RegionalAnaesthesiaBasicSciencesAnaestheticCourse
Dr Vassilis ATHANASSOGLOUFRCA
ConsultantAnaesthetistandLecturerinMedicineOxfordUniversityHospitalsNHSTrust,UK
Geneva,5th June2017
FacultyDisclosure
Acknowledgements
Dr SvetlanaGalitzine
Dr Soumitra Ghosh
Dr PaulTownsley
Dr Istvan Daroc
Dr MichaelMould
Dr ChrisSpiteri
✓ No, nothing to disclose Yes, please specify:
NuffieldOrthopaedic Centre(NOC)
“Regionalanaesthesiaalwaysworks– ifyouputtherightamountoftherightstuffinthe
rightplace”
LearningObjectives
40mintorefreshyourknowledgein:
• Physiologyandpathophysiology
• Pharmacology
• Physicsandequipment
• Appliedanatomyandselectedblocks
LearningObjectives
40mintorefreshyourknowledgein:
• Physiologyandpathophysiology
• Pharmacology
• Physicsandequipment
• Appliedanatomyandselectedblocks
Regionalanaesthesia intendstoblockgenerationandconductionoftheactionpotentialinthecentralandperipheralnervoussystem
Keyconceptstounderstand
• Howthisworksatcellularlevel- Actionpotentialofthenervecell• Someofthemolecularmechanismsbehindit– Na+ andK+ voltagegated
channels• Propagationofactionpotential
https://commons.wikimedia.org/wiki/File:Action_potential_reloaded.jpg
http://droualb.faculty.mjc.edu/Course%20Materials/Physiology%20101/Chapter%20Notes/Fall%202011/chapter_7%20Fall%202011.htm
https://www.studyblue.com/notes/note/n/4-the-action-potential/deck/15442360
http://www.zoology.ubc.ca/~gardner/action_potential.htm
https://www.studyblue.com/notes/note/n/ch-11/deck/15452839
http://www.zuniv.net/physiology/book/images/n1-8ok.jpg
https://patentimages.storage.googleapis.com/WO2009131639A1/imgf000021_0001.png
Copyright © 2017 American Society of Regional Anesthesia and Pain Medicine
http://www.ijri.org/viewimage.asp?img=IndianJRadiolImaging_2014_24_3_217_137025_t1.jpg
Mechanismsofnerveinjury
• Traumatic(mechanicalandinjection)
• Vascular(ischaemic)
• Chemical(Neurotoxic)
• Inflammatory
Etiology ofPeripheralnerveinjury• Anaestheticfactors
• Typeofanaesthetic• Intraneural injection• Nervestructure• Needletype
• Surgicalfactors• Surgicalpositioning• Tourniquet• Postsurgicalinflammatoryneuropathy
• Patientfactors• Preoperativeneuralcompromise• Lumbarspinalcanalstenosis
Havewemadeperipheralnerveblockssaferbyusingnervelocalisationtechniquesormonitors?
Physiology
Ref: xxx:
40mintorefreshyourknowledgeon:• Physiologyandpathophysiology• Pharmacology• Physicsandequipment• Appliedanatomyandselectedblocks
http://www.anaesthesiauk.com/article.aspx?articleid=220
40mintorefreshyourknowledgeon:• Physiologyandpathophysiology• Pharmacology• Physicsandequipment
• PrinciplesofUS• PrinciplesofNS• Dualguidance:helporhindrance?
• Appliedanatomyandselectedblocks
Soundisalongitudinalwavethattravelsinastraightlineandrequiresamediumtogothrough
Frequencyexceedingtheupperlimitofhumanhearing,whichis20,000Hzor20kHz
MedicalUltrasound2MHzto16MHz
Amplitude
Imageproducedbypassinganelectricalcurrentthroughapiezoelectrical crystal
LowFrequency3MHz
HighFrequency10MHz
Frequencyvsresolution
Broadbandvsnarrowband
USwavesinteractionwithtissuesReflection:scatteringvsspecularRefractionTransmissionAttenuation
Theultimategoalofanyultrasoundsystemistomakeliketissueslookthesameandunliketissueslookdifferent
ResolutionAxial
Lateral
Spatial
Temporal
Peripheralnervestimulator
http://www.frca.co.uk/Documents/149%20Nerve%20stimulation%20for%20peripheral%20nerve%20blockade.pdf
Current:E = K (Q/r2)
Polarity:needle– cathode
Frequency:1– 2Hz
Stimulatingneedleshttp://www.frca.co.uk/Documents/149%20Nerve%20stimulation%20for%20peripheral%20nerve%20blockade.pdf
USvsPNSUS
Directvisualisation nerveandvesselsIncreasesafety
PNSAvoidsintraneural injectionIncreasesafety
MythsPainonintraneural injectionNervestimulationat0.2mAwhenintraneural
40mintorefreshyourknowledgeon:• Pharmacology• Physiologyandpathophysiology• Physicsandequipment• Appliedanatomyandselectedblocks
PP
PP
T TT
T
Sciatic-yellow
Femoral–grey
Lat cutan –lightgrey
Obturator-green
https://en.wikipedia.org/wiki/Brachial_plexus
https://en.wikipedia.org/wiki/Lumbar_plexus
http://teachmeanatomy.info/lower-limb/nerves/sacral-plexus/
Sonoanatomy forparticularPNBs
1. Interscalene2. Supraclavicular3. Infraclavicular4. Axillary5. Femoral6. Popliteal
Interscalene block
Indications: SurgerytoshoulderLandmarks: Scalenus anterior&medius,sternocleidomastoidmuscle&subclavianartery
Supraclavicularblock
Indications: Surgerytothearm&handLandmarks: Subclavianartery,pleura&firstrib
Infraclavicular block
Indications: Surgerytoarm&handLandmarks: Clavicle,axillaryartery&vein,pleura,pectoralismajor&minormuscles
AxillaryblockIndications: Surgerytoforearm&handLandmarks: Anterioraxillaryfold,posterioraxillaryfold,axillaryartery&vein
Femoralnerve
Poplitealblock
Indications: Foot&anklesurgery(+/- saphenousnerveblock)Landmarks:Poplitealvessels(veinsuperficialtoartery),bicepsfemoris
Thankyouforyourattention!
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