1.Anaesthesia Techniques Dr. Tarun Yadav Moderator : Dr. S. Ninave

2. Introduction of Anaesthesia The word Anaesthesia means nosenses was coined by Oliver Wendell Homes. John Lundy coined the term balanced anaesthesiaHypnosisComponents of balanced anaesthesia are 1. Hypnosis(sleep,lack of awareness) 2. Analgesia(decreased response to noxious stimuli) 3. Areflexia (lack of movements, muscle relaxation)AnalgesiaAreflexia 3. Types of Anaesthesia General Anaesthesia Regional Anaesthesia 4. PAC Pre-Anaesthetic Check Up Good communication between patient andanesthesia 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 (510 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 vocalcords. 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 alarge 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 , sittingposition 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 IndicationsAll 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 isTuohys 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 lateralposition. 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 needleand 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 ofpain 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 isused. 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 plexusresult 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 headturned 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 2540 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 C7T1 (ulnar nerve) but is usually inadequate for procedures on the shoulder and upper arm (C5C6). 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 armabducted, 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 CutaneousNerve block. Radial Nerve Block. Median Nerve Block. Ulnar Nerve Block. 37. INTRAVENOUS REGIONAL ANESTHESIA OF THE ARM Bier block For short surgical procedures (< 4560 min) on the forearm, hand, andeven 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 adouble 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 23 min through the catheter, which is removed at the end of the injection. Anesthesia is usually well established after 510 min. Patients often complain of tourniquet pain after 2030 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 1520 min because it is inflated over an anesthetized area. Tourniquet must be left inflated for at least 1520 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