Acute & Critical Care Medicine Flashcards
Crystalloids vs Colloids
Differences between them
Crystalloids:
* Less costly
* Fewer adverse reactions
Colloids:
* More expensive
* Large molecules (protein or starch)
* Remain in the intravascular space
* Increases oncotic pressure
* No clear clinical benefit over crystalloids
Crystalloids
Name common fluids
5% Dextrose (D5W)
* Used when water needed intracellularly as it contains “free water”
Lactated Ringer’s (LR)
* Contains NaCl, KCl, CaCl2, Na-lactate (lactate converted to bicarbonate)
0.9% NaCl (normal saline, NS)
Multiple electrolyte injection (Plasma-Lyte A)
LR and NS common fluids that are used for volume resucitation in shock states
***More examples of crystalloids; D50, D5NS, D51/2NS, 1/2NS
Colloids
Name common fluids
Albumin 5%, 25% (Albutein, AlbuRx)
* Most commonly use colloid
* Particularly useful when there is a significant edema (cirrhosis)
Hydroxyethyl starch (Hespan, Hextend)
* Boxed warning - avoid use in critical ilness (including sepsis) due to mortality and renal injury
Dextran (Dextran 40)
What is hyponatremia?
Na < 135 mEq/L
Hypotonic hypovolemic hyponatremia
Causes and treatments
- Can be caused by diuretics, salt-wasting syndromes, adrenal insufficiency
- Treatment: NaCl IV solutions
Hypotonic hypervolemic hyponatremia?
Causes and treatments
- Caused by fluid overload (e.g., cirrhosis, HF, renal failure)
- Treatment: diuresis with fluid restriction
Hypotonic isovolemic (euvolemic) hyponatremia?
Causes and treatments
- Can be caused by the syndrome of inappropriate antidiuretic hormone (SIADH)
- Treatment: stopping drugs that can induce SIADH, diuresis or restricting fluids
Correcting Na more rapidly than ____over ____ hours can cause ____ or ____ which can cause ___, ____, and ____.
Fill in the blanks
- 12 mEq/L
- 24
- Osmotic demyelination syndrome (ODS)
- Central pontine myelinolysis
- Paralysis, seizures and death
What is the treatment for SIADH and hypervolemic hyponatremia?
Arginine vasopressin (AVP) receptor antagonists (conivaptan, tolvaptan)
Tolvaptan (Samsca)
Safety/SEs/Monitoring
BW:
* Should be initiated and re-initiated in a hospital
* Overly rapid correction of hyponatremia is associated with ODS
SEs:
* Thirst, nausea, dry mouth, polyuria
Monitoring:
* Rate of Na increase
* Limited to <- 30 days due to hepatotoxicity
What is hypernatremia?
Na > 145 mEq/L is associated with a water deficit and hypertonicity
What is hypokalemia?
- K < 3.5 mEq/L
- Common in hospitalized patients
- Management includes; treating underlying causes (metabolic alkolosis, overdiuresis), some medications (such as amphotericin, insulin)
A drop of __ in serum K below __ represents a total body deficit if __ mEq
Fill in the blanks
- 1 mEq/L
- 3.5 mEq/L
- 100 - 400 mEq
Safe recommendations for IV K replacement through a ___ include a max infusion rate ___ and a max concentration of ___.
Fill in the blank
- Peripheral line
- <- 10 mEq/hr
- 10 mEq/100 mL
What makes IV potassium fatal?
K can be fatal when admistered indiluted or IV push
What should be checked if hypokalemia is resistant to treatment?
Serum magnesium (Mg is necessary for potassium intake)
What is recommended when Mg <1 mEq/L with life threatening symptoms? and what are those sympstoms?
- Magnesium sulfate
- Seizures, arrhythmias
Hypophosphotemia is considered __ ans is usually __ when PO4 is __
Fill in the blanks
- Severe
- Symptomatic
- < 1 mg/dL
What is initiated when PO4 is < 1 mg/dL?
IV phosphorus
What does immune globulin (IVIG or IGIV) contains?
Pooled immunoglobulin (IgG)
Where dose IgG is extracted from?
Plasma of a thousand or more blood donors
What does IVIG is only used for? Give examples
- Immunodefiency conditions
- Myasthenia Gravis, MS, Guillain-Barre syndrome
Treatment with IVIG can impair response to ___.
