Journal of Obstetric Anaesthesia and Critical Care

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 8  |  Issue : 1  |  Page : 24--28

Comparison of dural puncture epidural technique versus conventional epidural technique for labor analgesia in primigravida


Pritam Yadav, Indira Kumari, Aditi Narang, Nikita Baser, Vikram Bedi, Basant K Dindor 
 Department of Anaesthesiology, RNT Medical College, Udaipur, Rajasthan, India

Correspondence Address:
Dr. Aditi Narang
Department of Anaesthesiology, RNT Medical College, Udaipur, Rajasthan
India

Abstract

Background: Dural puncture epidural (DPE) is a method in which a dural hole is created prior to epidural injection. This study was planned to evaluate whether dural puncture improves onset and duration of labor analgesia when compared to conventional epidural technique. Methods and Materials: Sixty term primigravida parturients of ASA grade I and II were randomly assigned to two groups of 30 each (Group E for conventional epidural and Group DE for dural puncture epidural). In group E, epidural space was identified and 18-gauge multi-orifice catheter was threaded 5 cm into the epidural space. In group DE, dura was punctured using the combines spinal epidural (CSE) spinal needle and epidural catheter threaded as in group E followed by 10 ml of injection of Ropivacaine (0.2%) with 20 mcg of Fentanyl (2 mcg/ml) in fractions of 2.5 ml. Later, Ropivacaine 10 ml was given as a top-up on patient request. Onset, visual analouge scale (VAS), sensory and motor block, haemodynamic variables, duration of analgesia of initial dose were noted along with mode of delivery and the neonatal outcome. Results: Six parturients in group DE achieved adequate analgesia in 5 minutes while none of those in group E (P < 0.05) achieved adequate analgesia. The mean VAS score was 4.97 ± 0.85 in group E and 4.33 ± 0.922 in group DE at 5 min (P < 0.05). Duration of analgesia of initial bolus dose was 99.37 ± 23.175 min in group E and 98.77 ± 24.955 min in group DE (P > 0.05). Conclusions: Both techniques of labor analgesia are efficacious; dural puncture epidural has the potential to fasten onset and improve quality of labor analgesia when compared with conventional epidural technique.



How to cite this article:
Yadav P, Kumari I, Narang A, Baser N, Bedi V, Dindor BK. Comparison of dural puncture epidural technique versus conventional epidural technique for labor analgesia in primigravida.J Obstet Anaesth Crit Care 2018;8:24-28


How to cite this URL:
Yadav P, Kumari I, Narang A, Baser N, Bedi V, Dindor BK. Comparison of dural puncture epidural technique versus conventional epidural technique for labor analgesia in primigravida. J Obstet Anaesth Crit Care [serial online] 2018 [cited 2019 Dec 6 ];8:24-28
Available from: http://www.joacc.com/text.asp?2018/8/1/24/230059


Full Text



 Introduction



Labor pain is one of the most painful events in lifetime of women and the intensity of labor pain often exceeds patient's expectations.[1] The combined spinal epidural technique (CSE) has been advocated over the conventional epidural technique for labor analgesia by several authors for the advantages of its rapid onset, profound analgesia, high patient satisfaction and verification of epidural space by the definitive return of cerebrospinal fluid (CSF) via the spinal needle, causing reduction in epidural catheter failures.[2] However, the CSE technique has the potential of causing haemodynamic instability, foetal bradycardia and other side effects of intrathecally given local anaesthetics and opioids.[3],[4] In order to minimize these side effects while retaining the advantages, a novel method of dural puncture epidural (DPE) is suggested by several authors in which a dural hole is created, without intrathecal administration of drugs, prior to epidural injection of drugs.

We planned this study to evaluate whether dural puncture epidural analgesia improves onset and duration of labor analgesia when compared with conventional epidural labor analgesia.

