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British Journal of Anaesthesia1998; 81: 507510

Comparison of epidural bolus administration of 0.25% bupivacaine and

0.1% bupivacaine with 0.0002% fentanyl for analgesia during labour

K. S. JAMES, E. MCGRADY, I. QUASIMANDA. PATRICK

SummaryWe have compared analgesia during labour pro-vided by two epidural drug regimens, in a dou-ble-blind, randomized, controlled study. Group Areceived 10-ml bolus doses of 0.1% bupivacainewith fentanyl 2 g ml1 while group B received0.25% plain bupivacaine 10 ml. Analgesia pro-vided by both techniques was similar, butwomen in group A retained motor power in theirlegs and 60% chose to get out of bed. Duration oflabour and time from insertion of the epidural todelivery was similar in both groups, but in group

A, duration of the second stage was significantlyshorter (P0.0003; 95% confidence interval (CI)

1.17, 0.27 h) and the incidence of forceps deliv-ery was lower (P0.032). Maternal satisfactionwith epidural analgesia, as assessed by VAS, washigher in group A (P0.04; 95% CI 0.001, 10.001).(Br. J. Anaesth. 1998; 81: 507510).

Keywords: analgesia, obstetric; analgesic techniques, epidural;anaesthetics local, bupivacaine; analgesics opioid, fentanyl

Despite providing excellent pain relief during labour,epidural analgesia using local anaesthetic agentsalone produces motor block in up to 85% ofpatients,1reduces maternal satisfaction with analge-sia,2and is associated with a prolonged second stageand increased incidence of instrumental delivery.3Epidural opioids offer the possibility of analgesiawithout motor block but when used alone do notprovide satisfactory analgesia throughout labour.4 5

Adding an opioid to local anaesthetic solutions canprovide effective analgesia with bupivacaine sparingand a reduction in motor block.2 68However, mostinvestigators have used a high concentration of localanaesthetic (usually 0.25% bupivacaine) to initiateanalgesia, or a larger test dose, for example 1.52%lidocaine (lignocaine) or 0.5% bupivacaine, both ofwhich contribute to motor block.7 9Similarly, the useof epidural infusions may hinder maternal mobility.

Collis and colleagues pioneered the mobileepidural using a combined spinalepidural tech-nique. Analgesia is established with intrathecal bupi-vacaine 2.5 mg and fentanyl 25 g, and maintainedwith epidural top-ups of 0.1% bupivacaine and fen-tanyl 0.0002%10 11; almost 50% of women are able toget out of bed at some point during labour.10However, problems associated with this techniqueinclude technical failure, post-dural punctureheadache10 11and chemical meningitis.12

The aim of this study was to compare, in a double-blind, randomized study, a mobile epidural using 0.1%

bupivacaine and 0.0002% fentanyl with a conventionalepidural using 0.25% bupivacaine throughout labour.

Patients and methods

After obtaining approval from the Hospital Ethics

Committee and written informed consent, we stud-ied 80 women requesting epidural analgesia inlabour. Women who had been given systemic opioidswithin 4 h of epidural request were excluded, as werethose with cervical dilatation greater than 4 cm.

I.v. access was secured but no i.v. fluid load wasgiven. An epidural catheter was sited at the secondlumbar interspace using a standard midline tech-nique with an 18-gauge Tuohy needle. The study wasdouble-blind, with randomization (computer-gener-ated numbers) and preparation of the epidural drugsolutions performed by the hospital pharmacy.Women were allocated randomly to one of two

groups. In group A, analgesia was established with 15ml of 0.1% bupivacaine with fentanyl 50 g andmaintained, on maternal request, with bolus doses of10 ml of 0.1% bupivacaine with fentanyl 2 g ml1. Ingroup B, analgesia was established with 15 ml of0.25% plain bupivacaine and maintained with 10-mlbolus doses of 0.25% plain bupivacaine.

Analgesia was measured using visual analogue scores(VAS) on a 100-mm line and a verbal scoring system(0no pain or pressure, 1aware of contraction but notpainful, 2aware of pressure or tolerable discomfort,3distressing pain or pressure). Measurements wereperformed every 10 min until analgesia was established

(verbal score of 1), and at 30 min and 1 h after the ini-tial dose. Thereafter, 2 hourly VAS were recorded untildelivery.

