Acute & Critical Care Medicine Flashcards
What is the cause of
hypervolemic hyponatremia
Fluid overload
e.g., cirrhosis, heart failure, renal failure
What is the cause of
hypervolemic hypernatremia
Intake of hypertonic fluids
What is the cause of
isovolemic hypernatremia
Diabetes insipidus
What is the treatment for
isovolemic hypernatremia
Desmopressin
What is the treatment for
hypervolemic hypernatremia
Diuresis
What is the cause of
hypovolemic hypernatremia
- Dehydration
- Vomiting
- Diarrhea
What is the treatment for
hypovolemic hypernatremia
Fluids
What is the treatment for
hypervolemic hyponatremia
- Diuresis with fluid restriction
- AVP receptor antagonists
AVP receptor antagonists: conivaptan, tolvaptan
What is the treatment for
isovolemic hyponatremia
- Stopping drugs that can induce SIADH
- Demeclocycline (SIADH)
- Diuresis
- Restricting fluids
- AVP receptor antagonists
What is the treatment for
hypovolemic hyponatremia
- Hypertonic (3%) sodium chloride IV for severe symptoms and/or Na < 120
Severe symptoms = seizures, coma, respiratory arrest
What is the cause of
isovolemic hyponatremia
SIADH
What is the cause of
hypovolemic hyponatremia
- Diuretics
- Salt-wasting syndromes
- Adrenal insufficiency
- Blood loss
- Vomiting
- Diarrhea
What can happen if sodium is being corrected faster than 12 mEq/L/24 hours?
Can cause osmotic demyelination syndrome (ODS) or central pontine myelinolysis, which can cause paralysis, seizures and death.
Tolvaptan (Samsca)
- PO
- Arginine vasopressin receptor antagonist; selective AVP antagonist [vasopressin 2 (V2) only]
- Should be initiate and re-initiated in a hospital with close monitoring of serum Na
- Overly rapid correction of hyponatremia (> 12 mEq/L/24 hrs) is associated with ODS
- Use is limited to ≤ 30 days due to hepatotoxicity
- SEs: thirst, nausea, dry mouth, polyuria
Which electrolyte must be corrected before correcting potassium?
Magnesium
What is the maximum IV KCl infusion rate and concentration for treating hypokalemia through a peripheral line?
- Max infusion rate: ≤ 10 mEq/hr
- Max concentration: 10 mEq/100mL
Never administer undiluted IV potassium or via IV push
Which route of administration is preferred for KCl?
PO
What is the preferred treatment when serum Mg is < 1 mEq/L w/ life-threatening symptoms (e.g., seizures, arrhythmias)?
IV magnesium sulfate
Vasopressor MOA
Stimulating alpha receptors → peripheral vasoconstriction and ↑ systemic vascular resistance (SVR)
Vasopressors
- Dopamine: dose-dependent receptor effects (D1 → beta-1 → alpha-1)
- Epinephrine: alpha-1, beta-1, beta-2
- Norepinephrine: alpha-1 > beta-1
- Phenylephrine: alpha-1
- Vasopression: vasopression agonnist
- Angiotensin II: vasoconstriction, aldosterone release
What is the boxed warning for all IV vasopressors?
All vasopressors are vesicants when administered IV
Treat extravasation with phentolamine (an alpha-1 blocker)
Vasopressor SEs
- Arrythmias
- Tachycardia (esp. dopamine, epinephrine)
- Necrosis (gangrene)
- Bradycardia (phenylephrine)
- Hyperglycemia (epinephrine)
What is the concentration of epinephrine used for IV push?
0.1 mg/mL
What is the concentration of epinephrine used for IM injection or compounding IV products?
1 mg/mL
What lab needs to be frequentlt/continuously monitored when giving continuous IV vasodilators?
Blood pressure
Low dose nitroglycerin MOA
Venous vasodilator
Preload
High dose nitroglycerin MOA
Arterial vasodilator
Afterload
Nitroprusside MOA
Mixed (equal) arterial and venous vasodilator
What are the metabolites of nitroprusside?
- Thiocyanate
- Cyanide
Hydroxocobalamin → reduce the risk of thiocyanate toxicity or to treat cyanide toxicity
Sodium thiosulfate + sodium nitrite → cyanide toxicity
Which vasodilator requires a non-PVC container?
Non-PVC container: glass, polyolefin
Nitroglycerin
Which vasodilator requires light protection during administration?
Nitroprusside
What color of nitroprusside solution would indicate that it has been degradated to cyanide?
Blue
Inotrope MOA
Increase the contractility of the heart
* Dobutamine – beta-1 agonist
* Milrinone – phosphodiesterase-3 inhibitor; also a vasodilator
What is the characteristic of a shock?
- Hypoperfusion
- Hypotension (SBP < 90 or MAP < 70)
What are the general principles for treating septic shock?
- MAP goal: ≥ 65
- Fill the tank: optimize preload with IV crystalloids (balanced fluids such as Lactated Ringer’s preferred)
- Squeeze the pipe: alpha-1 agonist activity (peripheral vasoconstriction) to ↑ SVR
- Kick the pump: beta-1 agnost activity to ↑ myocardial contractility and CO
What is the vasopressor of choice in septic shock?
Norepinephrine
What are the first-line analgesia in ICU?
IV opioids
What treatments are used to manage agitation in ICU?
- Benzodiazepines (lorazepma, midazolam)
- Non-benzo hypnotics (propofol, dexmedetomidine)
Which sedative can be used in both intubated and non-intubaed patients?
Dexmedetomideine (Precedex)
What can be used for delirium in ICU?
- Quetiapine
- Haloperidol
Propofol is contraindicated in patients with
egg or soy allergies
Dexmedetomideine MOA
Alpha-2 adrenergic agonist
List the risk factor for developing stress ulcers in ICU
- Mechanical ventilation > 48 hrs
- Coagulopathy
- Sepsis
- Traumatic brain injury
- Major burns
- Acute renal failure
- High dose systemic steroids
What prophylaxis are recommended to prevent stress-related mucosal damage in pts with risk factors for stress ulcer?
- H2RAs (can cause thrombocytopenia and mental status changes in the elderly or those with renal impairement)
- PPIs (associated with an increased risk of GI infections, fractures and nosocominal penumonia)
1.
Bupivacaine can be fatal if administered
intravenously
What is the purpose of epinepherine in the lidocaine/epinephrine combination product?
Epinephrine is added for vasoconstration, which keeps the lidocaine localized to the area where the numbing is needed.
List the commonly used anesthetics
- Lidocaine
- Desflurane, sevoflurane
- Bupivacaine, ropivacaine
Cisatracurium (Nimbex) MOA
Non-depolarizing NMBA: block acetylcholine from binding to the receptor
Succinylcholine
Depolarizing NMBA: activate the acetylcholine receptors and desensitizes them
Neuromuscular blocking agents
- Not routinely used
- Cause skeletal muscle paralysis
- Patients must be mechanically ventilated
- NMBAs do not provide sedation or analgesia, patients should receive adequate sedation and analgesia prior to starting an NMBA
- All agents should be labeled with a colored auxiliary label stating “Warning: Paralyzing Agent causes respiratory arrest”
What are hemostatic agents used for?
Stop the bleeding
Systemic hemostatic agents MOA
Inhibiting fibrinolysis or enhancing coagulation
* Tranexamic acid
* Recombinant Factor VIIa (NovoSeven RT)
