EXAM 2 Review Flashcards
- What is the mechanism of action of succinylcholine?
Ach agonist, mimics Ach binding to Ach receptors at ALPHA subunit causing sustained depolarization (opening of receptor ion channels)
2.What is the mechanism for the metabolism of succinylcholine?
Marjority metabolized before reaching NMJ
Hydrolysis by plasma cholinesterase (pseudocholinesterase)
Metabolism on dependent of DIFFUSION away from the NMJ
3.What metabolites are formed from the metabolism of succinylcholine?
Broken down into Acetate and Choline
or NO metabolites
4.What inhalation agent is associated with diffusion hypoxia?
Nitrous Oxide
occurs when N2O d/c abruptly leading to reversal of partial pressure gradients, leave blood to enter alveoli
5.What steps can be done to prevent diffusion hypoxia caused by ______?
Giving 100% oxygen for several minutes at the end of the case can help avoid diffusion hypoxia from occurring
6.What anticholinesterase inhibitor can be used to treat psychosis due to anticholinergic drugs?
Physostigmine 15-60mck/kg/IV
7.What drug characteristic is responsible for this effect of diffusion Hypoxia
Low Blood gas coefficient 0.46 so rapidly reversible with rapid onset. Leaves blood 34 times more rapidly
8.What condition can result in an exaggerated long duration of action with the use of succinylcholine?
Atypical Plasma Cholinesterase
9.Explain the difference between heterozygous and homozygous genetic alterations?
Heterozygous dibucaine #40-60 slightly prolonged block, 20-30 mns, only 1 ABNORMAL GENE
Homozygous dibucaine #20, very LONG block 6-8 hours due to 2 ABNORMAL GENES
10.What test can be used to diagnosis this condition of heterozygous and homozygous?
Dibucaine Test
11.What steps can the anesthesia care provider use to prevent an exaggerated long duration of action with the use of succinylcholine?
DIbucaine test Check twitches before giving NMB Avoid in pseudocholinesterase deficiency Use TOF Reversal agents Neogstimine before SCH can prolong block (don't do this ) if in phase 1 can go to phase 2 Obtain hx of patient.
12.Do all volatile anesthetics blunt the ventilatory stimulation evoked by arterial hypoxemia?
yes; all anesthetics including nitrous oxide profoundly depress the ventilatory response to arterial hypoxemia that is normally mediated by carotid bodies
13.What are the recommended steps used to avoid residual paralysis with the use of NDNMB?
Avoid long acting NDNMB (Pancuronium)
Use intermediate acting
Do not use unreliable indicators such as head lift, jaw clenching, grip strength and tidal volume leg lift
Use quantitative and objective (AMG, KMG, EMG) better legal ground in court
14.What volatile agents undergo the least amount of metabolism?
N2O
15.Which Inhalation agent undergoes the least amount of metabolism?
Nitrous Oxide (0.004%) –> Des 0.02, ISo 0.2 sevo 3-5% HALOTHANE –>20%
16.What is the clinical significance VA that undergoes the least amount of metabolism?
Produces less free fluorides and is therefore safer for the kidneys
Sevo does not produce TFA
17.What steps can the anesthesia care provider take to prevent myopathy associated with the use of succinylcholine?
may be prevented by prior administration of a NON paralyzing dose of NDNMB agent or by going to high dose Sch 3mg/kg straight to Block II
18.What is the intubation dose for each NDNMB agent?
Atracurium 0.5mg/kg IV over 60 seconds Cisatracurium 0.1mg/kg Mivacurium 0.15 mg/kg Pancuronium 0.08-0.12 mg/kg Rocuronium 0.6 - 1.0 mg/kg Vecuronium 0.08-0.12mg/kg
19.What would the expected result be from the use of succinycholine and a patient with myastenia gravis?
Resistant to Sch due to destruction of ACh receptors by antibodies
20.What would the expected result be from the use of NDNMB agents and a patient with myastenia gravis?
Very sensitive to NDNMB
- How should the neuromuscular blocker dosage to cause adequate muscle relaxation be altered when you administer volatile anesthetics?