Motor power was assessed using a modifiedBromage score 30 min after each top-up and at eachrequest to get out of bed (score 0no weakness, ableto straight leg raise against resistance, 1not able tostraight leg raise, able to flex knee, 2unable to flexknee, able to flex ankle, 3unable to move lowerlimb). If the mother could straight leg raise againstresistance she was allowed to get out of bed. Mode ofdelivery was recorded, as were time intervals betweentop-ups, duration of first and second stages of labour,and time from insertion of the epidural until delivery.Maternal satisfaction with analgesia was assessedusing a VAS, 24 h after delivery.

K. S. JAMES*, FFARCSI, E. MCGRADY, FRCA, I. QUASIM, FFARCSI, A.PATRICK, FRCA, Glasgow Royal Maternity Hospital, Glasgow.Accepted for publication: May 25, 1998.

*Address for correspondence: Directorate of Anaesthesia andIntensive Care, Glasgow Royal Infirmary, Glasgow G4 0SF.

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508 British Journal of Anaesthesia

Statistical analysis was performed using Minitab9.2. VAS pain scores for each patient were averagedto give one value, allowing comparison of the overalleffect of the analgesic regimens throughout labour.Averaging eliminated differences in the length oflabour. The calculation was time-weighted to elimi-nate bias resulting from shorter time intervals

between VAS scores initially as analgesia was beingestablished. A standard time interval of 1 h was used.All VAS were multiplied by the fraction of a 1-h timeinterval they covered (e.g. 30-min time intervals weremultiplied by 0.5 and 2 h intervals by 2.0). Thesederived values were totalled and divided by thelength of labour. Results were analysed using a ttestfor parametric data.

Duration of labour, second stage of labour, timeinterval from insertion of the epidural until delivery,time interval between top-ups and maternal satisfac-tion with analgesia were analysed using theMannWhitney Utest. Chi-square test was used to

compare mode of delivery between groups.Visual analogue scores for pain during labour,obtained using a standard technique of on-demandbolus administration of 0.25% plain bupivacaine(measured from other work) have a mean of approxi-mately 20 mm (SD approximately 9 mm). We canassume that if VAS were increased to 30 mm (50%increase), this would be clinically important. To com-pare the two groups with a power of 0.9 to detect adifference at a significance level of less than 0.05, thesample size required was 35 patients in each group.We studied 40 patients in each group to allow forwithdrawals from the study during labour.

Results

Seven women (five in group A, two in group B) wereexcluded from the study despite good analgesia ini-tially. The threshold for removal was low (womenrequesting more than two top-ups within 1 h). Thelength of time in the study before withdrawal for thefive women in group A was 2 h 25 min to 7 h 30 min.The two women in group B were withdrawn at 4 hand 4 h 25 min. All five women in group A required0.5% plain bupivacaine to provide adequate painrelief and all subsequently delivered by Caesarean

section because of failure to progress in labour. Bothwomen in group B required fentanyl to relieve rectalpressure. One subsequently had a Caesarean sectionbecause of failure to progress and the other instru-mental delivery after a long second stage.

For time to first painless contraction, data from allwomen were used, but for mode of delivery, length of

labour and second stage, and time between top-ups,only patients who completed the study were assessed(35 women in group A, 38 in group B). Patient char-acteristics (age, height, weight, parity and cervicaldilatation when epidural was sited) were similar ineach group.

Times to first painless contraction (verbal score1)were similar. After injection of the initial bolus, 10women recorded painless contractions in group Aand 11 in group B by 10 min. By 20 min, another14 patients in group A and 20 in group B were painfree, and all women reported pain-free contractionsby 30 min.

Total VAS for pain throughout labour were similarin both groups (P0.31; 95% confidence interval(CI)2.15, 6.63) (table 1). Although the time inter-val between top-ups was significantly shorter ingroup A (P0.0001; 95% CI 10.00, 30.00), womenin this group received significantly less bupivacaine(table 1).

In group A, 39 of 40 women were assessed as ableto get out of bed and 24 women got out of bed duringlabour. In group B, eight of 40 women were thoughtto be able to get out of bed and two got out of bedduring labour, but none in group B retained the abil-ity to walk after the first top-up.

Although satisfaction scores for labour were highin both groups, women in group A scored higher(table 1).

The time interval between insertion of the epiduraland delivery was similar in both groups and althoughwomen in group A had shorter labours, this was notsignificant (table 2). Duration of the second stageof labour was significantly shorter in group A(P0.0003; 95% CI1.17,0.27) (table 2) and morewomen in this group had spontaneous vertex delivery(77% compared with 58%) (table 3). There werefewer instrumental deliveries in group A (P0.03)(table 3). Caesarean section rates were similar.

