Neuraxial anaesthesia

spinal, epidural and caudal anaesthesia

1. Neuraxial anaesthesia DR. PRIYANKA MAHANTA SENIOR RESIDENT DEPT. OF ANAESTHESIOLOGY

2. Neuraxial anesthesia is a type of regional anesthesia that involves injection of anesthetic medication in the fatty tissue that surround the nerve roots as they exist the spine or into the cerebrospinal fluid which surrounds the spinal cord .

3. Spinal anaesthesia Epidural Caudal

4. history 1885 - J. Leonard Corning – first spinal anesthetic was administered accidentally 1891-Quincke demonstrated usefulness of spinal puncture in diagnosis 1898 - August Bier - first planned spinal anesthesia for surgery 1901- Cathelin and Sicard developed the technique of caudal epidural injection 1921- Spanish military surgeon Fidel Pagés performed lumbar epidural anesthesia 1951- Crawford used epidural anaesthesia for thoracic surgery

5. Anatomy Advantages Indications/ contraindications Physiologic effects Techniques Pharmacology Complications

6. Anatomy of vertebral column The spine is composed of the vertebrae and intervertebral disks. There are 7 cervical, 12 thoracic and 5 lumbar vertebrae. The sacrum is a fusion of 5 sacral vertebrae. small rudimentary coccygeal vertebrae

7. Anatomy of spinal cord Spinal canal contains the spinal cord with the meninges-pia, arachnoid and dura mater Subdural and epidural spaces are potential spaces

8. Extends from foramen magnum At birth, spinal cord ends at lower border of L3 At 1 year- at L2 >12 years- at lower border of L1 (50%) upper border of L2 (40%) body of T12 (5-6%) upper border of L3 (3%) length- 45 cm (males) 42 cm (females )

9. Dural sac –circular sac surrounding spinal cord Cranially attached to the circumference of foramen magnum Ends at S2 level( 35%)

10. Sagittal Section Through Lumber Vertebrae

11. SUPRASPINUS LIGAMENT Strong ,thick, fibrous band connecting apices of the spine from C7 to sacrum Extends from C7 to occiput as Ligamentum nuchae Thick and broad at lumbar region

12. INTERSPINOUS LIGAMENT Thin ,fibrous structure connecting the adjacent spines membranous

13. LIGAMENTUM FLAVUM Yellow elastic tissue Between laminae of adjacent vertebrae Right and left halves fuse at midline

14. DERMATOMES A dermatome is an area of skin innervated by sensory fibers from a single spinal nerve

15. Dermatomal levels T4 – nipples T6 – xiphoid T10 – umbilicus T12, L1 – inguinal ligament , crest of ileum S2-S4 – perineum

16. Dermatomal Levels of Spinal Anesthesia for Common Surgical Procedures Procedure Dermatomal Level Upper abdominal surgery T4 Intestinal, gynecologic , and urologic surgery Transurethral resection of the prostate T6 Vaginal delivery of a fetus , and hip surgery T10 Thigh surgery and lower leg amputations L1 Foot and ankle surgery L2 Perineal and anal surgery S2 to S5 (saddle block)

17. Advantages over ga Cost effective Less risk of pulmonary aspiration Avoid periop . respiratory complications Less post-op. thromboembolism Avoid systemic effects of GA drugs

18. contraindications ABSOLUTE Patient refusal Coagulopathy Raised intracranial tension Severe hypovolaemic shock Patients on anticoagulants/ thrombolytics / fibrinolytics Septicaemia / bacteraemia Infection at local site

19. contraindications Relative Valvular heart disease Previous spine surgery Spine deformity Uncooperative patient Peripheral nerve disease Uncontrolled hypertension Spine metastasis

20. physiological effects CVS Hypotension Bradycardia – Bezold Jarisch reflex With high sympathetic block, sympathetic cardiac accelerator fibers arising at T1-T4 are blocked, leading to bradycardia CNS Sequence of blockage of nerve fibres Autonomic-> Sensory -> Motor Recovery in reverse order Autonomic level is 2 segment higher than sensory which is 2 segment higher than motor - differential blockade

21. Respiratory system Affected in high spinal/ total spinal Medullary ischemia d/t untreated hypovolaemia Systemic toxicity of LA Gastrointestinal Contracted gut with sphincter relaxation d/t sympatholysis Nausea/ vomitting

22. Genitourinary system Impaired renal function if MAP < critical pressure for renal autoregulation Penile engorgement Endocrine system Decrease stress response to surgery

23. spinal anaesthesia

24. indications- spinal Lower limb orthopaedic surgeries Abdominal surgeries Urological procedures Obstetric and gynaecological procedure

25. Surface anatomy

26. Locating prominent cervical and thoracic vertebrae Spinous processes are palpable over the spine and help define the midline In cervical area first palpable spinous process is C2 Most prominent spinous process is C7 With the patients arms at the side the tip of the scapula generally corresponds with T7

27. What is Tuffier’s Line? A line drawn between the highest points of both iliac crests will correspond to either the body of L4 or the L4-L5 interspace.

