Download Paediatric spinal anaesthesia - Anesthesia Slides, Presentations

Paediatric spinal anaesthesia
clinical pearls
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab. DCA,
Dip. Software statistics
• PhD (physio)
• Mahatma Gandhi medical college and
research institute – Puducherry – India
History
• Spinal anesthesia was probably the earliest
form of regional anesthesia that was
considered a useful practice for children
• ( Bainbridge, 1901 ; Tyrell-Gray, 1909 ).
• Popularized in 1990 s
Why it came to lime light ??
• Premature infants – possible hernia
• Muscular and neuromuscular disease for abd.
And lower limb surgery.
Other indications
• The safety and success of spinal
• such as pyloromyotomy, gastrostomy
placement,
• myelomeningocele repair,
• cardiac surgery, and genitourinary
procedures.
• Moreover, spinal anesthesia has been
successfully used in high-risk infants and
• for cardiac catheterization,
To consider spinal in ??
•
•
•
•
•
facial dysmorphia
difficult intubation,
muscular dystrophy,
family history of malignant hyperthermia
or a full stomach with aspiration risk
Contraindications
• Coagulation abnormalities
• Systemic sepsis or local infection at the
puncture point
• Uncorrected hypovolaemia
• Parental refusal or an uncooperative child
• Neurological abnormalities such as spina
bifida,
• increased intracranial pressure
• Procedures lasting more than 90 minutes
• Are there any differences ??
Where does spinal cord end ?
• The conus
medullaris lies at a
lower level in
infants;
• therefore the L4-5
or L5-sacral
interspace should
be chosen for the
dural puncture
Difference
Intercristal line ??
• The intercristal line crosses the midline at the
S1 interspace in neonates, and at the L5
interspace in older children
differences
• The approach to the subarachnoid space requires a
straighter trajectory of the needle than in older
children.
• The distance to the subarachnoid space is small,
• cerebral spinal fluid (CSF) flow may be slow,
• ligamentum flavum is thin
Difference
• 4 mL/kg (2 mL/kg in adults) with 50% being in
the spinal canal compared with 25% in adults
• Duration – short
• Even bupivacaine 90 minutes
Technique
•
•
•
•
•
Positioning –
Flex back but extend neck
Sedate ??
Enough local , EMLA 60 minutes before
Ready with airways
Technique
• Standard monitors, IV access
• Distance from skin to subarachnoid space (cm)
= 0. 03 x height (cm)
• 1 inch 22 g spinal needle
• depth of 1 to 1.5 cm
• distance in millimeters = (age in years
• x2) + 10.
• Aspirate and slowly inject
• Don’t lift legs to place cautery
Sitting spinal – neonate
Technique
• The ligamentum flavum is very soft in children
and a distinctive “pop” may not be perceived
when the dura is penetrated.
• Be gentle and slow
Straight – 1 ml syringe
Characters of nerve fibres
• Small nerve fibres
• Nonmyelinated
• Small distances between nodes of ranvier
• Lumbar lordosis - Absent but in two years it
may be present
Differences
• fibrous sheaths around nerves are not well
developed and myelination is not complete
until about 2 years of age.
• This makes immature nerves more sensitive to
local anaesthetics and less concentrated
solutions than are used in adults usually result
in a dense block.
• In term babies the length of the spinal cord is
about 20 cm (in adults 65–70 cm).
• This means that the length to weight ratio is
four or five times higher in newborns than in
adults.
• so -- Dose differences
Assessing the block is difficult.
• The response to cold spray can be useful,
• observation of paradoxical respiratory muscle
movement
• loss of response to a low amperage tetanic
stimulus.
Level ??
•
•
•
•
Pacifier nipple
Spread of the block is less predictable
High level means –
no BP fall but apnea !!
• Monitor 24 hours
Bupi and tetra
• Heavy bupivacaine is recommended in a dose
of 0.3-1 mg/kg = 0.07-0.2 mL/kg of 0.5%
solution.
• 2 kg infant – hernia – 0.2 ml ??
• 6 kg infant – circumcision – 0.5 ml ??
• 14 kg 2 years – orchipexy – 1.5 ml
• 1% tetracaine, a dose of 0.5 mg/kg
• Empty the needle
Other drugs
• Doses ranging between 0.75 and 1.25 mg/kg
of isobaric solution of levobupivacaine
• addition of 100 μg clonidine to 20 ml bupi and
inject the necessary dose
• Or
• Add 1 μg / kg
• Other drug dosage schedules
Doses in mg / kg
Age
Bupi
Tetra
Ropi
Infants
0.5 – 1
0.5 – 1
0.5 – 1
1-7
0.3 – 0.5
0.3
0.5
>7
0.2 -0.3
0.2
0.4
Complications
• Less than 6 months of age, immature hepatic
metabolism of amide drugs
• Failure rate – 10 – 20 %
• Brady – ok but hypo - ??
• PDPH – restlessness . Hearing loss !!
• Potential traumatic puncture
• But – overall – very rare
Causes of haemodynamic stability
• immaturity of the sympathetic nervous
system
• smaller blood volume that is present in the
lower extremities
Summary
Dose and drugs
Position
Dexterity
Complications
Spinal – safe
In safe hands
Thank you all