Table 1 Pain scores (VAS) as weighted-average (mean, SD) (ttest), time interval between top-ups, total bupivacaine administered duringlabour, total fentanyl administered during labour and satisfaction with analgesia in labour (VAS) (median, interquartile range)(MannWhitney Utest) in groups A and B. Pvalues and 95% confidence intervals (CI) are also given

Group A Group B P 95 % CI

VAS pain (mm) 20.52 (10.16) 18.29 (9.43) 0.31 (2.15, 6.63)Time between top-ups (min) 90 (60117.5) 110 (82.5140) 0.0001 (10.00, 30.00)Total bupivacaine (mg) 45 (3550) 87.5 (62.5112.5) 0.001 (57.51,22.50)Total fentanyl (g) 110 (90120)Satisfaction with analgesia VAS (mm) 84 (75.7589.75) 77.5 (72.088.0) 0.04 (0.001, 10.001)

Table 2 Duration of labour, first stage and second stage, and time from insertion of the epidural to

delivery (h) (median, interquartile range) (MannWhitney Utest)

Group A Group B P 95% CI

Labour 7.33 (5.699.87) 8.35 (6.611.8) 0.17 (3.08, 0.50)1st stage 6.58 (4.968.66) 7.17 (5.429.5) 0.4 (0.07, 3.16)2 stage 0.78 (0.330.96) 1.5 (0.832.5) 0.0003 (1.17,0.27)Epidural to delivery 5.25 (3.56.29) 6.2 (4.729.17) 0.057 (2.733, 0.082)

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Epidural bupivacaine compared with fentanyl for analgesia in labour 509

Discussion

We have demonstrated that with an epidural top-up technique using 0.1% bupivacaine with fentanyl2 g ml1, analgesia was similar to that using 0.25%plain bupivacaine, but motor power was retainedallowing women to mobilize. There also appear to bebeneficial effects on the progress of labour, with aclinically important reduction in the length of the

second stage and instrumental delivery rate.With this technique, 39 of 40 women retainedadequate motor power to be judged able to walkand 60% chose to get out of bed during labour.Reduction in motor block allowing independentmovement and awareness of contractions withoutpain has been shown to be popular with mothers.10Retention of pelvic floor sensation and motor func-tion may allow appropriate coordinated pushing dur-ing the second stage, improving rotation and descentof the fetal head through the pelvis. Epidural localanaesthetic may attenuate endogenous oxytocinproduction reducing uterine contractility during the

second stage.13 14

The significantly lower dose ofbupivacaine required by women in group A mayallow better uterine function and explain the shortersecond stage of labour and reduced instrumentaldelivery rates observed in this study. These areimportant clinical findings because both a long sec-ond stage and instrumental delivery have associatedmorbidity for the mother,1517 pose a controversialpotential risk to the baby1820and negatively influencematernal satisfaction with the experience of labour.21Although epidural analgesia produces excellent anal-gesia, this does not automatically produce maternalsatisfaction with labour, and less effective methods of

analgesia have produced higher satisfaction scores.

21

We demonstrated high maternal satisfaction withboth epidural solutions, which was significantlygreater in the bupivacainefentanyl group.

Analgesia was established (verbal score1) by 30min in all women. Establishing analgesia with anepidural bolus is effective but takes longer than acombined spinalepidural technique, which has beendescribed widely.10However, it avoids the complica-tions of deliberate dural puncture.11The time differ-ence between establishing spinal rather than epiduralanalgesia should be viewed in the context of theduration of labour and the potential complications ofthe spinal component of a combined technique.

Comparing the two epidural solutions, we showedthat the duration of analgesia provided by each top-up was significantly shorter in group A than in groupB (table 1). This influences the management of theepidural with more frequent top-ups and care in rec-ognizing block regression to avoid loss of analgesia.However, the benefits of this solution are evident and

PCEA or continuous infusion may prevent thispotential problem.

In summary, we have shown that establishingepidural analgesia in labour with 15 ml of 0.1% bupi-vacaine combined with fentanyl 50 g, followed bytop-ups of 10 ml of 0.1% bupivacaine with 0.0002%fentanyl, produced similar analgesia to that obtained

from the same volume of 0.25% bupivacaine alone,but motor block was minimized. This may influencethe progress of labour, decreasing the duration of thesecond stage and incidence of instrumental delivery,and produce high maternal satisfaction with theexperience of labour.

Acknowledgement

We thank the Robertson Centre for Biostatistics, University ofGlasgow, for statistical advice.

