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Anaesthesia techniques

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  • 1. Anaesthesia Techniques Dr. Tarun Yadav Moderator : Dr. S. Ninave
  • 2. Introduction of Anaesthesia  The word Anaesthesia means “no senses” was coined by Oliver Wendell Homes.  John Lundy coined the term balanced anaesthesia Hypnosis Components of balanced anaesthesia are 1. Hypnosis(sleep,lack of awareness) 2. Analgesia(decreased response to noxious stimuli) 3. Areflexia (lack of movements, muscle relaxation) Analgesia Areflexia
  • 3. Types of Anaesthesia  General Anaesthesia  Regional Anaesthesia
  • 4. PAC  Pre-Anaesthetic Check Up Good communication between patient and anesthesia provider.  Thorough evaluation (History,exam,medical illness,treatment etc).  PAC Chart
  • 5. General Anaesthesia Protocol Premedication Benzodiazepines: Midazolam im 30-60 mins before surgery or iv midazolam before induction. Use : to induce sedation, produce amnesia & anxiolysis. Opiods: Butophenol/ Pentazocine iv before induction to produce analgesia. Antisialagogues: Glycopyrrolate/atropin just before induction. Antiemetics: Ondensetron/ metaclopramide iv just before induction.
  • 6. General Anaesthesia Protocol Preoxygenation: 3 minutes with 100% oxygen. Aim : to increase the oxygen reserve of the body in the form of Functional reserve capacity. The oxygen content of FRC filled with air is 500ml( 21 % of 2500ml) which lasts for 2 mins ( o2 consumption is 250 ml/min). With preoxygenation for 3 minutes the whole of air of FRC is replaced with 100% o2(denitrogination) increasing the oxygen content of FRC to 2.5 lts which lasts for 8-10 minutes.
  • 7. General Anaesthesia Protocol Induction: Intravenous induction is done with thiopentone/ propofol/ ketamine etc. Muscle relaxation for intubation: Done by succinylcholine(rapid sequence) or by long acting muscle relaxants like pancuronium, vecuronium, atracurium etc
  • 8. Equipment for Laryngoscopy  Oxygen source and self-inflating ventilation bag (e.g.,          Ambu bag) Face mask Oropharyngeal and nasopharyngeal airways. Tracheal tubes Tracheal tube stylet Syringe for tracheal tube cuff inflation Suction apparatus Laryngoscope handle (two), tested for working order and battery freshness Laryngoscope blades: Common blades include the curved (Macintosh) and straight (Miller) Pillow, towel, blanket, or foam for head positioning Stethoscope
  • 9. General Anaesthesia Protocol Intubation: Position:  The patient's head should be level with the anesthesiologist's waist.  Moderate head elevation (5–10 cm above the surgical table).  Extension of the atlantooccipital joint place the patient in the desired sniffing position  The lower portion of the cervical spine is flexed by resting the head on a pillow.
  • 10. Technique  The laryngoscope is held in the left hand.  With the patient's mouth opened widely(right hand), the blade is introduced into the right side of the oropharynx.  The tongue is swept to the left and up into the floor of the pharynx by the blade's flange.  The tip of a curved blade is usually inserted into the vallecula, and the straight blade tip covers the epiglottis.  With either blade, the handle is raised up and away from the patient in a plane perpendicular to the patient's mandible to expose the vocal cords
  • 11.  Endotracheal tube is introduced in b/w vocal cords.  Position of the tube is verified with auscultation and capnography.  Tube is fixed with adhesive.  Once position is confirmed IPPV is strated.
  • 12. General Anaesthesia Protocol Maintenance of Anaesthesia: Anaesthesia is maintained with Oxygen (minimum 33%) + N2O (66%) + inhalational agent( halothane, isoflurane , sevoflurance etc) + long acting muscle relaxant.
  • 13. General Anaesthesia Protocol Reversal: Non depolarizing muscle blockade is reversed with neostigmine + atropine/glycopyrrolate after regaining of spont. respiration. Extubation: Extubation is done after thorough suctioning of oral cavity and after patient meets extubation criteria.
  • 14. Regional Anaesthesia  Regional anaesthesia is anaesthesia affecting a large part of the body, such as a limb or the lower half of the body.  Regional anaesthetic techniques can be divided into central and peripheral techniques.  The central techniques include so called neuraxial blockade (epidural anaesthesia, spinal anaesthesia).  The peripheral techniques can be further divided into plexus blocks such as brachial plexus blocks, and single nerve blocks.
