central neuraxial blocks

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CENTRAL NEURAXIALBLOCKS

Dr. Anilkumar T.K.

Anaesthetist,

NMC Hospital,

Abudhabi, UAE



VERTEBRAL ANATOMY



SALIENT FEATURES

1. Spinal Cord ends at lower border of L1 in

adults, L3 in infants

2. Line joining the iliac crests is at L3-L4

interspace

3. Epidural Space lies between the walls of

vertebral canal & the spinal dura mater



SPINAL BLOCK

1. Indications

2. Landmarks

3. Technique



4. Drugs

5. Physiological Effects

6. Contraindications -

- Absolute

- Relative

7. Complications



PHYSIOLOGICAL EFFECTS

1. Nervous system -- Differential nerve blockade- Interindividual variability of nerve root

sizes

2. Cardiovascular System -

- Hypotension- Bradycardia



3. Respiratory System -

- Decrease in Vital Capacity- Apnea

4. Gastrointestinal System -- Constricted Gut

- Nausea/Vomiting

5. Renal System -

- Urinary Retention



COMPLICATIONS

1. Post Dural Puncture Headache

2. Urinary Retention

3. Labyrinthine Disturbances

4. Cranial Nerve Palsy

5. Spinal Cord Trauma



POST DURAL PUNCTURE HEADACHE

Pathophysiology of Dural Puncture -- Leakage of CSF

- Excess loss of CSF -

- intracranial hypotension

- reduction in CSF volume



Actual Mechanism -

- Low CSF pressure - traction on the

intracranial structures in the upright

position

- Compensatory increase in blood volume -

venodilatation



INCIDENCENeedle tip Needle gauge Incidence of PDPH

design (%)

Quincke 22 36

Quincke 25 3 –25

Quincke 26 0.3 –20

Quincke 27 1.5 –5.6



Needle tip Needle gauge Incidence of PDPHdesign (%)

Whitacre 20 2 –5

Whitacre 22 0.63 –4

Whitacre 25 0 –14.5

Whitacre 27 0

Tuohy 16 70



SPINAL NEEDLE TIP DESIGNS – QUINCKEN [L], SPROTTE [M] &

WHITACARE [R]



SUSEPTIBILITY

1. Younger age compared to Elderly people

2. Obstetrics Patients

3. Females

4. Larger Spinal Needles

5. Cutting Spinal Needles



PRESENTATION

1. Onset

2. Symptoms

- Headache

“An increase in severity of the headache

on standing is the sine qua non of post -

dural puncture headache”- Nausea & Vomiting

- Diplopia



DIAGNOSIS

1. History -

- Dural puncture- Symptoms of a postural headache

2. Diagnostic lumbar puncture

3. MRI

4. CT myelography

5. Radionuclide myelography



DIFFERENTIAL DIAGNOSIS

01. Viral, chemical or bacterial meningitis

02. Intracranial haemorrhage

03. Cerebral venous thrombosis

04. Intracranial tumour

05. Non-specific headache

06. Cerebral infarction

07. Sinus headache

08. Migraine

09. Drugs (e.g. caffeine, amphetamine)

10. Pre-eclampsia



DURATION

- 72% of headaches resolve within 7 days

- 87% resolve in 6 months

- With no treatment, over 85% of post-dural

puncture headaches will resolve within 6weeks



TREATMENT

The aim of management -

1. Replace the lost CSF

2. Seal the puncture site

3. Control the cerebral vasodilatation



1. Psychological

2. Supportive therapy

3. Posture

4. Abdominal binder

5. Pharmacological

6. Epidural blood patch



EPIDURAL BLOCK

- Thicker Needles

- Technique -

Space Detection -

- Loss of Resistance

- Hanging Drop



- Single Shot or Continuous Cathetertechnique

- “Test Dose”??



COMPLICATIONS

Intra Operatively -

1. Dural Tap

2. Total Spinal Anaesthesia

3. Shivering

4. Nausea/Vomiting

5. Urinary Retention



Post Operatively -

1. Headache

2. Epidural Haematoma

3. Epidural Abscess



PRECAUTIONS FORNEURAXIAL ANAESTHESIA

AND

ANALGESIA INPATIENTS TAKING

ANTICOAGULANT DRUGS



MINIMUM DELAY BETWEEN LAST DOSEOF ANTICOGULANT DRUGS &

PLACEMENT/REMOVAL OF EPIDURALCATHETER

1. Unfractionated Heparin - 02 - 04 hrs

2. LMWH - 10 - 12 hrs

3. Aspirin - 0 day

4. Clopidogrel - >/= 07 days5. Abciximab - 2 days

6. Fondaparinux - No epidural

MINIMUM DELAY AFTER PLACEMENT/



MINIMUM DELAY AFTER PLACEMENT/REMOVAL OF EPIDURAL CATHETER &

NEXT DOSE OF ANTICOAGULANTDRUGS

1. Unfractionated Heparin - 0.5 - 01 hr2. LMWH - 02 -12 hrs

3. Aspirin - Immediate

4. Clopidogrel - Immediate5. Abciximab - 02 - 04 hrs

6. Fondaparinux - No epidural



CONTRAINDICATIONS TONEURAXIAL ANAESTHESIA AND

ANALGESIAPT INR > 1.5

APTT > 40 Seconds

Platelet Count < 50,000 cells/ml

- If INR is increasing, the cut-off level wouldbe INR > 1.5

- If INR is decreasing, the cut-off level

would be INR >1.2



FASTING RECOMMENDATIONS TOREDUCE THE RISK OF PULMONARY

ASPIRATION

- Recommendations apply to healthy

patients undergoing elective procedures

- Not intended for women in labor

- The fasting periods noted apply to all ages



Ingested Material Minimum Fasting

Period (hrs)

Clear liquids 2

Breast milk 4

Infant formula 6

Non-human milk 6

Light meal 6



- Clear liquids include water, fruit juices

without pulp, carbonated beverages, clear

tea & black coffee

- Non-human milk is similar to solids ingastric emptying time



- A light meal typically consists of toast &

clear liquids. Meals that Include fried or fattyfoods or meat may prolong gastric emptying

time. Both the amount & type of foods

ingested must be considered when

determining appropriate fasting period



REFERENCES

- British Journal of Anaesthesia, 2003, Vol. 91,

No. 5, 718-729

- Miller’s Textbook of Anaesthesia, 6th Edition

- Aitkenhead Textbook of Anaesthesia,4th Edition

- Oxford Handbook of Anaesthesia, 1st Edition

- www.asahq.org- www.nda.ox.ac.uk/wfsa



THANK YOU

central neuraxial blocks

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