 Materials and Methods



Approval from the Institutional ethical committee was obtained for this prospective, double blind randomized study. It was conducted in a tertiary care teaching hospital on 60 term primigravida parturients of ASA grade I and II with uncomplicated pregnancy in vertex presentation after taking informed consent. Parturient in active labor requesting labor analgesia were included in this study. Exclusion criteria were hypersensitivity to study drugs, bleeding disorders, decreased platelet counts, local or systemic sepsis, blood/CSF in the epidural catheter during procedure, a history of drug abuse and parturient refusal. All cases were randomly assigned to one of two groups of 30 each, using a computer-generated table of random number:

Group E: Patients receiving epidural labor analgesia

Group DE: Patients receiving dural puncture epidural labor analgesia.

Study patients (n = 60) were randomly assigned to one of two groups of 30 each, using a computer-generated table of random number to receive either epidural analgesia or dural puncture epidural analgesia. Patients were kept unaware of the technique used for labor analgesia. Post procedural observations were made by an anaesthesiologist who was unaware of the technique. This was done to ensure a complete absence of observational bias by double blinding.

Sample size

Sample size was calculated on basis of previous study by Chetty et al.[5] a minimum of 17 parturients were required in each group to study the difference between both in VAS at 5 min, at a power of 80% and confidence interval of 95%. We enrolled 30 patients in each group in accordance with central limit theorem.

Study medication was prepared as follows: 10 ml of injection Ropivacaine (0.2%) was taken directly from a 20 ml ampoule (Ropin®, Neon), and 20 mcg of injection Fentanyl (Fenstud ™, Rusan Healthcare Pvt. Ltd.) was taken as four parts from a tuberculin syringe with markings to divide 1 ml (50 mcg/ml) into 10 parts and added to 10 ml of ropivacaine (0.2%) in both groups to achieve a concentration of fentanyl (2 mcg/ml).

Epidural analgesia was administered on maternal demand at a cervical dilation of approx. 3–4 cm and cervical effacement of 60–70%. After written informed consent was obtained by the anaesthetist performing the procedure, patients were subjected to a thorough pre-anaesthetic evaluation before taking into the operation theatre. VAS score was noted on a scale of zero (no pain) to ten (the worst imaginable pain) along with baseline vitals. After securing an 18G peripheral intravenous cannula, parturients of both groups were placed in left lateral position and under all aseptic precautions, 2% lignocaine HCl was infiltrated into the L3–4 intervertebral space in both the groups. In group E, using BD DURASAFE ™ PLUS CSE kit, epidural space was identified using a loss of resistance technique to normal saline with a 16G Tuohy needle and an 18-gauge multi-orifice catheter was threaded through the cephalic directed tip of the epidural needle 5 cm into the epidural space. In group DE, after identification of epidural space by 16G Tuohy needle, dura was punctured by 27G whitacre needle provided with CSE kit. After confirmation of CSF flow, needle was withdrawn and epidural catheter threaded as in group E. After negative aspiration of blood, a 10 ml dose of the study medication was injected in a fractionated manner of 2.5 ml fractions, waiting for 2 minutes between each aliquot while watching for clinical signs of an intravascular injection by asking the patient whether she was feeling dizzy, having tinnitus or a metallic taste. This dose was defined as first initial bolus dose and time was noted at the end of the injection.

After 5 min of the first initial bolus dose of study drug, adequacy of analgesia was assessed. Analgesia was considered adequate if VAS score is ≤3. Onset of analgesia was defined as from time of first bolus dose to time of achieving VAS ≤3. An additional 10 ml of study medication (second initial dose) was administered in case adequate analgesia was not achieved after duration of 15 min from first bolus dose. If analgesia was inadequate after 15 min of second initial dose of Ropivacaine; the given epidural was classified as epidural failure, and patient was withdrawn from the study. Motor block in the lower extremities was assessed by using a Breen Modified Bromage scale (BMBS: Grade 1 - as complete motor block to Grade 6 as no motor block):

