NMBD Intro Flashcards
dTc and SCh (Anectine)
- 1940 - 1960
Pancuronium (Pavulon)
- 1960
Atracurium (tracrium) and Vecuronium (Norcuron)
- 1980
Rocuronium (Zemuron)
- 1994
Cisatracurium (Nimbex) and Mivacurium (Mivacron)
- 1995 and 1997
Rapacurium (Raplon)
- 2001
Define the Effect of NMBD
- Interrupt transmission of nerve impulses at neuromuscular junction (NMJ)
Actions of a Depolarizing NMB
- Mimics the action of acetylcholine
Name the only Depolarizing Paralytic on market.
Succinycholine
Actions of Non-depolarizoing NMB
- Interferes with the actions of acetylcholine
Name (3) ways NMB minimize incidences of tissue trauma
- Decreased airway trauma
- Facilitates surgical exposure
- Minimizes injury from patient movement
Name the #1 Purpose of NMB
- Minimize incidence of tissue trauma
Name (3) common airway trauma symptoms
- airway edema
- hoarsness
- vocal cord injury
What are the (5) Clinical Classifications of NMB
- Depolarizing
- Non-depolarizing
- Long-Acting
- Intermediate Acting
- Short Acting
Name (1) Depolarizing NMB
- Succinylcholine ( Anectine)
Name () Non- Depolarizing NMB
Name (3) Long-Acting NMB
- Pancuronium (Pavulan)
- Doxacurium
- Pipecuronium
Name (4) Intermediate Acting NMB
- Atracurium (Tracrium)
- Vecuronium (Norcuraon)
- Rocuronium (Zemuron)
- Cisatracurium (Nimbex)
Name (1) Short Acting NMB
- Mivacurium (Mivacron)
Describe the potency of neuromuscular blocking drug (NMBD)
- ED95
Equal Potency of NMB
- Dose necessary to produce 95% suppression of single twitch
- In the presense of nitrous/barbituate/opioid anesthesia
ED95: Adductor pollicis muscle
- Single twitch at 1 Hz
- Ulnar nerve stimulated
Order of the NMB depends on (4) Factors
- # of presynaptic Ach containing vesicles released
- # of postsynaptic Ach receptors
- Blood flow to area
- Drug potency
________, ___________ moving muscles block faster than __________ muscles
- Small
- rapidly
- large
Smaller muscles blocks are more _____________, but less ______________.
- rapid
- intense
Name the (2) preferred monitoring sites
- Orbicularis oculi
- adductor pollicis
Monitoring site: Orbicularis Oculi
- Mores closely reflects diaphragm and laryngeal muscle blockade
- Underestimate residual paralysis
Monitor Site: Adductor pollicis
- Poor indicator of laryngeal relaxation
- Gold Standard for recovery
Ulnar Nerve Stimulation
- Place negative electrode (black) on wrist in line with the smallest 1-2 cm below skin crease
- postive electrode (red) 2-3 cms proximal to the negative electrode
- Response: Adductor pollicis muscle – thumb adduction
TOF: Single Twitch
- Usually 1 Hz/second decreasing to 0.1 Hz q 10 seconds
- Continously
- Onset of block = fade with each stimulus
Double Burst
- 2-3 short twitches following 2-3 short twitches
- Use 50 Hz (supramaximal current)
Why was the Double Burst developed?
Developed to improve detection of residual block
* Fade in 2nd response vs 1st
* Qualitatively better than TO4
Train of Four (TOF)
- 4 stimuli at 2 Hz in 1/2 second
When should TOF be used?
- Prior to NMBD: 4th twitch = 1st twitch …. TOFR 1
- After administration and return of 4 twitches
Amplitude of 4th twitch to 1st twitch
- If amplitude of 4th twitch 50% of 1st…. TOFR 0.5
- Experienced anesthetists’ unable to detect fade TOFR > 0.4
- May choose not administer reversal….poor choice
- Significant residual TOFR 0.7-0.9
Describe Tetanic Stimulation
- Very rapid. 50 Hz for 5 seconds
Name (1) cause of Tentanic Stimulation: Sustained Muscle Response
- Depolarizing blocks
Name (1) cause of Tetanic Stimulation: Non-Sustained Response
- non-depolarizing block
- Phase 2 block w. Succs
- Fade related to:
(1) presynaptic deplation of Ach or inhibition of release
(2) Frequency and length of stimulation
Define a Post-Tetanic Stimulation
- single twitch 3 seconds after tetanic stimulation
Why does post-tetanic stimulation occur?
- accumulation of calcium during ‘tetany”
- Excess calcium stimulates Ach release
What does it mean if their is no Post- Stimulation response?
- Intense Block
Effects of NMBD
Bedside evaluation of criteria to extubate
- Head lift
- Negative PIP 25 - 30 cmH20
Baillard, Clec’h, Catineua et al. Br J Anaesth….. 2 studies
- No anticholinesterace drugs used
- No nerve stimulators
Baillard, Clec’h, Catineua et al. Br J Anaesth…..: 1st study
- 1st study: 568 patients over 3 months
- 1/3 of patients extubated in OR
- Postop blockade 42%