Volatiles dose dependent increases in neuromuscular blockade
volatile enhances effects of NMB
DECREASE THE Dose
22.Which volatile anesthetic agent causes the greatest/least degree of bonchodilation?
Great –> SEVOFLURANE
Least –> DESFLURANE
23.What clinical scenarios may lead to a phase block with the use of succinylcholine?
low dose 0.5 - 1mg/kg phase I fasciculations 5 minutes duration
high dose 2-4 mg/kg phase II rapid 20-30 minutes,
24.What volatile anesthetic is most likely to cause nephrotoxicity?
Sevoflurane and Enflurane
25.Which volatile anesthetics are non-pungent and can be used for a mask induction?
SEVOFLURANE
26.What volatile agent is considered to be the most pungent?
DESFLURANE
- What are the volume of distribution for neuromuscular blocking agents?
smallest –Cisatracurium
Quarternary ammonium Vd 200ml/kg Atracurium 182-282 ml/kg Cisatracurium 31 ml/kg Mivacurium 211-278ml/kg Rocuronium 194-207 ml/kg Pancuronium 261 ml/kg
Succinylcholine
- Which induction agent has the highest context sensitive half life?
Halothane
Isoflurane 86 min
sevoflurane 65 min
Desflurane 14 min
- What is the onset of action for each NDNMB agent?
fastest? longest?
3-5 minutes PVAC Atracurium 3-5 minutes Cisatracurium 3-5 minutes Vecuronium 3-5 minutes Pancuronium 3-5 minutes
1-2 minutes
Rocuronium 1-2 minutes
- What are the absolute contraindications for nitrous oxide? (VPIAP)
Venous or arterial air embolism Pneumothorax Intraocular air / surgeries Acute INTESTINAL OBSTRUCTION Pernicious anemia B12 deficiency , N2O decrease B12 in liver.
32.At different times during the case, what is the predicted percentage of receptors occupied by NDNMB agent?
See other
33.How many receptor occupied right after administration with 0/4?
> 95% , no fade
- How many receptor occupied right after administration with 1/4?
90% no fade
- How many receptor occupied right after administration with 2/4?
85%, no fade
- How many receptor occupied right after administration with 3/4?
80% no fade
- How many receptor occupied right after administration with 4/4?
75% receptors blocked (recovery), 4th twitch is 0.2 (20%) of the 1st twitch , 4 twitches then there is FADE
- How many receptor occupied right after admin? with/without fade?
75% with fade
- What volatile anesthetic has a chloride in its molecular structure?
Isoflurane (1 fluoride substituated with chloride)
- What volatile anesthetic has a bromine in its molecular structure?
Halothane
- What effect does each of the volatile agents have on hepatic blood flow?
Hepatic blood flow decrease
or inhibition of drug metabolizing enzymes
- Do NMBA have sedative/analgesic effects?
ABSOLUTELY NO
- What are the potentially toxic compounds produced by the breakdown of volatile
TFA
Sevo –> Compound A at low flow, no TFA
Desflurane> ISo = CO
Des and ISO can be metabolized to acyl halides which are hepatotoxic
- What is the least amount of twitch required before attempting reversal for NDNMBA blockade?
During anesthetic techniques that do not enhance the effects of muscle relaxants (TIVA) a minimum TOF count of 2 should be present before administration of anticholinesterases
During anesthetic techniques that enhance the effects of muscle relaxants (such as inhaled Volatile anesthesia) a TOF count of 4 should be present before administration of anticholinesterases
- What is responsible for the faster onset of rocuronium?
The lack of potency of rocuronium to vecuronium is the Important reason for RAPID onset
large number of molecules given with a LESS potent agent are available to occupy a greater number of receptors
- What NMBA is recommended for rapid sequence intubation?
DNMB : RSI succinylcholine
NDNMB : Roc can also be used
- What volatile agent has the greatest effect on EEG?
Enflurane
- What pathological conditions may result in up-regulation of acetylcholine receptors?
Muscular dystrophies
GBS
Burns
- What patient characteristics can prolong the effects of atracurium?
Hypothermia
Acidosis
lack vec roc cis have atracurium miva Histamine release - What NDNMBA would be best for a patient with liver failure?
