Epidural Analgesia In Mothers Undergoing Trial Of Vaginal Birth After Previous Cesarean Section: A Prospective Study

Epidural Analgesia In Mothers Undergoing Trial Of Vaginal Birth After Previous Cesarean Section: A Prospective Study BY:

at e

DESAI PANKAJ PATEL PURVI GAJJAR FULVA AMIN SAMEER FROM: The Department of Ob-gyn Medical College and S. S. G. Hospital, Baroda, INDIA

pl

ic

Address for correspondence: Dr. Pankaj Desai “Guru Krupa”, Opp. Alankar Appartments Dandia Bazaar, BARODA; 390001, INDIA Phones: 91-265-2437793/ 2432519 Email: [email protected]

Short title: Epidural Analgesia In V.B.A.C.

du

Epidural Analgesia In Mothers Undergoing Trial Of Vaginal Birth After Previous Cesarean Section: A Prospective Study Warranty

The undersigned author warrants that this paper is original, is not under simultaneous consideration of any other journal and has not been published elsewhere. I sign for and accept the responsibility for releasing this material on behalf of any and all co-authors.

BARODA, INDIA Date: Friday, 02 April, 2004

[DR. PANKAJ DESAI]

1

TEXT INTRODUCTION

pl

ic

at e

SUMMARY: A disciplined approach to labor management results in lower cesarean section (cesarean section) rate. We currently have a 44.1 % epidural analgesia rate in our unit for all mothers in whom trial of labor is given irrespective of previous cesarean section scar. We clearly identified following questions answers to which we sought from this study: Is it safe to administer oxytocin when attempting VBAC under the cover of epidural analgesia? Does epidural analgesia increase the chances of instrumental vaginal delivery in subjects undergoing VBAC? Does epidural analgesia masks the pain of dehiscing scar? Do babies come out more distressed in mothers who have a VBAC under epidural analgesia? Does epidural analgesia affect the success of VBAC? This is a prospective case controlled study. All 52 subjects in whom VBAC was planned & were given epidural analgesia were enrolled in the study. Equal number of subjects in whom epidural analgesia was administered & with no history of previous cesarean section served as controls. It was found that oxytocin could be safely given in VBAC trials undergoing epidural analgesia. Administration of epidural analgesia for trials of VBAC did not increase a need for instrumental vaginal delivery. Administering epidural analgesia in mothers undergoing trial for VBAC does not compromise the fetus. Epidural analgesia in subjects undergoing trial for VBAC does not increase the chances of failures but in fact increase the chances of success. KEY WORDS: Labour epidural analgesia, V.B.A.C, instrumental vaginal delivery, Cesarean Section

du

A disciplined approach to labor management results in lower cesarean section (cesarean section) rate . However in any given institution, like that of ours where subjects with previous cesarean section constitute 10.3-11.3 %, attempting to bring about a vaginal birth in cases of previous cesarean section is quite expectable. In such a situation, pain relief for a mother with such a scarred uterus and now undergoing a trial of labor is a matter, which warrants an attention. Workers like Bolaji et al have clearly shown that it is safe to administer epidural analgesia in such subjects2. 1

Our group is involved in providing services of epidural analgesia for painless labor in a big way. We currently have a 44.1 % epidural analgesia rate in our unit for all mothers in whom trial of labor is given irrespective of previous cesarean section scar. Some of our colleagues in the anesthesia team expressed apprehension & at times blatant refusal to administer epidural analgesia in mothers to whom trial of labor was given after previous cesarean section. This was one of our principle forces behind this prospective study. We clearly identified following questions answers to which we sought from this study. ™ Is it safe to administer oxytocin when attempting VBAC under the cover of epidural analgesia? ™ Does epidural analgesia increase the chances of instrumental vaginal delivery in subjects undergoing VBAC? ™ Does epidural analgesia masks the pain of dehiscing scar? ™ Do babies come out more distressed in mothers who have a VBAC under epidural analgesia? ™ Does epidural analgesia affect the success of VBAC?

