Either a bolus dose of local is injected, or a plastic catheter is fed through the Tuohy needle, into the epidural space, in order to permit a continuous infusion technique.A Lumbar block is performed more commonly than a Thoracic block, and the epidural space is widest (0.5 cm) at this level. If the Tuohy needle is inserted too deeply, and a tear made in the dura, the CSF leakage can give the patient a bad headache.
|Indications||Post-op, intra-op, and palliative pain; trauma; Obstetrics.|
|Contra-indications||Raised intra-cranial pressure; spinal deformity; infection; obesity; allergic to opiates; neurologically diseased.|
|Advantages||Stable analgesia without peaks/troughs; increased patient mobility; fewer G.I. problems; better respiratory function; more patient satisfaction.|
|Disadvantages||Motor sensory weakness; catheter may dislodge; careful monitoring required.|
|Analgesics||1. Fentanyl (fast action and absorption into
2. Bupivicaine (15-20 minutes before action; 6-12 hours duration.)
|Emergency drugs||Atropine, Ephedrine, Naloxone.|
|Prohibitions||Avoid Trendelenburg position.|
|CSF leakage||Frontal headache, nausea. Treat with hydration, analgesia.|
|Infection||Backache, spasm, pyrexia, paralysis. Treat with analgesia and antibiotics.|
|Spinal haemotoma||Back/leg pain, urinary retention.|
|Motor weakness||Leg tingling/numbness. Treat with positioning and decreasing infusion rate.|
|Hypotension||Stop infusion and give oxygen. Have Naloxone available.|
|Breathing difficulty||Stop infusion, sit patient up, give oxygen, check catheter patency.|
|Bradycardia||Stop epidural, give oxygen. Have available: Atropine, Naloxone, and Ephedrine.|
|Urinary retention||Catheterise, give fluids.|
|Itching||Cool flannel, Ondansetron.|
An Epidural may be given at a Cervical, Thoracic, or Lumbar site; a Spinal must be given below L2, to avoid piercing the spinal cord.
Onset of analgesia is 25-30 minutes for an Epidural, but 5 minutes for a Spinal.
The indwelling catheter of an Epidural allows topping-up of analgesia; a Spinal is a one shot injection.
The larger space with the Epidural requires a larger dose (10-20 ml); a Spinal dose is 1.5-3.5 ml.