|Year : 2008 | Volume
| Issue : 3 | Page : 282-287
Comparison of Combined Spinal Epidural Technique and Low Dose Epidural Technique in Progress of Labour
Amit G Bhagwat1, CK Dua2, Kirti N Saxena3, Srikant Srinivasan1, Kanika Dua1
1 Senior Resident, Department of anesthesiology & critical care, Maulana Azad Medical College, Delhi, India
2 Director Professor & Ex HOD, Department of anesthesiology & critical care, Maulana Azad Medical College, Delhi, India
3 Professor, Department of anesthesiology & critical care, Maulana Azad Medical College, Delhi, India
|Date of Acceptance||01-Mar-2008|
|Date of Web Publication||19-Mar-2010|
Amit G Bhagwat
NU 17 A, Pitam Pura, New Delhi- 110034
The combined spinal epidural (CSE) technique is gaining popularity as it is associated with rapid onset of analgesia and it has a flexibility of an epidural catheter insertion. Though both epidural and CSE technique provide effective analgesia, epidural technique is reported to be associated with prolonged labour. By contrast, CSE technique is observed by many workers to be associated with shortened labour and increased rate of cervical dilatation. However, it is not clear whether rapid rate of cervical dilatation is the physiologic effect of the CSE technique or it is an artifact of patient selection, as CSE technique is usually used in the patient in advanced stage of labour requiring rapid analgesia.
We hypothesized that rapid cervical dilatation seen with CSE technique is physiologic effect of the technique and not mere an artifact and compared the CSE and epidural techniques with regard to progress of labour with special emphasis on rate of cervical dilatation and duration of labour.
Sixty healthy nulliparous parturients in spontaneous labour with singleton fetus were randomized in a prospective double blinded manner to receive either CSE analgesia or epidural analgesia. The epidural group (n= 30) received 10 ml bolus of 0.0625% bupivacaine+ 0.0002% fentanyl& the CSE group (n= 30) received intrathecally 25 mcg fentanyl + 1.25 mg bupivacaine. The rate of cervical dilatation was significantly greater in the CSE group as compared to the epidural group (3.5 ± 0.752 cm / hr vs. 2.0 ± 1.122, P = 0.000)& the duration of active stage of first stage of labour was significantly shorter in-group CSE (117.5 ±25.57 min vs. 192.5 ± 12 min, P = 0.000).
Keywords: Combined spinal epidural technique, Low dose epidural technique, Rate of cervical dilatation, Duration of labour
|How to cite this article:|
Bhagwat AG, Dua C K, Saxena KN, Srinivasan S, Dua K. Comparison of Combined Spinal Epidural Technique and Low Dose Epidural Technique in Progress of Labour. Indian J Anaesth 2008;52:282-7
|How to cite this URL:|
Bhagwat AG, Dua C K, Saxena KN, Srinivasan S, Dua K. Comparison of Combined Spinal Epidural Technique and Low Dose Epidural Technique in Progress of Labour. Indian J Anaesth [serial online] 2008 [cited 2013 May 20];52:282-7. Available from: http://www.ijaweb.org/text.asp?2008/52/3/282/60635
| Introduction|| |
Epidural analgesia remains a gold standard for providing pain relief during labour , . However, a major concern is whether epidural analgesia might be responsible for prolongation of labour, an increased risk of caesarean delivery or vaginal delivery requiring the use of forceps or vacuum extraction , .
The CSE technique is used frequently for its rapid onset of analgesia and better satisfaction among parturients when compared with epidural technique , . It has been observed that parturients who had received CSE analgesia were associated with shortened labour, though this may be an artifact of patient selection as CSE is usually administered to either multiparous parturients or parturient in advanced stage of labour in our institute,.
We designed this study in a prospective randomized double blinded manner to test our hypothesis that shorter duration of labour and rapid rate of cervical dilatation with CSE technique is due to anaesthetic technique and is not an artifact of patient selection.
| Methods|| |
After approval of the Institutional Review Board, this prospective randomized double blinded study was conducted on 60 ASA grade I parturients, admitted to Lok Nayak Hospital, New Delhi during the period of May 2006 to March 2007.
