The dura is too vulnerable to be breached routinely in labour

Internariod Journal of Obstetric Aneslhesra (1999) 8, 56-61 0 1999 Harcourt Brace&Co. Ltd

CONTROVERSIES

The dura is too vulnerable to be breached routinely in labour Proposer: R. Russell Department of Anaesthesia,

John Radcliffe Hospital, Oxford, UK

Is there a price to be paid for routinely breaching the dura in labour? Should we abandon epidural analgesia in favour of single-shot spinal or the combined spinalepidural (CSE) technique?Enthusiasts of CSE analgesia point to the rapid onset of pain relief and reduced motor block allowing maternal a m b u lation. There are, however, several disadvantages of dural puncture which have been largely ignored. So how advantageous is dural puncture and should it become routine?

required soon after intrathecal loading, are we to expect dangerously high blocks? Should the epidural dose be reduced and if so by how much? Such information is not yet available and until a large seriesis published, should dural puncture be performed routinely? 3. Side-effects of intrathecal narcotics W ith appropriate doses of intrathecal agents respiratory depression and hypotension should be avoided, but pruritus, nausea and vomiting all appear to be more frequent and severewhen opioids are a d m inistered spinally rather than by the epidural route. In a comparison of epidural bupivacaine with CSE fentanyybupivacaine, Collis and colleaguesreported itching in over 4 0 % of mothers receiving intrathecal fentanyl, with 3 % requiring intravenous naloxone.3 Norris and colleagues,in a study of over 1000 women who receivedeither epidural bupivacaine with or without opioids or CSE with a variety of spinal narcotics, demonstrated a significant increasein the incidence of pruritus, nauseaand vomiting in the CSE group.’

DISADVANTAGES O F DURAL PUNCTURE 1. Failure of intrathecal analgesia One of the advantagesof CSE analgesia is the rapidity of onset. However, in up to 1 0 % of casesthe spinal component fails to provide adequate analgesiaId and tim e to achieve pain relief is actually prolonged. Failure may occur when the dura is punctured and either the distal aperture of the spinal needle is covered by a root of the cauda equina or the needle passescompletely through the dural sac into the anterior epidural space. Failure also occurs if the dura is not breached as may occur if the epidural space is entered too laterally.

4. Neurological complications Postpartum neurological problems are more often of obstetric than of anaesthetic origin. Both transient and prolonged symptoms have been reported after epidural analgesia,6,7but, as yet, there are no large seriesof neurological problems following CSE. Studies of spinal analgesiaand anaesthesiawould suggestthat breaching the dura is more likely to produce neurological problems.8,9 Thus, combining epidural and spinal techniques increases the likelihood of neurological complications. Such problems may be the result of direct trauma, especially if repeated insertion of the spinal needle is required to obtain CSF. Inappropriate or contaminated injection is more likely to produce neurological damage when a d m inistered intrathecally than by the more forgiving epidural route. More disturbingly there have been several recent reports of m e n ingitis following dural puncture in labour.‘O~”

2. Variable spreadof epidural solutions If the dura is accidentally punctured with a 16 gauge Tuohy needle, subsequent epidural local anaesthetic a d m inistration may produce a high block with associated hypotension. Such high blocks also follow epidural’ injection after deliberate dural puncture and intrathecal injection with a smaller spinal needle. Leighton and colleagues demonstrated that epidural a d m inistration of 0.25% bupivacaine 13 m l produced significantly more blocks above T4 in women who had previously received intrathecal sufentanil 10 pg compared with those in which dural puncture had not been performed.5 Should urgent caesareansection be Robin Russell, Nuffield Dept of Anaesthesia, John Radcliffe Hospital, Oxford OX3 9DU, UK 56

Controversies 5. Post dural puncture headache

It has often been stated that the incidence of post dural puncture headache after CSE analgesia is no greater than that with epidural analgesia. Such opinions are based on data collected at postnatal interviews conducted within 48 hours of delivery The use of atraumatic spinal needles may, however, produce a much slower CSF leak and thus headache may not appear until several days after dural puncture. Arkoosh and colleagues followed 250 women for 2 weeks after dural puncture with either 25 gauge Quincke, 24 gauge Sprotte or 25 gauge Whitacre needles.‘*Not surprisingly, for the first 3 days headache was significantly more common in the 25 gauge Quincke group, but by 2 weeks over 6% of women in each group reported postural headache. 6. Fetal heart rate abnormalities