Grade 1 – Complete block (unable to move feet or knees)

Grade 2 – Almost complete block (able to move feet only)

Grade 3 – Partial block (just able to move knees)

Grade 4 – Detectable weakness of hip flexion while supine (full flexion of knees)

Grade 5 – No detectable weakness of hip flexion while supine (full flexion of knees)

Grade 6 – Able to perform partial knee bend

VAS and BMBS were assessed every 15 min. All parturient were given a trial walk to assess their ability to ambulate after half hour of onset of analgesia. An additional dose of Ropivacaine 10 ml was given as a top-up dose on patient request. A minimum gap of 15 min was kept between two subsequent top-up doses.

At any point of time during the study period, hypotension was defined as systolic blood pressure of <90 mmHg and planned to treat with bolus of 6 mg ephedrine HCl. Bradycardia was defined as heart rate <60 bpm and planned to treat with bolus doses of 0.4 mg atropine sulfate.

Data recording

Demographic characteristics (age, weight, height) and obstetric data (parity, dilatation of the cervix 0–10 cm) were noted prior to the initiation of labor analgesia.

VAS (pain), sensory level, motor block characteristics and HR and blood pressure were recorded before epidural (0 min-baseline), at 5 min, 10 min, 15 min and then every 15 min till 1 hour and then every 30 min till delivery. Sensory level was assessed by loss of sensation to prick by blunt head of a pin. Onset of analgesia was defined as duration from injection of first initial epidural bolus dose to attainment of VAS ≤3 and duration of analgesia of initial bolus dose was defined as time of administration of study drug until the time of demand of top-up for the first time. Motor block assessment was carried out by BMBS,[1],[2],[3],[4],[5],[6] Romberg's sign, straight leg raising test, rectus abdominis muscle test and trial walk. The time to request for subsequent top-up dose was recorded. Our obstetric department's protocols were followed for management of labor and mode of delivery (normal/instrumental delivery/caesarean delivery) and were noted. Injection delivery interval was noted as the time from first initial epidural dose until the delivery. Foetal heart rate was monitored by using a cardiotocograph. Apgar score at 1 and 5 min were recorded for assessment of neonatal outcome. Quality of maternal expulsive efforts was assessed by an obstetrician and graded as zero to three (Grade 0 = Failure, 1 = Incomplete, 2 = Good, 3 = Excellent). Quality of analgesia was assessed by asking parturients to grade from zero to three (Grade 0 = Failure, Grade 1 = Incomplete, Grade 2 = Good, Grade 3 = Excellent) after delivery. Occurrence of side-effects as nausea, vomiting, hypotension, hypersensitive reaction, shivering, fever, drowsiness, pruritus, respiratory depression, retention of urine and weakness in limbs were noted.

Statistical analysis

Dependence of one qualitative character on groups was tested using Chi square test and difference between means of different quantitative data among groups was tested by F test using one-way ANOVA. The analysis was performed using IBM SPSS version 2016. P < 0.05 was considered as statistically significant.

 Results



Both groups were comparable in terms of the demographic data (age, weight, height) and obstetric data (parity and cervical dilatation) [Table 1].{Table 1}

Both epidural and dural puncture epidural labor analgesia produced adequate labor analgesia in all the 30 parturients in both the groups, showing a 100% success rate of both techniques. Six (20%) parturients in group DE achieved adequate analgesia (VAS ≤3) in 5 minutes while none in group E achieved adequate analgesia. Number of parturients who achieved adequate analgesia during 5 to 10 minutes was also significantly higher (18) in group DE than in group E (10) (P < 0.05). A total of 86.7% parturients of group E accepted analgesia as excellent, while 13.3% labeled as good, while 100% parturients in group DE labeled analgesia as excellent. Overall, mean score for quality of analgesia was significantly higher in group DE (3.0) than in group E (2.87 ± 0.346) (P < 0.05). Duration of analgesia of initial bolus dose was 99.37 ± 23.175 min in group E and 98.77 ± 24.955 min in group DE (P > 0.05). The mean time to request for 1st top up dose was 114.57 ± 18.388 min in group E and 106.81 ± 17.585 min in group DE with no statistically significant difference on intergroup comparison (P > 0.05) [Table 2].{Table 2}

