NMB Monitoring Flashcards
Reasons to monitor
Inter pt variability in dosing, intub timing, titration to effect, readiness of reversal, adequacy of reversal, differentiates type of block, early recog of pseudocholinesterase def
When to monitor
Muscle relaxant used, hypothermia, neuro/renal/hepatic disease, post op power, gtt
1 hertz =
1 cycle/sec
10 hz=
0.1 hz=
Range
10 stim per sec
1 stim per 10 sec
0.1-100 hz
Stim which muscles: ulnar nerve, facial nerve
Adductor pollicis, orbicularis oculi
3 non main nerves that can be used
Median, post tibia, common peroneal
Placing of electrodes on ulnar nerve
- electrode 1 cm proximal to wrist crease. + electrode 2-5 cm of distal one.
Most sensitive to most resistant muscles
Extraocular, pharyngeal, masseter, adductor pollicis, abd rectus, orbicularis, diaphragm, VC
__ __ response reflect NMB extent of diaphragm better than response of __ __
Orbicularis > adductor pollicis
Pro and con to adductor pollicis monitoring
Diaphragm can still move even if no twitch on TOF. But no block left in diaphragm if adductor pollicis is recovered.
Single twitch stim
Common settings, use
0.1-1 hz. 0.1 frequency most common. Not diff between depol/nondepol. Assess baseline strength before NMB given
Does presence of full twitch height guarantee recovery from NMB
No
TOF
What it delivers
4 pulses of equal intensity of 2/sec (0.5 sec) to 2 hz freq
TOF
Detects which phase of block
Phase 2
TOF
Ratio when no NMB given
What happens w NDMR
What happens w depolarizing
- Fade and ratio decreases. 1 ratio remains, amplitude decreases
TOF pros
Shouldn’t be repeated more frequently than what
Less painful and dont need control value. 12 sec
Tectanic stim
Settings
50-200 hz for 5 sec
Tetanic stim
When sustained, not sustained
Sustained- normal nm transmission and depolarizing block.
Not- non depolarizing, phase 2
Post tetanic potentiation
What it is
Related to what
Ability during nondep block to inc evoked response to a seubsequent twitch. Rel to inc in ach mobilization after stim
How to post tetanic count
50 hz 5 sec. then 1 hz 3 seconds after tetanic stim
Post tetanic count values
1- intense block
3- less intense
Inc during surgical block
Post tetanic stim when it appears:
Panc for intubation before TOF?
Vec/roc/atra before TOF
35 min
10 min
PTC uses
Ensure coughing from intub elim (zero PTC), NDMR gtt, when no single twitch or TOF
Double burst stim
What it delivers
2 train of 3 impulses at 50 hz separated by 750 ms
Double burst stim
Evaluate what
Non paralyzed vs paralyzed
Ratio of 2nd to 1st response. Non par: equal strength. Par: 2nd response weaker
Double burst stim
TOF less than what hard to detect
Superior to what
Easier to feel what
0.3. Sup to TOF tactile eval, easier to feel fade in dbs than TOF
Phases of block
Pre block. Intense block (can intubate, no response). Moderate block (surgical). Recovery
Intense nm block phase
Occurs when, what its called, varies based on
3-6 min after med. no response period. Length varies based on agent, dose, and pt sensitivity
Moderate/surgical block
Begins when
1st response to TOF
TOF- % block- clinical None- 1 2 3 4
100, ett 90, surgery 80-90 75-80, needs reversal 0-75, recovery
When antagonism of block shouldn’t occur
Before at least 2, preferably 3 responses to TOF
When dbs most useful
After reversal
How many TOF twitches to begin recovery phase, ratio, or what
4 twitches, 0.4 or lift head/arm
TOF ratio 0.6 pt can do what
0.75
Lift head 3 sec, open eyes protrude tongue
Cough, lift head 5 sec, grip weak
Recovery phase
TOF ratio of what= return of nm function adequate
> 0.75
Phase 2 block
An abn response to what in who. Manifests as what two things
Depolarizing agent, genetically abn individual.
Post tetanic fade and prolonged block
Depol nm block
Phase 1: 3
Response typical, no fade to TOF or tetanic, no post tetanic potentiation
Phase 2 block with depolarizer: seen in who. Charac by what
Plasma cholinesterase def or normal pts w sux. Fade in TOF/tetanic stim, post tetanic potentiation
Phase 2
Reversal occurs in __ min 50% ppl. Advised recovery time. When can happen after this
10-15 min
20-25 min. Anticholinesterase reversal
receptors occupied with: TV, twitch height, tetanic stim 30 hz
80.
80-75 for last two
receptors occupied in VC, TOF, Tetanic stim 100hz, ins force, head lift 5 sec
75-80, 75-80, 50, 50, 33
TOF or __ hz when pt unconscious but not relaxed
0.1
After sux for intub when twitch returns.
4-8 min
