2. TECHNIQUE

2.1 Appropriate sterile technique is to be observed.

2.2 Betadine is the skin antiseptic of choice. However, care must be taken to ensure that the antiseptic solution does not contaminate the epidural needle or other material to be introduced into the epidural space.

2.3 The L2-3 and L3-4 interspace is preferable for access. Prior infiltration with local anaesthesia is necessary before introducing the epidural needle.

2.4 The lumbar epidural space is best identified by a loss of resistance technique since active labour is responsible for a continuous positive pressure in that region.

2.5 Having identified the epidural space, the catheter is introduced and the Tuohy needle removed. Risk of paravertebral positioning of the catheter is reduced by limiting the length of catheter within the epidural space to 2-5cm. Should difficulty be experienced in advancing the catheter then rotation of the epidural needle may be tried. The Tuohy needle should not be rotated while the catheter is in the needle. At no time should the catheter be withdrawn through the epidural needle as this may shave off the length of catheter.

2.6 A millipore filter is to be attached to the injection site on the catheter. This will limit bacterial contamination of the epidural space.

2.7 With the epidural catheter secured in position and the patient on her side or lying supine with a right-sides wedge, aspiration is attempted. If no blood or C.S.F. is obtained then injection of the appropriate volume and concentration of bupivacaine is made.

2.8 Segments required to be blocked for the first stage of labour are T10 to L1. For the second stage T10 to L1 and S2 to S4. When blocking for labour pain an additional two segments on either side of the above will usually provide adequate analgesia.

2.9 The recommended volume of drug to establish the block is 10-20ml given in 5 ml increments.

The formulation of drug should be that which produces maximum sensory block with the minimum of motor block, e.g. 0.125% bupivacaine with fentanyl 5mcg/ml.

2.10 Monitoring is to be according to the Standing Orders set out in separate schedule.

2.11 At no time following institution of the epidural block is the patient to be supine. If such a position is necessary, e.g. for examination, then the wedge must be inserted under the right buttock to produce the desired left lateral tilt to minimise caval occlusion.

2.12 For operative vaginal delivery, an appropriate volume of a more concentrated local anaesthetic agent will need to be used (e.g. bupivacaine 0.25%).

2.13 Epidural anaesthesia for caesarean section requires a block of segments T5-S4. The appropriate volume is determined by frequent testing of the height of block following incremented doses. The local anaesthetic concentration should provide a deep sensory block. Before surgery begins, testing of the adequacy of the block is mandatory. Additional doses of local anaesthetic may need to be given if the block is inadequate. Appropriate fluid loading (1 litre of Hartmann's solution) should be given before the block is begun and supplementary oxygen and additional fluids given to maintain normal blood pressure.

2.14 A record, on the Epidural Record Form, is to be kept of top-up doses and patient observations. The duplicate of this form is to be retained in the Suite until collection by the anaesthetic staff. This record should include a statement as to the adequacy of the resulting analgesia.