Fill in the blank
Vaccination
Name IV immunoglobulins
- Carimune NF
- Flebogamma DIF
- Gammagard
- Gamunex-C
- Octagam
- Privigen
Safety/SEs/Monitoring for IV immunoglobulins
BW:
- Acute renal dysfunction (more likely with products stabilized with sucrose
- Thrombosis
SEs:
- Headache, nausea, diarrhea, Injection site reactions, infusion reactions (facial flushing, fever, chills, hypotension - slow/stop infusion)
Warnings:
- Use slower infusion tae in renal and CV disease
What is the scoring tool used to determine prognosis and estimate ICU mortality risk?
The Acute Physiologic Assessment and Chronic Health Evaluation (APACHE II)
MOA of vasopressors
Vasopressors increases systemic vasculature resistance (SVR) which increases BP
Dopamine dosing
Low (renal) dose: 1-4 mcg/kg/min
* Dopamine -1 agonist
Medium dose: 5-10 mcg/kg/min
* Beta-1 agonist
High dose: 10-20 mcg/kg/min
* Alpha-1 agonist
List MOA of Epinephrine, Norepinephrine, Phenylephrine and Vasopressin
Epinephrine (Adrenalin, EpiPen)
* Alpha-1, Beta-1 and Beta-2 agonist
Norepinephrine (Levophed)
* Alpha-1 agonis activity > Beta-1 activity
Phenylephrine
* Alpha-1 agonist
Vasopressin (AVP, ADH)
* Vasopressin receptor agonist
Safety/SEs/Monitoring for vasopressors
BW:
* Dopamine and norepinephrine - extravasation; all vasopressors are vesicants when administered IV; treat extravasation with phentolamine (Alpha-1 blocker)
SEs:
* Arrhytmias, tachycardia (especially dopamine and epinephrine), gangrene (necrosis), bradycardia (phenylephrine), hyperglycemia (epinephrine)
Monitoring:
* Continuous BP monitoring
Notes:
* Solutions should not be used if they are discolored or contain a precipitate
* All vasopressors should be administered central IV line
* Epinephrine used for IV push 0.1 mg/mL (1:10,000 ratio strenght). IM injection is 1 mg/mL (1:1,000 ratio strenght)
What is NTG class? And when is it often used?
- Vasodilator
- Myocardial ischemia, uncontrolled HTN
NTG MOA
Low doses: venous vasodilator
High doses: arterial vasodilator
NTG - Safety/SEs/Monitoring
Contraindications:
* SBP <90 mmhg, use with PDE-5 inhibitors, riociguat
SEs:
* Headache, tachycardia, tachyplaxis (within 24-48 hrs of continuous administration)
Notes:
* Requires non-PVC container (glass, polyolefin)
What is nitroprusside and its metabolism?
- It is mixed (equal) arterial and venous vasodilator
- Metabolism results into thiocyanate and cyanide formation, which can cause to toxicity
Hydroxocobalamin can be administered to reduce the __ of __
Fill in the blanks
Reduce the risk of thiocyanate toxicity
What is used for cyanide toxicity?
Sodium thiosulfate + sodium nitrite
T/F: Nitroprusside should not be used in active Myocardial ischemia because it can cause blood to be diverted away from diseased coronary arterie (coronary steal).
TRUE
Nitroprusside - Safety/SEs/Monitoring
Nitropress, Nipride
BW:
* Cyanide formation might cause excessive hypotension. Not for direct injection so it should be diluted, D5W is preferred
Warnings:
* Increases ICP
SEs:
* Headache, tachycardia, thiocyanate/cyanide toxicity (risk increases in renal and hepatic impairment)
Notes:
* Requires light protection during administration; use only clear solutions, a blue color indicates degradation to cyanide - do not use
MOA of Inotropes
Increase the contractility of the heart
Dobutamine, Milrinone - MOA/Safety/SEs/Monitoring
These are inotropes
MOA:
* Dobutamine: Beta-1 agonist
* Milrinone: PDE-3 inhibitor
Notes:
* Dobutamine may turn slightly pink due to oxidation, but potency is not lost
Shock is characterized by __, usually in the setting of __
Fill in the blank
- Hypoperfusion
- Hypotension
What are the types of shock?
- Hypovolemic (hemorrhagic)
- Distributive (septic, anaphylactic, neurogenic)
- Cardiogenic (post-myocardial infarction)
- obstructive (massive pulmonary embolism)
What is hypovolemic shock?