28. Palpation of Spinous Process

29. Surface anatomy

30. Procedure Preparation of the patient, consent Pre-medication Anxiolytics To decrease acid secretions – H2 blockers, proton pump inhibitors Monitors Intravenous line – pre/co-loading with fluids Maintain strict asepsis

31. Positions Lateral flexed position - most commonly used - back parallel to edge of table - hips and knees flexed, neck and shoulder flexed towards knees - nose to knees

32. Positions Sitting position -patient should sit on the table with knees resting on the edge, legs hanging over the side and feet supported by a stool below for saddle block anaesthesia

33. Positions Prone position/ Buie’s position (Jackknife) suitable for hypobaric techniques patient should be in prone position with OT table flexed under his flanks, just above the iliac crests

34. Lumbar Extension versus Flexion

35. Technique Part preparation Locate site for needle insertion Inject LA Insert spinal needle and advance till dura is punctured If bone is encountered, withdraw the needle to subcutaneous plane and redirect more cephalad Midline approach

36. La y er s t ra v e rs e d b y t h e s pina l needle (posterior to anterior) Skin Subcutaneous tissue Supraspinous ligament Interspinous ligament Ligamentum flavum Duramater Sub dural space Arachnoidmater Subarachnoid space

37. Technique Paramedian approach 2 cm lateral to inferior aspect of superior spinous process advanced towards midline at 10-25° angulation Needle lies lateral to supraspinous and interspinous ligaments and penetrates ligamentum flavum and duramater in the midline

38. Taylor approach spinal needle is inserted 1 cm medially and 1 cm above the lowest prominence of posterior superior iliac spine Needle is directed upwards medially and forwards at an angle of 50 degrees

39. Spinal needles Quincke Babcock needle

40. Spinal needles Whitacre needle

41. Spinal needles Sprotte needle

42. Spinal needles Pitkin needle

43. Spinal needles Greene needle

44. Mechanism of action of la Local anaesthetics bind to  subunit of voltage gated Na channels, prevents channel activation and Na influx associated with membrane depolarization. For neuraxial anaesthesia the target binding sites are the spinal nerve roots in the subarachnoid and epidural spaces .

45. Drugs used in spina l anaesthesia Dose of LA used in spinal anaesthesia depends on Site of surgery Duration Additive used Patient factors- age, pregnancy Lignocaine 5% hyperbaric solution Rapid onset of action , intermediate duration Disadvantages – Transient neurological symptoms

46. Drugs used in spinal anaesthesia B u p iv a c a i n e 0.5% hyperbaric/ isobaric/ hypobaric solutions Levobupivacaine Isolated (S) entantiomer of bupivacaine 0.5% isobaric solution Less CNS and cardiac toxicity compared to bupivacaine Long duration of action Ropivacaine Less potent than bupivaine Less CNS and cardiac toxicity compared to bupivacaine 0.5- 0.75% isobaric solution

47. Adjuvants used To improve and prolong anaesthesia Reduce the need of high dose of LA To reduce adverse effects associated with LA Opioids- Fentanyl 10-25 µg Morphine 50-300 µg 2 agonist- Clonidine 30-60 µg Dexmedetomidine 5 µg Benzodiazepines- Midazolam 20 µg/kg (upto2.5 mg)

48. factors affecting spread of la in subarachnoid space

49. Factores affecting duration of block Dose Increased concentration of agent Pharmacological profile of drug like protien binding ,metabolism Type of drug used .Bupivacaine vs lignocaine Additives used

50. Assessment of levels of block Sensory level Pin prick using sterile needle Temperature sensation

51. Motor block Modified Bromage scale

52. epidural anaesthesia

53. indications Intra/post operative analgesia Thoracic/ abdominal surgeries with or without GA With spinal anaesthesia for prolong surgeries Painless labour Chronic pain management

54. advantages Less hypotension No post spinal headache Level of block can be changed Duration of surgery can be prolonged

55. Epidural Space ( Extradural or Peridural space) It lies outside duramater . Extends from foramen magnum to sacral hiatus

56. Contents of epidural space Anterior and posterior nerve root Epidural veins (Batson venous plexus) Spinal arteries Lymphatics Fat

