Lumbar Puncture and Spinal Anesthesia

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Lumbar Puncture and Spinal Anesthesia
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Principles of Spinal Anesthesia

• Local anesthetic agent injected into the
  subarachnoid space mixes with cerebrospinal fluid
  (CSF) and bathes the spinal cord and nerves
• Blocks conduction of impulses along all nerves
  with which it comes in contact
• Motor nerves blocked Muscles become paralyzed
• Sensory nerves both sensations of touch and
  pain should be blocked for operations
• Autonomic nerves control the size of blood
  vessels, heart rate, gut contraction and other
  functions not under conscious control, most
  easily blocked and cause
• Vasodilatation and drop in blood pressure
• Sensation of touch may be more preserved than
  that of pain

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Local Anesthetic Drugs for Spinal Anesthesia
Bupivacaine

• 0.5 hyperbaric
• Best agent to use
• Effect lasts longer than most other agents, for
  23 hours
• Plain bupivacaine may also be used
• 4 mL ampoule, preservative-free

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Local Anesthetic Drugs for Spinal Anesthesia
Lignocaine

• 5 hyperbaric (heavy) lignocaine
• Anesthesia lasts for about 4590 minutes
• Lignocaine 2 plain can also be used but short
  action
• Lignocaine from multidose vial not recommended
  for intrathecal injection may contain
  potentially harmful preservatives
• 2 mL ampoules, preservative-free

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Benefits

• If done properly, spinal anesthesia is safe, easy
  and cheap
• Patient satisfaction
• Good Apgar score of the baby
• Airway is free and does not need control
• Relaxation of abdominal muscles better for
  patients with asthma, diabetes and some
  cardiovascular diseases

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Limitations

• Takes longer than giving ketamine
• Risk of failure
• Hypotension
• Fear of excessively high blockmay cause
  respiratory block
• Risk of meningitis
• Risk of post-spinal anesthesia headache

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Contraindications

• Should not be performed under the following
  conditions
• Inadequate resuscitation drugs and equipment
• If patient refuses
• Sepsis at injection site or septicemia
• Uncorrected hypovolemia
• Clotting abnormality
• Uncooperative or semi-conscious patient
• Valvular stenosis (cardiac)
• Distorted anatomy of back

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Spinal Anesthesia Obstetric Setting

• Spinal anesthesia in the obstetric setting is a
  major procedure
• Full preparation of the operating room should be
  done
• Emergency drugs must be available and at hand
• Emergency equipment should be available and ready
  for use

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Spinal Anesthesia Obstetric Setting

• Patient history
• Previous history of spinal anesthesia
• History suggestive of dehydration
• Antenatal hemorrhage and treatment
• Bleeding other than vaginal bleeding
• Trauma or pathology of back
• Cardiac valvular disease

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Spinal Anesthesia Obstetric Setting

• Physical examination
• Signs of dehydration
• Cardiovascular system pulse, blood pressure
• Local examination of the back

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Spinal Anesthesia Obstetric Setting

• Laboratory investigations
• Platelet count
• Less than 100,000 Spinal anesthesia with blood
  transfusion only
• Less than 50,000 Refer/ketamine
• White cell count, if very highavoid spinal
  anesthesia
• Investigate medical conditions that would make
  spinal anesthesia a dangerous procedure

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Talking to the Patient

• Always take time to reassure the patient to
  relieve patients anxiety
• A scared patient
• Is less cooperative
• Is more difficult to manage
• May have elevated blood pressure
• Feels more pain and gets more nauseated

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Talking to the Patient (contd)

• It is important to explain that
• Spinal anesthesia stops pain
• They may feel some touch, but it will not be
  uncomfortable
• Their legs will feel weak or feel as if they do
  not belong to them any more
• If they feel pain they will be given a general
  anesthesia
• You will take care of them during the operation

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Monitoring the Patient

• Respiratory system
• Adequacy of airway and breathing Good practice
  to provide O2 by face mask at 24 L/minute but
  not always necessary
• Cardiovascular system
• Blood pressure and pulse rate should be measured
  at regular intervals
• In pregnant women, sudden fall in blood pressure,
  especially after spinal anesthesia, is more common

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Monitoring the Patient (contd)

• Psychological
• Talk to the patient while she is having the
  operation
• Reassure the patient
• Find out if she has any problems or discomfort
• Explain and address the problem

