What is the procedure for performing an epidural technique?

Epidural Technique: Procedure and Best Practices

The epidural technique should be performed using a midline approach with the patient in the lateral decubitus position, employing loss of resistance to either air or saline for identification of the epidural space, followed by insertion of a multi-orificed catheter at least 4 cm into the epidural space before securing it to the skin. 1, 2

Patient Positioning and Preparation

• Patient position: Lateral decubitus position is preferred over sitting position

  • Lateral position is associated with decreased rates of postdural puncture headache (PDPH) 1
  • While sitting position may provide better anatomical landmarks, the lateral position may reduce CSF leak if accidental dural puncture occurs

• Aseptic technique:

  • Strict aseptic technique must be observed throughout the procedure 1
  • Complete hand washing, sterile gloves, mask, cap, and proper skin preparation

Equipment Selection

• Needle selection:

  • 16G or 18G Tuohy needle (no significant difference in inadvertent dural puncture rates between these sizes) 1
  • Needle should have a curved tip to minimize risk of dural puncture

• Catheter:

  • Multi-orificed catheter recommended
  • Should be inserted at least 4 cm into the epidural space to minimize risk of displacement with patient movement 3

Procedural Steps

1. Identify appropriate interspace:

   • For labor analgesia: L3-L4 or L4-L5 interspace
   • For thoracic epidurals: Insert at the level corresponding to the dermatome of surgical incision (T5-T8 for upper abdominal procedures) 1

2. Local anesthetic infiltration:

   • Infiltrate skin and deeper tissues with 1-2% lidocaine

3. Epidural needle insertion:

   • Use midline approach (paramedian approach does not reduce risk of inadvertent dural puncture) 1
   • Advance needle through ligamentum flavum

4. Epidural space identification:

   • Use loss of resistance (LOR) technique with either air or saline
   • Both methods are equally effective 1, 2

5. Catheter insertion:

   • Thread catheter 4-5 cm into epidural space
   • Important: Have patient assume final position (lateral or sitting upright) before securing catheter to skin 3

6. Test dose administration:

   • Administer 3 ml of 0.5% bupivacaine as test dose 2
   • Observe for signs of intrathecal placement (rapid onset of dense motor block) or intravascular injection (tachycardia, metallic taste)

7. Catheter fixation:

   • Secure catheter to skin only after patient is in final position to prevent catheter displacement 3

Avoiding Complications

Preventing Inadvertent Dural Puncture

• Risk factors for inadvertent dural puncture:

  • Greater degree of cervical dilatation at time of insertion 1
  • Operator inexperience (3.77 times greater odds with low-volume specialists) 1
  • Nighttime procedures (19:00-08:00) have 6.33 times higher risk 1

• Confirming dural puncture if suspected:

  • Test fluid for glucose (97% accuracy) or pH (91% accuracy) to distinguish CSF from saline 1
  • Approximately one-third of inadvertent dural punctures go unrecognized 1

Managing Catheter Displacement

• Catheters frequently move inward with position changes from sitting flexed to lateral decubitus position 3
• This movement is most pronounced in patients with higher BMI 3
• To minimize displacement risk:
  • Insert catheter at least 4 cm into epidural space
  • Have patient assume final position before securing catheter 3

Post-Procedure Management

• Test sensory block (cold and pinprick) before induction of general anesthesia if used for surgical anesthesia 1
• Check sensory block daily or more frequently for ongoing epidural analgesia 1
• Adjust infusion to provide sufficient analgesia while allowing mobilization 1

Special Considerations

• COVID-19 patients: Consider pharmacological approaches before performing epidural blood patch if PDPH occurs 1
• Difficult airway patients: Regional anesthesia including epidural is strongly preferred over general anesthesia in patients with anticipated difficult airways 1

By following these evidence-based steps for epidural technique, you can maximize success rates while minimizing complications such as inadvertent dural puncture, catheter displacement, and inadequate analgesia.