Neuromuscular Blocking Agents

Front 1

Receptors located in the folds of post synaptic muscle membrane in very high concentrations and are not usually found extrasynaptically

Back 1

Nicotine muscle-type Ach receptors (nAchRs)

Front 2

5 protein subunits of nAchRs

Back 2

* 2 alpha

*beta

*gamma

*delta

Front 3

After birth the fetal nAChRs become mature or adult by

Back 3

Replacing the gamma subunit with epsilon

Front 4

The release of ACh quanta is antagonized by what electrolyte abnormality

Back 4

*hypocalcemia

*hypermagnesemia

Front 5

Upregulation of immature or fetal nAChRs is seen in conditions like

Back 5

*severe burns

*immobilization

*prolonged use of NMBAs in the ICU

*cerebrovascular accidents

Front 6

True or false. immature nAChRs have decreased sensitivity to agonists (ACh and SCh), and increased sensitivity to NMBAs

Back 6

False. increased sensitivity to agonists and decreased sensitivity to NMBAs

Front 7

Mode of action of non depolarizing NMBAs

Back 7

Compete with ACh for the 2 alpha subunits recognition sites thus preventing normal nAChRs function

Front 8

Defined as the time from IV drug administration until spontaneous recovery of ST to 25% of the baseline strength.

Back 8

Duration of action until recovery to 25% (DUR 25%)

Front 9

Defined as the time of spontaneous recovery of ST from 25% to 75% of control

Back 9

Recovery Index

Front 10

The reason for fasciculations seen in succinylcholine

Back 10

The inabililty of acetylcholinesterases to degrade SCh leads to membrane hyperpolarization and desensitization. The desensitization leads to flaccid paralysis

Front 11

True or false. SCh is degraded in the plasma by butyrylcholinesterase where almost 90% of the IV dose of SCh is hydrolyzed before reaching the NMJ

Back 11

True. other name for plasma choinesterase is butyrylcholinesterase

Front 12

Myalgias in SCh use can occur after how many days postoperatively

Back 12

1-2 days in 50-60% of pxs

Front 13

The most effective prophylaxis for myalgia without using non depolarizing NMBAs as pre treatment

Back 13

Pretreatment with NSAIDs (aspirin or diclofenac)

Front 14

True or false. SCh may increase intragastric pressure and the lower esophageal sphincter tone

Back 14

True

Front 15

How much does IOP increase after SCh administration

Back 15

15mmHg but lasts only for 5 mins

Front 16

How much will SCh increase the plasma levels of potassium

Back 16

0.5mEq/L

Front 17

Rare case reports have also associated administration of SCh with fatal hyperkalemia in children receiving what medication

Back 17

Beta blockers (propanolol)

Front 18

True or false. SCh can trigger Malignant hyperthermia

Back 18

True esp pxs anesthetized with volatile anesthetics

Front 19

Clinical duration of SCh if given at doses of 1mg/kg

Back 19

5-10 mins

Front 20

Children are more resistant than adults to the actions of SCh and the usual dose is increased to

Back 20

2-3mg/kg

Front 21

In obese pxs who need RSII, the dose of SCh should be calculated on the basis of ____ body weight

Back 21

Actual

Front 22

Most frequently undiagnosed skeletal muscle myopathy in pediatric pxs that can cause cardiac arrest and death after giving SCh

Back 22

Duschenne's muscle dystrophy

Front 23

Non depolarizing NMBAs can be classified into two based on their chemical structure

Back 23

*aminosteroid

*benzylisoquinolinium

Front 24

Why larger initial doses of non depolarizing NMBAs may be required in pxs with renal or hepatic failure?

Back 24

nondepolarizing NMBAs are distributed mostly in the ECF

Front 25

Downregulation of mature nAChRs occurs in conditions like

Back 25

*chronic neostigmine use (myasthenia gravis)

*organophosphorous poisoning

Front 26

True or false. The more potent the non depolarizing NMBA the more rapid the onset.

Back 26

False. Less potent agents such as rocuronium have more molecules than the potent ones.