Increased fetal heart rate abnormalities have been reported by some authors following the injection of intrathecal narcotics. Honet and colleagues randomized 60 women to receive intrathecal injection of either fentanyl 10 pg, pethidine 10 mg or sufentanil 5 pg. Variable and late decelerations were observed in 23% before but in 58% after injection.” In 73 mothers who received intrathecal sufentanil 10 lr.g, Cohen and colleagues reported significant fetal heart rate abnormalities in 15%.?” 7. Increased cost of equipment

For the needle through needle CSE technique, the long spinal needle may cost up to five pounds. At the John Radcliffe Hospital routine dural puncture would add nearly 510 000 to our annual budget. Nationally, with over 2 million deliveries each year in the UK, and an epidural rate of approximately 20%, the routine use of CSE would add in excess of &2 million pounds to current costs. ADVANTAGES

OF DURAL

PUNCTURE

What of the advantages of dural puncture? Speed of onset may be beneficial but is a difference of 10 minutes worth the increased risk of complications? Maternal ambulation and increased satisfaction resulting from reduced motor blockade are frequently cited advantages of CSE. Maternal ambulation is, however, also possible with epidural analgesia. Breen and colleagues randomised women to receive a bolus and infusion of either fentanyl or ultra low dose bupivacaine (0.04%) with fentanyl and adrenaline. Ambulation was possible in 70% who received fentanyl and in 68% who received fentanyl combined with bupivacaine and adrenaline.2’ Satisfaction with

57

labour analgesia was high in both groups. No other benefits of reduced motor block resulting from CSE have been conclusively demonstrated. Do the advantages of dural puncture outweigh the disadvantages to the extent that we should use this technique routinely in labour? Intrathecal injection may offer some benefits but in comparison with modern epidural management it is only its speed of onset that is clearly superior. Against this there are many hazards which may complicate dural puncture. So is it worth this increased risk? REFERENCES 1. Collis RE, Baxandall ML, Srikantharajah ID, Edge G, Kadim MY, Morgan BM. Combined spinal epidural (CSE) analgesia: technique, management, and outcome of 300 mothers. International Journal of Obstetric Anesthesia 1994; 3: 75581. 2. Norris MC, Grieco WM, Borkowski M et al. Complications of labor analgesia: epidural versus combined spinal epidural techniques. Anesth Analg 1994; 79: 529-537. 3. Collis RE, Davies DWL, Aveling W. Randomised comparison of combined spinal-epidural and standard epidural analgesia in labour. Lancet 1995; 345: 1413-1416. 4. D’Angelo R, Anderson MT, Philip J, Eisenach JC. Intrathecal sufentanil compared to epidural bupivacaine for labor analgesia. Anesthesiology 1994; 80: 120991215. 5. Leighton BL, Arkoosh VA, Huffnagle S, Huffnagle HJ, Kinsella SM, Norris MC. The dermatomal spread of epidural bupivacaine with and without prior intrathecal sufentanil. Anesth Analg 1996; 83: 526529. 6. Ong BY, Cohen MM, Esmail A et al. Parasthesias and motor dysfunction after labor and delivery. Anesth Analg 1987; 66: 18822. I. Holdcroft A, Gibberd FB, Hargrove RL, Cumming M, Kozody R, Palahniok RJ. Neurological complications associated with pregnancy. Br J Anaesth 1995; 75: 522-526. 8. Vandam LD, Dripps RD. A long term follow-up of 10,098 spinal anesthetics. Surgery 1955; 38: 463469. 9. Phillips 0, Ebner H, Nelson AT, Black MH. Neurological complications following spinal anesthesia with lidocaine. Anesthesiology 1969; 30: 284289. 10. Cascio M, Heath G. Meningitis following a combined spinalepidural technique in a labouring term parturient. Can J Anaesth 1996; 43: 399402. 11. Stallard N, Barry P. Another complication of the combined extradural-subarachnoid technique. Br J Anaesth 1995; 75: 370-371. 12. Harding SA, Collis RE, Morgan BM. Meningitis after combined spinal-extradural anaesthesia in obstetrics. Br J Anaesth 1994; 73: 545-547. 13. Newton JA Jr, Lesnik IK, Kennedy CA. Streptococcus salivarius meningitis following spinal anesthesia. Clin Infect Dis 1994; 18: 840-841. 14. Lau WM, Chen FS, Wong SY, Chuah EC, Tan PP. Bacterial meningitis - a rare complication following spinal anesthesia. Ma Tsui Hsueh Tsa Chi 1993; 31: 127-130. 15. Bugedo G, Valenzuela J, Munoz H. Aseptic meningitis following spinal anesthesia. Rev Med Chil 1991; 119: 44&442. 16. Lee J, Parry H. Bacterial meningitis following spinal anaesthesia for caesarean section. Br J Anaesth 1991; 66: 3833386. 17. Roberts SP, Petts HV Meningitis after obstetric spinal anaesthesia. Anaesthesia 1990; 45: 376-377. 18. Arkoosh VA, Norris MC, Leighton BL, Huffnagle, HJ, Sharkey SJ, Lessin J. Headache in parturients after dural puncture. A comparison of three needle types. Anesthesiology 1992; 77: A1017. 19. Honet JE, Arkoosh VA, Norris MC, Huffnagle J, Silverman NS, Leighton BL. Comparison among intrathecal fentanyl, meperidine and sufentanil for labor analgesia. Anesth Analg 1992; 75: 734-739.

