Spinal anaesthesia involves injecting local anaesthetic into the subarachnoid space to block nerve impulses from the lower half of the body. It was first performed in 1898 and involves accessing the spinal canal between vertebrae to administer drugs. Proper patient positioning, needle selection, and drug choice are important to achieve the desired level and duration of anaesthesia while avoiding complications like hypotension, neurological issues, or infection. Close monitoring is needed due to potential effects on heart rate, breathing, and blood pressure.

1. SPINAL ANAESTHESIA
Moderator : Dr Aradhna
Presented by : Dr Tetikcha

2. Introduction
• Spinal anaesthesia is a form of central neuraxial block involving
injection of local anaesthetic in the subarachnoid space.

3. History
• First case of spinal
anaesthesia was
performed by August Bier
in 1898 using local
anaesthetic cocaine.
• The use of intrathecal
opioids was described in
1901 by Romanian
Surgeon, Nicolae
Racoviceanu-Pitesti.

4. ANATOMY
• Spinal cord ends lower border of L3
in children and lower border of L1 in
adults.
• Due to differential growth between
the bony vertebral canal and the
central nervous system.

5. • 33 vertebrae - 7 cervical, 12
thoracic, 5 lumbar, 5 sacral and 4
coccygeal vertebrae.

6. • Skin
• Subcutaneous tissue
• Supraspinous ligament
• Interspinous ligament
• Ligament flavum (also called the
yellow ligament)
• Dura mater
• Arachnoid mater
• Pia mater.

7. CEREBROSPINAL
FLUID.
• Formed by the choroid plexus of the cerebral ventricles
• Resides in subarachnoid space.
• Total volume : 100 -160 mL.

8. APPLIED
• In cervical and lumbar vertebrae——
— spinous process is in horizontal
orientation—— a needle placed in
perpendicular position.
• In mid thoracic —— a cephalad
needle angulation is required.

9. SURFACE
ANATOMY
• Most prominent spinous process is
C7
• Spinous process of T7 — Inferior
angle of scapula.
• Tuffier line/ Intercrestal line —
Spinous process of L4
• Posterior superior iliac spine — S2

10. SEQUENCE OF EFFECTS OF SPINAL ANAESTHESIA.
• Sympathetic nervous system fibers
• Loss of cold temperature
• Loss of pinprick sensation
• Loss of touch sensation.
• Loss of motor function.

11. Cardiovascular
Blocking of sympathetic fibers
Vasodilation of venous capacitance fiber
Pooling of blood in the periphery and lower extremities
Decrease in circulating blood volume
Decrease in blood pressure ; triggers compensatory baroreceptor response
and increase heart rate.
High neuraxial block may lead to decrease in heart rate

12. RESPIRATORY
• Blockade of the intercostal and the abdominal muscle -
compensated by unaltered function of the diaphragm and other
accessory respiratory muscle.
• Rx: reassurance
• Rarely,respiratory arrest associated with spinal anaesthesia is due
to hypoperfusion of respiratory centre’s in brain stem.
• Rx100% oxygen and IPPV

13. CENTRAL NERVOUS SYSTEM
• Spinal anaesthesia induced hypotension may decrease
regional cerebral blood flow in elderly and those with pre-
existing hypertension.
• There is no change in the cognitive function after surgery in
any of these patients.

14. Gastrointestinal
• Nausea and vomiting may be associated with Neuraxial block
and are primarily related to gastrointestinal hyperperistalsis
caused by unopposed parasympathetic (vagal) action.

15. RENAL
• Urinary bladder supplied by S2-S4 usually gets blocked leading to decreased
bladder tone and retention of urine.
• Neuraxial blocks are a frequent cause of urinary retention which delays
discharge of outpatient and necessitates bladder catheterisation in inpatient.

16. ADVANTAGE OF SPINAL ANAESTHESIA
• Safe, reliable technique
• Good alternative for day care surgery
• Minimal risk for postoperative respirative depression
• Limited stress response to surgery
• Cost effective

17. INDICATION
• Includes surgies of the lower abdomen , lower limb,pelvis , genitals and most
urological case
• Can also be used for analgesia.

18. CONTRAINDICATON
• Absolute
1. Patient refusal
2. Localised sepsis
3. Allergy to any of the drugs planned for administration

19. • Relative
1. Uncooperative patient
2. Pre-existing neurological deficits
3. Demyelinating lesion
4. Previous spinal surgery/ spinal
stenosis
5. Severe AS or fixed cardiac output
6. Hypovolemia
7. Pt on thromboprophylaxis

20. TECHNIQUE
1. PREPARATION:
• STERILITY
• Assessment,explanation, consent and examination of the patient.
• Availability of resuscitation equipment
• Adequate intravenous acccess
• Establishing monitoring of the patient (pulse oximetry ,non invasive BP and
electrocardiography.
• Prepared pack containing drapes, filter, spinal needle, sterilisation solution and
local anaesthetic for skin infiltration.

