EPIDURAL ANESTHESIA

EPIDURAL ANESTHESIA Epidural anesthesia is a regional anesthesia that blocks pain in a particular region of the body The goal of an epidural is to provide analgesia, or pain relief, rather than anesthesia, which leads to total lack of feeling. Epidurals block the nerve impulses from the lower spinal segments. This results in decreased sensation in the lower half of the body.

EPIDURAL ANESTHESIA Anatomy Epidural space – base of skull (foramen magnum) to the coccyx (sacrococcygeal membrane) Distance from skin to epidural space – 4-5 cm Epidural space contains loose areolar tissue, fat, arterial and venous networks, lymphatics, spinal nerve roots LA deposited in epidural space Block spinal nerve roots that traverse peridural space Blocks sympathetic nerves traveling with the anterior roots Applications range from sensory analgesia, minimal motor block, or dense anesthesia and full motor block – controlled by drug choice, concentration, dosage

Types – selective blockade possible because it can be performed at any level of spine Cervical epidural Thoracic epidural Lumbar epidural Caudal epidural Factors Influencing Spread of Solution Height of patient Drugs used Volume Concentration Level of puncture and catheter insertion

Technique Method Position Single dose injection Fractional – continuous epidural – repeated injections of LA through catheter inserted into epidural space Position Cervical epidural – sitting (C7) Thoracic epidural (T7) Lumbar epidural (L1-L2, L2-L3, L3-L4, L4-L5) Lateral Decubitus, full flexion

Method of Identifying Epidural Space Principle: negative pressure in space Loss of resistance Plunger of syringe pushed without resistance once epidural needle is in Hanging Drop Drop of saline at hub of epidural needle is sucked in once it enters space

Indications All operations below diaphragm May be used in Poor risk patients Cardiac diseases Pulmonary diseases Metabolic disturbances When GA is contraindicated When spinal anesthesia is contraindicated Painful conditions including post-op pain relief

Contraindications – similar to spinal Severe hemorrhage Coagulation defects Previous laminectomy Uncooperative / apprehensive Local inflammation at site Patient refusal Advantages Well-defined area of anesthesia Longer duration More severe disturbances of spinal anesthesia minimized GI complaints minimized Catheterization minimized Less respiratory effects

Disadvantages Physiologic Effects Drugs: low-dose LA, opiods Technically more difficult Muscle relaxation not complete Large volume necessary Danger of dural puncture Incomplete / patchy block Physiologic Effects Similar to those observed in spinal anesthesia Slower onset Less intensity of motor and sensory block Drugs: low-dose LA, opiods

Epidural anathesia Spinal anathesia Site of injection In the epidural space Subarachnoid space Onset and duration Slow onset and continous duration (use catheter) Rapid onset and limited duration advantages Can be used in analgesia Not used Needle dose Curved,longand blunt (touhy) 10_30ml Small and sharp 1_4ml space Any space usually lumber lumber Quality of sensory and motor nerve block less More liable toxicity Hypotention gradual total spinal +++ systemic toxicity +++ Sudden + +

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