58 International Journal of Obstetric Anesthesia 20. Cohen SE, Cherry CM, Holdbrook H, El Sayad YY, Gibson RN, Jaffe RA.. Intrathecal sufentanil for labor analgesia sensory changes, side effects and fetal heart rate changes. Anesth Analg 1993; 77: 1155-l 160.

21. Breen TW, Shapiro T, Glass B, Foster-Payne D, Oriol NE. Epidural anesthesia for labor in an ambulatory patient. Anesth Analg 1993; 11: 919-924.

Opposer: F. Plaat Hammersmith Hospital, London, UK Use of the intrathecal route as part of the combined spinal epidural (CSE) technique is new. It was not until the early 1990s that reports on its use for labour analgesia started appearing. As with spinal anaesthesia in the 198Os,doubts about the technique remain. In an editorial concerned with new techniques in regional analgesia in obstetrics, David Bogod considered that safety should be our first consideration when trying to ‘fine tune an already effective therapy’ in other words epidural analgesia.’ How effective is epidural analgesia? Whilst most mothers rate their pain relief highly with epidurals, in one national survey this was not associated with high levels of overall satisfaction.* In ‘the pursuit of perfectiorP we must produce a barely perceptible sensory block, which maintains sensation, alleviates pain and does not inhibit mobility. This is more likely to be achieved using CSE than epidurals alone. First let us consider if this can be done without risks and side effects to the mother. POTENTIAL

needles, making only one attempt to puncture the dura, and placing the Tuohy needle carefully, this risk appears very small. Hypotension A fall in systolic blood pressure to below 90 mmHg may occur after epidural labour analgesia in 17-28% of cases,’and after intrathecal opioids without local anaesthetic in 14% of cases.9Using an intrathecal dose of bupivacaine 2.5 mg with fentanyl 25 yg, only 5% of women had a decrease in systolic blood pressure to below 100 mmHg.‘” All these episodes occurred in the first 20-30 min. None were associated with changes in the fetal heart or with maternal symptoms. There was no significant difference in the incidence of hypotension in the first 20 min between those with epidurals and those receiving this dose of intrathecal bupivacaine and fentanyl.” Small intrathecal doses of fentanyl and bupivacaine do not cause clinically significant hypotension, but monitoring during the first 30 min is mandatory.

HAZARDS OF CSEs Infection

Headache There does appear to be an increased risk of headache amongst labouring women who undergo deliberate dural puncture. The incidence reported varies from O-2.5%.‘6 In the study by Collis et al. of 300 women the incidence of positional headache due to single deliberate dural puncture was 0.6%.5 This is against a background of a l-2% risk of accidental dural puncture with the Tuohy needle, from which 80% of women develop postural headache as a consequence. The incidence of headache after spinal anaesthesia varies between 1 and 40%,7 depending on the type and size of needle used. Norris et al. found that women receiving epidural analgesia were significantly more likely to have unintended dural puncture than those with CSE.6 They suggest that CSE analgesia may in fact be inherently safer than inducing epidural blockade. In summary: at present the numbers are too small to determine how great the increased risk of headache associated with CSE is. By using small pencil point F. Plaat, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK.