Written informed consent was taken from 60 at term nulliparous parturients in established labour (cervical dilatation = 4 cm) belonging to ASA physical status I. The exclusion criteria were cervical dilatation > 5 cm, nonvertex presentation or any contraindication to neuraxial analgesia.
Double-blinded randomization to the CSE (Group CSE) or epidural (Group E) group was accomplished by means of a computer generated randomization list (Microsoft Excel TM 7.0; Microsoft, India). The procedure was carried out by one anaesthesiologist while the observations were made by the second one who was not present at the time of the procedure. The progress of labour and other obstetric parameters were assessed by an obstetrician who was also blinded to the group allocation.
All the parturients in both the groups were familiarized with a visual analogue scale (0= no pain, 10 =worst pain imagined). Baseline pain score, pulse, BP, fetal heart rate and initial rate of oxytocin infusion were noted just before the procedure. Only those parturients with cervical dilatation of 4 - 5 cm were included in study. After preloading the parturients with 10 ml.kg1 of Ringer's lactate solution, the parturients were positioned laterally for the central neuraxial blockade. In both the groups, using strict asepsis, epidural space was identified at the L2-3 or L3-4 interspace with a 17G Tuohy needle using the loss of resistance( with saline ) technique.
In group E, an 18G epidural catheter was introduced and advanced 3-4 cm cephalad. After a negative test dose of 3ml of 1.5 % lidocaine with 15 µgm epinephrine, a 10 cc bolus of 0.0625% bupivacaine + 0.0002% fentanyl was administered via the epidural catheter. After ten minutes (from initial 10 cc bolus) an epidural infusion of 0.0625% bupivacaine and 0.0002% fentanyl was started using a patient controlled epidural analgesia (PCEA) pump at the rate of 8-12ml.hr -1 and subsequently titrated to maintain a sensory level of T10.
In group CSE, a 25-guage Whitacre needle was placed via the shaft of the epidural needle and the dura punctured. After return of clear CSF, 1.25 mg bupivacaine (1ml of 0.125 % bupivacaine solution prepared by adding 3 ml of NS in 1 ml of 0.5 % bupivacaine heavy) with fentanyl 25 µgm in 0.5 ml, so as to make a total volume of 1.5 ml , was administered (0min). This was followed by placement of an 18G multiholed epidural catheter, 3-4cm cephalad into the epidural space. After ten minutes (from injection of intrathecal drug) an epidural infusion of 0.0625% bupivacaine and 0.0002% fentanyl was started using a patient controlled epidural analgesia (PCEA) pump at the rate of 8-12 ml.h -1 and subsequently titrated to maintain a sensory level of T10. The PCEA pump was covered by an opaque carrying bag, which accompanies the pump kit, in order to blind the observer.
Breakthrough pain (VAS > 3) or pain during second stage of labour was treated by giving a bolus of 10 ml of infusion drug with a lockout time of 10 min. Infusion rate was decreased to 6 ml.h -1 if sensory level is higher than T10 , patient has a modified Bromage score of less than 3 or if patient has hypotension. Institutional protocols for treatment of pruritus, nausea / vomiting, hypotension were used.
| Assessment|| |
Following parameters were observed during the study period, which extended from the initiation of the block till the delivery of the baby. Maternal heart rate and blood pressure were recorded at 10min interval during the first 30 min and then at every 30 min till the end of the study period.
Progress of labour with special reference to the rate of cervical dilatation was monitored by the obstetrician as per standard hospital protocol, as also were the obstetrical outcome and operative intervention. In our institute, per vaginal examination is being done at an interval of 4 h or when symptoms of full cervical dilatation occurs, however in our study per vaginal examination were done at a interval of two hrs, as in our previous work (unpublished data) duration of first stage of labour with low dose epidural technique were usually 2 to 3 hrs. We estimated the rate of cervical dilatation by linear interpolation between two examinations as is suggested by Tsen et al  .
