Parturient Controlled Epidural Analgesia with and without Basal Infusion of Ropivacaine and Fentanyl: A Randomized Trial.

INTRODUCTION: Parturient controlled epidural analgesia (PCEA) is an established method of providing safe and effective labor analgesia.
OBJECTIVE: The aim of this single-blind, randomized controlled trial was to compare the efficacy of PCEA with or without basal infusion (BI) of ropivacaine and fentanyl for the effective management of labor pain associated with normal vaginal delivery.
MATERIALS AND METHODS: A total of 78 nulliparous parturients with vertex presentation at term and with cervical dilatation of 3-5 cm demanding for epidural analgesia (EA) were enrolled in the study. EA was initiated and maintained with ropivacaine 0.125% and fentanyl 2 μg/mL. Following an initial epidural loading volume of 8-10 mL, parturients were randomly allocated in two groups of 39 each. PCEA group received bolus of 5 mL at 200 mL/h with lockout interval of 15 min and with maximum volume of local anaesthetic was 20 mL/h and PCEA + BI group - receiving added BI rate of 5 mL/h along with same programmed parameters of PCEA pump.
RESULTS: No statistically significant difference was observed between the groups in terms of demographic characteristics, duration of labor, delivery methods, maternal satisfaction as well as Apgar score. Mean demand bolus in group PCEA + BI was 0.39 ± 0.59, whereas in group PCEA was 3.31 ± 0.77 (P < 0.05). Mean volume of drug used in group PCEA + BI was 25.57 ± 2.75 mL, while in group PCEA was 22.42 ± 4.56 mL (P = 0.0005). In PCEA + BI group, Visual Analog Scale (VAS) score was 0.07 ± 0.35 at 60 min and 0.06 ± 0.33 at 120 min, whereas in PCEA group, VAS was 0.32 ± 0.62 at 60 min and 0.26 ± 0.50 at 120 min (P = 0.05), respectively.
CONCLUSION: BI when added to PCEA, it significantly reduces breakthrough labor pain and demand boluses without prolonging labor duration but at the cost of increased requirement of drug volume when compared to PCEA only group. Copyright:

INTRODUCTION

The aim of labor analgesia is to provide high quality and rapid onset pain relief along with minimal maternal and fetal side effects without affecting duration and outcome of labor. Multiple modalities including epidural analgesia (EA) have been advocated for the management of labor pain.

Parturient controlled EA (PCEA) is a form of EA which is safe and effective method for managing labor pain since its inception in 1988 by Gambling.[1] PCEA allows parturient autonomy in the control of the analgesia as it offers the ability of dose titration, thereby reducing total drug consumption along with reduced incidence of motor blockade and better maternal satisfaction.

Epidural opioids[23] with local anesthetic not only reduce the requirement of local anesthetics[456] but also subsequently provides better maternal hemodynamic stability along with diminished chances of motor blockade. Among opioids, fentanyl is highly potent with a rapid onset of action (10 min for epidural) and relatively short duration of action (2–4 h for epidural). Among local anesthetics, ropivacaine is preferred over other local anesthetics for EA because of its ability to produce differential sensory blockade and dose-dependent motor blockade[7] with a wide therapeutic window.

We designed this single-blind randomized study to evaluate and compare the efficacy of PCEA with or without basal infusion (BI) of ropivacaine and fentanyl for effective management of labor pain associated with normal vaginal delivery.

MATERIALS AND METHODS

Following approval of the Institutional Ethics Committee (F.1/Acad/MC/JU/17/17571) and informed written consent, 78 primigravida, who requested analgesia for childbirth at term with singleton and vertex presentation of the fetus were included in this prospective randomized single-blinded study. Patients were assessed and approved by obstetrician for normal vaginal delivery.

The exclusion criteria were multiparty, preeclampsia, eclampsia, pregnancy-induced hypertension, multiple gestation, any contraindication to regional anesthesia such as a bleeding diathesis, and need for cesarean section during the study.

