Programmed intermittent epidural bolus for labour analgesia during first stage of labour: a sequential allocation trial to determine the effective interval time between boluses of a fixed volume of 2.5 mL of bupivacaine 0.25% plus fentanyl 8 µg·mL-1

An Innovative Approach to Determine Programmed Intermittent Epidural Bolus Pump Settings for Labor Analgesia: A Randomized Controlled Trial

BACKGROUND

Three settings are required on a programmed intermittent epidural bolus (PIEB) pump for labor analgesia: the PIEB next bolus (PIEBnb), PIEB interval (PIEBi), and PIEB volume (PIEBv). The ideal settings for these parameters are still unknown. We hypothesized a mathematical modeling tool, response surface methodology (RSM), could estimate 3 PIEB pump parameters while balancing 3 clinically important patient outcomes simultaneously. The study objective was to use RSM to estimate PIEB settings (PIEBnb, PIEBi, and PIEBv) while maximizing maternal satisfaction, minimizing the need for clinician-administered boluses, and optimizing the ratio of delivered/requested patient-controlled epidural analgesia (PCEA) boluses simultaneously.

METHODS

With institutional ethics approval, a double-blind randomized trial was completed in a tertiary care labor and delivery center. Nulliparous, English-speaking American Society of Anesthesiologists (ASA) physical status II patients aged 18 to 45 years at full term, single gestation in vertex presentation, in spontaneous labor and ≤7 cm cervical dilation were included. Patients with comorbidities, contraindications to neuraxial analgesia, using chronic analgesics, <152 cm, or body mass index (BMI) >45 kg/m2 were excluded. After informed consent, labor analgesia was initiated using 10 mL ropivacaine 0.2% with 10 µg/mL fentanyl solution and PCEA (volume 6 mL every 10 minutes). Patients were randomized to predetermined PIEB settings. RSM identified 3 pump settings that represented a stationary point that best maximized or minimized 3 outcomes simultaneously: PCEA ratio (a ratio closest to 1), clinician bolus (optimal is 0), and maternal satisfaction (visual analog scale, 0-100, ideal response is ≥90).

RESULTS

Of 287 potential participants, 192 did not meet inclusion criteria or declined to participate, and 26 were withdrawn, leaving 69 patients for study inclusion. Using RSM, the suggested PIEB settings for all the primary study outcomes were as follows: PIEBnb = 29.4 minutes, PIEBi = 59.8 minutes, and PIEBv = 6.2 mL. These PIEB settings corresponded to the following clinical outcomes: maternal satisfaction at 93.9%, PCEA ratio at 0.77, and need for clinician bolus at 0.29. The dermatome sensory score was between T10 and T5 in 89% of the patients. The median lowest Bromage score was 4.

CONCLUSIONS

This novel study used a mathematical model to estimate PIEB pump settings while simultaneously maximizing 3 clinical outcomes. Equally weighted clinical outcomes prevent maximal outcome optimization and may not reflect patient priorities. Future studies or quality improvement endeavors could use RSM methodology to estimate PIEB pump settings targeting optimal values for a single clinical outcome of determined importance to parturients.

Optimum programmed intermittent epidural bolus interval time of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL: a randomized controlled trial

Background

The aim of our study was to administer adequate local anesthetic in programmed intermittent epidural bolus (PIEB) to avoid breakthrough pain and decrease the use of manual and PCEA boluses. We, therefore, conducted this study to determine the effective PIEB interval time between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL in 90% of subjects (EI90), without the use of patient-controlled epidural analgesia (PCEA).

Methods

A total of 80 subjects were included in the final statistical analysis from 23 August 2022 to 22 November 2022. The subjects were randomly assigned to one of four different PIEB time intervals: 40, 50, 60, and 70 min (groups 40, 50, 60, and 70), respectively. The primary outcome was the effective epidural labor analgesia, defined as no use of PCEA bolus or a manual bolus until the end of the first stage of labor or within 6 hours after loading dose administration. The PIEB EI90 (95% CI) between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL was estimated using probit regression.

Results

The effective PIEB interval time between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL in 90% of subjects without the use of PCEA was 45.4 (35.5-50.5) minutes using probit regression. No statistical differences were found in the proportion of subjects with Bromage score > 0, hypotension, pruritus, nausea, and vomiting between groups. However, the highest sensory block (pinprick) in the 40-min group was significantly higher than that in the other groups.

Conclusion

The estimated value for EI90 for PIEB between boluses of ropivacaine 0.0625% with dexmedetomidine 0.4 μg/ml at a fixed volume of 10 mL using probit regression was 45.4 (35.5-50.5) minutes. Furthermore, future studies are warranted to be established to determine the optimal parameters for different regimens in clinical practice.