2

SUBJECTS & METHODS

at e

This is a prospective case controlled study. It was carried out in the department of Ob Gyn, Medical College & S.S.G. Hospital, and Baroda at its 4th unit. The study period was of three and half years commencing from July 2000 to Feb 2004. All 52 subjects in whom VBAC was planned & were given epidural analgesia, were enrolled in the study. Equal number of subjects in whom epidural analgesia was administered & with no history of previous cesarean section served as controls. The mothers who were administered epidural analgesia immediately after the indexed case constituted the group of “controls”. There was one control for each indexed case.

du

pl

ic

After a careful clinical assessment, subjects were administered a 540 ml. of lactated Ringer’s solution as a pre-load. After this epidural analgesia was administered in a dose of 8 cc of Bupivacaine in a concentration of 0.125% through an epidural catheter. 8.5-9 cm of catheter length was introduced. The site of injection was either space of L 2-3 or L3-4. In 70.04 % of subjects, epidural analgesia could be achieved with the first prick, in the remaining two pricks were required. In the both the groups, epidural analgesia was administered when subjects were in active labor with the station at minus 2 to minus 3. Top-ups were given as and when pain perception appeared as judged by the doctor or demanded by the mother. Level of loss, motor loss: whether present or absent, hypotension and tachycardia after the procedure were noted. Obstetric outcome was also carefully monitored for: mode of delivery, indication for intervention if any, duration of stages of labor and postpartum obstetric complications if any. Neonatal outcome was evaluated on the basis of APGAR score at 0, 1 & 5 minutes. Intrapartum complications due to epidural analgesia in the form of nausea or vomiting, rigors, fetal bradycardia, respiratory depression, dural leak, speech loss, high spinal and micturition difficulty were carefully observed. The data so obtained was statistically evaluated using EpiInfo software, Vol. 3.2; February 2004 (latest) http://www.cdc.gov/epiinfo RESULTS

During this period of study, there were 3450 confinements in this 4th unit of department. Of these, 340 subjects of were previous cesarean section, which brings the overall incidence of previous cesarean section in subjects to 9.85 %. Of the 340 subjects, 172 were given a trail for vaginal birth. That brings the overall incidence for the trial of VBAC is 50.58 %. Epidural analgesia was administered to 52 of these cases. Subjects who were moderately anemic or were not nil by mouth for at least 4 hours or had a cervical dilatation of >4 cm &/OR a station beyond -2 were not given epidural analgesia & therefore excluded from this study. Safety of oxytocin administration: In an attempt to answer the first question that we raised in the section of “Introduction”, safety of administrating oxytocin in these subjects was evaluated. All 52 cases in both the groups were given oxytocin. None of the mothers in the indexed cases had a scar rupture or a wound dehiscence. Thus the apprehension that in absence of perception of pain a rupturing scar may go unnoticed, compromising with feto-maternal safety was found to be untrue. Thus oxytocin can be safely given in VBAC trials undergoing epidural analgesia.

3

When trying to analyze fetal effects of oxytocin administration, 8 subjects had fetal distress in first stage of labor requiring cesarean section. However it will be too simplistic to presume that this was due to oxytocin administration. It is possible that these could be subjects with a borderline cephalo- pelvic disproportion, which last time warranted a cesarean section and this time the trial ending in a fetal distress again. In this way, multiplicity of the reasons can be cited for fetal distress. Instrumental vaginal delivery

at e

On analysis of this data for second question that we had raised regarding instrumental vaginal delivery, as shown in Table 1 the incidence of instrumental vaginal delivery was equal in both groups. Thus administration of epidural analgesia for trials of VBAC did not increase a need for instrumental vaginal delivery. Infact 4 of 8 subjects who required a forceps or a vacuum were due to prophylactic indication of previous cesarean section. This obviously was not attributable to epidural analgesia in trial of VBAC.

ic

Fetal distress

Successful outcome

pl

One more aspect was studied in this paper was the fetal safety of epidural analgesia in mothers undergoing VBAC. As shown in Table 2 none of the babies were born in either group with APGAR score of < 6 indicating severe birth asphyxia. Even the number of those babies born with APGAR score between 6 to 8 was not significantly different in either groups (Chi square = 0.16; p value > 0.05). This means administrating epidural analgesia in mothers undergoing trial for VBAC does not compromise the fetus.

du

The last question that we examined was related to the end point of a successful VBAC. On the face of dry statistical analysis, the difference between cases & controls requiring cesarean section is statistically significant but here this statistical analysis can not be applied here. This is because as such the chances of cesarean section in subjects undergoing VBAC are high. Therefore it was necessary to evaluate this data by the law of probability rather by the test of significance. In this unit amongst all the cases in whom trial for VBAC were given, 73.7 % require a repeat cesarean section. On the basis of this, by the law of probability of the 52 cases amongst indexed cases 38 would require a cesarean section. However as shown in Table 3 only 20 required a cesarean section clearly indicating epidural analgesia in subjects undergoing trial for VBAC does not increase the chances of failures but in fact increase the chances of success. DISCUSSION VBACs are here to stay. It is now proved that VBAC require fewer blood transfusions, fewer post partum infections, shorter hospital stay & no increase in perinatal mortality3. The aspects that now catch the attention are the improving the success of trials following VBACs & safe pain relief methods in VBACs. Both of these are matters of concern in present study as well. Scar dehiscence is a rare occurrence following VBAC in carefully selected cases4. In fact in the present study there was no scar dehiscence indicating the safety of the procedure.