With the parturient lying on her left side, following local anesthetic infiltration of skin, 18G Touhy needle was introduced in the L3-4 or L2-3 epidural space by using loss of resistance to normal saline technique and 20G epidural catheter was threaded and secured. After confirming the absence of a return of blood or cerebrospinal fluid in the catheter, a test dose of 3 mL of 2% lignocaine with 1:200,000 epinephrine was administered to exclude intravenous or subarachnoid catheter placement. All parturients received bolus of 8–10 mL according to height of parturients and level of analgesia.

Thereafter using computer-generated random numbers, parturients were randomly assigned in two groups comprising 39 parturients each; group PCEA + BI and group PCEA.

A previously programmed PCEA device (T34 L-PCATM4HANSRAJ NAYYAR Medical, INDIA) was connected and started 30 min later. All parturients were given the control button and were made well conversant about the use of PCEA pump and numerical rating score with scores ranging from 0 to 10 (0 = no pain and 10 = worst pain imaginable). Thereafter, patients were instructed to initiate a bolus dose.

Programmed parameters of the PCEA pump were: Bolus of 5 mL, lockout interval 15 min, with BI rate of 5 mL/h, and maximum volume of local anesthetic was 20 mL/h. All boluses in the PCEA group and PCEA + BI group were delivered with the same rate of 200 mL/h. Drug used was ropivacaine 0.125% and fentanyl 2 μg/mL.

In the PCEA + BI group, the pump was programmed to deliver continuous BI of ropivacaine 0.125% and fentanyl 2 μg/mL at the rate of 5 mL/h, with the possibility of using an on demand button and other programmed parameters. In PCEA group, programmed parameters of PCEA pump were same but without BI.

All the parameters were recorded every 5 min for first 30 min, every 30 min for 60 min, and then every hour till the delivery of the baby. It included parturients vital parameters (heart rate [HR], mean arterial pressure and oxygen saturation), fetal HR, degree of sensory block (via pin-prick method), degree of pain relief (via Visual Analog Scale), and degree of motor blockade (via modified Bromage scale as used by Breen et al.[8]).

Assessment of cervical dilatation and effacement was done by the attending obstetrician according to their protocol. APGAR score of neonate was assessed at 1 and 5 min interval following delivery. Side effects such as nausea and vomiting were noted and treated accordingly. At last, maternal satisfaction with analgesia was assessed following delivery.

Parameters such as duration of labor analgesia, i.e., time from epidural insertion to delivery and number of demand topup along with total drug consumption were also noted in both group. At the end, following delivery and recording of above parameters, epidural catheter was removed just before shifting of the parturient to postnatal ward.

Statistical analysis

We calculated that 38 patients in each group would be needed to detect an intergroup difference (α = 0.05, β = 0.2) with power of 80% and a significance level of 5%, and this power analysis was based on results of a Bermerich D. H.[9] et al. study. Data were analyzed by using SPSS (IBM) for Windows version 22.0. USA. Statistical comparison was carried out by using the Chi-square or Fisher's exact test for nonparametric and independent Student's t-test for parametric data. Numerical variables were presented as frequency, percentage, and mean ± standard deviation and categorical variables presented as frequency (%). A value of P < 0.05 and P < 0.001 was taken as significant and highly significant, respectively.

RESULTS

Demographical features such as height, weight, and age were comparable in both groups. There was also no statistical difference in terms of cervical dilation as well as cervical effacement [Table 1].

Table 1

Characteristics of parturients including demography

	Mean±SD		P
	PCEA plus background infusion PCEA + BI (n=38)	PCEA (n=38)
Age (years)	22.94±2.64	22.71±2.84	0.708
Height (cm)	158.44±2.21	157.63±2.31	0.121
Weight (kg)	59.10±1.95	59.07±1.90	0.952
Cervical dilation (cm)	4.46±0.49	4.47±0.50	0.99
Cervical effacement (%)	77.63±11.95	81.31±11.43	0.173

*Values are mean±SD (95% confidence interval). CI=Confidence interval, SD=Standard deviation, PCEA=Parturient controlled epidural analgesia, BI=Basal infusion

Mean duration of labor analgesia, i.e., time from epidural insertion to delivery in group PCEA + BI was 175.44 ± 21.70 and 173.55 ± 20.62 in group PCEA. This difference was not significant as also demonstrated by P = 0.697.

