central neuroaxial blockade
Post on 15-Apr-2017
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Neuraxial AnesthesiaNeuraxial anesthesia is a type of regional
anesthesia that involves injection of anesthetic medication in the fatty tissue that surround the nerve roots as they exist the spine (also known as an epidural) or into the cerebrospinal fluid which surrounds the spinal cord (also known as a spinal). This numbs the patient from the abdomen to the toes and often eliminates the need for general anesthesia.
HISTORY1885 - J. Leonard Corning – first spinal anesthetic was administered accidentally The needle was made of gold1898 - August Bier - first planned spinal anesthesia for
surgery In 1921, Spanish military surgeon Fidel Pagés (1886–
1923) developed the modern technique of lumbar epidural anesthesia
Robert Andrew Hingson (1913–1996), working at the United States Marine Hospital in New York, developed the technique of continuous caudal anesthesia.
Advantages over Regional Anaesthesia over GA
Safe, reliable technique in patients at risk of apnoea, bradycardia, desaturation, cardiac or respiratory complications after GA
Good alternative for day care surgeries
Minimal risk of postoperative respiratory depression
Limited stress response to surgery
Cost effective
VERTEBRA
33 Vertebrae◦ 7 Cervical◦ 12 Thoracic◦ 5 Lumbar◦ 5 Sacral◦ 4 Coccygeal
Spinal CordSpinal Cord
Adult Begins: Foramen Magnum Ends: L1
Newborn Begins: Foramen Magnum Ends: L3
Terminal End: Conus MedullarisFilum Terminale: Anchors in sacral regionCauda Equina: Nerve group of lower dural
sac
Sagittal Section Through Lumber Vertebrae
Supraspinous Ligament
(Outer most layer)
Intraspinous Ligament
(Middle layer)Ligamentum
Flavum(Inner most
layer)
CONTRAINDICATIONSAbsolutePatient RefusalInfection At The Site Of InjectionCoagulopathy And Other Bleeding DisordersSevere HypovolemiaIncreased Intracranial PressureSevere Aortic StenosisSevere Mitral Stenosis
CONTRAINDICATIONSRelativeSepsisUncoperative PatientPreexisting Neurological DeficitsSevere Spinal Deformity
ControversialPrior Surgery At The Site Of InjectionComplicated SurgeryProlonged OperationMajor Blood Loss
SURFACE ANATOMY
PATIENT POSITIONINGSITTING POSITION
PATIENT POSITIONINGLATERAL DECUBITUS
Midline ApproachSkinSubcutaneous tissueSupraspinous ligamentInterspinous ligamentLigamentum flavumEpidural spaceDura materArachnoid mater
Paramedian or Lateral ApproachSame as midline excluding supraspinous &
interspinous ligaments
Anatomic Approach
Spinal Needle Types
Quincke Whitacre Sprotee
Selection of equipmentsSelection 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
FACTORS AFFECTING LEVEL BARICITY OF DRUGPOSITION OF PATIENTDOSESITEAGECURVATURE OF SPINEPATIENT HEIGHTPREGNANCY
Spinal Anesthesia Levels
DRUGSBUPIVACAINE HEAVYDOSE<5 KG -- 0.5MG/KG BODY WT5-15 KG -- 0.4MG/KG BODY WT>15 KG -- 0.3MG/KG BODY WT
Complications of Spinal AnaesthesiaHypotensionBradycardiaCardiac ArrestTotal Spinal AnesthesiaNeurological Complecations – Cauda Equina
SyndromePost Dural Puncture HeadacheInfection
BackacheInflammatory reaction due to tissue traumaMay result in back spasmsShort lived, analgesics, iceMay last a few weeksBack ache may be a sign of serious
complications such as epidural/spinal hematoma, abscess
Careful evaluation to determine if a common/benign complication or something more serious
Postdural Puncture HeadacheCaused by disrupting the integrity of the duraCan occur due to: spinal anesthesia, “wet” tap with
epidural, epidural catheter migration, tip of the epidural needle “indenting” the dura enough to cause a leak.
Headache occurs due to leakage of CSF through the dura
Decrease in intracranial pressure occurs due to the leak
Upright position in the patient leads to traction on the dura, tentorium, and blood vessels resulting in pain.