Programmed intermittent epidural bolus in maintenance of epidural labor analgesia: a literature review

Programmed intermittent epidural bolus (PIEB), administered by the infusion pump programmed to deliver boluses of epidural solution at certain intervals, is gradually gaining more attention as a technique to maintain the labor analgesia in recent years. Many studies find that it may have some advantages when compared with other methods. However, its exact effectiveness and optimal regimen are still unclear. We conducted a literature search in PubMed, Web of Science, and Cochrane Database of Systematic Reviews for studies published between January 2010 and June 2022. Of the 263 publications identified, 27 studies were included. The purpose of this review is to discuss the effects of PIEB with continuous epidural infusion (CEI) and patient-controlled epidural analgesia (PCEA) in maintenance of epidural labor analgesia on labor outcomes and elucidate the latest research progress of implementation strategies.

High Dosage of Patient-Controlled Epidural Analgesia (PCEA) with Low Background Infusion during Labor: A Randomized Controlled Trial

BACKGROUND

Patient-controlled epidural analgesia (PCEA) is well documented; however, it is unclear whether a high dosage of PCEA with a low dosage of background infusion during labor can be a safe and effective application.

METHODS

Group LH was administered a continuous infusion (CI) of 0.084 mL/kg/h with PCEA of 5 mL every 40 min. Group HL was given a CI of 0.028 mL/kg/h and PCEA of 10 mL every 40 min; Group HH was given a CI of 0.084 mL/kg/h and PCEA of 10 mL every 40 min. The primary outcomes were VAS pain score, the number of supplemental boluses, incidence of pain outbreaks, drug dose for pain outbreaks, PCA times, effective PCA times, anesthetic consumption, duration of analgesia, duration of labor and delivery outcome. Secondary outcomes included adverse reactions such as itching, nausea and vomiting during analgesia and neonatal Apgar scores 1 min and 5 min after birth.

RESULTS

A total of 180 patients, 60 in each group were randomly assigned to one of three groups included group LH, group HL or group HH. The VAS scores were obviously decreased in HL group and HH group in comparison with LL group at 2 h after analgesia and the time point of full cervical dilation and delivery of baby. The time for third stage of labor in HH group was increased compared with LH group and HL group. Incidence of pain outbreaks in LH group was obviously increased compared with HL and HH group. The effective PCA times in HL group and HH group were remarkably reduced compared with those in LH group.

CONCLUSIONS

High dose of PCEA with a low background infusion can reduce effective PCA times, incidence of outbreak pain and the total amount of anesthetics without diminishing analgesia effects. However, high dose of PCEA with a high background infusion can enhance analgesia effect but increase the third stage of labor, instrumental delivery ratio and the total amount of anesthetics.

Optimization of programmed intermittent epidural bolus volume for different concentrations of ropivacaine in labor analgesia: a biased coin up-and-down sequential allocation trial

Background and objectives

To date, programmed intermittent epidural bolus (PIEB) has been widely used in obstetric analgesia, while no optimal PIEB regimen has been proposed. This study aimed to assess effective analgesia in 90% of women (EV90) with different concentrations of ropivacaine (0.075% and 0.1%) combined with 0.5 µg/mL sufentanil, at an interval of 40 min using the biased coin design-up-and-down method (BCD-UDM), and to explore whether there is a difference in EV90 with the increase of ropivacaine concentration.

Methods

In total, 103 primiparous women were assigned to two groups, including group A (n = 52) and group B (n = 51). Parturients in group A were treated with 0.075% ropivacaine and 0.5 µg/mL sufentanil, while those in group B were treated with 0.1% ropivacaine and 0.5 µg/mL sufentanil. Used the biased coin up-and-down sequential allocation method to determine the EV90. The secondary outcomes were sensory block level, motor block, and adverse events (hypotension, urinary retention, and pruritus).

Results

The results revealed that EV90 was 10 mL (95% confidence interval (CI):8.03–11.54) in group A, and EV90 was 9 mL (95% CI:7.49–10.51) in group B by the isotonic regression method. The highest level of the sensory block was T8, and the lowest was T12. No case of hypotension was recorded,and only 4 parturients complained of motor block.

Conclusion

With an interval of 40 min, the optimal PIEB bolus volume of 0.075% ropivacaine and 0.5 µg/mL sufentanil was 10 mL, 0.1% ropivacaine and 0.5 µg/mL sufentanil was 9 mL. Moreover, the PIEB volume decreased along with the higher concentration of ropivacaine.

Trial registration

ChiCTR registration number: ChiCTR2000040917. Registration date: December 15, 2020.

