Automated regular boluses for epidural analgesia: a comparison with continuous infusion

Influence of different volumes and frequency of programmed intermittent epidural bolus in labor on maternal and neonatal outcomes: A systematic review and network meta-analysis

STUDY OBJECTIVE

In labor, programmed intermittent epidural bolus (PIEB) can be defined as the bolus administration of epidural solution at scheduled time intervals. Compared to continuous epidural infusion (CEI) with or without patient controlled epidural analgesia (PCEA), PIEB has been associated with decreased pain scores and need for rescue analgesia and increased maternal satisfaction. The optimal volume and dosing interval of PIEB, however, has still not been determined.

DESIGN

Systematic review and network meta-analysis registered with PROSPERO (CRD42022362708).

SETTINGS

Labor.

PATIENTS

Pregnant patients.

INTERVENTIONS

Central, CINAHL, Global Health, Ovid Embase, Ovid Medline and Web of Science were searched for randomized controlled trials that examined pregnant patients in labor who received CEI or PIEB with or without a PCEA component. Network meta-analysis was performed with a frequentist method, facilitating the indirect comparison of PIEB with different volumes and dosing intervals through the common comparator of CEI and substituting or supplementing direct comparisons with these indirect ones. Continuous and dichotomous outcomes were presented as mean differences and odds ratios, respectively, with 95% confidence intervals. The risk of bias was evaluated using the Cochrane risk of bias 2 tool.

MAIN RESULTS

Overall, 30 trials were included. For the first primary endpoint, need for rescue analgesia, PIEB delivered at a volume of 4 ml and frequency of 45 min (4/45) was inferior to PIEB 8/45 (OR 3.55; 95% CI 1.12-11.33), PIEB 10/60 was superior to PIEB 2.5/15 (OR 0.36; 95% CI 0.16-0.82), PIEB 4/45 (OR 0.14; 95% CI 0.03-0.71) and PIEB 5/60 (OR 0.23; 95% CI 0.08-0.70), and PIEB 5/30 was not inferior to PIEB 10/60 (OR 0.61; 95% CI 0.31-1.19). For the second primary endpoint, maternal satisfaction, no differences were present between the various PIEB regimens. The quality of evidence for these multiple primary endpoints was low owing to the presence of serious limitations and imprecision. Importantly, PIEB 5/30 decreased the pain score at 4 h compared to PIEB 2.5/15 (MD 2.45; 95% CI 0.13-4.76), PIEB 5/60 (MD -2.28; 95% CI -4.18--0.38) and PIEB 10/60 (MD 1.73; 95% CI 0.31-3.16). Mean ranking of interventions demonstrated PIEB 10/60 followed by PIEB 5/30 to be best placed to reduce the cumulative dose of local anesthetic, and this resulted in an improved incidence of lower limb motor blockade for PIEB 10/60 in comparison to CEI (OR 0.30; 95% CI 0.14-0.67). No differences in neonatal outcomes were found. Some concerns were present for the risk of bias in two thirds of trials and the risk of bias was shown to be high in the remaining one third of trials.

CONCLUSIONS

Future research should focus on PIEB 5/30 and PIEB 10/60 and how the method of analgesia initiation, nature and concentration of local anesthetic, design of epidural catheter and rate of administration might influence outcomes related to the mother and neonate.

Programmed intermittent epidural bolus as an ideal method for labor analgesia: a randomized controlled trial

BACKGROUND

Although programmed intermittent epidural bolus (PIEB) is effective for labor analgesia, an appropriate flow rate has not been established. Therefore, we investigated the analgesic effect based on different epidural injection flow rates.

METHODS

Nulliparous women scheduled for spontaneous labor were enrolled in this randomized trial. After injection of intrathecal 0.2% ropivacaine 3 mg with fentanyl 20 μg, participants were randomized to three study groups. Epidural analgesics, 10 ml during one hour, were administered with patient controlled epidural analgesia as follows (0.2% ropivacaine 60 ml, fentanyl 180 μg, and 0.9% saline 40 ml): continuous (n = 28, 10 ml/h for continuous infusion), PIEB (n = 29, 240 ml/h for bolus infusion of 10 ml), or manual (n = 28, 1200 ml/h for bolus injection of 10 ml). The primary outcome was hourly consumption of the epidural solution. The time interval between labor analgesia and the first breakthrough pain was investigated.

RESULTS

The median (Q1, Q3) hourly consumption of epidural anesthetics was significantly different among the groups (continuous: 14.3 [8.7, 16.9] ml, PIEB: 9.4 [6.2, 9.8] ml, manual: 8.6 [7.6, 9.9] ml; P < 0.001). The time to breakthrough pain for the PIEB group was longer than that for the other groups (continuous: 78.5 [35.8, 185.0] min, PIEB: 200.0 [88.5, 441.5] min, manual: 60.5 [37.3, 162.0] min, P = 0.027).

CONCLUSIONS

PIEB, with a low-flow rate, provided more adequate labor analgesia than a continuous epidural infusion or manual injection with a high-flow rate.

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.

Automated mandatory bolus versus basal infusion for maintenance of epidural analgesia in labour

BACKGROUND

Epidural analgesia is often used for pain relief during labour and childbirth, and involves administration of local anaesthetics (LA) into the epidural space resulting in sensory blockade of the abdomen, pelvis, and perineum. Epidural opioids are often co-administered to improve analgesia. Administration of epidural medications can be accomplished by basal infusion (BI) or automated mandatory bolus (AMB). With BI, medications are administered continuously, while AMB involves injecting medications at set time intervals. Patient-controlled epidural analgesia (PCEA) on top of AMB or BI enables patients to initiate additional boluses of epidural medications.  The superior method of delivering epidural medications would result in lower incidence of pain requiring anaesthesiologist intervention (breakthrough pain). Also, it should be associated with lower incidence of epidural-related adverse effects including caesarean delivery, instrumental delivery (use of forceps or vacuum devices), prolonged duration of labour analgesia, and LA consumption. However, clear evidence of the superiority of one technique over the other is lacking. Also, differences in the initiation of epidural analgesia such as combined spinal-epidural (CSE) (medications given into the intrathecal space in addition to the epidural space) compared to epidural only, and medications used (types and doses of LA or opioids) may not have been accounted for in previous reviews.  Our prior systematic review suggested that AMB reduces the incidence of breakthrough pain compared to BI with no significant difference in the incidence of caesarean delivery or instrumental delivery, duration of labour analgesia, and LA consumption. However, several studies comparing AMB and BI have been performed since then, and inclusion of their data may improve the precision of our effect estimates.

OBJECTIVES

To assess the benefits and harms of AMB versus BI for maintaining labour epidural analgesia in women at term.

SEARCH METHODS

We searched CENTRAL, Wiley Cochrane Library), MEDLINE, (National Library of Medicine), Embase(Elseiver), Web of Science (Clarivate), the WHO-ICTRP (World Health Organization) and ClinicalTrials.gov (National Library of Medicine) on 31 December 2022. Additionally, we screened the reference lists of relevant trials and reviews for eligible citations, and we contacted authors of included studies to identify unpublished research and ongoing trials.

SELECTION CRITERIA

We included all randomised controlled studies that compared bolus dosing AMB with continuous BI during epidural analgesia. We excluded studies of women in preterm labour, with multiple pregnancies, with fetal malposition, intrathecal catheters, those that did not use automated delivery of medications, and those where AMB and BI were combined.

DATA COLLECTION AND ANALYSIS

We used standard methodology for systematic review and meta-analysis described by Cochrane. Primary outcomes included: incidence of breakthrough pain requiring anaesthesiologist intervention; incidence of caesarean delivery; and incidence of instrumental delivery. Secondly, we assessed the duration of labour; hourly LA consumption in bupivacaine equivalents, maternal satisfaction after fetal delivery, and neonatal Apgar scores.  The following subgroup analyses were chosen a priori: epidural alone versus CSE technique; regimens that used PCEA versus those that did not; and nulliparous versus combination of nulli- and multi-parous women. We used the GRADE system to assess the certainty of evidence associated with our outcome measures.

