M5 Flashcards by John Lin

Why does a patient desaturates 5 min after retrobulbar block

Local anesthetic in CSF causing high spinal

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What is ecothiophate and what anesthetic drug should be avoided?

Irreversible cholinesterase inhibitor used for chronic glaucoma. Avoid using succinylcholine and other drugs metabolized by plasma cholinesterases including pseudocholinesterase.

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Next best step in treatment of patient with likely corneal abrasion

Topical antibiotics

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Protopathic sensation

Noxious (painful)

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Epicritic sensation

Non-noxious (touch, pressure, temperature, proprioception)

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Nociceptive pain is caused by activation of what type of receptors

High threshold peripheral nociceptive receptors

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Nociceptive pain is transmitted via what types of nerves

A-delta and C nerve fibers

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Pain fibers enter spinal cord via which nerve roots?

Mostly dorsal nerve root but some enter via ventral nerve root

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Primary area of pain pathway that opioids act upon

Dorsal horn where 1st order neurons synapse with 2nd order neurons

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How is resistance to flow related to length and radius?

Resistance proportional to 8 times length

Resistance inversely proportional to radius to 4th power

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What’s an intrinsic property of a transplanted lung that is kept intact?

Hypoxia pulmonary vasoconstriction

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Which procedure is hypotension most likely, insertion of venous cannulation or insertion of aortic cannulation?

Venous cannulation can significantly reduce preload

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What are advantages to off pump cabg?

Decreased incidence of respiratory infection and afib postop, less inotrope use, fewer blood transfusions

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Mechanism of heparin

Binds to anti-thrombin 3, which accelerates inhibition of thrombin and factors 9 and 10

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Next best step if heparin causes no change in ACT prior to CPB

Give 2 units of ffp then give heparin. Pt likely has anti-thrombin 3 deficiency

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Functions of thromboxane

1) Platelet aggregator, facilitating clot formation. 2) Vasoconstrictor that reduces blood flow to site of clot

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Pulmonary artery pressure rise after protamine administration for heparin reversal

Heparin protamine complexes can cause thromboxane release from macrophages

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Hypotension after protamine administration for heparin reversal

Dose dependent histamine release from mast cells

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Best way to decrease time to rewarm patient

nitroglycerin infusion

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Fast pain is carried by what type of nerve fibers?

A delta fibers (myelinated)

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Delayed slow secondary pain is carried by what type of nerve fibers?

C fibers

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Induction agents except for ketamine work on which type of GABA receptor?

GABA-A receptor

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Propofol should be discarded after being drawn into a syringe after how many hours?

12 hrs, it used be 6 hrs before EDTA preservative was added.

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What part of egg is used in propofol?

Egg lecithin from the egg yolk. People allergic to eggs are allergic to egg albumin which is in egg white.

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Pretreatment with what drug can decrease etomidate associated myoclonus?

Opioids

Reason why etomidate causes burning pain

Propylene glycol solvent that etomidate is in

Etomidate causes increase in ICU mortality because of?

Prolonged infusions causing adrenal suppression

In what percent of patients does a single induction dose of etomidate cause adrenal suppression?

All patients

Hydrophilic or lipophilic drug has smaller volume of distribution

Hydrophilic

Induction agent that is completely metabolized by liver on a single pass

Propofol

2 pathways signaled by G protein coupled receptors

1) cAMP -> PKA | 2) phospholipase C -> IP3

Where is propofol metabolized?

Liver and lung

How is fospropofol different than propofol?

Water soluble, prodrug that has to be metabolized by liver to release propofol and formaldehyde

How does barbiturates affect tolerance to pain?

Decrease tolerance to pain

Barbiturate injected in artery causes?

Limb gangrene due to arterial spasm and vasoconstriction, treatment is stellate ganglion block

Morphine metabolite

Morphine-6-gluconoride, major contributor to mu receptor mediated respiratory depression

Oversized BP cuff affects BP measurement how

BP will be underestimated

Correlation between central venous pressure and left ventricular end diastolic volume

None at all

Betadine or chlorhexadine use has lesser catheter related bloodstream infection

Chlorhexadine

How does insulin affect glycogen and protein synthesis?

Increases

Hypernatremia or hyponatremia is associated with hypothyroidism?

