Critical Care Flashcards
(42 cards)
When 1 L of NS is given, how much will stay in the intravascular space?
250mL
Crystalloids Versus Colloids
Crystalloids: contain various concentrations of electrolytes or dextrose that pass between semi-permeable membranes, mostly staying in extravascular or interstitial space
-Benefits: less costly, less adverse reactions
-Ex: 5% Dextrose (D5W), 0.9% NaCl (NS), Lactated Ringer’s (LR), Plasma-Lyte A
Colloids: LARGE molecules (typically protein or starch) dispersed in solution that remain in INTERVASCULAR space and increase oncotic pressure
-Ex. albumin, hydroxyethyl starch, dextran
-Hydroxyethyl starch: BBW for mortality, renal injury, and coagulopathy
When would you give certain types of crystalloids or colloids?
Crystalloids: usually first line for fluid replacement
-NS or LR: often in shock states for volume resuscitation
-Hypertonic saline: can be used in stroke or enchepalitis combined with hyponatremia when brain is susceptible to having higher Na+ concentrations that could shift fluid from periphery into brain
-D5W: when “free water” is needed INTRACELLULARLY –> does NOT go into intravascular (DO NOT use for fluid resuscitation)
Colloids: if pt is actively bleeding or Hgb <7
Hyponatremia is Na < _______, but usually isn’t symptomatic until Na <_______.
Hypernatremia is Na > ______.
What are s/sx of hyponatremia? Severe s/sx?
<135; <120; >145
Hyponatremia: HA, confusion, lethargy, gait disturbances
-Typically from cerebral edema and increased intracranial pressure
-Severe s/sx: seizures, coma, respiratory distress
Which electrolyte can cause risk of osmotic demylination syndrome (ODS) or central pontine myelinolysis (paralysis, seizures, death) if replaced too quickly? What is the max rate that this electrolyte should be corrected?
Na+ - correct no more rapidly than 12 mEq/L/24 hours
Causes and Treatment of Hyponatremia
Hypervolemic: fluid overload (ex. cirrhosis, HF, renal failure) –> diuretics with fluid restriction preferred TX
-Arginine vasopressin (AVP) receptor antagonists (conivaptan, tolvaptan)
Hypovolemic: diuretics, self-wasting syndromes, adrenal insufficiency, blood loss, or N/V –> correct underlying cause
-Severe: hypertonic 3% NaCl IV
Isovolemic: syndrome of inappropriate antidiuretic hormone (SIADH) –> diuresis w/ fluid restriction, D/C drugs contributing to SIADH, demeclocyline, AVP receptor antagonists
Conivaptan:
-Brand
-MOA
-ROA
-AVEs
-CIs
-Monitoring
Brand: Vaprisol
MOA: dual arginine vasopressin antagonist (vasopressin 1A and 2)
ROA: injection
AVEs: orthostatic hypotension, fever, hypokalemia, injection site rxns (>60%)
CIs: hypovolemic hyponatremia, anuria, concurrent usage w/ strong CYP3A4 inhibitor
Tolvaptan:
-Brand
-MOA
-ROA
-AVEs
-CIs
Brand: Samsca
MOA: selective arginine vasopressin antagonist (vasopressin 2 = V2)
ROA: PO (tablet)
AVEs: THIRST, DRY MOUTH, NAUSEA, POLYURIA, weakness, hyperglycemia, hypernatremia
-Avoid usage >30 days and in liver disease/cirrhosis (HEPATOTOXICITY)
CIs: hypovolemic hyponatremia, anuria, concurrent usage w/ strong CYP3A4 inhibitor, inability to sense or respond to thirst, urgency to raise Na+
Hypernatremia: Causes and Treatment
Hypovolemic: dehydration, N/V -> fluids
Hypervolemic: intake of hypertonic fluids –> diuresis
Isovolemic: diabetes insipidus (DI) which decreases antidiuretic hormone (ADH) –> desmopressin
Potassium:
Hyperkalemia is often from ________ and is defined as K+ > ______mEq/L.
Hypokalemia, which is a more common experience in hospitalized pts, is defined as K+ <____mEq/L. A drop of 1 mEq/L below this value represents a total body deficit of ___-___mEq.
Hyperkalemia: from CKD often; K+ > 5-5.5 mEq/L
Hypokalemia: <3.5mEq/L; 100-400 mEq (in other words, for every 10mEq given, K+ will increase by 0.1mEq/L)
hich electrolyte is typically diluted prior to being given IV? What is the concern of higher concentrations?
Potassium - higher concentrations particularly in peripheral lines can be painful to the pt and low or high levels of K+ can cause cardiac arrhythmias (typically no more than 10mEq/hr or 10mEq/100mL in concentration).
In severe scenarios, a central line can be used that higher concentrations can be given.
In general, PO potassium should be given first prior to IV.
If supplementing potassium, but not increasing, what electrolyte may need to be replaced as it necessary for potassium uptake?
Magnesium
Treatment and causes of hypokalemia
Causes: metabolic acidosis, overdiuresis, medications (insulin, amphotericin, diuretics)
When feasible, give PO potassium first - if NOT IV (potassium chloride premixed IV preferred)
Hypomaganesemia:
-Mg <___mEq/L
-Causes
-Treatment
Mg <1.3 mEq/L
Causes: alcohol use, diuretics, amphotericin B, vomiting/diarrhea
Treatment:
-If life-threatening (seizures, arrhythmias) and Mg <1mEq/L: IV mangesium sulfate
-If Mg <1.5mEq/L, but >1mEq/L: magnesium oxide PO
-Treatment should continue for 5 days to fully replace body’s stores
Phosphorus:
-Hyperphosphatemia is often due to __________.