MAIN RESULTS

We included 18 studies of 4590 women, of which 13 enrolled healthy nulliparous women and five included healthy nulli- and multiparous women. All studies excluded women with preterm or complicated pregnancies. Techniques used to initiate epidural analgesia differed between the studies: seven used combined spinal epidural, 10 used epidural, and one used dural puncture epidural (DPE). There was also variation in analgesics used. Eight studies utilised ropivacaine with fentanyl, three used ropivacaine with sufentanil, two utilised levobupivacaine with sufentanil, one used levobupivacaine with fentanyl, and four utilised bupivacaine with fentanyl. Most of the studies were assessed to have low risk of randomisation, blinding, attrition, and reporting biases, except for allocation concealment where eight studies were assessed to have uncertain risk and three with high risk. Our results showed that AMB was associated with lower incidence of breakthrough pain compared to BI (risk ratio (RR) 0.71; 95% confidence interval (CI) 0.55 to 0.91; I2 = 57%) (16 studies, 1528 participants), and lower hourly LA consumption in bupivacaine equivalents (mean difference (MD) -0.84 mg/h; 95% CI -1.29 to -0.38, I2 = 87%) (16 studies, 1642 participants), both with moderate certainty. AMB was associated with an estimated reduction in breakthrough pain incidence of 29.1% (incidence 202 per 1000, 95% CI 157 to 259), and was therefore considered clinically significant. The incidence of caesarean delivery (RR 0.85; 95% CI 0.69 to 1.06; I2 = 0%) (16 studies, 1735 participants) and instrumental delivery (RR 0.85; 95% CI 0.71 to 1.01; I2 = 0%) (17 studies, 4550 participants) were not significantly, both with moderate certainty. There was no significant difference in duration of labour analgesia (MD -8.81 min; 95% CI -19.38 to 1.77; I2 = 50%) (17 studies, 4544 participants) with moderate certainty. Due to differences in the methods and timing of outcome measurements, we did not pool data for maternal satisfaction and Apgar scores. Results reported narratively suggest AMB may be associated with increased maternal satisfaction (eight studies reported increased satisfaction and six reported no difference), and all studies showed no difference in Apgar scores. WIth the exception of epidural alone versus CSE which found significant subgroup differences in LA consumption between AMB and BI, no significant differences were detected in the remaining subgroup analyses.

AUTHORS' CONCLUSIONS

Overall, AMB is associated with lower incidence of breakthrough pain, reduced LA consumption, and may improve maternal satisfaction. There were no significant differences between AMB and BI in the incidence of caesarean delivery, instrumental delivery, duration of labour analgesia, and Apgar scores. Larger studies assessing the incidence of caesarean and instrumental delivery are required.

Combined Programmed Intermittent Bolus and Patient-Controlled Bolus Is a More Favorable Setting for Epidural Pain Relief Than Continuous Infusion

Epidural analgesia is a suitable and effective treatment for labor pain. However, the preferable modality setting for delivery remains debatable. This study adopted a programmed intermittent epidural bolus (PIEB) setting in conjunction with a patient-controlled epidural analgesia (PCEA) setting to improve the quality of labor analgesia and reduce the number of medical staff. We conducted a prospective observational analysis of primigravida parturients scheduled for spontaneous labor, which required epidural analgesia for painless labor. A total of 483 healthy primigravida parturients with singleton pregnancies were included in this cohort; 135 nulliparous patients were assigned to the continuous infusion setting (CEI) group and 348 to the PIEB + PCEA group. Compared to the CEI setting, the PIEB + PCEA setting significantly reduced the manual rescue by the clinician, extended the time required for the first manual rescue dose, and acclaimed good maternal satisfaction. The use of the CEI mode increased for poor performance requiring more than two rescues with an odds ratio of 2.635 by a binary logistic regression analysis. Using the PIEB + PCEA setting as the maintenance infusion had a longer duration for the first requested manual rescue, fewer manual rescue boluses, excellent satisfaction, and no significant increase in adverse events compared to the CEI setting.

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.

Comparison of different delivery modalities of epidural analgesia and intravenous analgesia in labour: a systematic review and network meta-analysis

PURPOSE

In labour, neuraxial analgesia is the standard in the provision of pain relief. However, the optimal mode of delivering epidural solution has not been determined, and some parturients may need an alternative to epidural analgesia. We sought to conduct a systematic review and network meta-analysis to compare continuous epidural infusion (CEI), programmed intermittent epidural bolus (PIEB), computer-integrated CEI, computer-integrated PIEB, patient-controlled epidural bolus (PCEA), fentanyl patient-controlled analgesia (PCA), and remifentanil PCA, either alone or in combination.

METHODS

We searched CENTRAL, CINAHL, Ovid Embase, Ovid Medline, and Web of Science for randomized controlled trials that included nulliparous and/or multiparous parturients in spontaneous or induced labour. The maintenance epidural solution had to include a low concentration local anesthetic and an opioid. Specific subgroups in the obstetric population such as preeclampsia were excluded. Network meta-analysis was performed with a frequentist method, and continuous and dichotomous outcomes are presented as mean differences and odds ratios, respectively, with 95% confidence intervals.

RESULTS

Overall, 73 trials were included. For the first coprimary outcome, the need for rescue analgesia, CEI was inferior to PIEB and PIEB + PCEA was superior to PCEA alone, with a low certainty of evidence given the presence of serious limitations and imprecision. The second coprimary outcome, the maternal satisfaction, was improved by PIEB + PCEA compared with CEI + PCEA and PCEA alone, with a low quality of evidence in view of the presence of serious limitations and imprecision. Fentanyl PCA increased the requirement for rescue analgesia and decreased maternal satisfaction relative to many methods of delivering epidural solution. In terms of secondary outcomes, PIEB increased analgesic efficacy compared with CEI, and PCEA reduced local anesthetic consumption at the expense of inferior analgesia relative to CEI and PIEB. PIEB + PCEA was superior to CEI + PCEA in regard to the pain score at 2 h and 4 h, consumption of local anesthetic, incidence of lower lower limb motor blockade and the rate of spontaneous vaginal delivery. Fentanyl and remifentanil PCA did not provide the same level of analgesia as all epidural methods, resulted in increasing analgesic ineffectiveness with time spent in labour, and predisposed to a higher incidence of side effects such as nausea and/or vomiting and sedation. Remifentanil PCA was superior to fentanyl PCA for analgesia at an early time point, and it increased the incidence of oxygen desaturation relative to other strategies of delivering epidural solution.

CONCLUSIONS

Opioid PCA did not provide the same level of analgesia as epidural methods with a higher incidence of side effects. We interpret the findings of our systematic review and network meta-analysis as suggesting PIEB + PCEA to be the optimal delivery mode of epidural solution. Nevertheless, the potential differing importance of the various maternal, fetal, and neonatal outcomes in determining which is optimal has not, to our knowledge, been elucidated yet.

STUDY REGISTRATION

PROSPERO (CRD42021254978); registered 27 May 2021.

Comparison of Continuous and Programmed Intermittent Bolus Infusion of 0.2% Ropivacaine after Ultrasound-Guided Continuous Interscalene Brachial Plexus Block in Arthroscopic Shoulder Surgery

Background

Despite the clinical effectiveness of the programmed intermittent bolus (PIB) method for epidural analgesia, evidence for this method in continuous interscalene brachial plexus block (CIBPB) is unclear. This study aimed to investigate the pain relief effect after arthroscopic shoulder surgery according to the administration method by comparing the PIB and continuous infusion methods among the administration methods of local anesthetics.

Methods

Sixty-four patients aged >19 years scheduled for elective arthroscopic shoulder surgery were enrolled and divided into two groups. Ultrasound-guided CIBPB was performed to control postoperative pain. The infusion pump was programmed so that 0.2% ropivacaine was continuously injected at 1.1 mL/h in group A, whereas in group B, 0.1 mL/h was continuously injected and 4 mL was periodically injected at 4 h intervals. In both groups, a further infusion of 4 mL of 0.2% ropivacaine was administered if the patient requested additional analgesia, and the lockout time was set at 30 min. Postoperative pain quality was assessed using a visual analog scale (VAS), and the incidence of patients requiring additional analgesics, motor blockade using a modified Bromage scale (MBS), and consumed doses of local anesthetic were assessed.

Results

The VAS and incidence of rescue analgesics were performed when the patient could communicate voluntarily after admission to the post-anesthetic care unit, and at 24 and 48 h after surgery showed no significant difference between the two groups. The MBS at 24 h after surgery was significantly higher in group B (p = 0.038). In the comparison of consumed doses of local anesthetic, group B had a significantly higher bolus injection dose (p = 0.047) and frequency of bolus use in the 24 h after surgery (p = 0.034).

Conclusion

The PIB method in CIBPB after arthroscopic shoulder surgery provided a similar analgesic effect, with a higher bolus injection dose of local anesthetic and increased motor blockade than the continuous infusion method.

Programmed intermittent epidural bolus in parturients: A meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the efficacy and safety of programmed intermittent epidural bolus (PIEB) in parturients.