Theoretically, infection is one of the greatest risks of breaching the dura, particularly if a catheter is subsequently placed epidurally near the site of puncture. There are no figures for the actual incidence of infective complications following epidural, spinal or CSE in obstetrics, but there have been a handful of case reports. Meningitis has been described following manual removal of the placenta,” multiple attempts to puncture the dura,‘* accidental dural puncture,13 and after repeated blood-patching.‘4 In the absence of positive microbiology, one of the cases of meningitis following CSE was ascribed to chemical meningitis, caused by contamination with disinfectant.15 Another two case reports were similar in that the dura was breached more than once, and in both the epidural catheter was resited.‘5,‘6One of the women was given a blood patch and subsequently developed meningism. All three patients made a full recovery after receiving intravenous antibiotics. These case reports are not evidence that CSEs are more dangerous than epidurals. What they should tell us is that multiple invasion of the intrathecal or epidural space is dangerous and precautions should be

Controversies taken against causing aseptic or chemical meningitis. The risk of infective complications should not be forgotten whatever the technique used. Neurological sequelae There have been several attempts to quantify the incidence of serious complications including neurological sequelae following regional blockade.‘7,‘8 A comparison of spinals and epidurals showed no difference in this respect.” No cases of neurological complications following CSEs have yet been reported. DISADVANTAGES OF AN INTRATHECAL FIRST DOSE Failure of the spinal component It has been claimed that CSE using a single space may lead to a higher failure rate of the spinal than is found during a double space or single shot method. In a study by Lyons comparing the needle through needle with the sequential technique, the spinal failed in 16% of cases in the former and only 4% in the latter.20This is in contrast to a failure rate of 45% reported elsewhere.ti In the studies reported by Collis et al., the technique was practised by trainees new to the method, who found it easy to 1earn.4,5In contrast, the majority of failures in the study by Lyons et al. occurred at the hands of more experienced anaesthetists.*’ Time consuming Does this technique increase the workload for the anaesthetist and midwife? The intrathecal first dose does have a shorter duration than an epidural dose” and is associated with the need for a greater number of top-ups during labour. However, the mean difference in duration was found to be 12 min and that between the number of top-ups less than one top-up per labour. On the other hand, other studies have shown no increase, or a decrease, in the number of times an anaesthetist has to be called after CSE compared with conventional epidurals.“,2’ Catheter through hole in dura It is claimed that the epidural catheter may be inadvertently threaded through the hole in the dura. This has caused great concern among anaesthestists. Laboratory studies in cadavers however suggest it is impossible to force the catheter through the hole made by a 27 gauge pencil-point needle unless the dura has been breached five times.22In none of the handful of case reports of this complication can it be assumed with confidence that the catheter achieved the intrathecal

59

position via the hole made by the spinal needle. It is well known that intrathecal migration of catheters can occur at any time and there is no evidence that there is a greater risk of this when the dura is deliberately punctured with a fine pencil point needle. Top-ups through hole in dura Epidural top-ups may enter the cerebrospinal fluid through a dural tear, producing higher levels of block than expected23and this may occur when CSE is used for caesarean section.*4*25 However, this does not appear to happen when the epidural injection is given more than 30 min after the spinal dose, which is usual when the technique is used for labourz6 In a series of over 1200 top-ups, including larger top-ups for caesarean section, no unexpectedly high blocks were encountered.5 ADVANTAGES OF AN INTRATHECAL DOSE FOR LABOUR ANALGESIA