Maximum height of sensory blockade was achieved in both groups, range being T6 to T8 dermatome. Majority of parturients in both groups achieved a sensory blockade up to T8 dermatome.

While comparing total number of demand boluses in both groups during entire duration of labor analgesia, we found that mean of demand boluses in group PCEA + BI was 0.39 ± 0.59 mL and 3.31 ± 0.77 mL in group PCEA [Table 2]. This difference was both statistical and clinical significant as more demand bolus was required in PCEA group patients [Figure 1].

Table 2

Number of demand top-up

Top-up	PCEA + BI (n=38)	PCEA (n=38)	P
0	25	0	<0.0001
1	11	0	0.0004
2	2	5	0.430
3	0	18	<0.0001
4	0	13	<0.0001
5	0	2	0.493
Mean±SD	0.39±0.59	3.31±0.77	<0.0001

SD=Standard deviation, PCEA=Parturient controlled epidural analgesia, BI=Basal infusion

Figure 1

Showing total number of demand boluses in both groups

When we compared total drug used in both groups, we found that the mean of group PCEA + BI was 25.57 ± 2.75 while group PCEA mean was 22.42 ± 4.56. This difference was found to be highly significant as P value was <0.001. This demonstrated that more drug was used by group PCEA + BI patients.

When the Visual Analog Scale (VAS) was observed, we found statistical significant (P < 0.05) difference at 60 min and 120 min [Table 3]. The rest all other time both groups were comparable in terms of VAS values.

Table 3

Mean changes in the Visual Analog Scale in both groups

VAS	PCEA + BI (n=38)	PCEA (n=38)	P
Baseline	7.39±0.67	7.10±0.76	0.085
5 min	3.86±0.96	3.55±0.64	0.097
10 min	0.71±0.80	0.71±0.51	0.999
15 min	0.00±0.00	0.00±0.00	NA
20 min	0.00±0.00	0.00±0.00	NA
25 min	0.00±0.00	0.00±0.00	NA
30 min	0.00±0.00	0.00±0.00	NA
60 min	0.07±0.35	0.33±0.62	0.040
120 min	0.06±0.33	0.29±0.50	0.043
180 min	1.03±0.82	0.00±0.00	NA

NA=Not applicable, PCEA=Parturient controlled epidural analgesia, BI=Basal infusion, VAS=Visual Analog Scale

APGAR scores in both groups were comparable at both 1 min and at 5 min intervals. While observing for side effects in terms of nausea and vomiting, no significant difference was observed in between groups (P > 0.05).

No significant difference was observed in terms of patients’ acceptance in both groups.

Most of the patients in both groups had excellent acceptance of labor analgesia [Figure 2].

Figure 2

Showing patients acceptance in both groups

DISCUSSION

Our study results demonstrated that both PCEA plus BI and demand-only PCEA using 0.125% ropivacaine combined with 2 μg/mL fentanyl were effective in the management of labour pain and resulted in high maternal satisfaction. However, the use of continuous background infusion in PCEA + BI group significantly reduced breakthrough pain, but at the same time, there was increased local anesthetic (L. A.) consumption. There was no difference in sensory or motor block characteristics, neonatal outcome, or adverse events between groups.

Our study results were similar to Bremerich et al.[9] where they demonstrated that PCEA using ropivacaine with sufentanil with a BI appears to be more effective in lowering pain scores of parturient compared with the demand-only PCEA. However, in contrary to our study, they obtained similar results without increasing the total amount of L. A. used.

In another study carried by Lim et al.,[10] they found that demand-only PCEA (5-mL bolus, 15-min lockout interval) resulted in less local anaesthetic consumption but an increased incidence of breakthrough pain, higher pain scores, and shorter duration of effective analgesia when compared with PCEA with background infusion (5 mL bolus, 10–12-min lockout interval, and 5–10 mL/h infusion).

Till date, only few studies[11121314] have compared efficacy, total epidural drug consumption, and physician-administered supplemental bolus application during labor in PCEA plus continuous BI versus demand-only PCEA. However, the role of a continuous background infusion is still controversial, and contradictory results have been obtained.

Like all other previous studies, parturients of both groups were comparable in terms of maternal age, weight, height, cervical dilation, and effacement. All the demographic and obstetric characteristics were similar between the two groups.

