MD DA DNB MD Acu Dip Diab DCA Dip Software statistics PhD physio Mahatma Gandhi medical college and research institute puducherry India Epidural anaesthesia ID: 932235
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Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statisticsPhD (physio) Mahatma Gandhi medical college and research institute , puducherry – India
Epidural
anaesthesia
part 1.
Slide2Are they same ?? Peridural Extradural Epidural
Slide3History Corning in 1885 Uptake of drugs in spinal cord by injections can produce anaesthesia 100 years ??
Slide4History Heile – 1913 , Paramedian approach tried Pages 1921 Feel
Slide5Dogliotti & Gutierrez – 1939 Described fundamentals action and results for the first time In 1945 Tuohy introduced the needle which is still most commonly used for epidural anaesthesiaCleland - obstetrics 1949 – nm blockers offset the role of EA
Slide6Now - prime uses Surgical anaesthesia , labour analgesia , post op pain relief and Chronic pain relief Epidural blood patch
Slide7How many vertebrae ??There are 24 individual vertebrae: 7 cervical,12 thoracic and5 lumbar. The five (fused) sacral vertebrae and the coccyx (made up of 3–5 rudimentary vertebrae) not always classed as being a part of the vertebral column.
Slide8Boundaries of epidural space ?? Above : Foramen magnum – periosteal and spinal layers of dura fuse Below : the sacrococcygeal membrane
Slide9Epidural space
Slide10Boundaries Anterior : Posterior longitudinal ligament, vertebral bodies, intervertebral disc Posterior Laminae and ligamentum flavum Laterally : pedicles and interverbral foramina
Slide11Boundaries AP
Slide12Anatomy
Slide13Cut section
Slide14Distance from dura to lig. Flavum Lumbar 2 : 5 – 6 mmMidthoracic : 3 – 5 mm Cervical : 1.5 – 2 mm
Slide15Contents fat, vessels and nerve roots Fat : Important pharmacological space : Depot for drugs Obese – more capacious epidural space
Slide16Vessels Arteries : intersegmental arteries from Laterally mainly Veins : Segmental connections Valveless , sluggish More anterior
Slide17Vascular network
Slide18Different epidural spaces Cervical : Fusion of the spinal and periosteal layers of dura mater at the foramen magnum to lower margin of C7 Thoracic : Lower margin of C7 to upper margin of L1 Lumbar : Upper margin of L1 to upper margin of S1 Sacral : Upper margin of S1 to sacrococcygeal membrane
Slide19Contents Dural sac ends at approximately S2. Contains the spinal cord (to the lower border of L1) and cauda equina Spinal nerves In pairs. Lymphatics are present around the region of the nerve root and function to remove foreign material. Connective tissue- Variable dorso median folds, median fold.
Slide20Nerve supply The spinal canal and its contents have their own innervation. The anterior dura is heavily innervated fortunately for spinal, epidural anaesthesia,the posterior dura is sparsely suppliedThe periosteum is pain sensitive but the ligamentum flavum is not
Slide21Slide22Methods of entry InterlaminarThe ‘usual’ method. Loss of resistance methods. Transforaminal Directs solution to the anterior epidural space. Radiological guidance mandatory. Specialist use onlyTranssacralDirect vision Spinal endoscopyParavertebral Frequent epidural blockade
Slide23Location A 4 mm wide space to be located 4 – 8 cm depth No obvious end point
Slide24Location of space
Slide25Other positions Epidural anesthesia and analgesia is most often performed in the lumbar region.Thoracic epidural blocks are technically more difficult to accomplish than lumbar blocks because of greater angulation and marked overlapping of the spinous processes at the vertebral level
Slide26Other positions the potential risk of spinal cord injury with inadvertent dural punctureCervical blocks are usually performed with the patient sitting, with the neck flexed, using the midline approach. Clinically, they are used primarily for management of painCaudal epidural
Slide27Spinous process
Slide28Angulation of puncture
Slide29Why is epidural pressure negative ??Dural tenting and coning Negative intra thoracic pressureRecumbent position
Slide30Denting
Slide31Position
Slide32Approaches Cervical, Thoracic,Lumbar,Caudal
Slide33Techniques Median paramedian ↓ ↘ ↙ ↓Loss of Hanging drop resistance1. air filled 2. fluid filled 3. both
Slide34Midline and paramedian – skin entry – 10 – 15 deg.
Slide35Midline As the epidural needle enters the midline of the back over the bony spinous processes, it passes through (1) skin, (2) subcutaneous fat, (3) supraspinous ligament, (4) interspinous ligament, (5) ligamentum flavum, and (6) epidural space
Slide36Paramedian anesthetized skinsubcutaneous tissues, paraspinous muscle, lamina of the inferior vertebraThe needle tip is walked medially until the base of the spinous process is encountered,The needle tip is then marched superiorlyuntil it “walks off” of the lamina, encounter resistance as it meets the ligamentum flavum.
Slide37Bromage grip
Slide38Hanging drop technique Hanging drop method
Slide39False hanging drop Initial aspiration feeble Persistent neg. pressure – nil Cardiac pulsations absent Catheter – passage – no
Slide40Air, fluid and Bubble
Slide41Other adjuncts Peripheral nerve stimulator Ultrasound
Slide42Ultrasound proved useful
Slide43supplementsRadiological screening is helpful for difficult epidural entry.Spinal endoscopy adds another dimension to epidural catheterization
Slide44Lumbar and thoracic
Slide45Equipments Needle Accessories Catheter
Slide46Touhy and huber tipcrawford, bromage – outdated
Slide47LEE needle
Slide48Macintosh balloon
Slide49Odom s indicator
Slide50Others U tube manometer Zorraquin s bulb Zelenka bulb Auditory devices
Slide51Adjuvants 5 ml syringe Glass – sticky ?? Air filled - jerky Fluid filled – smooth slow, controlled
Slide52Space Sudden loss of resistance No further movement Never advance without syringe control
Slide53Now that space entered Aspiration Test dose Water injection Rapid saline (Duran sign)
Slide54Aspiration 2 ml syringe Repeat after 2 ml air injection Aspirate again
Slide55Test dose 3 – 5 ml of ligno + adrenaline Advantages – intrathecal , intravascular ,catheter easy ,vigilance for beginners Disadvantages – 5 ml for old age !! Time ?? After test dose , puncture possibleCatheter insertion – useless
Slide56Drip back test 15-20 ml given at a rate of 10 ml / minuteFluid drips back What is it ??
Slide57Why drip back ??CSF Too rapid injection Injection gone into tissue planes Temperature test Glucose oxidase test
Slide58Accidental dural puncture Abandon the procedure Convert into SA Try again in the same space Try again in different space Continuous spinal anaesthesia Epidural blood patch
Slide59Catheter Vinyl Nylon PVCPTFE
Slide605 ml initially Test dose Threading easy Start the block Sacral sparing – NO
Slide61Space ok – catheter now Slow 10 cm – some resistance , rotate No excess force 3 – 4 cm ok Aspiration and test dose again !!Insert from below up – WHY ?
Slide62Catheterisation
Slide63Drugs and comp[lications Part 2 Next time
Slide64Thank you all