METHODS

The PubMed, Embase, and the Cochrane Library (from inception to July 2021) were searched for identification of randomized placebo-controlled trials in which PIEB was applied in parturients. The outcomes were the effect of analgesia, satisfaction score, mode of delivery, duration of labor, neonatal condition, and adverse events. The pooled odds ratios (OR), weighted mean difference (WMD), and 95% confidence intervals (CIs) were calculated using random- and fixed-effects models.

RESULTS

PIEB was found to be associated with decreased total consumption of ropivacaine (WMD = -15.83, 95% CI: -19.06 to -12.60, P < .00001; I2 = 61%; P for heterogeneity = .04), total consumption of sufentanil (WMD = -4.93, 95% CI: -6.87 to 2.98, P < .00001; I2 = 68%; P for heterogeneity = .05), numbers of patients who require patient-controlled epidural analgesia bolus (OR = 0.27, 95% CI: 0.14-0.51, P < .0001; I2 = 65%; P for heterogeneity = .01), the number of attempts (WMD = -4.12, 95% CI: -7.21 to -1.04, P = .009; I2 = 100%; P for heterogeneity < .00001), rate of breakthrough pain (OR = 0.47, 95% CI: 0.28-0.80, P = .005; I2 = 47%; P for heterogeneity = .09). Eight studies focus on the duration of analgesia. After by meta-analysis, we found that the pain visual analogue scale (VAS) score at 30 minutes, 2 hours, 4 hours, and 5 hours in PIEB group was significantly lower when compared with control group, (WMD = -0.15, 95% CI: -0.26 to -0.04, P = .006; I2 = 0%; P for heterogeneity = .64), (WMD = -0.79, 95% CI: -1.32 to 0.25, P = .004; I2 = 97%; P for heterogeneity < .00001), (WMD = -1.00, 95% CI: -1.08 to -0.91, P < .00001; I2 = 0%; P for heterogeneity = .67), (WMD = -1.81, 95% CI: -3.23 to -0.39, P = .01; I2 = 98%; P for heterogeneity < .00001), respectively. Nineteen studies discussed the mode of delivery between 2 groups. The results suggest that the rate of normal delivery is significantly higher in PIEB group compared with control group (OR = 1.37, 95% CI: 1.08-1.75, P = .01). The time of first and second stage of labor are significantly shorter in PIEB group compared with control group, the result is (WMD = -10.52, 95% CI: -14.74 to 4.76, P < .00001; I2 = 0%; P for heterogeneity = .86), (WMD = -1.48, 95% CI: -2.26 to -0.69, P = .0002; I2 = 35%; P for heterogeneity = .10), respectively. Thirteen studies concerned the satisfaction score of patients. The satisfaction score of patients in the PIEB group was significantly higher when compared with control group (WMD = 0.91, 95% CI: 0.42-1.39, P = .0003; I2 = 98%; P for heterogeneity < .00001). The Apgar score at 1, 5 minutes in PIEB group are significantly higher (WMD = 0.07, 95% CI: 0.02-0.13 P = .007; I2 = 55%; P for heterogeneity = .04), (WMD = -0.08, 95% CI: -0.12 to -0.05, P < .00001; I2 = 21%; P for heterogeneity = .27), respectively.

CONCLUSIONS

PIEB is a good alternative for labor analgesia with better analgesic effect, maternal and infant outcome.

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.

Pain management during labor: use of intermittent drug delivery devices for improvement of obstetric and neonatal outcome and reduction of healthcare burden: A large non-inferiority randomized clinical trial

BACKGROUND

Automated continuous epidural administration of local anesthetics provides a more stable analgesic block with decreasing of healthcare staff compared to manual boluses administration (TOP-UP) but is associated to high rate of operative vaginal delivery. We hypothesized that the use of programmed intermittent automated boluses (PIEB) is able to provide a good quality of analgesia and decreasing of anesthesiologic workload without increasing the rate of instrumental vaginal birth in comparison with TOP-UP technique. Laboring nulliparous woman aged between 18 and 46 years were randomized to epidural analgesia with 0.0625% levobupivacaine and sufentanil administered by PIEB or by TOP-UP techniques. Primary outcome was instrumental vaginal delivery rate and secondary outcomes were quality of analgesia, total and time-related drugs doses used, motor block, newborn outcome, and anesthesiologic workload.

RESULTS

Six hundred twenty-nine were randomized, and 628 were included in the intention-to-treat analysis. The rate of instrumental vaginal delivery was similar in the PIEB and TOP-UP groups (13.2% vs 9.7%, OR 1.4 95% CI 0.8 to 2.5; p 0.21). There was no difference between groups regarding mode of delivery (cesarean section vs vaginal birth), newborn outcome, and motor block. Patients in the PIEB group received more total and time-related drugs doses and a better quality of analgesia. Anesthesiological workload was significantly reduced in the PIEB group.

CONCLUSIONS

Our study demonstrated that epidural anesthesia with programmed intermittent epidural boluses by an automated device provides an effective and safe management of labor analgesia with improvement of pain control and sparing of man workload compared to manual top-up protocols.

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

PURPOSE

We studied the programmed intermittent epidural bolus (PIEB) time interval between boluses of 2.5 mL of bupivacaine 0.25% with fentanyl 8 µg·mL^-1 to produce effective analgesia in 90% of women (EI90) during the first stage of labour.

METHODS

In a double-blind sequential allocation trial using a biased coin up-and-down design to determine the EI90, the PIEB boluses of 2.5 mL of 0.25% bupivacaine plus fentanyl 8 µg·mL^-1 were delivered at varying intervals-60, 50, 40, and 30 min. The primary outcome was the adequate response of the patient to the PIEB regimen, defined as no use of supplemental analgesia for six hours or until the first stage of labour was completed, whichever came first. The secondary outcomes were the upper sensory block level to ice, motor block and hypotension. The isotonic regression with extrapolation approach was used to estimate the EI90.

RESULTS

In the 20 women studied, the estimated EI90 was 20 (95% CI, 5.9 to 28.8) min. For the secondary outcomes, we classified women into those assigned to 30 min (16 women) and those assigned to more than 30 min (four women). The median upper sensory block for women in the 30-min group and more than 30 min were T6 (or T5) and T7, respectively. No participants experienced motor block. Hypotension occurred in one patient in the 30-min group.

CONCLUSION

The estimated EI90 for boluses of 2.5 mL of bupivacaine 0.25% with fentanyl 8 µg·mL^-1 was 20 (95% CI, 5.9 to 28.8) min. These results suggest that there is no advantage in using this regimen compared with those reported in the literature using the same dose of bupivacaine in concentrations of 0.0625% and 0.125%.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT03735771); registered 7 November 2018.

Quality of labor epidural analgesia at a high-volume tertiary care obstetric unit: a before-and-after study

INTRODUCTION

We wanted to better understand the quality of our labor epidural practice at a large urban academic medical center. Several practice changes were implemented between 2011 and 2017, namely a more uniform epidural loading dose of local anesthetic that includes fentanyl, an increase in both the hourly baseline offer and maximum allowed hourly amount of bupivacaine, and the change from a continuous epidural infusion to a programmed intermittent epidural bolus (PIEB) regimen. We aimed to assess the impact of those changes on the quality of labor analgesia.

METHODS

We performed two separate audits representing before-and-after groups. The audits were performed in November 2011 (before group) and November-December 2017 (after group). The data for 2011 were extracted from a previously published study. Hence, we conducted a similar audit in 2017, including only outcomes that were included in the previous audit. The primary outcome was the presence of pain >3 (Numerical Rating Scale 0-10) at any time during first or second stage of labor. Secondary outcomes included top-up requirements, and women's pain perception during the first and second stage of labor according to a postpartum questionnaire.

RESULTS

We studied 294 and 247 women in the before-and-after groups, respectively. The proportion of women reporting pain >3/10 at any time during labor and delivery significantly decreased in the after group (30% vs 41%; p<0.01). In an adjusted analysis, there was a 35% reduction in the likelihood of pain scores>3 for the after group (OR 0.65, 95% CI 0.46, 0.94). Women in the after group received fewer top-ups by nurses (3% vs 24%, p<0.001). Most women in both cohorts (85% before and 87% after) were satisfied with the overall quality of analgesia.

DISCUSSION

A bundle of practice changes implemented in our clinical practice, including the PIEB regimen, has resulted in a significant improvement in the quality of labor analgesia. However, despite all the implemented changes, 30% of women still experience pain during labor and further optimization of our practice is warranted.