Atracurium
Cisatracurium
- How does each Sevoflurane affect CVP?
NO INCREASE in RAP or CVP
53.How does Desflurane affect CVP?
INCREASE CVP
54.How does Isoflurane affect CVP ?
INCREASE CVP
55.What are absolute contraindications for the use of succinylcholine?
Hx MALIGNANT hyperthermia
Myotonia congenita and dystrophica
Duschenne muscular dystrophy
56.In a patient with renal failure, what agent would have the greatest degree of duration of action prolongation?
Pancuronium, Vecuronium
57.In a patient with renal failure, what agent would have the LEAST degree of duration of action prolongation?
Atracurium and Cisatracurium (undergoes Hoffman)
58.What are the clinical characteristics of nitrous oxide?
INCREASE in CMRO2 Produces either NO effect or MODEST increase in BP CO modestly increased by Nitrous oxide Increase RAP Does not increase PaCO2
59.What drugs will prolong the duration of action of NMBA?
VA ABT LA Cardiac dysrhythmias Diuretics Mag Lithium Ganglionic Blockers Cyclosporin
- Which volatile anesthetic can be safely used above 1.5MAC without causing apnea?
Isoflurane
61.Which volatile agent can cause an isoelectric EEG at 2 MAC?
Isoflurane produces isoelectric EEG at 1.5 MAC and 2 MAC
62.What is the best way to manage a patient that has a significantly long prolonged block from succinycholine?
Keep them sedated and ventilated
63.What inhalation agents have greatest least degree of muscle paralysis?
Most –>Desflurane
Least –> NITROUS
64.What are triggers for MH?
Volatile anesthetics
SUCCINYLCHOLINE
65.What anticholinesterase agent can be used to treat CNS side effects from anticholinergic agents?
Physostigmine 15-60mcg/kg IV, increased risk of NV though
66.What anticholinergic agent is classified an a quatinary ammonium compound? What about their VD?
Glycopyrrolate Quarternary ammonium compound; DOES NOT CROSS CNS and Is highly ionized
DECREASED VD
67.How does this change the volume of distribution of quaternary compared to tertiary ammonium compounds.
Quarternary - Decreased Vd
Tertiary - Increased Vd
68.How does VD affect the clinical effects of this agent of quaternary compound?
Does not Cross CNS, no sedation
69.What are all of the clinical effects anticipated after the administration of any anticholinergic agent?
Increase HR
Smooth Muscle Relaxation
Decrease gastric H+ Ions (increase pH)
Antisialalogue
- What anticholinergic agent has greatest antisialagogue effects?
SCOPOLAMINE then glycol -> Atropine
71.What anticholinergic agent has fastest onset of action?
Atropine
72.What anticholinergic agent has slowest onset of action?
Glycopyrrolate
73.Which anticholinergic agent is the most sedating?
SCOPOLAMINE
74.Which anticholinergic agent is the LEAST sedating?
GLYCOPYRROLATE
- Do any of the anti-cholinergic agents effect fetal heart rate?
No
76.What anticholinergic agent causes greatest amount of mydriasis?
SCOPOLAMINE
77.What anticholinergic agent causes LEAST amount of mydriasis?
GLYCOPYRROLATE
78.What is the mechanism by which each of the anticholinesterase agents attaches to cholinesterase?
Reversible Electrostatic attachment to anticholinesterase by EDROPHONIUM
79.What is the mechanism of action of suggamadex?
- Modified gamma cyclodextrin, selective relaxant binding agent specifically designed to encapsulate the STEROIDAL NMBAs vec and Roc
- Work by forming a complex with the NMBs by preventing their binding to nicotinic receptors at the NMJ, resulting in reversal of NMB
80.What are the indications for suggamadex?
Indicated for reversal of blockade done by STEROIDAL NMBA
81.What are major precautions/contraindications with the use of suggamadex?
Clearance decrease in RENAL IMPAIRMENT
Avoided in patients with a creatinine clearance of <30ml/min
Conscious memory is suppressed by
Volatile anesthetics
How much of MAC of ISOFlurANE suppresses memory
0.45 MAC
How much of MAC of Nitrous suppresses memory
0.6 MAC