  • 15. Common Local Anaesthetics
  • 16. Central techniques: Neuraxial blockade (epidural, spinal anaesthesia). Spinal Anaesthesia (Subarachnoid block i.e.SAB) It is the most commonly used anaesthetic technique. Indications Any below umblical surgery.
  • 17. Procedure  SAB can be given in lateral position , sitting position or prone position.  Approach may be midline(most common), lateral or taylors(lumbosacral).  After cleaning and draping lumbar puncture is done in desired space (usually at L3-L4 or L4-L5) and local anaesthetic drug is injected after confirming the free flow.
  • 18.  Site of action : spinal nerves.  Commonly used drugs are : xylocane 5 %(H), Bupvicane 0.5% (H), Tetracane 1%, Ropvicane 0.75 %. Spinal needles : Dura cutting : Quinke-Babcock, greene. Dura Separrating : pencil point needle, Whitcre, Sporte
  • 19. Factors affecting height of block:  Volume, Baricity, Hyperbaric technique, Position of patient, Intra-abdominal pressure, Spinal curvature, age ,obesity, Height etc Factors affecting duration of block: Dose, Increased concentration, Pharmacological profile like protein binding, metabolism Type of drug used. Long acting , short acting Addetivies : Adr, Buprinorphine etc
  • 20.            Complications of Spinal Anaesthesia Hypotension Bradycardia Nausia vomiting Respiratory paralysis : commonly due to hypotension not high spinal High spinal/ total spinal Local anaesthetic toxicity. Cardiac arrest Broken needle Bloody tap Urinary retention(postop) Post spinal headache(postop)
  • 21. Epidural Anaesthesia  Indications All surgeries which can be performed under spinal anaesthesia can be performed under epidural anaesthesia plus upper abdominal surgeries, thoracic surgeries(uder thoracic epidural) and even neck surgeries (under cervical epidural). To control post operative pain. For labour analgesia. chronic pain due to cancer and chronic pain conditions. Acute occulusive vascular conditions.
  • 22. Epidural Needle  The most commonly used needle for epidural is Tuohy’s needle.  It has a blunt curve of 15 to 30 degree at tip(Huber tip).  Other needles are Weiss and Crawford.
  • 23. Technique  Like spinal it can be given in sitting or lateral position.  Usually epidural space is encountered at 4-5 cm from skin and has a negative pressure.  Common methods to Locate Epidural Space Loss of resistance technique Hanging drop technique
  • 24.  Once the needle is confirmed in epidural space.  Epidural catheter is passed through the needle and 3-4 cm of catheter should be in epidural space ( according to the desired level). A microfilter is attached to prevent contamination.  Test dose of 3 ml of 2 % lignocane with adrenaline is given and if within 5 minutes there is no evidence of spinal block(inability to move foot) or intravascular injection(trachycardia) further dose can be given.  Adhesive is applied afterwards.  Drug is given according to desired level.
  • 25.  Onset of effect takes place in 15-20 minutes.  Successful block is assessed by : Absence of pain by pin prick.  Site of Action :Ant & Post. Nerve roots, Mixed Spinal Nerves
  • 26.  Drugs used for epidural Anaesthesia  Lignocane(with or without adr) 1-2% conc is used. Usually 2-3 ml is required for blocking 1 segment, so normally 15-20 ml of drug is required.  Bupvicane 0.25 % to 0.5 % is used.  0.25 % produces only sensory loss. While 0.5 % produces motor block.  Other drugs used ropvicane , prilocane etc.
  • 27. Advantages & Disadvantages  Only sensory block may     be produced if needed. No sympathetic block. Less hypotension compared to SAB. Top up doses may be given in prolonged surgeries. Post op pain relief. •Respiratory depression. •Urinary retention •Prurutis •Spread of infecton/meningitis •Patchy effect •Delayed onset of action •Kinking •Dura puncture •Hypotension •Intravascular injection •Epidural haematoma/ paraplegia
  • 28. Nerve Blocks( Upper limb) Brachial plexus blocks  Interscalene block.  Supraclavicular block.  Infraclavicular block.  Axillary block.  Midhumeral Brachial Plexus Block
  • 29. Anatomy of Brachial Plexus
  • 30. Supraclavicular (Subclavian) Brachial Plexus Block  The supraclavicular approach to the brachial plexus result in a more even distribution of local anesthetic and can be used for procedures on the arm, forearm, and hand.  Anatomy  At the lateral border of the anterior scalene muscle, the brachial plexus passes down between the first rib and clavicle to enter the axilla.  The trunks are tightly oriented vertically on top of the first rib just posterior to the subclavian artery.