INITIAL

Rapid reliable analgesia Injecting intrathecal local anaesthetics, opioids or both is a means of obtaining almost instantaneous analgesia. Such rapid onset cannot be achieved by the epidural route. Women receiving 2.5 mg of bupivacaine with fentanyl intrathecally recorded lower pain scores significantly more quickly than those given 25 mg of the drug epidurally4 (Fig. 1). Stacey et al. found 100% of women achieved complete sacral analgesia by 10 min, with a median time to complete analgesia of 3 min.*’ In another study, 91% of women with subarachnoid block had pain-free contractions within 8 min.’ Such rapid and reliable analgesia is obviously advantageous when labour is progressing fast, analgesia is requested late on, or is required for urgent obstetric intervention. I would argue that it is appropriate for all women requesting epidural analgesia in labour. Although the majority of women receiving epidurals would repeat the experience,‘* first time mothers underestimate their subsequent analgesic requirementsz9 and are reluctant to have this form of pain relief Their request for epidural analgesia indicates an unbearable level of pain. In these circumstances, how can nearly instantaneous analgesia be unnecessary? In the study by Collis et a1.,4primiparae who received CSEs were more satisfied than those with epidurals. Indeed, the efficacy of the first dose has been shown to be the most important factor relating to satisfaction with regional analgesia.jO Less motor block and more mobility Maintenance of motor power has been shown to increase maternal satisfaction3’ reduce the incidence

60 International Journal of Obstetric Anesthesia

. Standard epldural group 0 Combined spinal-cpidural

0

5

10

group

15

20

Time in minutes

Fig. 1 Median pain scores (VAS, not pain reliefscore as on figure) after siting the block in the standard epidural group (bupivacaine 0.25%) and in the combined spinal-epidural group. Time in minutes on the horizontal axis. Vertical bars indicate interquartile ranges. From Collis et a1.4by permission of author and publisher.

of long-term backache32 and may even decrease the rate of operative delivery.j3 Motor block is a likely consequence of increasing bupivacaine usage. An intrathecal initial dose can minimize or abolish the need for local anaesthetic while providing adequate analgesia. D’Angelo et al. compared intrathecal sufentanil with epidural bupivacaine and found more rapid analgesia and lower overall bupivacaine usage in the sufentanil group.34 Collis et al., using intrathecal bupivacaine with fentanyl followed by epidural topups used 9.6 mg of bupivacaine per h’ and Morey et al., using the same technique with a PCEA system reduced this to 8.5 mg of bupivacaine per h.35 Breen et al. considered that minimal motor block with effective analgesia could be achieved using the epidural route,36but an initial dose of 6 mg of bupivaCaine with fentanyl and adrenaline resulted in a proportion of women disappointed with their analgesia.” Russell et al. reported a bupivacaine usage of 8.9 mg per h using an epidural infusion of bupivacaine with fentanyl.-‘* However, this increases by more than 5 mg per h if the initial dose of 35 mg bupivacaine is included in the calculation.

Both Collis et al. and Russell et al. found a very low incidence of motor block with over 80% of women free of this complication by 6 hours.5,38The women in Russell’s study did not ambulate. There appears to be great concern about the medicolegal implications of allowing women to walk with epidural analgesia. No falls have been reported in the literature, and in an audit of 6000 ambulatory epidurals there were no more falls among women with epidurals than amongst women without (unpublished data). It is often said that women do not want to ambulate in labour - they want to rest. It may not be so straightforward. Buggy et al. found a high incidence of proprioceptive dysfunction using low dose epidural analgesia after a traditional test dose.39Not only that, but women’s subjective perception of their ability to walk correlated poorly with the presence of such abnormalities. The authors concluded that ambulation must be dangerous. Using an intrathecal first dose leads to a markedly lower incidence of such abnormalities.40.4’We asked women if they felt confident to walk, and if so, to ambulate. The majority did feel confident and demonstrated normal gait, whether after the first intrathecal dose or after the first epidural top-up (Table 1). There were only two out of 101 occasions, when women felt confident but demonstrated abnormal gait. Normal gait was strongly correlated with the absence of abnormal motor and proprioceptive function. Of those lacking confidence to walk, 95% did show proprioceptive abnormalities and motor block. I suggest that women can accurately assesstheir ability to walk and that those with epidurals who “don’t want to” cannot do so. The advantages of being mobile in labour are still a matter of debate. A review of randomised studies on upright versus recumbent positions show no adverse effects of the upright position and some advantages.42 It is possible that preventing women in labour, with their well-known hypercoagulable state, from spending many h immobile may be beneficial. Moreover, there does seem to be a maternal preference for not being confined to bed. It appears to be a common experience of those who use CSEs for labour that mothers and midwives show great enthusiasm for the chance to mobilize.

