Spinal before epidural single interspace CSE technique for labour.

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Compared with single modality techniques, the combined spinal and epidural (CSE) method of providing regional anaesthesia has a number of important advantages [1]. The spinal injection provides analgesia of rapid onset, whilst epidural catheter placement provides the ability to extend or prolong the block. Thus, it is no longer necessary to use large initial doses of intrathecal drugs to ensure adequate anaesthesia, hence avoiding unwanted cardiovascular effects of high spinal blockade, such as hypotension. These properties of CSE have led to the technique's recent increase in popularity, especially in obstetric anaesthesia practice where rapid and extendable analgesia without hypotension are desirable. The emergence of CSE as a popular technique appears to stem from the development of small pencil-point spinal needles that cause less headache and greatly reduce the chance of inadvertent epidural catheter placement into the subarachnoid space via the dural puncture hole [1]. Several methods have been described for the performance of CSE. Classically, two lumbar spine interspaces are used, with the epidural catheter being placed first via a Tuohy needle, followed by intrathecal puncture and injection. This enables a test dose to be given to check the position of the epidural catheter before performing the spinal. More recently, the single lumbar interspace needle-through-needle method has been described, which involves first inserting the Tuohy needle, then performing the spinal injection using a ‘needle-through-needle’ technique and finally placing the epidural catheter. An extra-long spinal needle or special CSE kit is required, of which several are now sold. However, the needle-through-needle technique has several potential complications. The spinal needle, especially when fine bore (27 gauge), is liable to kink as it passes through the hub of the Tuohy needle. Hence, cerebrospinal fluid flow via the spinal needle may not be detected, leading to uncertainty as to whether it has punctured the dura and entered the subarachnoid space. The spinal needle may also form a tract which the epidural catheter may follow into the subarachnoid space. To overcome these potential problems needle-beside-needle techniques have been developed and several specialised kits are also now available. However, the needle-beside-needle technique is also not without its problems. In addition to the need for specialised kits, the epidural space also has to be identified first, as with the ‘needle-through-needle’ technique, prior to performing a spinal injection. Furthermore, in both these techniques, the Tuohy needle can become dislodged during the insertion of the spinal needle, resulting in inadvertent dural puncture. In the labouring woman, the problem of inadvertent dural puncture may be accentuated due to excessive patient movement. Also, it is desirable to provide rapid pain relief. We therefore believe that when treating labour pains, the spinal part of CSE should be performed first before inserting the Tuohy needle and epidural catheter. This will provide near instant pain relief, making the subsequent epidural placement a lot easier and safer and without local discomfort. There will be no need for expensive CSE kits that may not always be readily available. By limiting the intrathecal dose, unwanted hypotension can be avoided and we recommend using a single lumbar interspace so that the patient only has one injection of local anaesthetic. This also reduces the extent of spinal ligament bruising and subsequent postdelivery backache. The use of a fine-bore pencil-point spinal needle almost eliminates the possibility of the epidural catheter passing through the spinal puncture hole [1]. By using low dosages for ‘top ups’ the possibility of a high or total spinal, in the unlikely eventuality of epidural catheter migration into the subarachnoid space, is almost totally eliminated. Our preferred technique for performing CSE in labouring women is to use either the L3–4 or L4–5 interspace. Under aseptic conditions, the chosen interspace is infiltrated with local anaesthetic. Then, with the patient either sitting upright or lying lateral, spinal puncture is performed using a 27 gauge pencil-point (Whitacre) needle, injecting 2.0–2.5 mg of bupivacaine 0.25% plain with 20–25 μg fentanyl. This provides almost immediate relief of labour pains. With the patient more comfortable and co-operative, the epidural catheter is then placed using a 16 gauge Tuohy needle at the same interspace. The catheter is then secured and flushed with l ml normal saline to prevent any clotting. For extending or prolonging the block, we use 5–12 ml of a mixture of bupivacaine 0.0625–0.125% and fentanyl 2.5–4 μg.ml−1. Therefore, the total dose of bupivacaine with each top-up never exceeds 15 mg, making the possibility of a total spinal extremely unlikely. We have now used this ‘spinal before epidural, single interspace, technique’ in our obstetric practice for well over a year. Our results have been very pleasing with a high degree of patient satisfaction.