Exam 2 part III Flashcards
with administration of succinylcholine IOP is increased by __________mmHg for _______________ min
5-15; 10-15
T/F: the IOP increase with succinylcholine administration is less than that one experiences with a cough or sneeze
TRUE
theory behind increased IOP with succinylcholine administration
dilation of choroidal vessel and the contraction of extraocular muscles
when would a small increase in IOP 2/2 succinylcholine administration be problematic?
with open globe injury, could –> extrusion of intraocular contents **avoid succ with open globe injury
what causes the increase in ICP with succinylcholine administration
- 2/2 increase in cerebral activity and cerebral blood flow 2. exact cause is unknown due to inconsistent observations
how can you prevent the increase in ICP with succinylcholine administration
- hyperventilation 2. NDMR pre-tx 3. lidocaine pre-tx
massester rigidity 2/2 to succinylcholine administration (and NOT MH) should stop when?
when fasciculations stop
if your pt has masseter rigidity is experienced by pt with succinylcholine, what are your options
- wait and see if rigidity stops with fasciculations 2. stop and reschedule with different anesthetic plan and test for MH 3. switch to TIVA and have MH meds prepped and on stdby
masseter rigidity as a side effect of succinylcholine administration (not MH) is most often seen in what pt population?
peds
histamine release with succinylcholine
is slight, but causes anaphylaxis more than any other anesthetic drug
what is the mechanism by which succinylcholine causes MH
unknown
contraindications for succinylcholine
- MH 2. hyperkalemia 3. burn pt with >35% TBSA; 3rd degree burn 4. severe muscle trauma 5. severe sepsis 6. muscle wasting, prolonged immbolization 7. extensive muscle denervation (ex: SCI) 8. DMD 9. atypical pseudocholinesterase 10. allergies 11. children and teens esp under the age of 8
why is succinylcholine c/i in kids under the age of 8
due to the risk of: 1. hyperkalemia 2. rhabdomyloysis 3. cardiac arrest 2/2 undiagnosed cardiomyopathies or dystrophies
why is succinylcholine c/i with DMD?
pts with DMD have leaky K channels (NOT extrajunctional receptors) so risk of hyperkalemia
Non-depolarizing Muscle relaxants are of 2 categories, what are they?
- benzoquinolones 2. steroids
NDMR are dosed by ____________________
Lean body mass (LBM)
how do you calculate LBM in men?
(1.10 x wt in Kg) - 128[weight^2/(100x ht in meters)^2]
how do you calculate LBM in women
(1.07 x weight in kg) - 148[wt^2/(100 x ht in meters)^2]
reasons why you would choose one NDMR over another
- profile of the drug 2. pt condition 3. procedure
MOA of NDMR
binds to one alpha subunit on the nicotinic receptor which prevents Ach binding and prevents the ion channel from opening –> no muscle depolarization
NDMR are described as ___________________ blocks, meaning an increase in Ach at the NM jx will have what effect?
competitive; increase in Ach will remove the NDMR from the receptor
when might you have a situation (molecularly) where succinylcholine is occupying one alpha subunit and a NDMR is occupying the other
- pretx with NDMR 2. use succ to induce, but use NDMR for case 3. used NDMR for case but had laryngospasm (which is tx’d with succinylcholine)
in the presence of volatile anesthetics your NDMR maintenace dose may be decreased by _____________%
15
T/F: an NDMR will augment another NDMR –> denser block
TRUE
T/F: 1st dose = roc, 2nd dose = vec –> denser block
TRUE
if you give a NDMR and you notice flushing and pt is not easier to bag, you should think what is happening
histamine release 2/2 NDMR
what NDMR at high doses cause the most histamine release
Atracurium and Mivacurium
how do you decrease the risk of histamine release with NDMR ?
- slow injection rates 2. pretreat with antihistamines
which NDMR causes the greatest vagolytic response –> tachycardia
pancuronium
CV effects of NDMR (general)
- drug induced release of histamine & vasoactive substances 2. effects at cardiac muscarinic receptors –> vasolytic response –> tachycardia
s/e of NDMR is histamine release, what are the s/sx of histamine release
- bronchospasm 2. skin flushing 3. bradycardia (isnt it actually tachycardia?)4. Hotn
if your patient is hypokalemic, and you have to give NDMR, d/t _______________ duration of block (with hypoK) you should _________ dose of NDMR
increased; decrease
if your patient is hypokalemic and you are going to induce with succinylcholine you should _______________ the dose
increase
if your patient is hyperkalemic, and you induce with NDMR you should _______________ dose
increase; d/t the duration of block being decreased 2/2 hyperK
what is a priming dose of NDMR
giving 10-15% of usual intubating dose 5 min before induction
what is the purpose of a “priming dose” of NDMR
if give 10-15% of induction dose 5 min before; you will have some receptors occupied, so when you give the remaining dose paralytic effects will occur faster
what are some issues that could occur with a “priming dose” of NDMR
may produce: distress, dyspnea, diplopia, and dysphagia O2 desaturation in patients with marginal pulmonary reserve
what is a “defasciulating dose”
giving NDMR 5 minutes before administration of succinylcholine
if you give a defasciculating dose of NDMR, you must ____________ dose of succinylcholine to _________mg/kg
increase; 1.5-2.0
PNS monitoring intraop helps prevent
- over/under dosing of MR 2. residual paralysis in recovery/PACU
repeat NMBA doses should be guided by what
- nerve stimulator 2. clinical signs (SV, movement, etc)
T/F: clinical signs that muscle relaxant has worn off may precede twitch response
TRUE
if you see __________________ on your EtCO2 waveform, or have _____________ on ventilator, you may need to redose your muscle relaxant
curare cleft; increased peak inspiratory pressures
which NDMR are Benzylisoquinolones
- atracurium 2. cisatracurium
intubating dose of atracurium
0.5 mg/kg
onset of atracurium
2-3 min
DOA of atracurium
20-60 min
ED95 of atracurium
0.2-0.25 mg/kg
intubating dose of cisatracurium
0.1-0.5 mg/kg
onset of cisatracurium
2-4 min
DOA of cisatracurium
40-75 min
ED95 of cisatracurium
0.05 mg/kg
cisatracurium is _______________ x as potent as atracurium and ___________x as potent as rocuronium
3-4; 5
metabolism of atracurium
- 2/3 by ester hydrolysis via nonspecific esterases 2. 1/3 via hoffman elimination
half life of atracurium
20 min
atracurium is ______% protein bound
82
metabolites of atracurium are secreted in the ____________& _____________
bile and urine
metbolism of cisatracurium
- 77% hoffman elimination 2. 23% nonspecific esterases via ester hydrolysis
half life of cisatracurium
20-25 min
________% of cisatracurium is eliminated in the urine
7