4

at e

Some workers believe that epidural analgesia may increase the incidence of cesarean section5 but they too contend that there may not be the causal relationship between epidural analgesia & cesarean delivery. The matter of concern therefore is if epidural analgesia were to increase the incidence of cesarean section how good is it to administer in cases where we are attempting VBAC? The results of the present study allay this apprehension completely. In fact it was found that successful VBAC was more likely when epidural analgesia was given rather than otherwise. It is possible that a disciplined approach to labor management, which is an integral part of such a monitoring, might have contributed to less cesarean section. Epidural analgesia abolishes the perception of pain during labor, which is a result of increased uterine pressure. On the other hand, the scar rupture results in pain due to the shearing off of uterine fibers. This pain is totally different. Thus the apprehension that epidural analgesia masks the pain of a rupturing uterus is unscientific6.

ic

Besides the maternal safety being questioned, the other area where concern is expressed is regarding fetal safety. It was comprehensively found in the present study that epidural analgesia in cases of VBAC does not affect perinatal morbidity &/or mortality. These have been corroborated by other studies as well1, 2, 7, and 8.

CONCLUSION;

pl

It can therefore be concluded from this study that administering epidural analgesia in mothers undergoing trial for VBAC is safe, does not increase maternal or perinatal morbidity and may in fact improve chances of successful VBAC.

du

ACKNOWLEDGEMENTS

The authors are thankful to Department of Anesthesia for their active co-operation in this study. They are also thankful to The Dean, The Professor and Head, Department of Ob-Gyn., Medical College, Baroda, India & the Superintendent, S.S.G. Hospital, Baroda, India for allowing them to carry out this study.

5

REFERENCES

ic

at e

1. Videla F L, Satin A J, Barth W H, Hankins G D: Trial of labor – A disciplined approach to labor management resulting in high rate of vaginal delivery: Am.J.Perinatol; 1995; 12(3); 181-184 2. Bolaji I I, Meehan F P: Post cesarean section delivery: Eur.J.Obstat.Gynecol.Reprod.Biol; 1993; 51(3); 181-192 3. Turner N J, Leader L R: Vaginal birth after cesarean section policy: Obstet.Gynecol.Clin.N.A; 1999; 26(2) ; 295-304 4. Rudick V, Niv D, Hetman P M: Epidural analgesia for planned vaginal delivery previous cesarean section: Int .J. Gynecol. Obstet.; 1996; 53(2) ; 121-132 5. Chestnut D H: Does epidural analgesia affect the incidence of cesarean section delivery: Reg.Anesth.;1997 ; 22(6) ; 495-499 6. Uppington J: Epidural analgesia & previous cesarean section: Anesthesia; 1983; 38(4); 336-341 7. Miller M, Leader L R: Vaginal delivery after cesarean section: Aust. NZ .J. Obstet. Gynecol.; 1992; 32(3) ; 213-216 8. McNally O M, Turner M J: Aust .NZ. J. Obstet. Gynecol.; 1999; 39(4) ; 425-429

TABLES

pl

Table 1: Instrumental vaginal delivery

du

Normal vaginal delivery Instrumental vaginal delivery

CASES

CONTROLS

24

28

8

8

$2 = 0.07 p-value = 0.8 (not significant)

Table 2: APGAR score at birth 6 to 8 >8

CASES 36 16

CONTROLS 35 13

$2 = 0.16 p-value = 0.69 (not significant) No baby was found to be with APGAR score at birth of < 6 in both study groups. 6

Table 3: Cesarean sections CONTROLS

24

28

20

4

at e

Normal vaginal delivery Cesarean section

CASES

$2 = 7.85 (Yates’s corrected) p-value = 0.005 (significant)

ic

Important disclaimer information: This research paper is awaiting approval for publication in ObGyn journal. This file represent the duplicate of the original paper provided here only for information purpose to healthcare professionals.For information regarding copyright policy & other matter(s), kindly contact author at address given at the top page.

du

pl

This page is posted originally at http://www.sbamin.com/downloads/epipdf.pdf Dr.Samir B.Amin ; M.B.B.S. Intern doctor,Medical College,Baroda A-314,Subodhnagar, b/h Manjalpur township-1, Manjalpur,Baroda-11(Guj) India Cell: +91 265 3126975 [email protected] Yahoo !, Hotmail Id : drsbamin

site created & hosted : 25/08/2003 Last updated : 29/04/2004 12:52 IST +0530 Baroda Disclaimer/Disclosure details copyright©2004:sbamin.com

7