A Meta-Analysis of Comparing Intermittent Epidural Boluses and Continuous Epidural Infusion for Labor Analgesia

With the development of medical equipment and techniques in labor anesthesia, it is a major issue to investigate the risks and treatment effects among techniques such as continuous epidural infusion (CEI) and intermittent epidural bolus (IEB). However, there is a controversial result regarding two techniques. This study was conducted through meta-analysis of randomized controlled trials (RCTs) for labor analgesia between the CEI and IEB techniques. The pooled results were presented as weighted mean differences (WMDs) together with 95% confidence intervals (CIs) and odds ratios (ORs) together with 95% CIs, respectively. Eleven RCTs were included in this meta-analysis. Four hundred sixty-five parturients accepted CEI, whereas 473 parturients accepted IEB labor analgesia. Elven identified low- risk bias studies were recruited for meta-analysis. The results presented no statistical difference in cesarean delivery rate between IEB and CEI (OR, 0.96; 95% CI, 0.67-1.37) and duration of second stage of labor (WMD, -3.82 min; 95% CI, -8.28 to 0.64). IEB had statistically significant lessened risk of instrumental delivery (OR, 0.59; 95% CI, 0.39-0.90) and for the use in local anesthetic (WMD, -1.71 mg bupivacaine equivalents per hour; 95% CI, -1.88 and -1.55). Accepted IEB had a higher score of maternal satisfaction (WMD, -6.95 mm; 95% CI, -7.77 to -6.13). Based on evidence, IEB showed a greater benefit for slightly reducing the use in local anesthetic, reduced risk of instrumental delivery, and improved maternal satisfaction for the requirement of labor epidural analgesia for healthy women. In the future, more studies need to be conducted to practice the IEB regimen and explore its influence on labor analgesia.

Comparative analgesic efficacy and safety of intermittent local anaesthetic epidural bolus for labour: a systematic review and meta-analysis

BACKGROUND

Continuous epidural infusion (CEI) is commonly used for labour analgesia, but concerns over potential motor block, second-stage labour complications, and ineffective analgesia in late labour have prompted examining intermittent epidural bolus (IEB) as an alternative. However, evidence comparing these modalities is conflicting. The meta-analysis evaluates the analgesic efficacy of CEI vs IEB.

METHODS

Databases were searched for trials comparing CEI to IEB for labour analgesia. The two co-primary outcomes were risk of breakthrough pain and difference in area under the curve (AUC) for pain scores during the first 4 h post-epidural initiation. Local anaesthetic consumption, maternal outcomes (i.e. delivery mode, labour duration, and maternal satisfaction), and side-effects of epidural analgesia were also evaluated. Results were pooled using random-effects modelling. Trial sequential analysis (TSA) was used to evaluate evidence reliability.

RESULTS

Twenty-seven studies (3133 patients) were analysed. Compared with CEI, IEB decreased risk of breakthrough pain by 38% (risk ratio [95% confidence interval {CI}] of 0.62 [0.48, 0.81]; P=0.0004; I²=47%; 1164 patients) and reduced AUC of pain during the 4 h interval by 32.9% (mean difference [95% CI] of -16.7 mm h^-1 [-18.9, -14.4]; P<0.0001; 1638 patients). Intermittent epidural bolus enhanced maternal satisfaction, shortened labour duration, decreased motor block, and reduced local anaesthetic consumption. The difference between the two groups was not statistically significant for epidural side-effects or mode of delivery. The TSA indicated adequate power for reliable inferences.

CONCLUSIONS

Intermittent epidural bolus provides improved labour pain control during the first 4 h after epidural initiation with less breakthrough pain. Moderate- to high-quality evidence of intermittent epidural bolus superiority support its use as a safe and effective continuous epidural infusion alternative for labour analgesia.

Does programmed intermittent epidural bolus improve childbirth conditions of nulliparous women compared with patient-controlled epidural analgesia?: A multicentre, randomised, controlled, triple-blind study

BACKGROUND

Epidural analgesia may change the mechanics of childbirth. These changes are related to the concentration of the local anaesthetic used epidurally but probably also to its mode of delivery into the epidural space.

OBJECTIVE

To determine whether the administration of programmed intermittent epidural boluses (PIEB) improves the mechanics of second-stage labour compared with patient-controlled epidural analgesia (PCEA) with a background infusion.

DESIGN

A randomised, controlled, triple-blind study.

SETTING

Multicentre study including four level III maternity units, January 2014 until June 2016.

PATIENTS

A total of 298 nulliparous patients in spontaneous labour were randomised to a PIEB or PCEA group.

INTERVENTION

After epidural initiation with 15 ml of 0.1% levobupivacaine containing 10 μg of sufentanil, patients received either an hourly bolus of 8 ml (PIEB) or a continuous rate infusion of 8 ml h (PCEA): the drug mixture used was levobupivacaine 0.1% and sufentanil 0.36 μg ml.

MAIN OUTCOME MEASURES

The primary outcome was a composite endpoint of objective labour events: a posterior occiput position in the second stage, an occiput position at birth, waiting time at full cervical dilatation before active maternal pushing more than 3 h, maternal active pushing duration more than 40 min, and foetal heart rate alterations. Vaginal instrumental delivery rates, analgesia and motor blockade scores were also recorded.

RESULTS

From the 298 patients randomised, data from 249 (124 PIEB, 125 PCEA) were analysed. No difference was found in the primary outcome: 48.0% (PIEB) and 45.5% (PCEA) of patients, P = 0.70. In addition, no difference was observed between the groups for each of the individual events of the composite endpoint, nor in the instrumental vaginal delivery rate, nor in the degree of motor blockade. Despite an equivalent volume of medication in the groups, a significantly higher analgesia score at full dilatation was observed in the PIEB group, odds-ratio = 1.9 (95% confidence interval, 1.0 to 3.5), P = 0.04.

CONCLUSION

The mechanics of the second stage did not differ whether PIEB or PCEA was used. Analgesic conditions appeared to be superior with PIEB, especially at full dilation.

TRIAL REGISTRATION

NCT01856166.

Intermittent epidural bolus versus continuous epidural infusions for labor analgesia: A meta-analysis of randomized controlled trials

There are inconsistent results regarding the efficacy and safety of intermittent epidural bolus (IPB) versus continuous epidural infusions (CPI) for labor analgesia. This study used a meta-analytic approach to assess the safety and treatment efficacy of IPB versus CPI for labor analgesia based on randomized controlled trials (RCTs). Four electronic databases were used to identify eligible RCTs. Pooled effect estimates at 95% confidence intervals (CIs) were calculated using a random-effects model. Twenty-two RCTs with 2,573 parturients were selected for final analysis. The findings revealed no significant differences between IPB and CPI for the incidences of cesarean and instrumental delivery. IPB was shown to be associated with shorter total duration of labor [weighted mean difference (WMD): −21.46; 95% CI: −25.07 to −17.85; P < 0.001], duration of the first of stage of labor (WMD: −13.41; 95% CI: −21.01 to −5.81; P = 0.001), and duration of the second stage of labor (WMD: −4.98; 95% CI: −9.32 to −0.63; P = 0.025). Furthermore, IPB significantly reduced the incidences of required anesthetic interventions compared with CPI [relative risk (RR): 0.61; 95% CI: 0.39–0.95; P = 0.030], whereas there was no significant difference between IPB and CPI for the time required in the first anesthetic intervention (WMD: 7.73; 95% CI: −33.68–49.15; P = 0.714). The local anesthetic IPB (bupivacaine equivalents) was associated with lower milligrams per hour of local anesthetic (WMD: −0.89; 95% CI: −1.41 to −0.36; P = 0.001) and better maternal satisfaction (WMD: 8.76; 95% CI: 4.18–13.35; P < 0.001). There were no significant differences between IPB and CPI for the risk of adverse events. This study found that parturients with IPB have short total duration of labor and duration of the first and second stage of labor, reduced requirements for additional anesthetic interventions, and improved maternal satisfaction.

Epidural bolus versus continuous epidural infusion analgesia on optic nerve sheath diameter in paediatric patients: A prospective, double-blind, randomised trial

The use of programmed intermittent epidural bolus for postoperative analgesia may have greater analgesic efficacy than continuous epidural infusion. However, the rapid delivery speed used with an epidural bolus is more likely to increase intracranial pressure. We compared the effects of lumbar epidural bolus versus continuous infusion epidural analgesia on intracranial pressure in children using optic nerve sheath diameter as a marker. We randomly assigned 40 paediatric patients to bolus or infusion groups. Epidural analgesia (0.15% ropivacaine 0.3 ml·kg⁻¹) was administered via bolus or infusion. Ultrasonography was used to measure the optic nerve sheath diameter before (T0), at 3 min (T1), 10 min (T2), and 70 min (T3) after starting the pump. There were statistically significant between-group differences in optic nerve sheath diameter over time (P_{Group x Time} = 0.045). From T0–T3, the area under the curve values were similar between the two groups. Although there were differences in the patterns of optic nerve sheath diameter change according to the delivery mode, the use of lumbar epidural bolus did not increase the risk of intracranial pressure increase over that of continuous infusion. Further research is needed to investigate intracranial pressure changes after continuous application of each delivery mode.