  • 31. Technique  The patient is positioned supine with the head turned about 30° to the contralateral side.  The interscalene groove is palpated at its most inferior point, which is just posterior to the subclavian artery pulse.  After a skin wheal with local anesthetic, a 22-gauge, 1.5-in needle is directed just above and posterior to the subclavian pulse and directed caudally at a very flat angle against the skin. The needle is advanced until a paresthesia is encountered or muscle contraction of the forearm is noted
  • 32.  If contraction is still observed or palpated with the     stimulator voltage decreased to 0.5 mA, then 25–40 mL of local anesthetic is injected. COMPLICATIONS A relatively high incidence of pneumothorax (1– 6%) Hemothorax has also been reported. Horner's syndrome and phrenic nerve block often occur.
  • 33. Axillary Brachial Plexus Block  It is optimal for procedures from the elbow to the hand. This approach tends to produce the most intense block in the distribution of C7–T1 (ulnar nerve) but is usually inadequate for procedures on the shoulder and upper arm (C5–C6).  ANATOMY The subclavian artery becomes the axillary artery beneath the clavicle, where the trunks of the brachial plexus split into anterior and posterior divisions. At the lateral border of the pectoralis minor muscle, the cords form large terminal branches. In the axilla, the musculocutaneous nerve has already left the sheath and lies within the coracobrachialis muscle.
  • 34. Technique  The patient is positioned supine with the arm abducted, the elbow flexed at 90°, and externally rotated at the shoulder leaving the arm lying across the patient's head.  The pulse of the axillary artery is identified as high (proximal) in the axilla as possible.  a 22-gauge, 1.5-in needle is inserted until bright red blood is aspirated.  The needle is then slightly advanced or withdrawn until blood aspiration ceases.
  • 35.  Injection can be performed posteriorly, anteriorly, or in both locations in relation to the artery.  A total of 40 mL of local anesthetic is usually injected.
  • 36. PERIPHERAL NERVE BLOCKS OF THE ARM  Intercostobrachial & Medial Brachial Cutaneous Nerve block.  Radial Nerve Block.  Median Nerve Block.  Ulnar Nerve Block.
  • 37. INTRAVENOUS REGIONAL ANESTHESIA OF THE ARM  Bier block  For short surgical procedures (< 45–60 min) on the forearm, hand, and even the leg.  It is most commonly used for a carpal tunnel release.
  • 38. Technique  An intravenous catheter is inserted on the dorsum of the hand and a double pneumatic tourniquet is placed on the arm.  The extremity is elevated and exsanguinated by tightly wrapping an Eschmark elastic bandage from a distal to proximal direction  The upper (proximal) tourniquet is inflated, the Eschmark bandage is     removed, and 0.5%lidocaine (25 mL for a forearm, 50 mL for an arm, and 100 mL for a thigh) is injected over 2–3 min through the catheter, which is removed at the end of the injection. Anesthesia is usually well established after 5–10 min. Patients often complain of tourniquet pain after 20–30 min. When this occurs, the lower (distal) tourniquet is inflated and then the proximal tourniquet is deflated Patients usually tolerate the lower tourniquet for another 15–20 min because it is inflated over an anesthetized area. Tourniquet must be left inflated for at least 15–20 min to avoid a rapid intravenous systemic bolus of local anesthetic.
  • 39. SOMATIC BLOCKADE OF THE LOWER EXTREMITY  Lumbar Plexus (Psoas) Block  Femoral Nerve & "Three-in-One" Block  Fascia Iliaca Block  Lateral Femoral Cutaneous Block  Lateral Femoral Cutaneous Block  Obturator Nerve Block  Sciatic Nerve Block  Popliteal Block  Saphenous Nerve Block  Ankle Block
  • 40. SOMATIC BLOCKADE OF THE TRUNK  Superficial Cervical Plexus Block  Intercostal Block  Paravertebral Nerve Blocks  Inguinal Nerve Block  Penile Block

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