Where C a and C b and T a and T b , represents the results and timing, respectively, of two cervical examinations. Using this formula, we calculated the rate of cervical dilatation of active stage of first stage of labour wherein active stage of first stage of labour is defined as time from initiation of analgesia to full cervical dilatation. Initial cervical examination was done just before insertion of catheter and only parturients with cervical dilatation between 4 to 5 cm were included in the study.
- Visual analogue scale was used for assessing pain wherein '0' represented no pain and '10' represented the worst possible pain.
- Evaluating response to pinprick at 30 min interval was used to assess the level of sensory block ade.
- Motor blockade was assessed at 30min interval by using a Modified Bromage scale (MBS) as suggested by Breen et al .
- Neonatal assessment was done by determining Apgar score at 1 min and 5 min, umbilical venous and arterial blood gas and acid base were ana lyzed. Also need for oxygen, tracheal intubation, IPPV and naloxone was recorded in all neonates. Any side effects viz pruritus, nausea/ vomiting, hypotension or any other side effect were also recorded.
| Results|| |
All the 60 parturients except for one parturient in Group CSE completed the study. This parturient in Group CSE was taken up for emergency caesarean section and was not included in calculation of rate of cervical dilatation or duration of active stage of first stage of labour. Demographic profiles of the parturients are shown in [Table 1].
Initial cervical dilatation in both the groups were comparable (4.5 ± 0.44 cm in Group CSE vs 4.25 ± 0.44 cm in Group E , P > 0.05 ) at the study entry point (i.e. cervical dilatation at the time of initiation of analgesia). However rate of cervical dilatation was more in Group CSE when compared to Group E [Table 2]. Most of the parturients in Group CSE (26 / 30) had a rate of cervical dilatation between 2-4 cm.h -1 with a mean rate of cervical dilatation of 3.5 ± 0.75 cm.h -1 . In Group CSE, one parturient's rate of cervical dilatation could not be calculated because patient was taken up for caesarean section for fetal bradycardia.This patient was not included for statistical analysis. Most of the parturient's in Group E (28/ 30) had a rate of cervical dilatation of 1- 3 cm.h -1 with mean rate of cervical dilatation being 2.0 ± 1.12 cm.h -1 . The P value when calculated by Mann- Whitney test was P= 0.000 (highly significant), i.e. rate of cervical dilatation in Group CSE was significantly higher than Group E.
To rule out the possibility that major cervical dilatation had already happened before the onset of analgesia and to ensure that initial cervical dilatation were comparable at the study entry point, we excluded all the parturients who had cervical examination more than one hour back and included only those who had cervical dilatation of 4 to 5 cm at the time of initiation of block, all the parturients with cervical dilatation > 5 cm were also excluded from the study. Both the groups were comparable with respect to initial cervical dilatation (4.5 ± 0.44 cm in Group CSE vs 4.25 ± 0.44 cm in Group E, P > 0.05). Parturient's demographic data were comparable in both the groups. Labour management was based on standard protocol followed in our institution. Both the techniques were comparable in providing effective analgesia, wherein effective analgesia was defined as VAS < 3 at 30 min.
Quality of analgesia (excellent, good, fair, poor) was graded as excellent by all the patient in both the groups (P>0.05). All the parturients in Group CSE has VAS score = 0 at 30 min where as in Group E 27/30 parturients had a VAS score of 0 while the rest had a VAS score between 1 to 3 (P> 0.05). None of the parturient in our study required intervention / treatment for nausea / vomiting, hypotension or pruritus. Sensory level in both the groups was comparable (T10, median dermatomal level to pinprick). MBS was comparable in both the groups and all the patients were allowed to ambulate (only with an accompanying nurse / mid wives) as per their wish. Duration of second stage of labour and mode of delivery did not differ between groups.
All neonates in-Group E and Group CSE had APGAR score of 9 at 1 min and 5 min. One patient inGroup CSE had fresh stillbirth, which was due to an obstetrical complication (cord around neck) .This patient, was excluded from the study while calculating the result. The rest 29/30 patients of Group CSE had an APGAR score of 9 at 1 min and 5 min.