Programmed intermittent epidural bolus for labour analgesia: a randomized controlled trial comparing bolus delivery speeds of 125 mL·hr-1 versus 250 mL·hr-1

PURPOSE

Programmed intermittent epidural bolus (PIEB) provides better analgesia for labour pain than continuous epidural infusion does. Nevertheless, commonly used PIEB regimens are associated with high sensory block. We hypothesized that a PIEB technique with slower bolus delivery speed would produce lower sensory levels.

METHODS

We recruited term nulliparous women with singleton pregnancies during the first stage of labour. All participants had an American Society of Anesthesiologists Physical Status score of II-III, had epidural catheters placed at L3/4, and had epidural analgesia maintained with PIEB 10 mL every 40 min using 0.0625% bupivacaine with fentanyl 2 µg·mL^-1. Women were randomized to receive PIEB delivered at 250 mL·hr^-1 (G250) or 125 mL·hr^-1 (G125). The study was completed six hours after the loading dose or at full cervical dilatation, whichever occurred first. The primary outcome was the presence of sensory block to ice ≥ T6 in at least one assessment during the study period (maximum six hours).

RESULTS

We analyzed data from 90 women. The proportion of women presenting sensory block ≥ T6 at any time was not different between G125 and G250 groups (60.0% vs 64.4%; difference, -4.4%; 95% confidence interval [CI], -24.5 to 15.6; P = 0.66). The median [interquartile range] highest sensory block level was also not different between G125 and G250 groups (T6 [T7-T5] vs T5 [T7-T5], P = 0.39). Women in the G125 group had a lower incidence of hypotension than women in the G250 group did (11.1% vs 33.3%; difference, -22.2%; 95% CI, -38.8 to -5.67; P = 0.01). Quality of analgesia and patient satisfaction were not different between groups.

CONCLUSION

The maintenance of epidural analgesia with a PIEB delivery speed of 125 mL·hr^-1 did not produce lower sensory block levels when compared with 250 mL·hr^-1. The slower injection speed regimen was associated with lower incidence of hypotension, but this secondary finding warrants confirmation in a future trial.

TRIAL REGISTRATION

www.ClinicalTrials.gov (NCT03236298); registered 1 August 2017.

A comparison of maternal fear of childbirth, labor pain intensity and intrapartum analgesic consumption between primiparas and multiparas: A cross-sectional study

Objectives

To describe and compare fear of childbirth and in-labor pain intensity between primiparas and multiparas and explore the association between the amount of actual pain relief and fear of childbirth.

Methods

A convenience sampling method was used. A total of 260 women undergoing spontaneous or induced labor, including 97 primiparas and 163 multiparas, were recruited in a large academic specialized hospital in Guangzhou, China, from February 2018 to August 2019. The clinical data of maternal and neonatal were extracted from a structured electronic medical record system. Other demographic information, such as employment and family monthly income, was collected by a questionnaire. The Numeric Rating Scale (NRS) and the Chinese version of the Childbirth Attitude Questionnaire (C-CAQ) were applied to assess maternal in-labor pain intensity and fear of childbirth. The analgesic consumption and the frequency of manual boluses as rescue analgesia were stored and collected from the analgesia pump.

Results

Eighty-two (84.5%) primiparas and ninety-nine (60.7%) multiparas received epidural analgesia (P < 0.001). In the epidural subgroup, the primiparous average fear of childbirth (36.46 ± 10.93) was higher than that of the multiparas (32.06 ± 10.23) (P = 0.007). However, multiparas reported more intense in-labor pain [8.0 (8.0, 9.0) vs. 8.0 (7.0, 8.0)], had more successful manual boluses per hour [2.68 (1.65, 3.85) vs. 1.77 (0.90, 2.47)], more hourly analgesic consumption [23.00 (16.00, 28.25) vs. 17.24 (11.52, 21.36) mL] and more average analgesic consumption [0.35 (0.24, 0.45) vs. 0.26 (0.19, 0.35) mL/(h·kg)] than the primiparas (P < 0.05). Spearman's correlation analysis showed that the maximum in-labor pain was weakly positively correlated with fear of childbirth (r = 0.09) (P < 0.05), hourly analgesic consumption (r = 0.16) (P < 0.01) and average analgesic consumption (r = 0.17) (P < 0.05). No statistically significant association was uncovered between analgesic consumption and maternal fear of childbirth.

Conclusions

Fear of childbirth is a potential predictor of labor pain intensity. Further study is needed to explore its role and value in pain management during delivery. Parity is not a determinant of pain relief use and should not be a preconceived preference of obstetric care team members to determine the distribution of epidural analgesia, especially when analgesia resources are insufficient.