|Year : 2021 | Volume
| Issue : 2 | Page : 157-163
Comparison of ropivacaine (0.2%) and ropivacaine (0.125%) with 2 μg/ml fentanyl for epidural labor analgesia: A randomized controlled study
Kalyani Manasa Rapeti1, Santhisree Mulam2, B Sowbhagya Lakshmi2, Ankur Sharma3
1 Department of Anesthesiology, AIIMS, Jodhpur, Rajasthan, India
2 Department of Anesthesiology and Critical Care, Rangaraya Medical College, Kakinada, Andhra Pradesh, India
3 Department of Trauma and Emergency (Anesthesiology), AIIMS, Jodhpur, Rajasthan, India
|Date of Submission||05-Oct-2020|
|Date of Decision||18-Dec-2020|
|Date of Acceptance||03-May-2021|
|Date of Web Publication||29-Sep-2021|
Dr. Kalyani Manasa Rapeti
Department of Anesthesiology, AIIMS, Raipur
Source of Support: None, Conflict of Interest: None
Aim: The aim of this study was to determine the minimum effective local anesthetic concentration required to provide good analgesia with less consumption of opioids.
Objective: Among various labor analgesic techniques, epidural analgesia is the most effective form of analgesia. This study aimed to determine the minimum effective local anesthetic concentration required to provide good analgesia with less consumption of opioids. The objective of this study was to evaluate the efficacy of 0.125% and 0.2% ropivacaine, both with fentanyl 2 μg/ml for epidural labor analgesia.
Materials and Methods: A total of 50 term parturients of American Society of Anesthesiologists physical status Grade I and II with vertex presentation in active labor were randomly assigned to two groups, Group R1 and Group R2, which received 10 ml of 0.125% ropivacaine with injection fentanyl 2 μg/ml and 10 ml of 0.2% ropivacaine with fentanyl 2 μg/ml, respectively, as an initial bolus dose and intermittent top-up doses epidurally. Characteristics of the block, onset and duration of analgesia, and total analgesic requirements were noted. Pain and overall satisfaction scores were assessed with the Visual Analog Scale score. The maternal and fetal outcomes were recorded.
Results: Maternal demographic characteristics were comparable. Although both the concentrations are effective in providing optimal labor analgesia, decreasing the concentration of ropivacaine has resulted in an increased number of repetition of doses and thus an increased consumption of fentanyl. There were no significant differences between the two groups regarding motor block, hemodynamic, and neonatal outcomes.
Conclusion: We conclude that 0.2% ropivacaine was found superior in terms of faster onset, prolonged duration, lesser breakthrough pain requiring lesser top-ups, and hence a lesser consumption of opioids. Hence, we conclude that the use of 0.2% ropivacaine is superior to 0.125% ropivacaine with fentanyl.
Keywords: Epidural labor analgesia, fentanyl, intermittent boluses, ropivacaine
|How to cite this article:|
Rapeti KM, Mulam S, Lakshmi B S, Sharma A. Comparison of ropivacaine (0.2%) and ropivacaine (0.125%) with 2 μg/ml fentanyl for epidural labor analgesia: A randomized controlled study. Indian Anaesth Forum 2021;22:157-63
|How to cite this URL:|
Rapeti KM, Mulam S, Lakshmi B S, Sharma A. Comparison of ropivacaine (0.2%) and ropivacaine (0.125%) with 2 μg/ml fentanyl for epidural labor analgesia: A randomized controlled study. Indian Anaesth Forum [serial online] 2021 [cited 2022 May 24];22:157-63. Available from: http://www.theiaforum.org/text.asp?2021/22/2/157/326970
| Introduction|| |
The pain during childbirth is the most severe form of pain women will endure in their lifetime. It is often said that delivering a child is a rebirth for mothers. Painless labor, complete freedom from labor pain, is a dream of every parturient woman. Although labor analgesia has evolved from the 18th century with the use of ether to the present-day practice of regional techniques incorporating modern technology, it has not reached most of the general public in developing country like India, where labor pain is considered as a natural process and women have to bear through this phase, lack of support from relatives, lack of awareness and knowledge among both health professionals and parturients, nonacceptance, lack of resources for provision in major part of health-care facilities in southern India, and safety concerns.,, To fulfill their dream of pain-free labor, every woman should have an opportunity to undergo labor analgesia technique of her choice.
Of the various available labor analgesic techniques, epidural analgesia is the most effective form of analgesia. Several studies are being done to find the minimum concentration of local anesthetics required to provide good quality of analgesia in combination with various adjuvants and to minimize the risks associated with them, to facilitate patient ambulation with preservation of motor function and somatic sensation in the lower limbs resulting in better maternal satisfaction.