Epidural analgesia initiated when parturients mean cervical dilation (in cm) was 3.33 ± 0.547 and 3.33 ± 0.479 in groups E and DE, respectively. Effacement of the cervix (%) in groups E and DE at the time of initiation of labour analgesia was 65.7 ± 6.8 and 67.3 ± 5.8 in groups E and DE, respectively.

The mean VAS score of parturients was 4.97 ± 0.85 in group E and 4.33 ± 0.922 in group DE at 5 min, whereas it was 3.9 ± 0.845 group E and 2.97 ± 0.964 in group DE at 10 minutes after the injection of bolus dose (P < 0.05) [Table 3]; [Figure 1].{Table 3}{Figure 1}

There was no significant variation in the hemodynamics (pulse, BP) from the baseline and no statistical significant difference in both the groups (P > 0.005).

On comparing both groups, no significant decrease in total amount of consumption of local anesthetic was observed. The mean cumulative consumption of ropivacaine in group E was 33.33 ± 16.046 mg and 34.67 ± 15.698 mg in group DE (P > 0.05). There was no significant difference in the haemodynamic parameters of parturients in both groups. None of the patients in any group required ephedrine or atropine. The injection delivery interval in our study was 140.63 ± 60.735 min in group E and 137.27 ± 52.245 min in Group DE, which did not achieve statistical significance on inter group comparison (P > 0.05). One pregnant patient was delivered by caesarean section in DE group with indication being meconium stained liquor. All other patients, in both groups were delivered with spontaneous normal vaginal delivery with episiotomy. Neonatal outcome was favorable in both groups with no significant deleterious effect.

 Discussion



Dural hole created during CSE technique may increase subarachnoid passage of epidural drugs was suggested by Leach and Smith [6]. In vitro studies by Bernards et al.,[7] and Swenson et al.[8] concluded that passage of epidurally given drugs to subarachnoid space via dural hole was directly proportional to size of the dural hole.

There are differing views regarding superiority of DPE technique over conventional epidural technique for labor analgesia. Thomas et al.[9] and Gupta et al.[10] in their study showed that DPE technique did not provide superior labor analgesia when compared with a traditional epidural technique, but Cappiello et al.[2] suggest that DPE technique may benefit parturient by improving sacral spread, onset and bilateral nature of epidural labor analgesia as compared to standard epidural analgesia.

The present study shows earlier onset in DE groupas mean time to achieve adequate analgesia (VAS ≤3) was 11.00 ± 3.86 min in group DE, which was significantly lesser than 13.33 ± 2.39 min in group E (P < 0.05) and number of parturients achieving adequate analgesia in 5 min and 10 min was significantly higher in group DE than in group E (P < 0.05). Mean VAS score of parturients observed after 5 min and 10 min of injection was significantly lower in group DE in comparison to group E (P < 0.05).

In the present study, quality of analgesia better in DE group as 86.7% parturients of group E accepted analgesia as excellent, while 13.3% labeled as good; while 100% parturients in group DE labeled analgesia as excellent. Overall, mean score for quality of analgesia was significantly higher (3.0) in group DE than (2.87 ± 0.346) in group E (P < 0.05).

No difference in duration of analgesia of bolus dose, mean time to request for first top-up dose, requirement of mean cumulative dose of ropivacaine or mean injection-delivery interval was noted.

