Chapter 53: Acute and Critical Care Medicine Flashcards
Crystalloids
- D5W
- NS
- LR (contains NaCl, KCl, CaCl2, Na-lactate)
Colloids
Albumin 5%, 25% (Albutein, AlbuRX)
Stay in intravascular space and increase oncotic pressure
Hyponatremia
Na<35meq/l
Correcting more rapidly than 12meq/l over 24 hours can cause osmotic demyelination syndrome (ODS) or central pontine myelinolysis which can cause paralysis, seizures, and death.
Hypotonic Hypovolemic Hyponatremia
Can be cause by diuretics, blood-loss, vomiting, diarrhea.
Treatment is to correct cause and administer NaCl IV solutions
Hypotonic Hypervolemic Hyponatremia
Cause by fluid overload (cirrhosis, HF, or renal failure)
Treatment is diuresis with fluid restriction
Arginine Vasopressin (AVP) receptor antagonists
Conivaptan and Tolvaptan
May be used to treat SIADH and hypervolemic hyponatremia.
They increase excretion of free water while maintaining sodium
Tolvaptan
Limited to <=30 days use due to hepatoxicity
Boxed warning: Should be initiated in a hospital, rapid over correcting can cause ODS
SE: thirst, nausea, dry mouth, polyuria
Hypernatremia
NA>=145meq/l
Associated with water deficit and hypertonicity
Hypokalemia
K<3.5meq/l
In general a drop of 1 meq/l in serum K below 3.5 represents a total body deficit of 100-400 meq
K replacement
Safe administration through a peripheral IV line include a max infusion rate of <=10 meq/hr and a max concentration of 10 meq/100ml
IV K can be fatal if administered undiluted or through IV push
Magnesium is necessary for K uptake
Hypomagnesium
Mg<1.3 meq/l
When serum Mg is <1 meq/l with life-threatening symptoms (seizures, arrhythmias) IV replacement is recommended. Magnesium Sulfate is used for IV replacement.
When serum Mg is >1 meq/l and <1.5 Mg can be replaced orally, most commonly with Mg Ox
Hypophosphatemia
Considered severe and is usually symptomatic when serum PO4 is < 1 mg/dL, IV PO4 is used for replacement.
Intravenous Immunoglobulins
Carimune NF, Flebogamma DIF, Gammagard, Gamunex-C, Octagam, Privigen
-Use slower infusion rate in renal and CV disease
APACHE II
The Acute Physiologic Assessment and Chronic Health Evaluation II: scoring tool used to determine prognosis and ICU mortality risk
Vasopressors
Most work by stimulating alpha receptors which causes vasoconstriction and increases systemic vascular resistance (SVR) which increases BP
Dopamine MOA
Dependent on dose
- Low (renal) dose: 1-4mcg/kg/min (dopamine-1 agonist)
- Medium dose: 5-10mcg/kg/min (beta-1 agonist)
- High dose: 10-20mcg/kg/min (alpha-1 agonist)
Epinephrine
Adrenaline
Alpha-1, Beta-1, and beta-2 agonist
Norepinephrine
Levophed
Alpha-1 agonist activity > beta-1 agonist activity
Phenylephrine
Neo-synephrine
Alpha-1 agonist
Vasopressin
Vasostrict
Vasopressin receptor agonist
Vasopressors warnings, SE, notes
Boxed warnings: all vasopressors are vesicants, when administered IV, treat extravasation with phentolamine
SE: arrhythmias, tachycardia, necrosis (gangrene), bradycardia (phentolamine), hyperglycemia (epinephrine)
Notes: solutions should not be used if they are discolored or contain a precipitate, should be administered through central line, epinephrine used for IV push is 0.1mg/ml (1:10,000) and IM is 1mg/ml (1:1,000)
Phentolamine
Alpha-1 blocker that antagonizes the effects of the vasopressor
Nitroglycerin uses
Often used when there is active myocardial ischemia, or uncontrolled HTN but effectiveness may be limited to 24-48 hrs due to tachyphylaxis (tolerance)
Nitroprusside MOA and uses
It is a mixed (equal) arterial and venous vasodilator at all doses.
Should not be used it active myocardial ischemia because it can cause blood to be diverted away from diseased coronary arteries (“coronary steal”)
Nitroprusside toxicity
Metabolism results in thiocyanate and cyanide formation which can cause toxicity. Hydroxocobalamin can be administered to reduce risk and sodium thiosulfate + sodium nitrite (Nithiodote) is used for cyanide toxicity
Nitroglycerin MOA, CI, SE
MOA: low doses is a venous vasodilator; high doses is a arterial vasodilator
CI: SBP<90, use with PDE-5 inhibitor
SE: HA, tachycardia, tachyphlaxis
Notes: requires non-pvc container (glass, polyolefin)