, cardiac arrest, coma, & paralysis
How does magnesium work as an opioid-sparing drug?
it antagonizes NMDA receptors
What classic sign should you assess in an OB patient receiving magnesium for preeclampsia?
loss of deep tendon reflexes