Do Epidural Catheter Size and Flow Rate Affect Bolus Injection Pressure in Different Programmed Intermittent Epidural Bolus Regimens? An In Vitro Study

BACKGROUND

The optimal programmed intermittent epidural bolus regimen for labor analgesia remains unknown. Some studies indicate that better drug spread in the epidural space results from greater injection pressure; however, there is a lack of data regarding the maximum pressure generated by epidural bolus injection using different catheters and flow rates.

METHODS

We evaluated the flow and pressure characteristics of 11 commonly used epidural catheters combined with 3 different infusion pumps that deliver epidural infusions according to the programmed intermittent epidural bolus regimen. Pressure changes were measured over time at flow rates of 100, 250, and 400 mL·hour and with a bolus volume of 10 mL. To account for repeated measures, linear mixed models were used. Features were selected with a backward stepwise procedure continued until only statistically significant variables were left in the model.

RESULTS

We performed 660 measurements. The mean maximal pressure generated during bolus injection ranged from 86 to 863 mm Hg for different flow rates and catheter designs. The interaction between flow rate and catheter gauge resulted in 1.31, 1.65, and 2.00 mm Hg of pressure increase for 18G, 19G, and 20G catheters, respectively, per 1 mL·hour of increased flow rate (P< .001). Analyses including wire-reinforced catheters revealed a 1.16, 1.76, and 2.36 mm Hg pressure increase for 18G, 19G, and 20G catheters, respectively, per 1 mL·hour of increased flow rate (P< .001). In some cases, it triggered the occlusion pump alarm.

CONCLUSIONS

Significant differences were observed in the in vitro maximum pressure value among the various catheter and flow rate combinations with a higher pressure value for wire-reinforced catheters used in the study. The optimal flow rate and epidural catheter combination may allow for delivery of the bolus with high flow rate without triggering the occlusion alarm.

Is breakthrough pain better managed by adding programmed intermittent epidural bolus to a background infusion during labor epidural analgesia? A randomized controlled trial

BACKGROUND

Breakthrough pain (BTP) is a common problem during labor analgesia. Programmed intermittent epidural bolus (PIEB) has demonstrated superior to background epidural infusion (BEI) concerning BTP, but the effect of combining both modes remains unknown. We hypothesized that this combination could reduce BTP incidence.

METHODS

Nulliparous parturients with early cervical dilation were randomized to receive 5 mL/h BEI of levobupivacaine 0.125% plus fentanyl 1.45 µg/mL (standard group) or 5 mL/h BEI + 10 mL/h PIEB (PIEB group). In case of BTP, patient-controlled epidural analgesia (PCEA) boluses of 10 mL (20-min lockout interval) were administered. If PCEA was insufficient, a 10-mL clinician bolus was delivered. The primary endpoint was the percentage of parturients who required supplementary epidural boluses.

RESULTS

One hundred and twenty women were recruited. Eighty-nine percent of parturients required supplementary boluses in standard group versus 30% in PIEB group (RR=3.07; 95% CI: 1.99-4.76; P<0.001). Adding PIEB prevented BTP in 70% of cases. Duration of effective analgesia was longer in PIEB than in standard group (P=0.003). Supplementary boluses were decreased (P<0.001), while local anesthetic consumption increased (P<0.001) by PIEB addition. Sensory-motor block, mode of delivery, maternal satisfaction and neonatal outcomes were equally distributed in both groups.

CONCLUSIONS

Adding PIEB to BEI+PCEA improved labor analgesia by significantly reducing the needs of rescue analgesia and prolonging the duration of effective analgesia. This combination provoked a higher consumption of local anesthetic with no detected clinical consequences.

A biased coin up-and-down sequential allocation trial to determine the optimum programmed intermittent epidural bolus time interval between 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg·mL-1

PURPOSE

The optimal epidural mixtures and settings for programmed intermittent epidural bolus (PIEB) labour analgesia have yet to be determined. A previous study by our group demonstrated that 10 mL boluses of bupivacaine 0.0625% with fentanyl 2 µg·mL^-1 administered every 40 min provided effective analgesia during the first stage of labour for 90% of women, without breakthrough pain. We wanted to determine the effective PIEB time interval of 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg·mL^-1 under the same study circumstances, aiming at a future comparative study.

METHODS

This double-blind dose-finding study used the biased coin up-and-down sequential allocation method to determine the effective PIEB interval 90% (EI90) needed to provide effective analgesia without breakthrough pain during the first stage of labour. We used fixed 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg.mL^-1 and studied time intervals of 60, 50, 40, and 30 min. The first patient was assigned an interval of 60 min and the remaining intervals were assigned as per the biased coin up-and-down method.

RESULTS

The estimated EI90 was 36.5 min (95% confidence interval [CI], 34.0 to 39.0) by the truncated Dixon and Mood method and 34.2 min (95% CI, 30.8 to 41.5) by the isotonic regression method. We found that 20/40 women had an upper sensory block to ice above T6, 34/40 women had no motor block, and no woman required treatment for hypotension.

CONCLUSION

The EI90 between 5 mL boluses of bupivacaine 0.125% with fentanyl 2 µg·mL^-1 during the first stage of labour is approximately 35 min.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT #02758405); registered 2 May, 2016.

Generalisability of randomised trials of the programmed intermittent epidural bolus technique for maintenance of labour analgesia: a prospective single centre cohort study

BACKGROUND

Several randomised controlled trials show that maintenance of labour epidural analgesia with programmed intermittent epidural bolus reduces the maternal motor block compared with maintenance with a continuous infusion. However, these trials were usually restricted to healthy nulliparous parturients. To assess the generalisability of these randomised controlled trials to 'real-world' conditions, we compared maternal motor function (modified Bromage score) over time between healthy nulliparous and parous women using routinely collected quality-control data.

METHODS

After ethical approval, all parturients receiving programmed intermittent epidural bolus labour analgesia between June 2013 and October 2014 were included in this prospective cohort study. Bupivacaine 0.1% with fentanyl 2 μg ml^-1 was used allowing for patient-controlled bolus every 20 min. The maternal motor function (primary outcome) was regularly assessed from insertion of the epidural catheter until delivery.

RESULTS

Of the 839 parturients included, 553 (66%) were nulliparous and 286 (34%) were parous. The parous women had a shorter median duration of epidural analgesia (3 h 59 min vs 5 h 45 min) and a higher incidence of spontaneous delivery (66% vs 37%). The probability of being in a certain Bromage category at birth was similar in nulliparous and parous women in a general additive model adjusting for duration of epidural analgesia, number of rescue top-ups, and number of catheter manipulations (cumulative odds ratio: 1.18; 95% confidence interval: 0.98-1.41). Parous women required a higher time-weighted number and volume of rescue top-ups.

CONCLUSIONS

The results of the randomised controlled trials on a reduced motor block with programmed intermittent epidural bolus seem generalisable to parturients typically not included in these trials.

Patient intermittent epidural boluses (PIEB) plus very low continuous epidural infusion (CEI) versus patient-controlled epidural analgesia (PCEA) plus continuous epidural infusion (CEI) in primiparous labour: a randomized trial

Epidural maintenance technique for labour analgesia updates constantly. Thanks to infusion pumps, the recently developed programmed intermittent epidural bolus (PIEB) may reduce the use of anesthetic drugs and minimize unintended consequences such as cardio or neurotoxicity. Nevertheless, it is not yet a general practice. So far, there are no comparative studies in the literature that address levobupivacaine-based CEI + PCEA versus CEI + PIEB + PCEA. A randomized double-blind trial was carried out to evaluate if PIEB could reduce local anesthetic use compare to PCEA. Primiparous pregnant patients were divided into two groups: PIEB group (continuous infusion plus intermittent automatic doses) and PCEA group (continuous infusion plus PCEA). The primary objective was to analyze the differences between both groups regarding levobupivacaine total dose. The secondary objectives were to find out the differences concerning pain control, motor blockage, satisfaction score, labour time and delivery outcomes. Statistical analyses were done by protocol. The study recruited 200 patients (103 PIEB, 97 PCEA). The total dose administered was significantly higher in PIEB group: PCEA group 52.97 mg, IC 95% 45.65-60.28 mg and PIEB group 62.04 mg, IC 95% 55.46-68.61 mg (p = 0.021). PIEB group required fewer top up boluses (median value1; range 0-2) than CEI + PCEA group (median value 6; range 3-9) p < 0.05. Satisfaction scores were higher in PIEB group (p = 0.039, CI 95% 1.23-1.42). CEI + PIEB was found to be a good alternative to CEI + PCEA with very high rates of satisfaction in both groups although it was higher in PIEB group. PIEB group required fewer PCEA boluses. Further studies are needed to determine the best approach for epidural pain management.Clinical Trial Number and Registry URL: NCT03133091 ( https://clinicaltrials.gov/ct2/show/NCT03133091?term=MB+Rodriguez&rank=1) .

