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Regional anaesthesia in children


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Title: Regional anaesthesia in children

Regional anaesthesia in children
Presenter B. Uma Moderator Dr. Asha Tyagi
University College of Medical Sciences GTB
Hospital, Delhi
Regional anaesthesia in children
  • Differences in anatomy and physiology
  • Selection of techniques, agents and equipments
  • Central neuraxial blockade in children including
    caudal block

  • Regional anaesthesia in children first studied by
    August Bier in 1899
  • In 1900, Bainbridge reported a case of
    strangulated hernia repair under spinal
    anaesthesia in an infant of three months
  • Tyrell Gray, a British surgeon published a series
    of 200 cases of lower abdominal surgeries in
    infants and children under spinal anaesthesia in

  • Advantages over GA
  • Safe, reliable technique in infants at risk of
    apnoea, bradycardia and desaturation after GA
  • Good alternative for day care surgeries
  • Minimal risk of postoperative respiratory
  • Limited stress response to surgery
  • Cost effective

Perception of pain
  • Somatic pain has 3 components
  • Motivational directive
  • conveyed by unmyelinated C fibres
  • Slow/true pain
  • Fully functional from early fetal life
  • Leads to protective reflexes
  • Sensory discriminatory
  • Cognitive evaluative

Perception of pain(contd.)
  • Immature connections b/w dorsal horn neurons and
    C fibres till 2wks of life
  • Heightened response to nociceptive stimulation
    till 2 wks of life in response to large amounts
    of substance P
  • Immaturity of inhibitory control pathways till
    2wks of life

