regional anesthesia ed

8/12/2019 Regional Anesthesia ED

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Regional Anaesthesia&

Temperature ControlAizat


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Definition

Techniques of abolishing pain using localanaesthetic agents as opposed to generalanaesthesia.

Drugs that produce reversible conduction blockade of impulses along central &peripheral nerves producing ANS, sensoryblockade and skeletal muscle paralysis in thearea innervated by affected nerve


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Types

REGIONALANAESTHESIA

TOPICAL CENTRALNERVE BLOCK

SPINAL

ANAESTHESIA

EPIDURAL

ANAESTHESIA

PERIPHERALNERVE BLOCK

PLEXUS BLOCK SINGLE NERVE

BLOCK

INTRAVENOUSREGIONAL

(BIER BLOCK)


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Aim

Provide anesthesia for a surgical procedure

Provide analgesia pre& post-operatively orduring labour and delivery Diagnosis or therapy for patients with chronic

pain syndromes


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LA agent

Esters Procaine, chloropropaine, tetracaine,amethocaine, cocaine

Amides lignocaine, etidocaine, mepivacaine,bupivacaine,ropivacaine


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DRUGS Lignocaine (USA Lidocaine)

Presentation Clear aq solution lidocaine HCL Plain 0.5%(local infiltration, IVRA ), 1%, 2%(nerve blocks,

extradural anaesthesia) with adrenaline 1:200 000

Use of adrenaline: Vasoconstiction at site of injection rate of

absorption, systemic toxicity, duration of action Gel 2% with or without chlorhexidine

Clinical : onset in 2-20min; duration 60-120min Recommended max dose 1-3mg/kg (7mg/kg with adrenaline) How to prepare

Lignocaine concn : O.5%: 5mg/ml, 1%: 10mg/ml,2%:20mg/ml

E.g: 70kg 210mg : do not use more than 10ml of 2%lignocaine

C/I : Do not use with adrenaline in end arterial supply (fingers,toes, pinna, penis and nose)


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Bupivacaine Presentation clear colourless, aq solution

(bupivacaine hydrochloride ) Plain (0.25%, 0.5%, 0.75%) With 1:200 000 (5g/ml ) adrenaline Heavy 0.5% with 80mg/ml dextrose ( SG 1.026)

Recommended max dose 2mg/kg (150mg plus up to50mg 2 hourly subsequently)

Clinical- onset within 10-20min, duration of action 4-8hrs. 4X as potent as lidocaine, propensity forcardiotoxicity


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ADVANTAGES

Conscious patients assist in positioning early warning of adverse effects avoid airway manipulation & complications

Good quality block in term of motor and sensory adequate as per surgical requirement surgical / hormonal / psychological stress

Less post operative complications less sedated less nausea / vomiting reduce atelectasis pneumonia reduce risk of dvt

early oral intake


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DISADVANTAGES

Patients anxiety increased sympathetic tone unwanted psychological stress

Technically difficult procedure Co-operation from patients are required Abnormal sensation :

paraesthesia / hyperaesthesia


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COMPLICATIONS

Allergic reaction (rare


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Topical Anesthesia

Application of local anesthetic to mucous membrane- cornea, nasal / oral mucosa

Uses : absorb into dermis and block the nerve end awake oral, nasal intubation, superficial surgical procedure

Advantages : technically easy minimal equipment

Disadvantages : potential for large doses leading to toxicity


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Local/Field Anesthesia

Application of local subcutaneously to anesthetisedistal nerve endings

Uses: Suturing, minor superficial surgery, line placement, more

extensive surgery with sedation Advantages:

minimal equipment, technically easy, rapid onset Disadvantages:

potential for toxicity if large field


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Forehead block

2 nerves from superior orbital marginSupraorbital n: 2.5cm from midlineSupratrochlear n: upper medial corner of orbit

Insert needle from eyebrow midline directlaterally


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Auricular block

Nerve: auriculotemporal, greater auricular and lesseroccipital


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Peripheral Nerve Block Injecting local anesthetic near the course of a named

nerve Uses:

Surgical procedures in the distribution of the blockednerve Advantages:

relatively small dose of local anesthetic to cover large area;rapid onset

Disadvantages: technical complexity, neuropathy


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Wrist block

Median nerve : lies superficially between palmaris longus and FCRUlnar nerve : lies between FCU and ulnar arteryRadial nerve: over radial styloid up to extensor surface


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Digital nerve block

Web space approach. 2 dorsal & 2 palmar. NEVER use adrenaline


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Ankle block


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Saphenous nerve: ant and just above medial malleolusSuperficial peroneal nerve: above the ankle joint from anterior border of tibia to lateralmalleolusDeep peroneal n: above ankle joint between tibialis ant tendon and ext hallucis longusSural n: Lateral to achilles tendon to lateral malleolusTibia n: Medial to achilles tendon to lateral PTA (by palpation)


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Femoral block

Femoral nerve : Lateral to artery under inguinal ligament


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Plexus Blockade Injection of local anesthetic

adjacent to a plexus,e.gcervical, brachial or lumbarplexus

Uses : surgical anesthesia or post-operative analgesia in the

distribution of the plexus Advantages:

large area of anesthesia withrelatively large dose of agent

Disadvantages: technically complex, potential

for toxicity and neuropathy


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Biers block (IVRA) Indication : M&R of forearm # Drugs: 10ml of 1% lignocaine

Dosage :0.4ml/kg(2mg/kg), onset 3mins Technique

V/S monitoring & IV branula on bothhands

Torniquet affevted limb: 50-100mmhgabove SBP

Elevate hand above heart beofretorniquet

Confirm dissappearnace of radial pulsebefore injecting LA

Don t deflate cuff within


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Spinal vs Epidural

SPINAL EPIDURAL

site ofadministration :

subarachnoid space CSF (+)

extra dural space --loss of resistance

technically : easierSpinal needle

LOR

more difficultTuohy needle

CSF fluid

failure rate : low high


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Spinal vs Epidural

SPINAL EPIDURAL

onset : Fast Slow

duration : 2 to 2.5 hours( flexible)

flexible

level : lumbar ; sacral cervical to caudal

volume of LA : small

1.0 to 3.0 mls

large

5.0 to 30 mls


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Temperature control

Hypothalamus is the body thermostat Normal core temp: 37C (if taken internally)

36.8 0.4C (98.2 0.7F) in oral,axilla&rectal Ideal site : Pulmonary artery (gold standard)

Using thermistor cathether Blood mix from skin to viscera


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Take home message

LA produce reversible conduction blockage byinhibiting passage of Na ions through the ionselective NA channel at the nerve membrane.

Lignocaine 1-3mg/kg, 2% = 20mg/ml Serious systemic effect are cardiac arrythmias

and convulsion Identify anatomy first before giving LA Hypothalamus controls the body temp

regional anesthesia ed

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