Automated mandatory bolus versus basal infusion for maintenance of epidural analgesia in labour

BACKGROUND

Childbirth may cause the most severe pain some women experience in their lifetime. Epidural analgesia is an effective form of pain relief during labour and is considered to be the reference standard. Traditionally epidural analgesia has been delivered as a continuous infusion via a catheter in the epidural space, with or without the ability for the patient to supplement the analgesia received by activating a programmable pump to deliver additional top-up doses, known as patient-controlled epidural analgesia (PCEA). There has been interest in delivering maintenance analgesic medication via bolus dosing (automated mandatory bolus - AMB) instead of the traditional continuous basal infusion (BI); recent randomized controlled trials (RCTs) have shown that the AMB technique leads to improved analgesia and maternal satisfaction.

OBJECTIVES

To assess the effects of automated mandatory bolus versus basal infusion for maintaining epidural analgesia in labour.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, the World Health Organization International Clinial Trials Registry Platform (WHO-ICTRP) and ClinicalTrials.gov on 16 January 2018. We screened the reference lists of all eligible trials and reviews. We also contacted authors of included studies in this field in order to identify unpublished research and trials still underway, and we screened the reference lists of the included articles for potentially relevant articles.

SELECTION CRITERIA

We included all RCTs that compared the use of bolus dosing AMB with continuous BI for providing pain relief during epidural analgesia for labour in women.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Our primary outcomes were: risk of breakthrough pain with the need for anaesthetic intervention; risk of caesarean delivery; risk of instrumental delivery. Secondary outcomes included: duration of labour; local anaesthetic consumption. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included 12 studies with a total of 1121 women. Ten studies enrolled healthy nulliparous women only and two studies enrolled healthy parous women at term as well. All studies excluded women with complicated pregnancies. There were variations in the technique of initiation of epidural analgesia. Seven studies utilized the combined spinal epidural (CSE) technique, and the other five studies only placed an epidural catheter without any intrathecal injection. Seven studies utilized ropivacaine: six with fentanyl and one with sufentanil. Two studies used levobupivacaine: one with sufentanil and one with fentanyl. Three used bupivacaine with or without fentanyl. The overall risk of bias of the studies was low.AMB probably reduces the risk of breakthrough pain compared with BI for maintaining epidural analgesia for labour (from 33% to 20%; risk ratio (RR) 0.60; 95% confidence interval (CI) 0.39 to 0.92, 10 studies, 797 women, moderate-certainty evidence). AMB may make little or no difference to the risk of caesarean delivery compared to BI (15% and 16% respectively; RR 0.92; 95% CI 0.70 to 1.21, 11 studies, 1079 women, low-certainty evidence).AMB may make little or no difference in the risk of instrumental delivery compared to BI (12% and 9% respectively; RR 0.75; 95% CI 0.54 to 1.06, 11 studies, 1079 women, low-certainty evidence). There is probably little or no difference in the mean duration of labour with AMB compared to BI (mean difference (MD) -10.38 min; 95% CI -26.73 to 5.96, 11 studies, 1079 women, moderate-certainty evidence). There is probably a reduction in the hourly consumption of local anaesthetic with AMB compared to BI for maintaining epidural analgesia during labour (MD -1.08 mg/h; 95% CI -1.78 to -0.38, 12 studies, 1121 women, moderate-certainty evidence). Five out of seven studies reported an increase in maternal satisfaction with AMB compared to BI for maintaining epidural analgesia for labour; however, we did not pool these data due to their ordinal nature. Seven studies reported Apgar scores, though there was significant heterogeneity in reporting. None of the studies showed any significant difference between Apgar scores between groups.

AUTHORS' CONCLUSIONS

There is predominantly moderate-certainty evidence that AMB is similar to BI for maintaining epidural analgesia for labour for all measured outcomes and may have the benefit of decreasing the risk of breakthrough pain and improving maternal satisfaction while decreasing the amount of local anaesthetic needed.

Continuous epidural infusion versus programmed intermittent epidural bolus for labor analgesia: optimal configuration of parameters to reduce physician-administered top-ups

BACKGROUND AND OBJECTIVES

Programmed intermittent epidural bolus (PIEB) is a delivery mode associated with decreased local analgesia dosing, motor block, and physician-administered top-ups (PATUs) during labor analgesia. We hypothesized that PIEB delivery at different settings will result in fewer PATUs for labor analgesia than the same hourly volume of a continuous epidural infusion (CEI).

METHODS

"Before and after" study design of combined spinal-epidural (CSE) for labor, with bupivacaine 0.0625%-fentanyl 2 mcg/ml and patient-controlled epidural analgesia (PCEA; 5 ml bolus with 10 min lock-out). The "before" group (N = 120) received a CEI at 10 ml/hour. PIEB groups received a programmed bolus of 10 ml: every 60 min (PIEB60, N = 120), every 45 min (PIEB45, N = 140), or every 45 min with high flow (500 ml/hour) (PIEB45HF, N = 25).

MAIN OUTCOME MEASURES

Number of women requesting a PATU, time intervals from CSE to PATU and to delivery, and obstetric outcomes.

RESULTS

There was no difference in the proportion of women requesting PATUs between the CEI and PIEB60 groups (45/120 versus 52/120, respectively; p > .05). The PATU rate was lower in the PIEB45 group compared with the PIEB60 and CEI groups (23/140 versus 52/120 and 45/120, p < .005 and p < .05, respectively), and in the PIEB45HF versus PIEB60 groups (5/25 versus 52/120, p < .05). No difference in other outcomes was observed.

CONCLUSIONS

The number of women requesting a PATU was lowest with the PIEB45 and PIEB45HF settings. There were no differences in any other outcomes between groups. This study emphasizes the many variations in programming that need to be further tested to establish the benefits of PIEB delivery compared with traditional CEI with PCEA.

A randomized trial of automated intermittent ropivacaine administration vs. continuous infusion in an interscalene catheter

BACKGROUND

Ultrasound-guided interscalene nerve block with ropivacaine as local anesthetic agent given as boluses or continuous infusion is the preferred pain management after major shoulder surgery. The use of automated intermittent boluses has been shown to be superior to continuous infusion in sciatic and epidural nerve block.

HYPOTHESIS

Automated intermittent boluses reduce pain after major shoulder surgery.

METHODS

Seventy patients aged 18-75 years, scheduled for major shoulder surgery under general anesthesia with interscalene nerve block were included in this randomized controlled trial. Patients were allocated to either automated intermittent boluses with 16 mg ropivacaine every 2 h combined with patient-controlled administration or to a conventional regimen of continuous infusion of 8 mg/h (4 ml/h) of ropivacaine combined with patient controlled administration (2 ml, lockout time 30 min). Pain (Visual Analog Scale, VAS) was assessed every 8 h postoperatively.

RESULTS

Fifty-seven patients completed the study, 29 in the continuous infusion group and 28 in the automated intermittent bolus group. Shoulder arthroplasty was performed in 49 (86%) of the cases. There were no significant differences in VAS score from 8 to 48 h post-operatively. No significant difference in opioid usage was observed. The automated intermittent bolus group reported significantly less force on coughing and more hoarseness. A significantly lower volume of ropivacaine was used in the automated intermittent bolus group.

CONCLUSION

Automated intermittent boluses did not reduce pain or rescue opioid consumption compared with continuous infusion of ropivacaine. The automated intermittent bolus group had significantly less force on coughing and more hoarseness.