Spinal cord anatomy
Relevant Differences between Children and Adults
Anatomic factors Anaesthetic implications
Lower termination of spinal cord (L3-4) Increased risk of direct trauma to the spinal cord Avoid epidural approaches above L3
Lower projection of dural sac (S3-4) Increased risk of inadvertent penetration of the dura mater
Delayed myelinization of nerve fibers Easier intraneural penetration of local anesthetics Onset time shortened Diluted local anesthetic as effective as more concentrated anesthetic
Anatomic factors Anaesthetic complications
Cartilaginous structure of bones and vertebrae Danger of direct trauma and bacterial contamination of ossification nuclei Use short and short beveled needles
Lack of fusion of sacral vertebrae Persistence of sacral intervertebral spaces
Delayed development of curvatures of the spine Same orientation of epidural needles at all level before 6 months of age
Changing axis of coccyx and absence of growth of sacral hiatus Identification of sacral hiatus difficult above 6-8 years Increased failure rate of caudal anesthesia
Delayed ossification and growth of iliac crests Tuffiers line passes over L5-S1 interspace
Anatomic factors Anaesthetic implications
Increased fluidity of epidural fat Increased diffusion of local anesthetic up to 6-7 years of age with excellent caudal blockade
Loose attachment of sheaths and aponeuroses to underlying structures Larger volume of LA for epidural blocks due to leakage along spinal nerve roots Increased spread along nerve paths with danger of penetrating remote anatomic spaces and blocking distant nerves
Sympathetic immaturity, diminished autonomic adaptability of the heart, smaller vascular bed in lower extremities Hemodynamic stability during neuraxial blocks Fluid preloading and use of vasoactive agents unnecessary
Pharmacologic factors Anaesthetic implications
Low plasma protein content (HSA and AAG) Increased unbound free fraction of all local anesthetic greater danger of systemic toxicity
Increased cardiac output and heart rate Increased regional blood flow resulting in increased systemic absorption of LA shorter duration of action
Enzymatic immaturity Slower metabolism of LA with risk of accumulation
Increased extracellular fluids Increased distribution volume and mean body residency time of LA with increased risk of accumulation after continous infusion
Pharmacologic factors Anaesthetic implications
Red cell storage In neonates high hematocrit values and enlargement of erythrocytes result in consistent entrapment of LA In infants physiologic anemia reduces red cell storage protective effect against systemic toxicity of LA
Pulmonary extraction Children with right-to-left shunts undergo considerable increase in arterial plasma concentration of LA due to pulmonary bypass
Absorption from epidural space The time (Tmax) to reach peak plasma concentration (Cmax) remains basically unchanged Ropivacaine and Levobupivacaine Tmax is prolonged up to 2 hours in infants and Cmax is increased Reduced continous infusion rates/repeat injections dosage
Pharmacologic factors Anaesthetic implications
Metabolism Low plasma cholinesterase activity Decreased cytochrome P450 activity Phase 2 reactions immature upto 3yrs of age
Elimination half life gt1yr same as adults lt 1yr increased thus favoring accumulation with repeated injections
Systemic toxicity Thresholds of toxicity of the unbound form of LA 0.3 µg/ml for bupivacaine 0.6 µg/ml for ropivacaine
Hepatic extraction and clearance of aminoamides High hepatic extraction ratio GFR 30 of adult values
Pharmacologic factors Anaesthetic implications
Opioids morphine Elimination half-life of neuraxial opioids increase in neonates and infants CSF concentrations very high after epidural injection takes 12 to 24 hours before their decrease below minimal effective concentrations (near 10 ng/mL)
Fentanyl, sufentanil Acute respiratory depression (sudden apnoea)
Additives Clonidine Clearance in neonates is approximately one third that in adults owing to immature elimination pathways Several instances of respiratory depression in neonates and small infants Should be avoided during the first 6 month of life.
Commonly used additives in pediatric RA
Additive Recommended doses Maximum doses
Morphine Epidural Intrathecal 30 µg/kg 10 µg/kg 50 µg/kg 20 µg/kg
Fentanyl (epidural) 1-1.5 µg/kg 2.5 µg/kg
Sufentanil (epidural) 0.25-0.5 µg/kg 0.75 µg/kg
Clonidine (epidural) 1-1.5 µg/kg 2 µg/kg
Ketamine (epidural) 0.5 mg/kg 1 mg/kg
Psychological factors Anaesthetic implications
Delayed acquisition of body scheme and conceptualization, anxiety Inability of patients to locate precise body areas Concept of paresthesia not understandable Difficult cooperation Heavy sedation or general anesthesia is required in most patients
Indications of regional anaesthesia
  • Infraumbilical extraperitoneal surgeries like
    inguinal hernia, circumcision, hypospadias,
    orchidopexy, cystoscopy, colostomy for
    imperforate anus, rectal biopsy and other
    perineal surgeries
  • Lower extremity orthopaedic and reconstructive
  • Preterm and former preterm infants less than 60
    weeks post-conceptual age/less than 3
    Kg/hematocrit lt30 and with other co-morbidities
    who are prone to post-operative apnoea,
    bradycardia and desaturation after GA

  • Neonates with respiratory diseases like
    bronchopulmonary dysplasias, hyaline membrane
  • Children with h/o or high risk for malignant
  • Children with acute respiratory conditions,
    chronic disease of the airways like asthma or
    cystic fibrosis
  • Meningomyelocele, gastroschisis repair, open
    heart surgery etc in addition to light GA (rare)

  • Management of nonsurgical pain
  • Herpes zoster, AIDS, mucocutaneous
    leisons-regional blocks
  • Vaso-occlusive crisis of sickle cell disease
  • Non analgesic indications
  • Sympathetic blockade for severe trauma
  • Vascular insufficiency in Kawasaki disease
  • Severe frostbite
  • Accidental intra arterial injection of LA

Contraindications to regional anaesthesia
  • Absolute contraindications to neuraxial blocks
  • Severe coagulation disorders- constitutional or
  • Severe infection such as septicemia or meningitis
  • Hydrocephaly and intracranial tumoral process
  • True allergy to local anesthetics
  • Chemotherapies (such as with cisplatin)
  • Uncorrected hypovolemia
  • Cutaneous or subcutaneous lesions at the
    contemplated site of puncture
  • Parental refusal