-Hypophosphatemia: symptoms, causes, treatment
Hyperphosphatemia: caused by CKD
Hypophosphatemia:
-Caused by phosphate-binding drugs (calcium salts, sevelamer), chronic alcohol intake, hyperparathyroidism
-Treatment: when PO4 <1mg/dL typically give 0.08-0.16 mmol/kg in 500mL of NS or D5W over 6 hours; less severe: PO
-Treatment should last one week or longer to fully replace body’s stores
Intravenous immunoglobulin:
-Brands
-MOA
-ROA, administration notes
-TX
-AVEs
-CIs
Brands: Gammagard, Gamunex-C, Octagam, Privigen
MOA: immunoglobulin (IgG) from plasma of at least 1,000 or more (FDA minimum, but typically 3,000-10,000) donors to replace antibodies
ROA: IV - do NOT freeze, SHAKE, or heat
TX: immunodeficient patients
-Off-label: MS, myasthenia gravis, Guillain-Barre syndrome
AVEs: INFUSION RXNS (flushing, chest tightness, fever, chills, hypotension - SLOW/STOP infusion if needed), HA, nausea, diarrhea
-Rare: blood dyscrasias, renal failure (usually occurs within 7 days and more likely w/ products stabilized w/ sucrose)
-IMPAIRS RESPONSE TO VACCINES: NEED TO SPACE BETWEEN
CIs: IgA deficiency (use product with lowest IgA)
What is the APACHE II Test?
The Acute Psychologic Asessement and Chronic Health Evaluation II - ICU mortality risk assessment
What medications in the ICU are typically given through an central line?
- Vasopressors
- Vasodilators
- Inotropes
Often given as continuous infusion
Central line allows medications to be given into heart where maximum blood flow is. Blood dilutes concentratations, and medications can be given at higher concentrations.
Vasopressors: drugs, MOA
Drugs/MOA: cause peripheral vasoconstriction that increase systemic vascular resistance (SVR), increasing BP
-Phenylephrine: alpha1 agonist
-Norepinephrine: alpha 1 agonist > beta-1 agonist (DOC usually)
-Epinephrine: alpha-1, beta-1, and beta-2 agonist (not used as much since not selective)
-Vasopressin: vasopressin receptor agonist (constriction only, no inotropic or chronotropic effects)
Dopamine: dose-dependent receptor activity
-Low doses (1-4 mcg/kg/min): dopamine-1 agonist (improves renal function)
-Medium doses (5-10 mcg/kg/min): beta-1 agonist (positive inotropic effects beneficial in HF)
-High doses (10-20 mcg/kg/min): alpha-1 agonist (vasopressor)
Vasopressors (ex. dopamine, EPI, norepinephrine, phenylephrine, vasopressin):
-AVEs
-Warnings/BBW
-Monitoring
AVEs: arrhythmias, tachycardia (especially dopamine and EPI), bradycardia (phenylephrine), necrosis (gangrene), hyperglycemia (EPI), tachyphylaxis, peripheral and gut ischemia
Warnings: extreme caution w/ MAOIs, prolonged hypertension (especially dopamine, EPI, and norepinephrine)
BBW:
-Dopamine and norepinephrine: extravasation
-All others are vesicants when administered IV
-Treat extravasation with phentolamine (alpha-1 blocker - majority of vasopressors are alpha-1 agonists), alternatively nitroglycerin ointment can be used if unavailable
Monitoring: CONTINUOUS BP, HR, MAP, ECG, urine output, infusion site for extravasation
Epinephrine IV push dose should be at ____mg/mL. Epinephrine IM injection or compounding IV products dose should be at____mg/mL
IV push: 0.1mg/mL
IM injection/compounded IV: 1mg/mL
Vasodilators:
-Drugs
-MOA
-TX
-AVEs
-CIs
-Administration considerations
Drugs: nitroglycerin, nitroprusside
MOA:
-Nitroglycerin: at low doses, venous vasodilator; at high doses, aterial vasodilator
-Nitrprusside: mixed vasodilator (equal between arterial and venous)
TX: MI (nitroglycerin only), uncontrolled HTN
AVEs: HA, tachycardia, increased intracranial pressure
-Nitroglycein: tachyphylaxis within 24-48 hours
-Nitroprusside: BBW of cyanide toxicity (excessive hypotension especially in renal or hepatic impairement); “coronary steal” from greater effect on BP and causing blood to be diverted away from coronary arteries
CIs: nitroglycerin used with PDE5 inhibitors (hypotensive crisis) or riociguat or SBP <90mmHg
Administration:
-Nitroglycerin: requires non-PVC containers (ex. glass or polyolefrin): permeates PVC
-Nitroprusside: requires light protectionl use only clear solution (blue indicates degradation to cynanide)
Treatment for cyanide poisoning from nitroprusside
Sodium thiosulfate and sodium nitrate (Nithiodote)
-Hydroxocobalamin can be used to reduce risk of thiocyanate toxicity
Inotropes:
-Drugs
-MOA
-TX/When to use
-AVEs
-Monitoring
Drugs: dobutamine, milrinone
MOA: “inodilators” - intropes that increase contraction + vasodilation
-Dobutamine: beta-1 agonist with WEAK beta-2 and alpha-1 agonist
-Milrinione: phoesphodiesterase-3 (PDE-3) inhibitor - selective to cardiac and vascular tissue
TX: use only when BP is adequate to produce vasodilation and when contraction of heart needed (ex. MI)
AVEs:
-Dobutamine: hyper/hypotension, ventricular arrhythmias, tachycardia, angina
-Milrinone: ventricular arrhythmias, hypotension
Monitoring: continuous BP and ECG, HR, central venous pressure (CVP), MAP, urine output, LFTs, renal function (milrinone)
-Dobutamine may turn slightly pink from oxidation, but potency is NOT lost