P value calculated by Chi Square test was P = 1.026 (not significant) i.e. fetal outcome was similar between two groups. None of the babies required oxygen inhalation, endotracheal intubation, IPPV or naloxone.
| Discussion|| |
Neuraxial analgesia is now considered gold standard for providing pain relief during labour , . The CSE technique has gained popularity as it provides rapidity of spinal analgesia, minimal motor blockade and flexibility of epidural catheter to extend the block for caesarean section and for providing post operative analgesia , .
Despite advantages regional analgesia may have its own problems, most important of which are its effect on progress of labour and outcome  . Epidural analgesia may increase  , decrease  or have no effect on the rate of cervical dilatation in the first stage of labour  . In our institute, we usually administer CSE analgesia to either multiparous parturients or parturients at advanced stage of labour and have observed that parturients who were given CSE analgesia were apparently associated with faster cervical dilatations and hence shorter duration from initiation of analgesia to delivery of babies. However, these observations could have been confounded by an artifact of patient selection.
There are many randomized controlled trials previously comparing CSE with epidural technique; however these studies were confounded by use of different epidural regimen for CSE and epidural technique , .We designed this study hypothesizing that anaesthetic technique and not parturient selection are responsible for apparent rapid cervical dilatation and shorter duration of labour. In our study by including only nulliparous parturients with singleton fetus in vertex presentation and by blinding the observing anaesthesiologist and obstetrician to anaesthetic technique, we reduced the chances that our result could be explained on the basis of parturient selection. By using the same epidural drug in both the groups, we removed one more factor confounding the previous studies.
Our study had confirmed the results of a similar study by Lawrence et al  . In our study despite similar cervical dilatation at the time of initiation of analgesia, parturients in Group CSE were associated with more rapid rate of cervical dilatation and shorter duration of active stage of first stage of labour. Both the duration of second stage of labour and outcome of labour were similar in both the groups.
The mechanism for rapid rate of cervical dilatation with CSE technique is not known; however there may be many possibilities and has been discussed in previous studies. First, the use of CSE technique decreases the local anaesthetic exposure in the parturients ,.It has been shown that when exposed to local anaesthetic, uterine muscle strips show decrease in rate and strength of muscle contractions  . In our study, 13 / 30 parturients in Group CSE delivered with spinal analgesia only and there was no need to give epidural infusion in these parturients. Secondly, use of CSE technique, leading to rapid onset of analgesia, stabilizes the level of catecholamines. Levels of both epinephrine and nonepinephrine increase due to painful labour and rapid analgesia as is provided by CSE decreases the fluctuation in the levels of these catecholamines  . Decreased levels of epinephrine (a tocolytic) may be able to stimulate the uterine contraction  .
In our study we included only those parturients who had cervical dilatation of 4 to 5 cm just before initiation of analgesia and excluded parturients who had cervical examinations more than one hour before the initiation of analgesia, so as to rule out the possibility that substantial cervical dilatation might not have occurred before initiation of analgesia and hence remove a potential factor of bias which might have confounded the result of Lawrence et al  . Secondly , in our institute cervical examinations are performed at a interval of four hours so as to minimize frequent examinations and hence risk of infection. In our study however cervical examinations were performed at an interval of two hrs, this is done as we have observed that parturients with epidurals usually have 2- 3 hrs of first stage of labour. By fixing the intervals at which cervical examinations are done, we ensured that examinations were performed at comparable times in all parturients.
As in the study by Lawrence et al  , the potential weakness that there is uncertainty about the exact timing of full cervical dilatation remains in our study as well, however this is unavoidable as the interval between the two examinations were fixed. The second stage of labour in both the groups was similar.
In our study, modes of delivery were comparable between the two groups. However, our sample size is too low to detect whether anaesthetic technique will have any effect on the mode of delivery and there are substantial evidence that obstetrician's personal experience and preferences are more deciding factors than anaesthetic technique for outcome of labour  . Neonatal outcomes were good in both the groups. All the babies has APGAR score of 9 at 1 min& 5 min. APGAR score and umbilical blood gas analysis were comparable.
In conclusion, our study has confirmed that combined spinal epidural technique is associated with more rapid cervical dilatation and shorter duration of labour when compared with epidural technique.[Table 3]
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[Table 1], [Table 2], [Table 3]