The objective of this study was to evaluate 0.125% versus 0.2% ropivacaine, with 2 μg/ml of fentanyl in epidural labor analgesia, regarding their sensory and motor block characteristics as well as the fetomaternal outcomes.
| Materials and Methods|| |
We conducted a randomized controlled comparative study with two concentrations of a drug for labor analgesia. Parturients of American Society of Anesthesiologists (ASA) physical status Grade I and II, age 20–30 years, primi- or multigravida with previous normal vaginal deliveries, with singleton pregnancy having vertex presentation in established labor with 3–5 cm cervical dilatation, and a reassuring fetal heart rate tracing were taken up for the study. Patient refusal, raised intracranial pressure, hypovolemia, fixed cardiac output diseases, progressive neurological weakness, severe coagulopathy, platelet count <75,000/mm3, any local skin site infection or allergy to local anesthetics, or spine abnormalities were excluded from the study. We included 25 patients in each group. The study population was randomized into two groups by a computer-generated randomization chart. The blinding was done by three different anesthesiologists: one blinded to study group, one blinded to drug, and one who have monitored.
After obtaining the institutional ethical committee approval and informed consent from the parturient, this study was undertaken in a tertiary care teaching hospital. The two groups were Group R1 and Group R2 each comprising 25 parturients. Group R1 received 10 ml of injection 0.125% ropivacaine with injection fentanyl 2 μg/ml as an initial bolus dose and intermittent top-up doses epidurally. This solution was prepared by taking 2.5 ml of 0.5% ropivacaine in a 10 ml syringe and adding 20 μg of fentanyl and diluting total volume to 10 ml with normal saline. Group R2 received 10 ml of 0.2% injection ropivacaine with fentanyl 20 μg as initial bolus dose and intermittent top-up doses epidurally. This solution was prepared by adding 20 μg of fentanyl to 0.2% ropivacaine.
After taking informed written consent, the preanesthetic evaluation was done. Participating parturients in active labor were preloaded with 500 ml of Ringer's lactate and were monitored with pulse oximetry, electrocardiogram, and noninvasive blood pressure. Then, the patient was placed in the left lateral position and epidural space was identified with an 18G Tuohy needle, using a loss of resistance technique to air, and a 20G multi-orifice catheter was inserted cranially with a minimum length of 5 cm in the epidural space. After negative aspiration for cerebrospinal fluid and blood, 3 ml of the study medication was administered as per allocated group. After monitoring for motor weakness for 5 min and ruling out the subarachnoid administration of drug, an additional 7 ml of the study medication was administered in increments of 2–3 ml. This dose was defined as the first initial bolus dose and time was noted.
The adequacy of analgesia was assessed 5 min after the last dose of administration and every 2 min thereafter for 15 min. The severity was rated on the Visual Analog Scale (VAS) score by the patient. Epidural analgesia was considered adequate if the score was ≤3 and if the patient still not satisfied with the reduction of pain, additional 10 ml of study medication (second initial dose) was administered, and analgesia was reassessed in the same manner. The onset of analgesia was defined as the time from the first bolus dose to the time of achieving a VAS ≤3, and if pain relief was not satisfactory even on the second initial dose after 15 min, they were labeled as ropivacaine failure and were withdrawn from the study. Motor block was assessed using Modified Bromage Score (Grade 0: ability to lift against resistance, 1: ability to flex knees but unable to flex leg, 2: ability to move feet but unable to flex knee, and 3: no movement at all) every 2 min for 15 min and then every 15 min. All parturients were given a trial walk to assess their ability to ambulate. Additional top-up doses of study drug were given on patient demand on pain with a minimum gap of 15 min between two subsequent doses. This procedure was continued until the delivery of the baby. Parturients were monitored for vital parameters such as heart rate and blood pressure that are recorded every 5 min for the first 30 min and every 15 min thereafter. Hypotension was defined as a mean arterial blood pressure of <20% from the baseline and was treated with a bolus of injection phenylephrine 100 μg intravenous (IV). Bradycardia was defined as a heart rate <50 bpm and was treated with bolus doses of injection atropine sulfate 0.6 mg IV. Fetal heart rate (FHR) was monitored using cardiotocograph, and any evidence of FHR deceleration was recorded. After delivery, neonates were assessed using the Apgar score at 1 and 5 min. Parturients were interviewed after delivery for satisfaction level. The duration of analgesia after the initial bolus dose was recorded as the primary outcome as it denotes the requirement for repetition of dose. The secondary outcomes studied were obstetric outcome, motor blockade, and drug consumption in each group.
In the present proposed study, it is required to compare the mean values of duration of analgesia in both the study groups. Chhetty et al., in their study, found the mean duration of analgesia with Group R1 as 72.25 ± 40.26 min and Group R2 as 132 ± 56.81 min. The sample size of 15 for the current study was derived from this study, using the formula for comparison of two means.