In contrast to our observation, Cappiello et al.[2] observed reduction in VAS score at 20 min in DPE group and no difference in VAS scores at any time interval before or after 20 min of onset of analgesia. This difference can be possibly explained by use of 27G needle in present study as compared to 25G needle used by Cappiello et al., which resulted in smaller size of dural hole. This smaller size dural hole resulted in flux of epidural drugs to intrathecal space up to 10 minutes but not after that. Secondly, in present study ropivacaine was used while Cappiello et al. used bupivacaine and this variation might have resulted in difference in observation as Bernards et al.[7] proposed intrinsic diffusion capacity of drugs to be a factor influencing passage of drugs through dural hole. Difference in demographic profile and analgesia technique could have been other reasons for differing observations.

To best of our knowledge, no other author mentioned recording VAS while comparing DPE and epidural technique for labor analgesia in currently available literature.

In study of Gupta et al.,[10] patient satisfaction numerical rating scale was not difference in dural puncture epidural group and continuous labor epidural group Thomas et al.[9] also did not find any significant differences in quality of labor epidural analgesia, in terms of inadequate analgesia, unilateral, sacral sparing or number of top up doses required, when dural puncture was done by 27G whitacre needle prior to epidural dose. Cappiello et al.[2] observed improvement in sacral spread, onset and bilateral pain relief produced by epidural bupivacaine in nullipara patients when preceded by dural puncture with 25G pencil point needle. Suzuki et al.[11] reported significantly greater caudal spread of analgesia at 15 and 20 min with dural puncture by 26G whitacre needle before epidural injection of local anesthetics in patients of lower abdominal surgeries.

Present study observation of improved quality of analgesia in DPE group as assessed by parturients satisfaction scale is in contrast to that of Gupta et al. as they observed no difference in quality of analgesia between two groups. Use of different size of needle (27G in present study and 25G in Gupta et al.), epidural catheter (18G in present study and 19G in Gupta et al. study) and labor analgesia technique (bolus with intermittent top up in present study and continuous epidural infusion in Gupta et al.) along with different demographic profile could have resulted in contrasting observation. All other authors used parameters other than patient's satisfaction scale to define quality of analgesia, so could not be compared with present study. The use of patient satisfaction score points towards better analgesia in DPE. This may be due to the earlier relief in pain; as the duration of analgesia and VAS after onset remained the same in both.

Present study observation of no difference in duration of analgesia of bolus dose, mean time to request for first top-up dose, requirement of Mean cumulative dose of ropivacaine, mean injection-delivery interval and haemodynamic parameters of Heart rate (HR), Systolic BP (SBP) and Distolic BP (DBP) is in accordance with findings of other authors.

Neither of the technique produced significant motor block in laboring parturients and didn't affected maternal expulsive efforts. One patient was delivered by cesarean section in DE group with indication being meconium stained liquor. All other patients, in both groups were delivered with spontaneous normal vaginal delivery with episiotomy.

Neonatal outcome was favorable in both groups. Only one neonate had APGAR score of 6 at 1 min and 8 at 5 min. All other neonates had APGAR score of ≥7 at 1 min. No adverse effect on neonatal status and no significant difference in APGAR score between groups of epidural and dural puncture epidural were also observed by Capiello et al.[2]

No parturient had any significant adverse event, including post dural puncture headache (PDPH), during course of labor analgesia in any group.

Limitations and future directions

In this study, epidural bolus with intermittent top up dose (on maternal request) was used as facilities for continuous epidural infusion and PCEA were not available. There was no imaging facility to directly visualize intrathecal spread of drugs so as to assess continuous functioning of dural hole. Functioning of dural hole after longer durations is not certain and possibility of dural puncture before every top up dose can be explored in future studies.

 Conclusion



After analyzing observations of present study, we arrived at the conclusion that although both techniques are efficacious for labor analgesia in primigravida, dural puncture epidural technique has the potential to fasten onset and improve quality of labor analgesia when compared with conventional epidural technique, while using intermittent boluses of 10 ml of Ropivacaine 0.2% with fentanyl (2 mcg/ml) on maternal request.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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