Determination of the optimal programmed intermittent epidural bolus volume of bupivacaine 0.0625% with fentanyl 2 μg.ml-1 at a fixed interval of forty minutes: a biased coin up-and-down sequential allocation trial

The optimum time interval for 10 ml boluses of bupivacaine 0.0625% + fentanyl 2 μg.ml^-1 as part of a programmed intermittent epidural bolus regimen has been found to be 40 min. This regimen was shown to be effective without the use of supplementary patient-controlled epidural analgesia boluses in 90% of women during the first stage of labour, although with a rate of sensory block to ice above T6 in 34% of women. We aimed to determine the optimum programmed intermittent epidural bolus volume at a 40 min interval to provide effective analgesia in 90% of women (EV₉₀ ) during the first stage of labour, without the use of patient-controlled epidural analgesia. We performed a prospective double-blind dose-finding study using the biased coin up-and-down sequential allocation method in 40 women. The estimated EV₉₀ was 11.0 (95%CI 10.0-11.7) ml with the isotonic regression method and 10.7 (95%CI 10.3-11.0) ml with the truncated Dixon and Mood method. Overall, 18 women had a sensory block above T6, and 37 women exhibited no motor block. No women required treatment for hypotension. In conclusion, it is not possible to reduce the programmed intermittent epidural bolus volume from 10 ml, used in our current regimen, without compromising the quality of analgesia. Using this regimen, a high proportion of women will develop a sensory block above T6.

Effect of programmed intermittent epidural boluses and continuous epidural infusion on labor analgesia and obstetric outcomes: a randomized controlled trial

PURPOSE

Continuous epidural infusion and programmed intermittent epidural boluses are analgesic techniques routinely used for pain relief in laboring women. We aimed to assess both techniques and compare them with respect to labor analgesia and obstetric outcomes.

METHODS

After Institutional Review Board approval, 132 laboring women aged between 18 and 45 years were randomized to epidural analgesia of 10 mL of a mixture of 0.1% bupivacaine plus 2 µg/mL of fentanyl either by programmed intermittent boluses or continuous infusion (66 per group). Primary outcome was quality of analgesia. Secondary outcomes were duration of labor, total drug dose used, maternal satisfaction, sensory level, motor block level, presence of unilateral motor block, hemodynamics, side effects, mode of delivery, and newborn outcome.

RESULTS

Patients in the programmed intermittent epidural boluses group received statistically less drug dose than those with continuous epidural infusion (24.9 vs 34.4 mL bupivacaine; P = 0.01). There was no difference between groups regarding pain control, characteristics of block, hemodynamics, side effects, and Apgar scores.

CONCLUSIONS

Our study evidenced a lower anesthetic consumption in the programmed intermittent boluses group with similar labor analgesic control, and obstetric and newborn outcomes in both groups.

Implementation of Programmed Intermittent Epidural Bolus for the Maintenance of Labor Analgesia

Programmed intermittent epidural bolus (PIEB) is an exciting new technology that has the potential to improve the maintenance of epidural labor analgesia. PIEB compared with a continuous epidural infusion (CEI) has the potential advantage of greater spread within the epidural space and therefore better sensory blockade. Studies have demonstrated a local anesthetic-sparing effect, fewer instrumental vaginal deliveries, less motor blockade, and improvements in maternal satisfaction with PIEB compared with CEI. However, the optimal PIEB regimen and pump settings remain unknown, and there are a number of logistical issues and practical considerations that should be considered when implementing PIEB. The PIEB bolus size and interval, PIEB start time delay period, and patient-controlled epidural analgesia bolus size and lockout time can influence the efficacy of PIEB used for epidural labor analgesia. Educating all members of the health care team is critical to the success of the technique. This review summarizes the role of PIEB for the maintenance of labor analgesia, outlines implementation strategies, suggests optimal settings, and presents potential limitations of the technique.

A retrospective comparison of programmed intermittent epidural bolus with continuous epidural infusion for maintenance of labor analgesia

OBJECTIVE

To assess whether maintenance of labor epidural analgesia using programmed intermittent epidural bolus (PIEB) is associated with reduced local anesthetic (LA) consumption, patient-controlled epidural analgesia (PCEA) use, and rescue analgesia requirements compared to continuous epidural infusion (CEI).

RESEARCH DESIGN AND METHODS

This is a retrospective study at an academic university medical center. Women receiving epidural labor analgesia from March to July of 2015 were identified and categorized into three groups: 1) CEI 5 mL/hr, 2) PIEB 5 mL/60 minutes, 3) PIEB 3 mL/30 minutes. The LA consisted of bupivacaine 0.125 mg/mL and fentanyl 2 μg/mL. All patients had similar PCEA settings. Data were collected on pattern of LA usage, obstetric outcomes and Bromage scores.

MAIN OUTCOME MEASURES

The primary endpoint was total volume of LA consumed per hour. Secondary outcomes included need for clinician boluses, pattern of PCEA use, degree of motor blockade and delivery mode.

RESULTS

We included 528 patients (262 had CEI, 162 had PIEB 5 mL/60 minutes, and 104 had PIEB 3 mL/30 minutes). Median LA consumed was 10.3, 9.5, and 9.7 mL/hr, respectively (p = 0.10). There were no differences in PCEA attempts or rescue clinician boluses, but PCEA volume (p = 0.03) and ratio of PCEA attempts/given (p < 0.01) were significantly different among the groups. Patients receiving PIEB 3 mL/30 minutes used lower PCEA volume than patients receiving CEI (p = 0.04). Patients with PIEB 5 mL/60 minutes and PIEB 3 mL/30 minutes had a higher ratio of PCEA attempts/given than CEI patients (p = 0.01 and p < 0.01, respectively). There were no differences in Bromage scores (p = 0.14) or delivery mode (p = 0.55) among the groups.

CONCLUSIONS

The epidural maintenance regimen used (CEI vs. PIEB) was not associated with differences in LA consumption, motor blockade or delivery mode. Main limitations of the study include its single center retrospective design and the fact that patients were not randomized to treatment groups.

Comparison of continuous epidural infusion and programmed intermittent epidural bolus in labor analgesia

BACKGROUND

This study aims to investigate differences between continuous epidural infusion (CEI) and programmed intermittent epidural bolus (IEB) analgesia for the Chinese parturients undergoing spontaneous delivery and to approach their safety to parturients and neonates.

METHODS

Two hundred healthy American Society of Anesthesiologists class I or II, term (≥37 weeks' gestation), nulliparous women who requested analgesia for labor were recruited. Epidural analgesia was initiated with a solution of 0.15% ropivacaine 10 mL and maintained with 0.1% ropivacaine mixed with sufentanil 0.3 μg/mL by CEI at a rate of 5 mL/h combined with a patient-controlled epidural analgesia (PCEA) bolus of 5 mL of ropivacaine sufentanil mixture or IEB of 5 mL of ropivacaine sufentanil mixture combined with a PCEA bolus of 5 mL of ropivacaine sufentanil mixture. The lockout interval was 20 minutes in each arm between the CEI and the IEB group. After 20 minutes of first dosage, visual analog scale (VAS) score was obtained every 60 minutes. The maternal and fetal outcome and total consumption of analgesic solution were compared.

RESULTS

There was no difference in demographic characteristics, duration of first and second stages, delivery methods, sensory block, fetal Apgar scores, and the maternal outcomes between the CEI and IEB groups. There was a significant difference in VAS scores and epidural ropivacaine total consumption between the two groups (IEB vs CEI: 51.27±9.61 vs 70.44±12.78 mg, P<0.01).

CONCLUSION

The use of programmed IEB mixed with PCEA improved labor analgesia compared to CEI mixed with PCEA, which could act as maintenance mode for epidural labor analgesia.

Programmed intermittent epidural boluses for maintenance of labor analgesia: an impact study

INTRODUCTION

The aim of this impact study was to compare the analgesic efficacy and side effect profile of programmed intermittent epidural boluses (PIEB)+patient-controlled epidural analgesia (PCEA) to continuous epidural infusion (CEI)+PCEA for maintenance labor analgesia after the introduction of PIEB at our institution.

METHODS

We conducted a retrospective analysis after replacing the background CEI with PIEB for our labor PCEA. Pre-change pump settings were CEI 12mL/h with PCEA (12mL bolus, lockout 15min); PIEB settings were a 9mL bolus every 45min with PCEA (10mL bolus, lockout 10min). We compared medical records of all women receiving epidural or combined spinal-epidural labor analgesia for vaginal delivery for two months before PIEB implementation to a two-month period of PIEB utilization following a five-month introductory familiarization period. The primary outcome was the proportion of women requiring rescue clinician boluses.

RESULTS

Fewer patients in the PIEB group required rescue clinician boluses compared to the CEI group (12% vs. 19%, P=0.012). Time to first rescue bolus request and total bolus dose were not different. Peak (median [IQR]) pain scores were 2[0-5] with CEI and 0[0-4] with PIEB. There was no difference in instrumental delivery rates.

CONCLUSIONS

Using PIEB compared to CEI as the background maintenance epidural analgesia method in conjunction with PCEA reduced the number of women requiring clinician rescue boluses while providing comparable labor analgesia. The findings of this clinical care impact study confirm the results of randomized controlled studies and suggest PIEB may be a preferable technique to CEI for the maintenance of labor analgesia.