Hyponatremia: hypothyroid patients retain free water

Classic diuretic of choice to treat Cushing's syndrome

Spironolactone

Anesthetic considerations with Cushing's syndrome

Increased sensitivity to muscle relaxants, hypokalemic arrhythmias, difficult intubation for obesity and swelling

Healthy person can produce up to how much cortisol in a day when maximally stressed

300 mg of cortisol

Historically why is succinylcholine contraindicated with pheochromocytoma pts?

Supposedly fasciculations cause catecholamine release secondary to abdominal pressure

Historically why is pancuronium contraindicated with pheochromocytoma pts?

Pancuronium is vagolytic

Pheochromocytoma is associated with which syndromes?

MEN2A, NF1, Von Hippel-Landau

How are anaphylactoid reactions different from anaphylaxis?

Anaphylactoid reactions are NOT IgE mediated

MC type of vWD

Type I

Type of vWD that responds to DDAVP

Type I

One unit of plasmapheresis platelets will raise platelet count by how much?

60,000 because 1 unit equals a 6 pack of pooled platelets which comes from 6 donors

Cryoprecipitate contains what factors?

Factor 8, fibrinogen, vWF

Washing RBCs prevents what?

Anaphylaxis in IgA deficient patients by removing IgA from RBCs

Leukodepletion or leukoreduction of RBCs prevents what?

Febrile reactions and alloimmunization

Irradiation of blood products prevents what?

Graft vs host disease, irradiation destroys DNA

Febrile transfusion reaction is caused by?

Recipient antibodies toward donor WBCs

Post transfusion purpura is caused by

Immunologic complication towards platelet surface proteins presenting with thrombocytopenia a week after transfusion, very uncommon.

Typical onset of TRALI is within how many hrs?

2 hrs

Typically TRALI resolves within how many hrs?

What is the 2 hit theory of TRALI?

1) sequestration of neutrophils in lungs | 2) activation of neutrophils and immune response causing transient leukopenia

Transfusing 4cc/kg of prbcs will raise hgb by how much?

1 g/dL

Blood volume for premature neonate

100 mL/kg

Blood volume for full term neonate

85 mL/kg

Blood volume for infant/toddler

75 mL/kg

Blood volume for adult

60-70 mL/kg

Risk of hep B infection from blood transfusion

1:200,000

Risk of hep C infection from blood transfusion

1:2,000,000

Risk of HIV infection from blood transfusion

1:2,000,000

Nerve root that provides motor innervations to triceps and back of hand and middle finger

Nerve root that when damaged causes numbness of medial forearm and fifth finger and weakness in finger flexion

Ulnar nerve injury is characterized by?

Handgrip weakness and fifth finger numbness

Main advantage of retrobulbar block over peribulbar block

Decreased onset time of block

Half life of dabigatran

12 hrs

Preop instructions regarding herbal meds that cause increased risk of bleeding

Discontinue 1 week prior to surgery

Herbal med that interferes with warfarin

Ginseng

When do u stop giving 100% oxygen to patient with carbon monoxide poisoning?

When asymptomatic and carboxyHb is below 10%. 100% Oxygen shortens elimination half life by 5 times, hyperbaric oxygen by 10 times

Vapor output equation for a given gas flow and vapor pressure of anesthetic gas

Vapor output = (CG X SVP) / (Pb - SVP) ``` CG = carrier gas flow SVP = saturated vapor pressure Pb = atmosphere pressure ```

Which partition coefficient is necessary for calculation of time constant for volatile anesthetics?

Brain/blood partition coefficient. Time constant equals double the coefficient

Midazolam, fentanyl, barbiturates are water or lipid soluble?

Lipid soluble.

Obese patient should be induced with propofol based on what type of weight?

Ideal body weight. Propofol infusion should be based on total body weight

Proportion of sodium filtered by glomerulus that is typically excreted in the urine

Treatment for acute interstitial nephritis

Steroids

Digoxin toxicity symptoms

Ventricular arrhythmias, malaise, vision changes

For every increase of glucose of 100 mg/dL, the measured sodium falls by how much?

1.6 mEq/L

Normal value for urine sodium

Less than 20 mEq/L

Loss of cold discrimination under epidural anesthesia is how many levels above level of anesthesia?