References

1. Li DF, Ress GAD, Rosen M. Continuous extradural infusionof 0.0625% or 0.125% bupivacaine for pain relief in primigravid labour. British Journal of Anaesthesia 1985; 57:264270.

2. Murphy JD, Hutchinson K, Bowden MI, Lewis M, CooperGM. Bupivacaine versus bupivacaine plus fentanyl forepidural analgesia: effect on maternal satisfaction. British

Medical Journal1991; 302: 564567.3. Thorburn J, Moir DD. Extradural analgesia: the influence of

volume and concentration of bupivacaine on mode of deliv-ery, analgesia efficacy, and motor block. British Journal of

Anaesthesia1981; 53: 933939.4. Crawford JS. Experiences with epidural morphine in obstet-

rics.Anaesthesia1981; 36: 207209.5. Husemeyer RP, OConnor MC, Davenport HT. Failure of

epidural morphine to relieve pain in labour.Anaesthesia1980;

35: 161163.6. Vella LM, Willats DG, Knott C, Linton DJ, Justins DM,

Reynolds F. Epidural fentanyl in labour: an evaluation of thesystemic contribution to analgesia. Anaesthesia 1985; 40:741747.

7. McGrady EM, Brownhill DK, Davis AG. Epidural diamor-phine and bupivacaine in labour. Anaesthesia 1989; 44:400403.

8. Cohen SE, Tan S, Albright GA, Halpern J. Epiduralfentanyl/bupivavaine for obstetric analgesia. Anesthesiology1987; 67: 403407.

9. Chestnut DH, Laszewski LJ, Pollack KL, Bates JN, ManagoNK, Choi WW. Continuous epidural infusion of 0.0625%bupivavaine0.0002% fentanyl during the second stage oflabor.Anesthesiology1990; 72: 613618.

10. Collis RE, Baxandall ML, Srikantharajah ID, Edge G, Kadim

MY, Morgan BM. Combined spinal epidural (CSE) analge-sia: technique, management, and outcome of 300 mothers.International Journal of Obstetric Anesthesia1994; 3: 7581.

11. Collis RE, Baxandall ML, Srikantharajah ID, Edge G, KadimMY, Morgan BM. Combined spinalepidural analgesia withthe ability to walk throughout labour. Lancet 1993; 341:767768.

12. Harding SA, Collis RE, Morgan BM. Meningitis after com-bined spinalextradural anaesthesia in obstetrics. British

Journal of Anaesthesia1994; 73: 545547.13. Goodfellow CF, Hull MGR, Swaab DF, Dogterom J, Buijs

RM. Oxytocin deficiency at delivery with epidural analgesia.British Journal of Obstetrics and Gynaecology 1983; 90:214219.

14. Bates RG, Helm CW, Duncan A, Edmonds DK. Uterineactivity in the second stage of labour and the effect of epidural

analgesia. British Journal of Obstetrics and Gynaecology1985;85: 749755.

15. Sultan AH, Kamm MA, Hudson CN. Pudendal nerve dam-age during labour: prospective study before and after child-birth. British Journal of Obstetrics and Gynaecology1994; 101:2228.

16. Sultan AH, Kamm MA, Hudson CN, Thomas JM, BartramCI. Anal-sphincter disruption during vaginal delivery. NewEngland Journal of Medicine1993; 329: 19051911.

Table 3 Method of delivery (number of women) (chi-squaretest). SVDSpontaneous vertex delivery

Group A(n35)

Group B(n38) P

SVD 27 22 0.08Instrumental 2 9 0.03Caesarean section 6 7 0.89

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17. Snooks SJ, Swash M, Henry MM, Setchell M. Risk factors inchildbirth causing damage to the pelvic floor innervation.British Journal of Surgery1985; 72: S1517.

18. Friedman EA, Sachtleben-Murray MR, Dahrouge D, NeffRK. Long term effects of labor and delivery on offspring: Amatched-pair analysis. American Journal of Obstetrics andGynecology1984; 150: 941945.

19. Gilstrap LC, Hauth JC, Schiano S, Connor KD. Neonatal

acidosis and method of delivery. Obstetrics and Gynecology1984; 63: 681685.

20. Dieker LJ, Rosen MG, Thompson K, Lynn P. Midforcepsdeliveries: Long-term outcome of infants.American Journal ofObstetrics and Gynecology1986; 154: 764768.

21. Morgan BM, Bulpitt CJ, Clifton P, Lewis PJ. Analgesia andsatisfaction in child birth (The Queen Charlottes 1000mother survey). Lancet1982; 808810.