- Hemorrhagic
- Fluid resuscitation with crystalloids is the first line therapy when it is not caused by hemorrhage
- Vasopressors are recommended if the patient does not respond to crystalloid or blood product therapy
- Vasopressors will not be effective unless intravascular volume is adequate
What is sepsis?
A life-threatening organ dysfunction caused by a dysregulated host response to infection
What is septic shock?
- Sepsis in the presence of persistent hypotension requiring a vasopressor to maintain MAP>= 65 mmHg
- Broad spectrum antibiotics and fluid resuscitation with IV crystalloids is recommended to reduce mortality from sepsis and septic shock
- Norepinephrine is the vasopressor of choice in septick shock
Treatment of Septic shock
- Target MAP of >= 65 mmHg
MAP= [(2 x DBP) + SBP]/3 - Optimize preload with IV crystalloid fluids (PRN)
- Alpha-1 agonist activity (peripheral vasoconstriction) to increase SVR.
Beta-1 agonist activity to increase myocardial contractility and CO
What are the 2 common causes of ICU infections?
- Mechanical ventilation: pushes air into lungs
↑time on ventilator = ↑risk of infection (lung and others) - Foley catheters: indwelling urinary catheter
↑time with foley catheter = ↑risk of bladder infection
What is ADHF and cardiogenick shock?
ADHF: Patients with HF experiencing worsening symptoms;
- Sudden weight gain
- SOB when lying flat
- Decreasing functionality (unable to perform daily routine)
- SOB and fatigue
Cardiogenic shock: same worsening symptoms as above + hypotension and hypoperfusion
__ should only be stopped in an ADHF episode if hypotension or __ is present
Fill in the blank
- Beta-blockers
- Hypoperfusion
What is used to monitor ADHF? What is it?
- Catheter that is guided through the right side of the heart into the pulmonary artery, called Swan-Ganz or pulmonary artery (PA) catheter
- Catheter provides hemodynamic measurements of congestion (pulmonary capillary wedge pressure pr PCWP)
Treatment of ADHF
1) Patients with volume overload (edema, JVD and/or ascites):
* Loop diuretics
- Vasodilators can be added (NTG, nitroprusside)
2) Patients with hypoperfusion (decreased renal fx, altered mental status and/or cool extremities):
* Inotropes (dobutamine, milrinone)
- Consider adding vasopressor, if hypotensive (dopamine, norepinephrine, phenylephrine)
- Avoid vasodilators; these can decrease BP and worsen hypoperfusion
3) Patients with both volume overload and hypoperfusion:
* Combination of agents above
Inotropes are used for congestion and hypoperfusion when BP is adequate.
What is used first-line for analgesia? and how is it given?
Opioids given IV, such as morphine, hydromorphone and fentanyl are first-line for analgesia
What is analgosedation?
- AKA analgesia-based sedation is a sedation strategy that uses analgesia first to relieve pain and discomfort, which are primary causes of agitation
- Analgosedation is associated with less time on the ventilator and shorter ICU stay (LOS) compared benzos
Sedation and agitation
Management of agitation
Sedation; purpose, preferred agents
Sedation is used for some ICU patients to maintain synchronized breathing with the ventilator (prevent “bucking” the ventilator)
* Non-benzodiazepines (propofol and dexmedetomidine) are associated with improved ICU outcomes, shorter mechanical ventilation duration and decreased LOS
- Dexmedetomidine (Precedex) is the only sedative approved for use in intubated and non-intubated patients
- Benzos have an important role in sedation in the presence of seizures or alcohol/benzo withdrawal
- Sedatives are used with validated sedation scales that allow for titration to light (preferred) or deep sedation
- Sedation vacations: daily interruptions of continuous infusions of sedative drugs
- Agitation is managed with benzos (lorazepam, midazolam) and/or non-benzodiazepine hypnotics
1) Sedation with __ may reduce the incidence of __ and/or shorten the __ in patients who already have it
2) Atypical antipsychotics, primarily __ which is mildly sedating can be useful
Fill in the blanks
- Non-benzos, delirium, duration
- Quetiapine
Agitation/sedation
Safety/SEs/Monitoring - Dexmedetomidine, Propofol
Dexmedetomidine (Precedex) - Alpha-2 adrenergic agonist
SEs:
* Hypo/hypertension, bradycardia
Notes:
* Does not require refrigeration
* Duration of infusion should not exceed 24 hours
* Intubated and non-intubated
Propofol (Dilprivan)
CIs:
* Hypersensitivity to egg, soy
SEs:
* Hypotension, apnea, hypertriglyceridemia, green urine/hair/nail beds, propofol-related infusion syndrome (PRIS - rare but fatal)
Monitoring:
* Triglycerides (if administered longer than 2 days)
Notes:
* Bacterial growth; discard vial and tubing within 12 hours of use
* Oil -in-water emulsion (opaque, white solution); provides 1.1 kcal/mL
Agitation/sedation
Safety/SEs/Monitoring - Lorazepam, Midazolam
Lorazepam (Ativan): can cause propylene glycol toxicity (acute renal failure and metabolic acidosis)
Midazolam (Versed): use with potent CYP3A4 inhibitors is contraindicated, caution with continuous infusion - renal impairment (active metabolite)
Etomidate (Amidate): monitor s/sx of adrenal insufficiency
Ketamine (Ketalar): warning of emergence reactions (vivid dreams, hallucinations, delirium)
Risk factors for the development of stress ulcers
- Mechanical ventilation> 48 hours
- Coagulopathy
What are recommended agents for stress ulcers?