Table 1. Perceived and actual ability to ambulate with regional analgesia in labour. Women confident to walk (%I After intrathecal bupivacaine + fentanyl After one epidural dose of bupivacaine + fentanyl End of first stage of labour

87 97 15

Confident

women with normal gait W) 94 100 100

Controversies CONCLUSION The method I am advocating for establishing labour analgesia is not free from hazards or side-effects. Only time will tell whether the dura really is too vulnerable to breach. At present, the advantages of doing so should prompt us to continue. In 1985 Andrew Doughty predicted the introduction of improved techniques that would lead to greater levels of satisfaction with regional analgesia.’ I believe that CSE represents such a technique. REFERENCES 1. Bogod D. Advances in epidural analgesia for labour: progress versus prudence. Lancet 1995; 345: 1129. 2. Oakley A. The follow-up survey. In Chamberlain G, Wraight A, Steer P, eds. Pain and Its Relief in Childbirth. Edinburgh: Churchill Livingstone, 1993: 101-103. 3. Doughty A. Lumbar epidural analgesia-the pursuit of perfection. Anaesthesia 1975; 30: 741-751. 4. Collis RE, Davies DWL, Aveling W. Randomised comparison of combined spinal-epidural and standard epidural analgesia in labour. Lancet 1995; 345: 1413-1416. 5. Collis RE, Baxandall ML, Srikantharajah ID, Edge G, Kadim MY, Morgan BM. Combined spinal epidural (CSE) analgesia: technique, management, and outcome of 300 mothers. International Journal of Obstetric Anesthesia 1994; 3: 75-81. 6. Norris MC, Grieco WM, Borkowski M. Complications of labor analgesia: Epidural versus combined spinal-epidural techniques. Anesth Analg 1995; 79: 529-537. 7. Shnider SM, Levinson G. Anesthesia for cesarean section. In: Shnider SM, Levinson G, eds. Anesthesia for Obstetrics. Baltimore: Williams and Wilkins, 1987: 159-178. 8. Ong B, Cohen MM, Cumming M, Palahnuik RJ. Obstetric anaesthesia at Winnipeg Women’s Hospital 1975-83: anaesthetic technique and complications. Can J Anaesth 1987; 34: 294299. 9. Ducey JP, Knape KG, Talbot J. Intrathecal narcotics for labor cause hypotension. Anesthesiology 1992; 77: A997. 10. Shennan A, Cooke V, Lloyd-Jones F, Morgan B, De Swiet M. Blood pressure changes during labour and whilst ambulating with combined spinal epidural analgesia. Br J Obstet Gynaecol 1995; 102: 192-197. 11. Roberts SP, Petts HV Meningitis after obstetric spinal anaesthesia. Anaesthesia 1990; 45: 376-377. 12. Lee JJ, Parry H. Bacterial meningitis following spinal anaesthesia for Caesarean section. Br J Anaesth 1991; 66: 3833386. 13. Sansome AJT, Barnes GR, Barrett RF. An unusual presentation of bacterial meningitis as a consequence of inddvertant dural puncture. International Journal of Obstetric Anesthesia 1991; 1: 35-37. 14. Berga S, Trierweiler MW. Bacterial meningitis following epidural anesthesia for vaginal delivery: a case report. Obstet Gynecol 1989; 74: 437439. 15. Harding SA, Collis RE, Morgan BM. Meningitis after combined spinal-extradural anaesthesia in obstetrics. Br J Anaesth 1994; 73: 545-547. 16. Stallard N, Barry P. Another complication of the combined extradural-subarachnoid technique (letter). Br J Anaesth 1995; 75: 370-371. 17. Crawford JS. Some maternal complications of epidural analgesia for labour. Anaesthesia 1985; 40: 1219-1225. 18. Scott DB, Hibbard BM. Serious non-fatal complications associated with extradural block in obstetric practice. Br J Anaesth 1990; 64: 537-541. 19. Scott DB, Tunstall ME. Serious complications associated with epidural/spinal blockade in obstetrics: a two-year prospective

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