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!