Intervertebral epidural anaesthesia in paediatric surgery: success rate and adverse effects in 650 consecutive procedures

Abstract

Summa yThe success rate and occurrence of adverse effects are reported in a retrospective study of 650 (99 sacral, 468 lumbar, 76 thoracic and seven cervical) paediatric epidurals performed, mostly (91 %) under light general anaesthesia, by several anaesthetists. Seventeen-gauge Tuohy and 20-gauge (Potts-Coumand@ and Tuohy) needles were used. Anaesthetic solutions used were 1 % lignocaine, 0.5% bupivacaine and a mixture of equal volumes of 0.5% bupivacaine with either 1% lignocaine or 1% etidocaine, all containing 1:200 OOO adrenaline. The epidural space was identified by loss-of-resistance technique (LORT) with normal saline, air or COz. Up to five attempts were occasionally necessary. LORT using fluid resulted in more subarachnoidal penetrations than the LORT using air ( P < 0.05) which was easy and reliable but produced patchy anaesthesia ('painful gaps') in 4.2% of patients. C02-LORT was as easy and reliable as air-LORT and did not result in painful gaps. Lateral and rnid-line insertion routes were equally suitable whatever the level of approach. Twenty-gauge needles, especially Tuohy needles, resulted in significantly less dural punctures in young children. The spread of the local anaesthetic correlated with the volume injected and the height of the epidural approach. Epidural anaesthesia had little haemodynamic effects. Administration of epidural morphine improved the duration of postoperative pain relief but undesirable effects occurred in up to 50% of patients. Low doses of naloxone (2-5 pg-kg-'*h-') counteracted most adverse effects, avoiding urinary retention and delayed apnoea. Anaesthetists and residents without experience in paediatric anaesthesia had a good success rate in performing the techniques (under supervision of an experienced anaesthetist). At the same time, experience in regional anaesthesia would sigruficantly boost the confidence of the anaesthetist in managing such cases. The authors recommend using COZ instead of air in the LORT.

Epidural and subarachnoid blockade in children

“…Approaches to the epidural space in children have been described at thoracic [61], lumbar [68], sacral [69,70] and caudal levels [71]. These techniques may be difficult and there is a significant failure rate, particularly in smaller children.…”

“…In adults, the use of a loss of resistance to air technique has also been implicated in producing areas of incomplete analgesia [78,79], subcutaneous emphysema [80], lumbar nerve root compression with symptoms [81,82] and interscapular pain [83]. Because of these considerations, most workers now recommend that a loss of resistance to saline technique is used in preference to a loss of resistance to air technique [84], despite the fact that the loss of resistance to air ............................................................................................................................................................................................................................................. technique is considered by many to give a superior feel when performing epidural cannulation, has been found to result in fewer dural punctures than a loss of resistance to saline technique and in the event of any leakage of fluid there is no confusion about whether or not a dural tap has occurred [61]. The use of carbon dioxide in the loss of resistance syringe to provide the benefits of air without its risks has been suggested [61].…”

“…Because of these considerations, most workers now recommend that a loss of resistance to saline technique is used in preference to a loss of resistance to air technique [84], despite the fact that the loss of resistance to air ............................................................................................................................................................................................................................................. technique is considered by many to give a superior feel when performing epidural cannulation, has been found to result in fewer dural punctures than a loss of resistance to saline technique and in the event of any leakage of fluid there is no confusion about whether or not a dural tap has occurred [61]. The use of carbon dioxide in the loss of resistance syringe to provide the benefits of air without its risks has been suggested [61]. A recent innovation which merits consideration is the microdrip infusion method where an intravenous fluid administration set is connected to the epidural needle in place of a loss of resistance syringe and the drip chamber is held 1 m above the needle.…”

“…Spread was more extensive cranially than caudally and the cranial extent of spread ranged from T 1 to T 4 for midthoracic epidural catheters and from T 6 to T 10 for lumbar catheters [67]. Several patients who received either 1.25 ml.kg À1 of local anaesthetic solution via a lumbar Anaesthesia, 1998, 53, pages 980-1001 ........................................................................................................................................................................................................................................... epidural catheter or 0.75 ml.kg À1 via a thoracic catheter developed an excessively high block with a Horner's syndrome [61] and this emphasises the need for epidural injections to be made with caution considering the volume as well as the dose of local anaesthetic solution. The use of infusion epidural analgesia has not been compared with intermittent top-ups but would be expected to provide several advantages.…”

“…The anatomy of the plica and the transverse membranes is variable and they have been blamed for problems with catheter placement and the lateralisation of epidural blocks [60]. Unilateral blockade is an occasional feature of epidural blockade in children, with an incidence of 4% in singleshot caudals [1], 1% in sacral intervertebral blockade, 0.86% in lumbar blockade and has not been reported in thoracic blockade [61]. It therefore appears to be more common with caudal approaches than more cephalad approaches and is presumably related to the presence of the dorsal median raphe.…”