Ensuring the success of regional blocks
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Ensuring the success of regional blocks

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Ensuring the success of regional blocks Ensuring the success of regional blocks Presentation Transcript

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  • ENSURING THE SUCCESS OF REGIONAL BLOCKS Dr P Narasimha Reddy, MD,DA Professor & HOD Dept of Anesthesiology & Critical Care NRI Medical College & General Hospital Chinakakani, Guntur Dist, A.P.
  • Introduction
    • Regional anesthesia was popular
    • Tragic incident in Britain.
    • It was an art
    • Now it is a scientific and business like
    • Answerable to patient’s problems
    • Continuous search to improve safety and surety
    • Inventions like PNS and imaging techniques
  • History
    • 1884- Karl Koller –cocaine
    • 1889- Karl Ludwig- infiltration
    • 1884-William Halstead-LA directly into nerves
    • 1885-L.Corning-accidental-epidural
    • 1898-August Bier-spinal anesthesia
    • 1912-Kulen Kampff-supra.cl.block on himself
    • 1912-Von Perthes-PNS
    • 1944-AP Winni-perivascular technique
    • 1978-La-Grange-doppler u/s to locate nerves
    • 1992-Fried &Fritz- axillary block with u/s
  • Regional Blocks - Advantages
    • Simple
    • Economical
    • Complete analgesia
    • Reduced stress response
    • Good relaxation
    • Less blood loss
    • Less blood transfusions
  • Contd…
    • Good operating field
    • Conscious patient
    • Less action on immune system
    • Post –op analgesia
    • Minimal stay in hospital
    • Less incidence of DVT
    • Early bowel recovery
    • Early ambulation
  • Disadvantages
    • Failures
    • Neurological problems
    • Anxious patients
    • Action on free radicals – more
    • Anatomy
    • Pharmacology
    • Complications and side effects
    • Technique of blocks
    Pre-requisites
  • Select your patient
    • Patient – Exclude-
    • Over anxious
    • Needle phobia
    • Anti psychotic therapy
    • Language barrier
    • Morbid obesity
    • Severe arthritis
    • Degenerative nerve disorders &
    • Adolescent group
    • Success depends on your patient
  • Select Your Surgeon
    • Good sympathetic, understanding
    • Delicate hands and movements
    • No pulling
    • No pressure on the patient &
    • Not much of retraction
  • Select Your Block
    • Logical selection
    • Depends on site, duration & speed of surgeon
    • Eg., ISB for shoulder surgeries
    • AXB for fore arm and hand surgery
    • Missing nerves can be blocked separately
  • Select Your Drug
    • Depending on duration of surgery
    • Post – op analgesia
    • Use enantiomers than racemic mixtures
    • Use less toxic drugs
    • Ropivacaine is more sensory blocker
    • Bupivacaine not used in Biers block
  • Contd…
    • Adjuvants :
    • Sedatives –
    • Titration
    • Verbal contact
    • No drug prevents toxicity of LA
    • Vaso constrictors –
    • Epinephrine 1 in 2-2.5 lakhs
    • Freshly prepared solution
    • Prolongs block
    • Reduced toxicity
    • Used as a marker
    • Use full also with Bupivacaine
    Contd…
    • Soda - bicarb –
    • 1 ml for 10 ml of Xylocaine
    • 0.1ml for 10ml of Bupivacaine
    • Hyaluronidase –
    • Used in ophthalmic practice & field blocks
    Contd…
    • Additives :
    • Many drugs are being added to local anaesthetics –
    • Tramadol
    • Buprenorphine
    • Clonidine
    • Neostigmine
    Contd…
    • Ketamine
    • Fentanyl
    • Epinethrine
    • They prolong the block, prevent patchy
    • Analgesia, depth of block quick onset of
    • sensory & motor block
    Contd…
  • Select Your Equipment
    • Glass syringes are better than disposable
    • Short bevelled needles are better
    • Disposable kits are more useful
  • Select Your Technique
    • By facial clicks :
    • Nerves will be in fascial sheath
    • Anesthetist must feel the click when he enters the sheath
    • Well appreciated with short bevel needles
    • Success rate is 60-65%
    • By Paresthesias :
    • Moore said “no paresthesia – No anesthesia”
    • It is an abnormal sensation
    • It indicates needle tip near the nerve or nerve injury
    • Exaggerated paresthesias are undesirable & dangerous
    • Success rate is 70-90%
    Contd…
    • By Trans arterial injection :
    • Good indication that needle is in the sheath
    • Stan et al – safe with minimal complications & high success rate
    • Complications :
    • - Intra arterial injection
    • - Haematoma
    • - Needle can be deep into muscles
    Contd…
    • By peri-vascular injection :
    • Suggested by Winni
    • Ronie & Thomson opposed
    • Patridge, Katz and Bernischke demonstrated septae but they are thin
    • Anatomical land marks are very important
    • All these techniques depend on normal anatomy, but there are many anatomical variations
    • Skill & experience of anaesthesist will not work here
    • Success rate is 60-65%
    Contd…
    • Anatomical variations :
    • Tuffiers line crosses between L3-L4 or L5-S1
    • Termination of cord
    • Root size
    • Volume of CSF
    • 7 major configurations of B plexus
    • 61% defer from right to left
    Contd…
    • Peripheral Nerve Stimulator :
    • It is better than blind injection
    • Popularized by Dr. P. Raj
    • Success Rate 93%
    Contd…
    • Advantages :
    • Less latency
    • Less nerve injury
    • Less quantity of LA
    • Getting motor response with less than 0.5 mA
    Contd…
    • Pitfalls of PNS :
    • Correct polarity of the stimulating needle