Contraindications( contd.)
  • Absolute contraindication to PNB procedures
  • True allergy to the local anaesthetic agent
  • Relative contraindications
  • Patients at risk of compartment syndrome
  • Sickle cell ds a/w hypoxemia and hemodynamic
  • Extended malformations of vertebrae, spinal
    fusion, myelomeningoceles, open spina bifida, and
    major spondylolisthesis
  • Pre-existing neurologic disorder

Complications of regional anaesthesia
  • Local complications
  • Inappropriate needle insertion damaging the nerve
    and surrounding anatomic structures
  • Tissue coring and introduction of epithelial
    cells into tissues where they do not belong
  • Injection of neurotoxic solutions
  • Leakage around the puncture site which may cause
    partial block failure and favor bacterial
  • Systemic complications
  • Accidental iv injection of LA
  • Excessive dosing

Selection of materials, techniques and agents
  • Considerations for selection of suitable
  • Adequate sensory blockade
  • Minimal potential morbidity
  • Postoperative analgesia
  • Various approaches
  • Single-shot technique with either a short-acting
    or a long-acting local anaesthetic
  • Single-shot technique with local anaesthetic and
  • Catheter technique with repeat/continuous
    injections of local anaesthetic

Selection of equipments.(contd.)
  • Identification of anatomic space
  • Surface mapping or percutaneous guidance
  • Ultrasound techniques (Jockey probes)
  • Acoustic devices
  • Electrostimulation
  • Loss of resistance with air or saline
  • Whoosh test is now obsolete

Selection of equipments.(contd.)
  • Selection of anaesthetic agent depends on
  • Site/ extent of surgery
  • Expected duration of intense postoperative pain
  • Hospital stay vs early discharge

Local anaesthetic Usual conc. Max dose of plain soln mg/kg Max dose with epinephrine mg/kg
Lidocaine 0.25-0.2 5 10
Bupivacaine 0.125-0.5 2 3
Levobupivacaine 0.125-0.5 3 4
Ropivacaine 0.1-10 3 Not recommended
Selection of equipments.(contd.)
  • Selection of block needles and catheters

Block procedure Recommended device
Spinal anaesthesia Spinal needle (24-25 gauge 30, 50 or 100 mm long, Quincke bevel, stylet)
Caudal anaesthesia Short (25-30 mm) and short beveled (45-degree) needle with stylet
Epidural anaesthesia Tuohy needle (22, 20, and 19/18 gauge) LOR syringe and medium epidural catheter
PNB Insulated 21-23 gauge short beveled needles
Safety precautions
  • Acceptable environment for performing regional
  • Minimal mandatory monitoring
  • Anaesthetic and emergency drugs
  • Resuscitation equipments
  • Trained anaesthesiologist
  • Trained staff
  • iv line in situ

Discharge criteria- Modified Aldrete score
Parameters Scores
Level of consciousness Fully awake Arousable on calling No response 2 1 0
Oxygen saturation gt90 on room air gt90 on oxygen lt90 on oxygen 2 1 0
Circulation/ BP SBP within 20mm Hg of pre sedation values SBP within 20-50 mm Hg of pre sedation values SBP gt50 mm Hg of pre sedation values 2 1 0
Movement /activities Moves all extremities on command Moves 2 extremities Does not move 2 1 0
Respiration able to breathe and cough freely Dyspnea is with shallow breathing Apneic 2 1 0
Spinal anaesthesia
  • Anatomy and physiology
  • The spinal cord and dural sac of infants younger
    than 1 year of age end at a lower level
  • Volume of CSF
  • 10 mL/kg in neonates
  • 4 mL/kg in infants weighing less than 15 kg
  • 3 mL/kg in children
  • 1.5 to 2.0 mL/kg in adolescents and adults
  • 50 CSF volume is located within the spinal
    subarachnoid space versus 25 in adults
  • Lower CSF hydrostatic pressure
  • Children older than 5yr behave like adults after
    spinal anaesthesia, whereas younger patients
    remain hemodynamically stable, without
    significant hypotension or bradycardia