2 dermatomes

Major side effect of methergine

Hypertension (rhymes with methergine)

Major side effect of hemabate

Bronchospasm (avoid in asthmatics)

Ephedrine effect on fetus

Increases fetal metabolism and oxygen consumption

Active phase of labor affects which nerve roots and what type of nerve fibers account for pain

Lumbar nerve roots, small visceral afferent fibers

Side effect of ketorolac in pregnancy

Theoretical closure of ductus arteriosus, increased bleeding. Ketorolac is relatively ineffective to treat labor pain

Mortality of pregnancy in patient with eisenmenger's syndrome

30-50%

Narcotic with weak local anesthetic properties

Meperidine

Chorioamnionitis increases fetus' risk of?

Cerebral palsy

Risk of benzodiazepine use in pregnancy

Cleft palate

Normal CMRO2

3.5 mL/100 g/min

Normal cerebral blood flow

50 mL/100 g/min

How many times a day does entire CSF volume replace itself?

About 3 times a day. Avg adult CSF volume: 150cc.

Volume of venous air embolism that is fatal

300 cc

Hunt and Hess scale

0-5 for classifying severity of SAH 0: unruptured 1: mild 2: mod-severe 3: drowsy, confused 4: stupor, hemiparesis 5: comatose

Greatest risk over one week after ruptured cerebral aneurysm

Cerebral vasospasm (incidence is around 15%)

Triple H therapy for cerebral vasospasm prevention and treatment

Hypertension, hypervolemia, and hemodilution

Anti seizure medication should be continued for how long after a traumatic brain injury

7 days

How is neuraxial anesthesia controversial for patients with multiple sclerosis?

Small case studies show increased rate of MS flare ups compared to GA

Hot or cold temperatures exacerbates multiple sclerosis?

Hyperthermia

Why is succinylcholine relatively contraindicated for multiple sclerosis patients?

Since MS is an upper motor neuron demyelinating disease, patients are prone to hyperkalemia, especially in setting of paresis and paralysis

Myasthenia gravis patient's response to succinylcholine being given

Resistance to succinylcholine because of lack of acetylcholine receptors, and then more sensitive to non depolarizers

Why is neuraxial anesthesia considered contraindicated for Guillian-Barre syndrome patients?

Weak evidence shows increased risk of GBS exacerbation

3 things to avoid in a myotonic dystrophy patient with contracture

Succinylcholine, neostigmine, and hypothermia

Risk factors for postop mechanical ventilation in myasthenia gravis patients

Pyridostigmine > 750 mg/day, vital capacity < 2.9L, disease duration > 6 yrs

What are the effects of succinylcholine and non depolarizers in patients with Eaton Lambert syndrome?

Both are more sensitive in ELS patients

Greatest cause of perioperative morbidity in Duchenne's muscular dystrophy patients

Respiratory complications secondary to restrictive pulmonary disease and pulmonary hypertension

How does lithium affect muscle relaxants?

Lithium potentiates both depolarizing and nondepolarizing agents

Drug that is most commonly abused among anesthesiologist and most likely associated with relapse

Fentanyl

Normal vitals for preterm

HR 160 SBP 50 DBP 30 RR 50

Normal vitals for term newborn

HR 130 SBP 60 DBP 40 RR 50

Normal vitals for 1 yr old

HR 120 SBP 80 DBP 60 RR 25

Normal vitals for toddler

HR 90 SBP 100 DBP 60 RR 20

Eaton lambert syndrome and myasthenia gravis sensitivity to nondepolarizers is increased or decreased

Increased.

How does up regulation of extrajunctional acetylcholine receptors affect response to muscle relaxants

Resistance to nondepolarizers and more sensitivity to depolarizers

How does autoimmune disorders affect response to muscle relaxants

Increased sensitivity to both nondepolarizers and depolarizers

Metabolism of mevacurium

Pseudocholinesterase

Why doesn't glycopyrrolate cause mydriasis?

It's quaternary structure prevents it from cross blood brain barrier so CNS and pupillary effects are not seen

Treatment for central anticholinergic syndrome

Physostigmine (tertiary structure allows it to cross blood brain barrier to "reverse" effects of scopolamine

Systolic pressure is higher at aorta or radial artery?

Radial artery