Ultrasound-guided continuous interscalene block: the influence of local anesthetic background delivery method on postoperative analgesia after shoulder surgery: a randomized trial

BACKGROUND

Automated bolus delivery has recently been shown to reduce local anesthetic consumption and improve analgesia, compared with continuous infusion, in continuous sciatic and epidural block. However, there are few data on the influence of local anesthetic delivery method on local anesthetic consumption following interscalene blockade. This randomized, double-blind trial was designed to determine whether hourly automated perineural boluses (4 mL) of local anesthesia delivered with patient-controlled pro re nata (PRN, on demand) boluses would result in a reduction in total local anesthesia consumption during continuous interscalene blockade after shoulder surgery compared with continuous perineural infusion (4 mL/h) plus patient-controlled PRN boluses.

METHODS

One hundred one patients undergoing major shoulder surgery under general anesthesia with ultrasound-guided continuous interscalene block were randomly assigned to receive 0.2% ropivacaine via interscalene end-hole catheter either by continuous infusion 4 mL/h (n = 50) or as automated bolus 4 mL/h (n = 51). Both delivery methods were combined with 5 mL PRN boluses of 0.2% ropivacaine with a lockout time of 30 minutes. Postoperative number of PRN boluses, 24- and 48-hour local anesthetic consumption, pain scores, rescue analgesia (morphine), and adverse events were recorded.

RESULTS

There were no significant differences in either the number of PRN ropivacaine boluses or total 48 hour local anesthetic consumption between the groups (18.5 [11-25.2] PRN boluses in the continuous infusion group vs 17 [8.5-29] PRN boluses in the automated bolus group). Postoperative pain was similar in both groups; on day 2, the median average pain score was 4 (2-6) in the continuous infusion group versus 3 (2-5) in the automated bolus group (P = 0.54). Nor were any statistically significant intergroup differences observed with respect to morphine rescue, incidence of adverse events, or patient satisfaction.

CONCLUSIONS

In continuous interscalene blockade under ultrasound guidance after shoulder surgery, automated boluses of local anesthetic combined with PRN boluses did not provide any reduction in local anesthetic consumption or rescue analgesia, compared with continuous infusion combined with PRN boluses.

A comparison of continuous infusion and intermittent bolus administration of 0.1% ropivacaine with 0.0002% fentanyl for epidural labor analgesia

BACKGROUND AND AIMS

Minimal consumption of local anesthetic and opioid for epidural labor analgesia has been advocated for safe obstetric outcome and superior maternal satisfaction. The primary objective of this study was to evaluate and compare the analgesic efficacy of mode of administration of epidural 0.1% ropivacaine with 0.0002% fentanyl via continuous infusion or intermittent boluses during labor.

MATERIAL AND METHODS

Sixty term primi or second gravida healthy parturients in labor requesting epidural analgesia were recruited in this study. Lumbar epidural catheter was inserted, and analgesia initiated with 0.2% ropivacaine. Patients were randomized to receive ropivacaine 0.1% with fentanyl 0.0002% via either continuous infusion (Group A) or intermittent boluses (Group B) on an hourly basis. If the parturient complained of pain and visual analog scale (VAS) score was >3, an additional bolus of the study drug was given. VAS score, motor blockade, maternal hemodynamics and fetal heart sounds were frequently monitored. Side effects, mode of delivery and neonatal outcome were noted.

RESULTS

To achieve similar VAS, the mean total dose of ropivacaine was 18.78 ± 3.88 mg in Group A and 16.86 ± 4.3 mg in Group B, the difference being statistically significant (P = 0.04). Seventeen out of 30 patients in Group A that is, 56.6% and nine patients in Group B that is, 30% required additional top-ups, and this was significantly higher (P = 0.037). Side effects, mode of delivery and neonatal outcome were comparable in both groups.

CONCLUSION

Intermittent bolus administration provides a more efficacious route of drug delivery when compared to continuous infusion by significantly decreasing the total amount of local anesthetic plus opioid without adversely affecting patient safety or maternal satisfaction.

The efficacy of automated intermittent boluses for continuous femoral nerve block: a prospective, randomized comparison to continuous infusions

STUDY OBJECTIVE

To determine whether an automated intermittent bolus technique provides enhanced analgesia compared with a continuous infusion for femoral nerve block.

DESIGN

Prospective, single-blinded, randomized controlled trial (ClinicalTrials.gov Identifier: NCT01226927).

SETTING

Perioperative areas and orthopedic surgical ward of a university hospital.

PATIENTS

45 ASA physical status 1, 2, and 3 patients undergoing unilateral primary total knee arthroplasty.

INTERVENTIONS

All patients received single-injection sciatic and femoral nerve blocks plus femoral nerve catheter placement for postoperative analgesia. Patients were randomly assigned to an automated intermittent bolus (5 mL every 30 min with 0.1 mL/hr basal rate) or a continuous infusion (10.1 mL/hr) delivery method of 0.2% ropivacaine.

MEASUREMENTS

Consumption of intravenous patient-controlled analgesia (IV-PCA) and visual analog scale (VAS) pain scores were assessed postoperatively at set intervals until the morning of postoperative day (POD) 2.

MAIN RESULTS

The mean (SEM) cumulative IV-PCA dose (mg of hydromorphone) for the 36-hour postoperative interval measured was 12.9 ± 2.32 in the continuous infusion rate group (n = 20) and 7.8 ± 1.02 in the intermittent bolus group [n = 21, t(39) = 2.04, P = 0.048; a 39 ± 14% difference in total usage]. Pain scores were statistically significantly lower in the intermittent bolus group in the afternoon of POD 1 (t(39) = 2.47, P = 0.018), but were otherwise similar.

CONCLUSIONS

An automated intermittent bolus infusion technique for femoral nerve catheters is associated with clinically and statistically significantly less IV-PCA use (ie, an opioid-sparing effect) than a continuous infusion technique.

Comparision of efficacy of sufentanil and fentanyl with low-concentration bupivacaine for combined spinal epidural labour analgesia

Objectives:

The highly lipid-soluble opioids, sufentanil and fentanyl, are used in combination with low-concentration bupivacaine to provide combined spinal epidural (CSE) analgesia during labour. We designed a prospective, randomized, single-blind study to compare the efficacy of these two opioids with bupivacaine in terms of the quality of analgesia, side-effects and maternal and foetal outcome.

Methods:

Sixty parturients requesting labour analgesia were divided into two groups randomly. Group S (n=30) received bupivacaine heavy (2.5 mg) and sufentanil (5 mcg) intrathecally and 10 mL intermittent bolus of sufentanil 0.30 mcg/mL in bupivacaine 0.125% as epidural top-ups. Group F (n=30) received bupivacaine heavy (2.5 mg) and fentanyl (25 mcg) intrathecally and 10 mL intermittent bolus of fentanyl 2.5 mcg/mL in bupivacaine 0.125% as epidural top-ups. Duration of intrathecal and epidural analgesia, mean duration between epidural top-ups and total analgesic requirements were noted. Pain and overall satisfaction scores were assessed with a 10-point visual scale. Mode of delivery and neonatal Apgar scores were recorded.

Results:

Maternal demographic characteristics were comparable between the groups. Although CSE provided satisfactory analgesia in both the groups, parturients of group S had a significant prolongation of analgesia through the intrathecal route compared with parturients of group F. Incidence of caesarean, instrumental delivery did not differ between the groups. No difference in the incidence of motor blockade or cephalad extent of sensory analgesia was observed. Neonatal outcome and incidence of side-effects were similar in both the groups.

Conclusion:

We conclude that combined spinal epidural using sufentanil and fentanyl achieved high patient satisfaction and excellent labour analgesia without serious maternal or neonatal side-effects. Sufentanil provided a significantly longer duration of labour analgesia compared with fentanyl.

What's new in obstetric anesthesia? The 2011 Gerard W. Ostheimer Lecture

The "What's New in Obstetric Anesthesia" lecture was established by the Society for Obstetric Anesthesia and Perinatology in 1975 to update members on the preceding year's medical literature. In 1995, the lecture was renamed in honor of Gerard W. Ostheimer, an obstetric anesthesiologist from Brigham and Women's Hospital who contributed significantly to the knowledge and practice of obstetric anesthesia. The Ostheimer lecturer reviews the obstetric anesthesia, obstetric, perinatology, and health services literature to identify articles that are relevant to the practice of obstetric anesthesiology. This review summarizes the most relevant publications from the 2010 literature.