All statistical analyses were performed using IBM SPSS 20.0 (SPSS Inc., Chicago, IL, USA). Categorical variables in the two groups were compared using the Chi-square test with the calculation of the ∞2 statistic value and P value. Numerical variables are expressed as mean and standard deviation and were compared using the independent Student's t-test.
| Results|| |
Demographic data were comparable between both the groups in terms of age, weight, height, ASA class, and gravida status [Table 1]. Effective labor analgesia with no motor blockade was observed in both the groups with no failure rate. Initial VAS scores in both the groups were comparable (Group R1: 9.85 vs. Group R2: 9.92) [Table 2]. Effective analgesia, i.e., VAS ≤3, is achieved significantly earlier in Group R2 as compared to that in Group R1 (0–5 min vs. 5–15 min) [Figure 1]. The duration of analgesia after an initial bolus dose was 73.05 ± 27.24 and 126.45 ± 10.42 min in Groups R1 and R2, respectively (P < 0.001) [Table 3]. Mean VAS scores at 0, 5, 15, 30, 45, 60, 90, and 120 min following initial bolus were compared between both the groups [Figure 1]. The VAS score at 5 min after bolus in Group R1 was 4.8 and in Group R2 was 1.63, which was significantly lower, implying that there was comparatively rapid pain relief in Group R2. Forty percent (n = 10) of parturients in Group R1 did not require any top-up doses and delivered within the initial bolus dose duration, whereas up to 72% (n = 18) in Group R2 did not require any additional top-up doses till delivery. In Group R1, 28% required a single top-up dose, 20% required two top-up doses, and 12% required three top-up doses as compared to only 20% and 8% of parturients requiring two and three top-up doses, respectively, in Group R2 [Table 4].
In terms of the obstetric outcome among the parturient, 88% (n = 22) in Group R1 had normal vaginal delivery, 4% (n = 1) had forceps-assisted delivery, and 8% (n = 2) had cesarean delivery, whereas 76% (n = 19) had normal vaginal delivery, 8% (n = 2) by forceps-assisted delivery, and 16% (n = 4) had cesarean delivery in Group R2 [Table 5].
In Group R2, only 2 (8%) parturients required a single top-up dose, 5 (20%) required two top-up doses, and 18 (72%) had adequate analgesia until delivery after an initial bolus dose, whereas in Group R1, only 10 (40%) parturients could achieve effective analgesia until delivery after an initial bolus dose, 7 (28%) required a single top-up dose, and 5 (20%) required two top-ups and 3 (12%) requiring three top-up doses. Overall, a significantly higher number of parturients in Group R1 (n = 15, 60%) required one or more top-up doses (P < 0.001). The requirement for the initial top-up dose was earlier in Group R1 (58.15 ± 22.65 min) as compared to that in Group R2 (131.30 ± 57.11 min), P < 0.001. The mean number of top-up doses for each parturient was significantly higher in Group R1 (0.80 ± 0.65) than in Group R2 (0.05 ± 0.22), P < 0.001. The total amount of ropivacaine consumed in both the groups was comparable (P > 0.05) [Figure 2], but the total dose of fentanyl consumption was significantly higher in Group R1 (94.31 ± 4.93 μg) than in Group R2 (64.58 ± 2.83 μg) P < 0.001 [Figure 3] and [Table 6]. Maternal and fetal hemodynamic parameters were stable in both the groups [Figure 4]. Apgar scores were comparable between the two groups.
|Figure 4: Maternal systolic blood pressure in mmHg, comparison between the two groups|
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| Discussion|| |
In our study, we observed effective labor analgesia with no motor blockade and failure rate in both the groups. Prolonged duration of analgesia was achieved in Group R2 which can be attributed to the higher local anesthetic concentration when used with a similar concentration of fentanyl in both groups. Longer duration of analgesia decreases the top-up dose requirement and resulted in better maternal satisfaction by reducing breakthrough pain. Although Group R2 received a larger concentration of local anesthetic drug, the required number of top-up boluses was less in comparison to Group R1. Thus, the effective fentanyl consumption was less in Group R2 than in Group R1, where there is frequent repetition of top-up doses leading to higher effective consumption of fentanyl in this group.
Ropivacaine is a levo-isomer of local anesthetic, known to be associated with less systemic toxicity like cardiotoxicity when compared with bupivacaine, and has lesser motor blockade and superior analgesic effect, so it is preferred for providing epidural labor analgesia. Paddalwar et al., found that ropivacaine is safer with less systemic side effects like cardiotoxicity, and lesser motor blockade and better quality of sensory blockade compared to bupivacaine allowing the parturient to ambulate, when used as intermittent doses. Kumar et al., in their comparative study between ropivacaine and levobupivacaine in labor analgesia, concluded that levobupivacaine provided a better quality of analgesia with a caveat of increased rate of instrumental vaginal delivery than ropivacaine. Xueya Qian et al., in their study, compared the electromyographic activity among levobupivacaine, ropivacaine, and control groups using patient-controlled epidural analgesia (PCEA) during first stage of labor. They concluded that there was no suppressive action with ropivacaine, as seen in the control group, as well ropivacaine provided analgesic effect and satisfaction similar to levobupivacaine.