    • Positive electrode – secured to the patient
    • Loose connections and flat batteries must be avoided
    • Motor response must be in the distal group of muscles
    Contd…
    • Disadvantages :
    • Nerve stimulator settings have no consisting relationship to the proximity of the nerve
    • Neuropathies, diabetes, toxic neuropathy, chemotherapy, radiation, demyelinating disorders, multiple sclerosis, peripheral vascular disease, old age can mute the response
    Contd…
    • Amputees
    • Difficult to locate the nerves
    • Nerve damage can occur
    • Parasthesias after the block
    • Compartmental syndrome
    Contd…
    • Single Vs Multiple injections :
    • It is not clear weather single Vs multiple stimulation & injection are superior to single injection
    • AXB – 2, 3, 4 injections have high success rate
    • Neuroproxia is 1-7%
    Contd…
    • Continuous Catheter Technique :
    • Very exciting & developing area
    • Nerve is located with PNS using conductive needles
    • Catheter is passed 2 to 3 cm beyond the needle
    • STIMUCATH are used to locate the nerves & to find epidural space
    • This technique is used in particular places
    Contd…
    • Percutaneous Electrical Guidance (PEG):
    • New technique developed by W.Urmey
    • Noninvasive
    • Indentation of skin with cylindrical smooth tipped probe
    • The needle is passed through the channel in the probe
    • GROSSI proposed a new concept of anesthetic line
    Contd…
  • Imaging Technology
    • In 1978 Doppler U/s was used to locate the nerves
    • Fluoroscopy & U/s was used to locate the vessels
    • Software is available to image the nerves
    • Modern machines are affordable, portable with better resolution and penetration
    • Advantages :
    • Direct visualization of nerves
    • Direct visualization of other structures
    • Direct & indirect visualization of LA spread
    • Re-position of needle in case of misdistribution of LA
    • Avoidance of side effect
    Contd…
    • Avoidance of painful muscle contractions due to PNS
    • Faster onset
    • Longer duration of blocks
    • Improved quality
    • Blocks under GA
    • Neuropathies & Amputees
    Contd…
  •  
  •  
    • Basic Views :
    • Nerves can be imaged in short or long axis
    • Short Axis (SAX) – when probe is aligned perpendicular to the axis of the nerve, the nerve is seen in cross section
    • Long Axis (LAX) – when probe is aligned parallel to the axis of the nerve
    • Short Axis View is preferred due to easy identification of nerves, more stable view & allows to visualise circumferential spread of LA. This is called “Doughnut” sign
    Contd…
  •  
    • Needle Approaches :
    • In plane (IP) – long axis of the needle is oriented to the long axis of the probe
    • Entire needle can be seen
    • Out of plane (OOP) – the long axis of the needle is the oriented perpendicular to long axis of the probe
    • Only part of the needle is seen
    Contd…
    • Successful imaging of nerves :
    • Use lot of gel
    • Adjust gain, frequency and focus on U/s machine so that muscles appear fairly dim and nerves will be denser
    • Nerves run along the borders of other structures i.e., muscles
    • When scanning transversely slide change in angle of U/s probe along any axis results in better quality image
    Contd…
    • Interscalene groove trunks appear hallow like vessels without flow. But they appear mottled when followed peripherally
    • U/s cross section of nerve looks like a bundle of straws viewed end on
    • Follow a survey pattern using land marks are border of tissues
    • Using orientation on the screen
    Contd…
    • Many potential targets on screen move with U/s probe back and forth and get oriented to tissues i.e., nerves
    • Tendons & ligaments can move with nerves – when move the limb
    • Vessels - color Doppler, press
    • Repeated views of nerves on U/s machine
    Contd…
    • Equipment :
    • U/s machine (high resolution U/s) with compound imaging multi-frequency linear array probes and recording capabilities
    • 22G insulated needles are various lengths – 2” to 6”
    • High frequency and high resolution – low penetration 10-14 MHz
    • Broadband transducers 5-12, 8-14 MHz offers excellent resolution
    Contd…
    • Linear array transducers parallel sound beam HRUS software
    • Peripheral nerves – Hypo or hyper echoic, depending on size, sonographic frequency & angle of U/s bean
    • Longitudinal view – relatively hyper echoic band, multiple discontinuous, hypo echoic stripes separated by hyper echoic continuous lines
    Contd…
    • Failures in U/s :
    • Injection of LA into adjacent compartments
    • Injection can enter the muscles
    Contd…
    • Avoiding failures :
    • Your attention must be on the target on the screen
    • Never inject all the drug at a time
    • Reposition the needle at least twice or thrice during the injection
    Contd…
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    • Should anesthetist use ultrasound guided nerve blocks?
    • What about training?
    • - Learning curve
    • - first with PNS and later ultra sounding of the nerve ( dream ticket) afterwards directly with ultrasound.
  • Conclusion
    • Not as a first case
    • Centralize your equipment
    • Select proper block
    • Good knowledge of anatomy
    • No about potential complications on treatment
    • Select right patient
    • Pick the right surgeon
    • Be confident about your block
    • But still if you fail
    • Failures are the stepping stones for success
    Contd…
    • What about the future of regional anesthesia?
  •