Spinal anaesthesia(contd.)
  • Indications
  • Inguinal hernia repair in former preterm infants
    lt60 weeks of postconceptual age
  • Elective lower abdominal or lower extremity
  • Cardiac surgery or cardiac catheterization

Spinal anaesthesia(contd.)
  • Technique of spinal anaesthesia
  • Position
  • Lateral position with head extended to avoid
    airway compromise
  • Sitting position
  • Firm grasp of the awake infant by an assistant
  • Neonates and infants 1.5 22G spinal needle with
    stylet at L4-5 level
  • gt2yr longer needle, smaller guage
  • Pop felt as needle enters the ligamentum flavum
  • Free flow of CSF
  • Inject the LA slowly
  • Child to remain supine and legs should not be
    raised for any reason

Spinal anaesthesia(contd.)
Local anaesthetic (neonates) Dose mg/kg Volume ml/kg
0.5 bupivacaine isobaric/hyperbaric o.5-1 0.1-0.2
0.5 levobupivacaine 1 0.2
0.5 ropivacaine 1.08 0.22
Local anaesthetic (children) Usual dose
0.5 bupivacaine isobaric/hyperbaric 5 to 15 kg 0.4 mg/kg (0.08 mL/kg)gt15 kg 0.3 mg/kg (0.06 mL/kg)
0.5 levobupivacaine 5 to 15 kg 0.4 mg/kg (0.08 mL/kg)15-40 kg 0.3 mg/kg (0.06 mL/kg)gt40 kg 0.25 mg/kg (0.05 mL/kg)
0.5 ropivacaine 0.5 mg/kg (max 20 mg)
Caudal anaesthesia
Anatomy of sacral hiatus
Caudal anaesthesia(contd.)
  • Anatomy of sacral hiatus
  • V-shaped aperture formed d/t lack of dorsal
    fusion of the 5th and 6th sacral vertebral arches
  • Limited laterally by sacral cornua
  • Covered by sacrococcygeal membrane
  • Mean distance from skin to anterior sacral wall
    21 mm (2 mo to 7 yr)
  • Less suitable after 6-7yrs as
  • Change in axis of sacrum
  • Difficulty to identify sacral hiatus
  • Densely packed epidural fat

Caudal anaesthesia(contd.)
  • Indications of caudal anaesthesia
  • Surgical procedures below the umbilicus
  • As an adjuvant to GA
  • Sole anaesthetic technique in fully awake
    ex-premature infants younger than 60 wk of post
    conceptual age
  • Contraindications to caudal anaesthesia
  • Major malformations of sacrum (myelomeningocele,
    open spina bifida)
  • Meningitis
  • Intracranial hypertension

Caudal anaesthesia
Caudal anaesthesia(contd.)
  • Technique of caudal anaesthesia
  • Positioning the patient
  • Sims position
  • Semiprone
  • Prone- esp. in non anaesthetized (frog position)
  • Palpate for sacral cornua along the spinal
    processes at the level of sacrococcygeal joint
  • The sacral hiatus along with both PSIS forms an
    equilateral ?
  • Introduce needle in midline at 45 or less
  • Resistance felt on piercing the sacrococcygeal
  • Inject the LA with frequent aspirations
  • Finger should palpate the skin cephalad t the
    injection to ensure drug is not s/c

Caudal anaesthesia(contd.)
  • Technique using ultrasound
  • Linear ultrasound transducer set at highest
    operational frequency to achieve max. resolution
    of the superficial anatomy
  • Transducer placed in longitudinal plane b/w 2
    sacral cornua
  • Sacrococcygeal ligament identified
  • Needle introduced at 20
  • In difficult cases longitudinal paramedian

Caudal anaesthesia(contd.)
  • The armitage regime
  • O.5 ml/kg- all sacral dermatomes blocked
  • 1 ml/kg- sacral and lumbar dermatomes blocked
  • 1.25 ml/kg- upto midthoracic levels blocked