Previous studies also found that an addition of opioids like fentanyl to local anesthetics has improved the quality of analgesia.
In the present study, epidural labor analgesia was provided with 0.125% ropivacaine and 0.2% ropivacaine both mixed with fentanyl 2 μg/ml in 50 parturients. Adequate analgesia was achieved in both the groups with 100% success rate.
However, it was found that the onset of analgesia was quicker in Group R2 compared to Group R1 reason being greater concentration of the regimen compared to Group R1. Duration of analgesia of initial bolus was significantly longer in Group R2 compared to Group R1. Time of first top-up was significantly later in the 0.2% ropivacaine group compared to the 0.1% group, as observed by other studies. The requirement for top-up doses was less frequent in Group R2 and more frequent in Group R1 resulting in almost equal amount of ropivacaine consumption in both the groups (ropivacaine consumption in Group R1 was 58.23 ± 5.48 mg and in Group R2 was 65.88 ± 6.29 mg). However, because of frequent requirement of top-up doses in Group R1, there was significantly higher consumption of fentanyl, i.e., 94.31 ± 4.93 μg compared to 64.58 ± 2.83 μg in Group R2. The recent trend to operate with the least possible concentration of an adjuvant local anesthetic agent has resulted in a disadvantage such as the repeated need for top-up doses leading to higher opioid intake and higher occurrence of breakthrough pain requiring more workforce for frequent administration in busy labor wards. This increased consumption of opioids is also a concern as it can cause side effects such as nausea, pruritus, respiratory depression, and lower Apgar scores in neonates.
VAS score of 0.6 ± 1.06 was observed within 10 min in the study by Karhade and Sardesai where they used 0.2% ropivacaine with 25 μg fentanyl for the initiation, and similar results were observed in our Group R2, whereas in Group R1, the VAS score at 5 min was 4.8, which was similar to observations found in the study by Chhetty et al.
Various studies have reported that intermittent bolus dosing regimen is better than continuous infusion in terms of lower total drug consumption, lower incidence of instrumental and assisted delivery, and higher maternal satisfaction. This was explained by the fact that it mainly depends on the pressure generated by the speed of injectate during bolus, along with the volume of the drug administered, affecting the spread of the drug. Another study by Wong et al. found that infusion of the drug under low pressure as in continuous infusion causes predominate drug discharge from the proximal orifice of the epidural catheter whereas, when bolus is administered, it creates a high pressure during drug delivery and the drug discharges from the distal orifices of the catheter causing wider spread of the drug and thus improving the quality of analgesia.
Capogna et al., also in their randomized comparative study of programmed intermittent epidural bolus (PIEB) versus continuous epidural infusion (CEI) for labor analgesia using levobupivacaine 0.0625% with sufentanil 0.5 μg/mL, found that significantly higher percentage had motor block and instrumental delivery in the CEI group compared to the PIEB group. Furthermore, total drug consumption, number of patients requiring additional PCEA boluses, and mean number of PCEA boluses per patient were lower in the PIEB group.
Furthermore, in a meta-analysis of nine RCTs by George et al., where 344 subjects received CEI and 350 subjects received intermittent epidural boluses (IEBs), labor analgesia showed no statistical difference between IEB and CEI in the rate of cesarean delivery, duration of labor, or the need for anesthetic intervention. IEB has resulted in a small but statistically significant reduction in local anesthetic usage and better maternal satisfaction score.
Thus, with an intension to provide labor analgesia with lesser drug consumption and lesser breakthrough pain and to reduce the incidence of higher requirement for assisted and instrumental delivery and to improve maternal satisfaction, we opted to conduct IEB dosing regimen.
Choudhary et al. in their comparative study between the epidural analgesia group and the control group found that obstetric outcome was similar between the two groups with not much statistically significant difference. Furthermore, the neonatal outcome (Apgar score at 1 min and 5 min) was statistically similar in both groups (P = 0.569).
| Conclusion|| |
We conclude that both the concentrations of ropivacaine with fentanyl are effective in providing adequate epidural labor analgesia. However, 0.2% concentration of ropivacaine was found to give better results in terms of faster onset, prolonged duration of action, no significant motor blockade, and lesser breakthrough pain requiring lesser top-ups resulting in lesser consumption of opioids. Hence, this study concludes that the use of 0.2% ropivacaine with fentanyl provides superior quality blockade than 0.125% ropivacaine with fentanyl for labor analgesia.
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Conflicts of interest
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]