Front 27

Main metabolite of pancuronium that has 50% of parent compound potency which leads to significant accumulation

Back 27

3-OH Pancuronium

Front 28

Non depolarizing NMBA which has vagolytic effects as well as direct sympathomimetic effects; it blocks NE presynaptic uptake

Back 28

Pancuronium

Front 29

An intermediate duration NMBA that is devoid of cardiovascular effects and with the main metabolite of 3-desacetyl that is 60% of the parent compound potency

Back 29

Vecuronium

Front 30

Metabolite of rocuronium which has a very low neuromuscular blocking activity

Back 30

17-OH rocuronium

Front 31

Non depolarizing NMBA which has the lowest rate of IgE-mediated anaphylaxis

Back 31

Cisatracurium

Front 32

Incidence of analphylaxis following rocuronium may be higher than with other NMBAs due to sensitization to this anti tussive medication

Back 32

Pholcodine

Front 33

Increase in the incidence of IgE-mediated sensitization to NMBAs has been described in hairdressers because?

Back 33

repetitive exposure to quaternary ammonium compounds used in cosmetics and hair products

Front 34

In laparoscopic procedures, the duration of neuromuscular block produced by rocuronium is increased by 25% because

Back 34

The effects of pneumoperitoneum on hepatic perfusion and blood flow

Front 35

Dose of sugammadex in situations where cannot intubate and cannot oxygenate occurs after using rocuronium

Back 35

16mg/kg

Front 36

Long acting bisquaternary benzylisoquiunolinium nondepolarizing NMBA, it is also very potent thus with the least rapid onset and the longest acting

Back 36

Doxacurium

Front 37

2 metabolic pathway for the degradation of atracurium

Back 37

*non enzymatic degradation that is directly proportional with temp and pH (Hoffman elimination)

*hydrolysis by non specific plasma esterases

Front 38

True or false. Incidence of anaphylactic reaction of cisatracurium is similar to that of atracurium

Back 38

True

Front 39

Non depolarizing NMBA that is rapidly hydrolyzed in plasma by butyrylcholinesterases

Back 39

Mivacurium

Front 40

In mivacurium maintained paralysis, use of whole blood or fresh frozen plasma is not recommended because

Back 40

WB or FFP contains pseudocholinesterase

Front 41

True or false. Combining 2 chemically similar drugs with similar duration of action (atrac and cisatracurium) results in an synergistic potency

Back 41

False. Additive potency if chemically similar drugs and synergistic potency when diff classes

Front 42

In combining drugs with diff duration of action; using of mivacurium in a vecuronium based block will result in

Back 42

Recovery will follow the vecuronium block.

Rule: recovery will always follow that of the drug that blocked the majority (70-90% of the receptors)

Front 43

Adding depolarizing and non depolarizing NMBA results in

Back 43

mutual antagonism

Front 44

Order of inhalational anesthetic agents according to their potentiation of neuromuscular block

Back 44

desflurane>sevoflurane>isoflurane>halothane>nitrous oxide

Front 45

True or false. Local anesthetics can potentiate the effects of both depolarizing and non depolarizing NMBAs

Back 45

True

Front 46

Drugs that may potentiate the effects of NMBAs

Back 46

*streptomycin and neomycin

*aminoglycosides

*anticonvulsants (phenytoin, carbamazepine)

Front 47

Drug that when administered in critically ill pxs for prolonged periods of time in conjunction with neuromuscular blockade, will markedly increase the risk of myopathy

Back 47

Corticosteroids

Front 48

What is the sensitivity of pxs with neuromuscular disorders to NMBAs?

Back 48

Increased sensitivity to depolarizing NMBA and variable sensitivity to non depolarizing NMBAs.

Front 49

Why is the use of depolarizing NMBAs avoided in pxs with neuromuscular transmission disorders (Lambert-Eaton)

Back 49

Increased association MH and rhabdomyolysis in these disorders

Front 50

Factors that prolong the duration of NMBAs

Back 50

*hypothermia

*aging (dec. rate of elimination)

*hypermagnesemia

Front 51

Class of NMBAs that has significant hepatic and renal metabolism

Back 51

Aminosteroids

*Rocuronium

*Vecuronium

*Pancuronium

*Pipecuronium

Front 52

The frequency of ST stimulation should not exceed _____ because muscle fatigue may occur

Back 52

0.1 Hz ( 1 stimulus every 10 seconds)

Front 53

Single twitch modality is used clinically to deterimine

Back 53

onset of neuromuscular block

Front 54

The highest percent occupancy of the non depolarizing NMBAs that will not reflect any apparent fade in the TOF ratio.

Back 54

65-70%

Front 55

How many percent of the receptors are blocked when T4 disappears.