Postdural Puncture Headache- SymptomsOnset is generally within 12-72 hoursHeadache associated with upright position (i.e.
sitting or standing). Relief found with a supine position
Headache may be bilateral, frontal, retroorbital and/or occipital with or without radiation to the neck
Described as “throbbing” or constantMay be associated with nausea and/or
photophobiaTraction on the 6th cranial nerve can result in
diplopia and tinnitus
Postdural Puncture Headache- Conservative Treatment
Hydration- theoretically helps to encourage the production of CSF.
Analgesics- will decrease the severity of symptoms and include acetaminophen and NSAIDS
Caffeine- Helps to decrease symptoms by vasoconstriction of the cerebral vessels.
A dose of 300 mg of oral caffeine has been shown to decrease the intensity of PDPH
Epidural blood patch.
Epidural SpaceSpace that surrounds
the spinal meningesPotential spaceLigamentum FlavumBinds epidural space
posteriorlyWidest at Level L2 (5-
6mm)Narrowest at Level C5
(1-1.5mm)
Epidural AnatomySafest point of
entry is midline lumbar
Spread of epidural anesthesia parallels spinal anesthesia◦Nerve rootlets◦Nerve roots◦Spinal cord
Epidural Anesthesia
Order of BlockadeB fibersC & A delta fibers
Pain Temperature Proprioception
A gamma fibersA beta fibersA alpha fibers
Epidural AnesthesiaTest Dose: 1.5% Lido with Epi 1:200,000
◦Tachycardia (increase >30bpm over resting HR)
◦High blood pressure ◦Light headedness◦Metallic taste in mouth◦Facial numbness◦Note: if beta blocked will only see increase in
BP not HRBolus Dose: Preferred Local of Choice
◦10 milliliters for labor pain◦20-30 milliliters for C-section
Epidural AnesthesiaDistances from Skin to Epidural Space
Average adult: 4-6cmObese adult: up to 8cmThin adult: 3cm
Assessment of Sensory BlockadeAlcohol swab
Most sensitive initial indicator to assess loss of temperaturePin prick
Most accurate assessment of overall sensory block
Epidural AnesthesiaComplications
Penetration of a blood vesselHypotension (nausea &
vomiting)Intravascular catheterizationBack painWet tapInfection
Differences between Spinal and Epidural Anesthesia Spinal anaesthesia Extradural Anaesthesia
Level: below L1/L2, where the spinal cord
ends
Level: at any level of the vertebral column.
Injection: subarachnoid space i.e punture
of the dura mater
Injection: epidural space (between
Ligamentum flavum and dura mater) i.e
without punture of the dura mater
Identification of the subarachnoid space:
When CSF appears
Identification of the Peridural space: Using
the Loss of Resistance technique.
Dosis: 2.5- 3.5 ml bupivacaine 0.5% heavy Doses: 15- 20 ml bupivacaine 0.5%
Onset of action: rapid (2-5 min) Onset of action: slow (15-20 min)
Density of block: more dense Density of block: less dense
Hypotension: rapid Hypotension: slow
Headache: is a probably complication Headache: is not a probable. 32
Caudal AnaesthesiaBlock of the sacral and lumbar
nerve roots. This technique is popular in pediatric patients.
The S5 processes are remnants and form the cornua, which provide the main landmarks for indentifying the sacral hiatus. The hiatus is covered by the sacro-coccygeal membrane.
The canal contains areolar connective tissue, fat, sacral nerves, lymphatics, the filum terminale and a rich venous plexus.
Caudal anaesthesiaIndications of caudal anaesthesia:Surgical procedures below the umbilicusAs an adjuvant to GASole 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)MeningitisIntracranial hypertension
Caudal DosesPediatric population0.5 ml/kg, 0.25% bupivacaine
(sacro-lumbar block)1 ml/kg, 0.25% bupivacaine (upper abdominal block)1.2 ml/kg,0.25% bupivacaine (mid-thoracic block)(Doses described by Armitage).
Adults: 20-30 ml 0.25-0.5% bupivacaine. Average volume of the sacral canal is 30-35 ml.
Caudal AnesthesiaAnatomy
Sacrum Triangular bone 5 fused sacral vertebrae
Needle InsertionSacrococcygeal
membraneNo subcutaneous bulge
or crepitous at site of injection after 2-3ml
Caudal AnesthesiaPost Operative Problems
Pain at injection site is most commonSlight risk of neurological complicationsRisk of infection
Complications and side effects of neuraxial methods
THE END
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