57. Most common is Tuohy’s needle It is blunt bevel with curve of 15 to 30 degree at tip ( Huber Tip ) Blunt tip reduce the risk of accidental dural puncture and guide the catheter cephalad . Weiss – is winged Crawford – straight blunt bevel with no curve

58. The catheter is made of a flexible, calibrated, durable, radiopaque plastic with either a single orifice or multiple side orifices near the tip

59. EPIDURAL TECHNIQUES Patient preparation Explain to the patient Consent taking monitoring and resuscitation equipment intravenous access Strict asepsis Sterile drape Patient position-sitting or lateral Site of needle insertion depends on the extent of surgical field

60. Techniques to identify epidural space Loss of resistance technique – after piercing ligamentum flavum there is loss of resistance. Hanging drop technique ( Gutierrez’s sign)- drop of saline in hub sucked in due to negative pressure . MacIntosh extradural space indicator Odom’s manometer indicator

61. E pidural catheter is passed through the needle and 3 to 4 cm of catheter should be in epidural space.

62. A test dose is designed to detect both subarachnoid and intravascular injection . The classic test dose combines local anesthetic and epinephrine, typically 3 mL of 2 % lignocaine with 1:200,000 epinephrine (0.005 mg/mL ). Lignocaine , if injected intra-thecal, will produce spinal anesthesia that should be rapidly apparent- paresthesia E pinephrine , if injected intra-vascular, should produce a noticeable increase in heart rate (20% or more), with or without hypertension .

63. Factors affecting level Volume of drug Age Intra abdominal tumours , pregnancy Patient position Speed of injection Level of injection Length of vertebral column Conc of LA

64. Drugs used Lignocaine 2%- produce dense block Bupivacaine 0.0625-0.5% Levobupivacaine 0.0625-0.5% Ropivacaine 0.2- 0.75% Volume of drug injected- 1-2ml per segment to be blocked

65. caudal anaesthesia

66. indications-caudal Lower limb/ abdominal surgeries along with GA or sedation in paediatric patients Intra/ post op. analgesia Anorectal surgeries in adults

67. The caudal space is the sacral portion of the epidural space. Caudal anesthesia involves needle and/or catheter penetration of the sacrococcygeal ligament covering the sacral hiatus. The sacral hiatus is a defect in the lower part of the posterior wall of the sacrum formed by the failure of the laminae of S5 and/or S4 to meet and fuse in the midline .

68. The hiatus may be felt as a groove or notch above the coccyx and between two bony prominences, the sacral cornua . Its anatomy is more easily appreciated in infants and children.

69. The posterior superior iliac spines and the sacral hiatus define an equilateral triangle

70. Contents of the Sacral canal Dural sac which ends at the border of the 2nd sacral vertebra on a line joining the posterior iliac spine . The pia mater is continued as the filum terminale . Sacral nerves and the coccygeal nerve. Venous plexus formed by the lower end of the internal vertebral plexus. Areolar and fatty tissue

71. I n children, caudal anesthesia is typically combined with general anesthesia for intraoperative supplementation and postoperative analgesia. Commonly used for procedures below the diaphragm, including urogenital, rectal, inguinal, and lower extremity surgery. Pediatric caudal blocks are most commonly performed after the induction of general anesthesia.

72. The patient is placed in the lateral or prone position with one or both hips fl exed and the sacral hiatus is palpated. After sterile skin preparation, a needle or intravenous cannula ( 18–23 gauge) is advanced at a 45° angle cephalad until a pop is felt as the needle pierces the sacrococcygeal ligament.

73. The angle of the needle is then flattened and advanced 1-2 cm.

74. Aspiration for blood and CSF is performed, and, if negative , LA is injected. For continuous caudal block, a catheter can be placed. In adults undergoing anorectal procedures, caudal anesthesia can provide dense sacral sensory blockade with limited cephalad spread. Furthermore, the injection can be given with the patient in the prone jackknife position .

75. Drugs used for caudal block volume 0.5ml/kg for lumbosacral block 1ml/kg for thoraco -lumbar block 1.25 ml//kg for midthoracic block Bupivacaine Maximum dose 2.5 mg/kg (without Adr ) &3mg/kg (with Adr ) 0.25% for analgesia and 0.5% for motor block

76. Lignocaine Maximum dose 7mg/kg (without Adr ) & 10 mg/kg (with Adr ) 1% for analgesia and 2% for motor block Adults: 20-30 ml 0.25-0.5% bupivacaine .

77. complications of neuraxial anaesthesia

78. thank you