Back 55

75-80%

Front 56

How many percent of the receptors are blocked when TOFC becomes 0

Back 56

85-95%

Front 57

Type of neuromuscular monitoring done by repetitive stimulation at a frequency above 30Hz

Back 57

Tetanic stimulation

Front 58

True or false. Muscle stimulation at frequencies above 60Hz may result in muscle contraction fade even in the abscence of NMBAs

Back 58

True

Front 59

Type of neuromuscular monitoring that is used during the periods of profound neuromuscular block, consist of 5sec , 50Hz tetanic stimulus, followed by a series of 15-30 ST at frequency of 1Hz.

Back 59

Post-tetanic count

Front 60

True or false. The no. of post tetanic twitches is directly proportional to the depth of block

Back 60

False. inversely. the fewer the twitches, the deeper the block

Front 61

Type of neuromuscular monitoring which is done by delivering 2 intense stimuli separated by 0.75 sec and is used to detect fade when the TOF is less than 0.6

Back 61

Double burst stimulation

Front 62

Patients who are able to sustain headlift for 5 seconds have TOF ratio of

Back 62

0.5

Front 63

The best clinical test for neuromuscular recovery is

Back 63

ability to resist removal of a tongue blade from clenched teeth; but cannot be used in pxs who are still orally intubated

Front 64

Why is the ulnar nerve/APM combination is used more frequently in EMG?

Back 64

APM is the sole hand muscle on the radial side of the hand that is innervated by the ulnar nerve- decreasing the chance of direct muscle stimulation

Front 65

True or false. Onset time and recovery of the APM from non depolarizing NMBAs is delayed compared to the central muscles.

Back 65

True.

Front 66

When the pxs arms are not available for intraoperative monitoring, clinicians will often monitor what facial muscles.

Back 66

*corrugator supercilli - corresponds to laryngeal adductors

*orbicularis oculi

Front 67

Monitoring of neuromuscular blockade in the lower extremities is done through

Back 67

Flexor hallucis brevis - time course is similar to that of the APM

Front 68

In electrode placement, the facial nerve is best stimulated at the...

Back 68

anterior portion of the mastoid process

Front 69

Threshold (minimum requirement) for full recovery

Back 69

TOF 0.90 or more

Front 70

Sugammadex dose for reversal if PTC is at 1 or 2

Back 70

4mg/kg

Front 71

TOFC values before attempting pharmacologic reversal with anticholinesterases.

Back 71

TOFC 2 or 3

Front 72

Why is physostigmine not used for pharmacologic reversal of neuromuscular block.

Back 72

It is a tertiary amine that crosses the BBB and exert central effects

Front 73

Administration of small doses of neostigmine (30mcg/kg) a time when recovery of neuromuscular function is complete may produce

Back 73

upper airway collapse and may decrease the activity of the genioglossus muscle

Front 74

Why is pharmacologic reversal using neostigmine during deep block is not recommended?

Back 74

Neostigmine is characterized by initial rapid (partial) recovery, followed by a later slower recovery

Front 75

Attempts at pharmacologic reversal using doses of neostigmine larger than 70mcg/kg or using a combination of cholinesterase inhibitors to hasten recovery should be avoided because.

Back 75

Additional cholinesterase inhibitors may actually block the ACh receptors, leading to neuromuscular weakness.

Front 76

Optimum dose of neostigmine when atracurium-induced light (shallow) block is antagonized

Back 76

20mcg/kg

Front 77

True or false. Neostigmine induced speed of reversal is faster in children than in adults and slower in the elderly

Back 77

True

Front 78

Edrophonium is a less effective as an antagonist than neostigmine because

Back 78

forms ionic (and much weaker) bonds with the acetylcholinesterase enzyme rather that the stronger, covalent bonds

Front 79

The dose of edrophonium to antagonize shallow block (TOFC 4)

Back 79

0.50mg/kg

Front 80

How long should you wait before giving again rocuronium after sugammadex reversal

Back 80

24 hours

Front 81

Major side effect associated with sugammadex administration

Back 81

hypersensitive reaction

Front 82

For diagnosis of hypersensitivity reactions during general anesthesia, an elevated _____ levels is highly predictive of IgE-mediated anaphylaxis

Back 82

serum tryptase

Front 83

True or false. In the morbidly obese px, the dose of sugammadex has been calculated based on ideal body weight

Back 83

True

Front 84

In patients with myasthenia gravis, patients are generally resistant to the effects of _____ and more sensitive to the effects of _______

Back 84

Resistant to the effects of SCh and more sensitive to the effects of nondepolarizing muscle relaxants

Front 85

A cucurbit uril derivative that has been reported to inactivate both steroidal and benzylisoquinolone nondepolarizing NMBAs by encapsulation

Back 85

Calabadion-1