Pain scores during labor and delivery

In 2006, Ocampo et al.[15] compared PCEA alone to PCEA with 5 or 10 mL/h of continuous BI of 0.125% bupivacaine and 2 μg/mL of fentanyl for the maintenance of labor analgesia. They reported reduced incidence of breakthrough pain in patients receiving PCEA + BI.

Another typical concern in employing demand-only PCEA is an increase in breakthrough pain episodes. In that sense, continuous infusion should cover the period between a bolus and the next. In the trial designed by Lim et al.,[10] the incidence of breakthrough pain was defined as a failure of the PCEA to provide an adequate pain relief (VAS > 3), with the necessity for the attending anesthesiologist to inject a top-up bolus of LA.

In our study, PCEA plus continuous BI significantly reduced the incidence of pain peaks during labor and delivery, but PCEA only group had a significant number of parturients with breakthrough pain.

Demand bolus doses and total drug dose administered

When a bolus-based PCEA is used, a common finding is an increased number of self-administered boluses. This can be considered as an adequate use of the PCEA by the patients who control their labor pain, according to their threshold of pain and the labor stage. In our study, demand bolus in form of 0.125% ropivacaine + fentanyl 2 μg/mL taken by parturients were more in PCEA only group, and the difference was significant in between the groups. Similar findings were observed in the study carried by Brogly et al.[16]

In the present study, we observed that the addition of a continuous BI to PCEA significantly increases the hourly and cumulative drug consumption. Similar findings were also observed in the study carried by Boselli et al.[13]

Sensory and motor block

Most parturients in both groups titrated their sensory block level up to T8, in contrast to other methods of epidural pain relief during labor (e.g., top-ups, CEI), where higher sensory levels were observed. Till date, no study has found any significant difference in the cephalad spread when PCEA plus continuous BI and demand-only PCEA have been compared.

In the present study, motor block was assessed using a Modified Bromage scale for entire period of analgesia. There was no weakness in any parturient of both group and the studies done by Vallejo et al.[17] and Bremerich et al.[9] also showed no difference in the number of patients with no motor weakness.

Satisfaction score

Maternal satisfaction was also high and equivalent in both groups. It was surprising that despite having distressing pain sometimes during labor, satisfaction was high. Similar results were also observed in a study carried by Bremerich et al.[9] and Srivastava et al.[18]

Duration and outcome of labor

As far as the duration of labor was considered, there was no significant difference between both groups, so the use of a BI did not apparently affect the duration of labor in our study. Compared to PCEA plus BI, demand-only PCEA has not proved to be superior in increasing vaginal delivery rate or reducing labor duration. Similar findings were found in studies carried by Boselli et al.[13] and Bremerich et al.[9]

Fetal heart rate and APGAR score

Till date, there has been no evidence of fetal compromise or adverse neonatal outcome in any PCEA studies comparing different anesthetic solutions and administration regimen.[111319] In our study, APGAR and FHR were employed to assess new-borns, and there was no evidence of neonatal depression or the need of assisted ventilation in any neonate.

Side effects

No serious side effects or equipment dysfunction have been described during labor in PCEA with or without background infusion. Despite this low incidence of problems, we believe that quality of analgesia, progress of labor, extent of sensory and motor block, maternal hemodynamics, and fetal HR tracings should be monitored throughout EA to find out any adverse effects. However, in the present study, LA toxicity was not observed in either group. The incidence of side effect was similar in both groups.

CONCLUSION

On the basis of our results, we found that both PCEA plus continuous BI and demand-only PCEA using 0.125% ropivacaine plus 2 μg/mL fentanyl were safe, effective, and gave the women a feeling of “self-control” on pain. PCEA plus continuous background infusion significantly reduced breakthrough pain during labor and reduced demand bolus requirement without prolonging the labor duration and motor block. There was no difference in sensory or motor block characteristics and mode of delivery but more drug was required in PCEA + BI group. Therefore, it is difficult to convincingly prove that which method is superior to other in a relatively small sample size. Hence, we conclude that each center should select a technique which is suitable based on the availability of anesthetist, equipment, and expectation of parturient as well as obstetrician.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.