- H2RAs
- PPIs: associated with an increased risk of GI infections (C.difficile), fractures and nosocomial pneumonia
What are commonly used anesthetics?
Local:
* Lidocaine (Xylocaine), benzocaine, liposomal bupivacaine
Inhaled:
* Desflurane (Suprane), sevoflurane (Ultane), isuflurane (Forane), nitrous oxidea
Injectable:
* Bupivacaine (Marcaine, Sensorcaine), lidocaine (Xylocaine), ropivacaine (Naropin)
Inhaled anesthetics can cause __ .
Fill in the blank
Malignant hyperthermia (MH)
Bupivacaine, commonly used in __, can be fatal if administered __.
Fill in the blank
- Epidurals, IV
What is lidocaine/epinephrine combination is used for?
- Used for some local procedures that require an anesthetic, such as inserting an IV line
- The epinephrine is added for vasoconstriction, which keeps the lidocaine localized to the area where the numbing is needed
- Deaths have occurred due to mix-ups with epinephrine products and lidocaine/epinephrine products
What is the purpose of neuromuscular blocking agents? When to use them?
- Cause paralysis of the skeletal muscle
- Patients can require the use of an NMBA in surgery conducted under general anesthesia to facilitate mechanical ventilation, treat muscle spasms (tetany) or to prevent shivering in patients undergoing hypothermia after cardiac arrest
- Adequate sedation and analgesia should be initiated prior to starting an NMBA. Patients must be mechanically ventilated as these agents paralyze the diaphragm
- NMBAs should be labeled with colored auxiliary label stating “WARNING, PARALYZING AGENT”
Depolarizing vs Non-Depolarizing NMBA
Agent names, important information about them, SEs (if applicable)
Depolarizing NMBA:
* Succinylcholine: reserved for intubation, NOT for continuous neuromuscular blockade
Non-Depolarizing NMBA:
* SEs - Flushing, bradycardia, hypotension, tachyphylaxis
* Cisatracurium (Nimbex) - metabolized by Hofmann elimination (independent of renal and hepatic fx)
Notes:
– Patients receiving NMBAs are unable to breathe, move, blink or cough. Thus, special care must be taken to protect the skin, lubricate the eyes and suction the airways frequently to clear secretions
–Glycopyrrolate (Robinul) is an anticholinergic drug that can be used to reduce secretions
Non-Depolarizing NMBAs
Short t1/2 intermediate-acting: Atracurium, Cisatracurium
Intermediate-acting: Rocuronium, Vecuronium
Long-acting: Pancuronium
What are hemostatic agents used for? Name the agents
- Hemostasis: causing bleeding to stop
- Systemic hemostatic agents: inhibit fibrinolysis or enhancing coagulation
- Topical hemostatic agents: most are used surgically. Names often include “throm” (e.g., Recothrom, Thrombin-JMI)
Hemostatic Agents:
* Aminocaproic acid (Amicar, tablet/solution/injection)
- Tranexamic acid (Cyklokapron, injection) (Lysteda, tablet - also approved for menorrhagia)
- Recombinant Factor VIIa (NovoSeven RT, injection)
Medications used for delirium
- Haloperidol (Haldol)
- Quetiapine (Seroquel)