Bupivacaine in Concentration Dose Possible additives
Single dose caudal 0.175- 0.5 0.75- 1.25 ml/kg (max. 3 ml/kg) Epinephrine 2.5- 5 µg/kg Clonidine 1- 2 µg/kg Morphine 30- 70 µg/kg
Continous caudal 0.1- 0.25 0.4 ml/kg Fentanyl 2- 5 µg/kg
Caudal anaesthesia(contd.)
  • Complications with caudal blocks
  • Risks during performance of the block
  • Intravascular placement
  • Needle into subarachnoid space
  • Needle into sacral marrow
  • Risks from injection of LA
  • Side effects of other agents used
  • Block failure (3- 5)

Epidural anaesthesia
  • Anatomy and physiology of epidural space
  • The epidural space surrounds the spinal cord and
    the meninges from the foramen magnum to the
    sacral hiatus
  • Limited posteriorly by the vertebral laminae and
    the ligamenta flava
  • Communicates quite freely with the paravertebral
  • Near the spinal ganglia, connected with the
    subarachnoid space owing to protrusion of
    arachnoid granulations
  • Contains blood vessels and lymphatics
  • Filled with loose fat in infants and in children
    up to 6 to 8 years of age

Epidural anaesthesia(contd.)
  • Indications of epidural anaesthesia
  • Major abdominal surgeries
  • Retroperitoneal, pelvic and thoracic surgeries
  • Pectus excavatum repair
  • Scoliosis corrective surgeries
  • Controversial in cardiac surgeries
  • Contraindications to epidural anaesthesia
  • Severe malformations of spine and spinal cord
  • Intraspinal leisons and tumors
  • Tethered cord syndrome
  • Hydrocephalus, unstable epilepsy
  • Previous spine surgery

Epidural anaesthesia(contd.)
  • Technique (for lumbar epidural anaesthesia)
  • Midline approach below L2-L3 interspace, which
    represents the lower limit of the conus
  • Paramedian approach in spinous process anomaly or
    spine deformity
  • Semiprone position with the side to be operated
    lowermost and the spine bent to enlarge the
    interspinous spaces
  • LOR with air in infants and saline in older
  • Distance from skin to epidural space 1 mm/kg b/w
    6mo- 10yr
  • Disconnect the LOR syringe
  • No reflux of biological fluid at hub
  • Catheter is inserted to not more than 3 cm in
    order to avoid buckling, knotting, and
    lateralization of blockade or erratic migration

Epidural anaesthesia(contd.)
Agent Initial dose Continous infusion (max dose)
Bupivacaine, levobupivacaine Solution 0.25 with 5 µg/mL (1/200,000) epinephrineDoselt20 kg 0.75 mL/kg20-40 kg 8-10 mLgt40 kg same as for adults lt4 mo 0.15 mL/kg/hr of 0.125 or 0.3 mL/kg/hr of 0.0625 (0.2mg/kg/hr)4-18 mo 0.2 mL/kg/hr of 0.125 or 0.4 mL/kg/hr of 0.0625 (0.25mg/kg/hr)gt18 mo 0.3 mL/kg/hr of 0.125 or 0.6 mL/kg/hr of 0.0625 (0.3mg/kg/hr)
Ropivacaine Solution 0.2Dose same regimen in mL/kg as for bupivacaine Same age-related infusion rates in mg/kg/hr as for bupivacaine (0.1, 0.15, or 0.2)Do not infuse for more than 36 hr in infants lt 3 mo
  • Bernard DJ. Regional anesthesia in children. In
    Miller RD, editor. Millers Anaesthesia. 7th ed.
    Philadelphia Churchill Livingstone 2010.
  • Pawar D. Regional anaesthesia in pediatric
    patients. Indian J. Anaesth.200448(5).
  • Davis PJ, Cladis FP et al. Smiths anaesthesia
    for infants and children. 8th ed. 2012.

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