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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