21. 2. POSITIONING:
• Sitting position. Lateral decubitus.
Jackknife position

22. Spinal needles
• Can be divided into
1. Blunt tipped: Whitacre needle and
Sprotte needle
2. Sharp(cutting ) tipped : Quinke

23. PROJECTION AND
PUNCTURE
Approach may be
• Median
• Paramedian
• Taylor

24. Factors affecting height of the block
• Drug factor
• Patient factor
• Procedure factor.

25. 1. Baricity:is the ratio of the density of the local anaesthetic solution to the
density of CSF.
• Density of CSF :1.00059g/L
• Local anaesthetic agent can be classified as: -
Isobaric:same density as CSF. -
Hyperbaric:higher density than CSF. -
Hypobaric:lower density than CSF.
• Clinical importance: enable to influence the distribution of local anaesthetic
spread based on gravity.
2. Dose:
• The larger the dose , the more cephalad the level of anaesthesia that will be obtained.
Drug Factor

27. PATIENT FACTOR
1. ADVANCED AGE
• Advanced age =increased block height
• In older patient CSFdecrease whereas it’s specific gravity increase.
• Further the nerve roots are more sensitive to local anaesthetic in elder populations.
2. CSF VOLUME
• The increased abdominal mass in obese patient and possibly increased epidural fat may
decrease the CSF Volume and increase the spread of local anaesthetic and height
block.

28. 3. PREGNANCY
Spread of local anaesthetic is enhanced in pregnancy:
• changes in the lumbar lordosis
• Decrease in the volume of CSF
• progesterone mediated increase in neuronal sensitivity.

29. PROCEDURE FACTOR
• Patient position
• Level of injection
• Needle type and orientation of the orifices.

30. COMPLICATION
1. Post -dural puncture headache:
• Loss of CSF through the dura — traction.
• Characterised by frontal or occipital headache within 3 days of the procedure.
• Associated with nausea , vomiting , neck pain , dizziness, hearing loss cortical blindness
and even seizures.
• worsen with the upright or seated posture
• relieved by lying supine
• Spontaneously resolution occur within 7 days.
• Management: supine positioning ,hydration,caffeine and oral analgesic and epidural patch.
NEUROLOGICAL

31. 2. Paraplegia:
• mechanism- multifactorial.
• Anterior spinal artery syndrome
3. Transient Neurologic Symptoms
• Characterised by bilateral or unilateral pain in the buttock radiating to the leg.
• Likelihood of TNS is highest after intrathecal lidocaine and mepivacaine.
• Management: NSAIDs are the first line of treatment.

32. CARDIOVASCULAR
1. Hypotension:
• Risk factor:peak block height greater than or equal to T5 , age older than or equal to 40 yrs ,
baseline systolic pressure less than 120 mm Hg, spinal anaesthesia at or above the level of L2-L3
interspace and addition of phenylephrine to the local anaesthetic
• Common symptom : nausea vomiting,dizziness and dyspnea.
• Management: Phenylepinephrine / epinephrine /Mephentermine.
2. Bradycardia
• Risk factor:baseline HR<60 /min,age younger than 37 yrs,male, and prolonged case duration.
• Management: atropine.
• Prophylactic infusion of colloid and crystalloid :no longer recommended.

33. 2. Bradycardia
• Risk factor:baseline HR<60 /min,age younger than 37 yrs,male, and prolonged
case duration.
• Management;
• Phenylepinephrine
• Ephedrine
• Mephetamine.

34. INFECTION
• Source of infection in spinal anaesthesia includes the equipment , the patient
or the practitioner .
• Oral bacteria such as Streptococcus viridans are a common source of
infection
• Other factor that increases the likelihood of infection include presence of
concomitant systemic infection , diabetes, immune compromised state.

35. Other
• Backache
• Nausea and vomiting
• Urinary retention
• Pruritis

36. Local anaesthetics:
1. Short or intermediate acting:
• Procaine
• Chloroprocaine
2. Intermediate acting
• Lidocaine: associated with TNS and permanent nerve injury
• Mepivacaine
• Prilocaine
2. Long acting :
• Bupivacaine
• Levobupivacaine
• Ropivacaine

38. Spinal Additives:
• Vasoconstrictor:epinephrine, phenyephrine
• Alpha -2 agonist:clonidine, dexmedetomidine and epinephrine.
• Opioids:

39. Thank you