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Monitoring the Extent of the Block

• Monitor the level of block
• Patient has full power in the legs
• The block is only on one side
• The block is not high enough
• The block has gone too high
• Assessing the height of the block
• Difference between temperature, touch and motor
• Test your own block

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Complications

• Postoperative
• Headache
• Neurological complications
• Bacterial meningitis
• Epidural abscess
• Pain

• Intra-operative
• Total spinal block
• Hypotension
• Bradycardia
• Pain

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Total Spinal Block

• Rare but serious complication
• Means the block has gone very high
• Effects
• Respiratory arrest paralysis of the intercostal
  and phrenic nerves
• Bradycardia no sympathetic stimulation to the
  heart
• Hypotension massive vasodilatation
• Unconsciousness and cardiac arrest local
  anesthesia has reached CSF around the brain

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Management of Total Spinal Block

• Be attentive to patients anxiety
• Ask for help
• Intubate and ventilate the patient with 100
  oxygen
• Treat hypotension and bradycardia
• Sedate the patient
• Continue ventilation until spinal block becomes
  lower and patient can breathe by herselfrecovery
  will depend on the amount and type of anesthesia
  used and how high the block has gone

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Hypotension

• Due to vasodilatation and functional decrease in
  the effective circulating volume
• Management
• Reverse vasodilatation and increase circulating
  volume
• Give vasopressure immediately if not responding
  to fluid therapy
• Raise patients legs Do not tilt table to raise
  legs if hyperbaric (heavy) spinal anesthetic
  agent is used in the preceding 15 minuteswill
  cause high block
• Increase IV infusion to maximum until blood
  pressure is restored
• Give atropine if pulse rate is slow

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Hypotension Management (contd)

• Vasopressure Agent Ephedrine
• Constricts blood vessels and increases the heart
  rate
• DOES NOT reduce flow to the placenta
• Comes in 30 or 50 mg ampoules (1 mL of
  fluid)dilute this to 5 or 10 mL of normal saline

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Ephedrine Dosage Information

• 36 mg IV bolus Effect lasts for 515 minutes
• Check blood pressure and pulse if no improvement
  give another bolus repeated doses are less
  effective
• Maximum dose 60 mg
• As IV infusion with normal saline Add 1015 mg
  in one bottle and titrate against blood pressure

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Bradycardia

• Heart rate lt 60/minute Give atropine 300600 ?g
  IV
• Heart rate lt 70/minute with hypotension Give
  atropine 300600 ?g IV
• Hypotension with heart rate gt 70/minute Give
  ephedrine

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Pain

• From the start of the operationmaybe the spinal
  anesthesia is not working yetwait for about 10
  minutes
• Pain after the surgery is underway Block is not
  high enough
• Pain on closure of peritoneum
• Pain toward end of surgery Anesthetic effect is
  wearing off

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Management of Pain

• Talk to the patient and reassure her that you
  will take care of her pain
• Depending on the cause of the pain and progress
  of surgery the following may be used
• Pethidine 25 mg IV
• Pentazocine 510 mg IV
• Ketamine .25.5 mg/kg body IV
• Non-steroid anti-inflammatory drug ketorolac 10
  mg IV, if available
• Local infiltration with local anesthesia agent by
  surgeon
• If necessary consider the need to convert to
  ketamine infusion anesthesia

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Spinal Headache

• Begins within 24 hours of spinal anesthesia
• Postural worse by sitting up and relieved by
  lying down
• Occipital in type and may be associated with a
  stiff neck
• Nausea, vomiting, dizziness and photophobia may
  accompany it
• More common in young females and in obstetric
  patients

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Preventing Spinal Headache

• Use the smallest needle for spinal puncture
• 16 gauge Headache in 75 of patients
• 20 gauge Headache in 15 of patients
• 25 gauge Headache in 1 of patients
• Make as few punctures in the dura as possible to
  get the CSF this is achieved with repeated
  practice
• Keep patient lying down until the anesthesia has
  worn off
• Treat with analgesics Paracetamol or codeine

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Postoperative Complications

• Permanent neurological complications
• Extremely rare
• Happens when wrong drug is injected!
• Always check the drug yourself before drawing the
  solution in the syringe
• Bacterial meningitis Inadequate sterile
  precautions taken this should NEVER happen
• Epidural abscess Formation of hematoma and
  subsequent infection