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Anesthesia and analgesia · Feb 2020
Randomized Controlled Trial Comparative StudyComparison of Programmed Intermittent Epidural Boluses With Continuous Epidural Infusion for the Maintenance of Labor Analgesia: A Randomized, Controlled, Double-Blind Study.
Programmed Intermittent Epidural Boluses delivered by a commerically-available epidural pump, did not improve outcomes over continuous epidural infusion other than a lower incidence of motor block.
pearl- Oluremi A Ojo, Jennifer E Mehdiratta, Brock H Gamez, John Hunting, and Ashraf S Habib.
- From the Department of Anesthesiology, Duke University, Durham, North Carolina.
- Anesth. Analg. 2020 Feb 1; 130 (2): 426-435.
BackgroundProgrammed intermittent epidural boluses may improve the spread of local anesthetics compared to continuous epidural infusion, improving labor analgesia and obstetric outcomes. However, there are limited data from studies using commercially available pumps capable of coadministering programmed intermittent epidural boluses or continuous epidural infusion with patient-controlled epidural analgesia. Therefore, we performed this prospective, randomized, double-blind study to compare the impact of programmed intermittent epidural boluses versus continuous epidural infusion on labor analgesia and maternal/neonatal outcomes. We hypothesized that programmed intermittent epidural boluses will result in lower patient-controlled epidural analgesia consumption compared to that with continuous epidural infusion.MethodsFollowing standardized initiation of epidural labor analgesia, women were randomized to receive 0.1% ropivacaine with 2 µg/mL fentanyl as 6-mL programmed intermittent epidural boluses every 45 minutes or continuous epidural infusion at 8 mL/h in a double-blind fashion with similar patient-controlled epidural analgesia settings in both groups. The primary outcome was patient-controlled epidural analgesia consumption per hour. Secondary outcomes included a need for physician interventions, patterns of patient-controlled epidural analgesia use, motor blockade, number of patients who developed hypotension, pain scores, duration of second stage of labor, mode of delivery, and maternal satisfaction.ResultsWe included 120 patients (61 in programmed intermittent epidural boluses group and 59 in continuous epidural infusion group) in the analysis. The median (interquartile range) patient-controlled epidural analgesia volume consumed per hour was not significantly different between the groups: 4.5 mL/h (3.0-8.6 mL/h) for the continuous epidural infusion group and 4.0 mL/h (2.2-7.1 mL/h) for the programmed intermittent epidural boluses group (P = .17). The Hodges-Lehmann location shift estimate of the difference (95% CI) from the continuous epidural infusion to the programmed intermittent epidural boluses group is 0.9 mL/h (-0.4 to 2.2 mL/h). There were also no significant differences between the groups in any of the secondary outcomes except for higher median (interquartile range) patient-controlled epidural analgesia attempts per given ratio per hour in the programmed intermittent epidural bolus group (0.17 [0.10-0.30] vs 0.12 [0.08-0.18]; P = .03) and more motor block in the continuous epidural infusion group (those with Bromage score <5, 27.5% vs 50.0%; P = .03).ConclusionsUnder the conditions of our study, we did not find improved outcomes with programmed intermittent epidural boluses compared to continuous epidural infusion except for less motor block with programmed intermittent epidural boluses. Future studies should assess whether smaller but clinically important differences exist and evaluate different parameters of programmed intermittent epidural boluses to optimize analgesia and outcomes with this mode of analgesia.
This article appears in the collection: Programmed Intermittent Epidural Bolus for Labour Analgesia.
Notes
What’s so special about Programmed Intermittent Epidural Boluses?
Programmed Intermittent Epidural Bolus (PIEB) techniques have been advocated as an improvement over continuous epidural infusions because of the potential to optimise local anaesthetic spread through the epidural space.
Other studies have suggested that PIEBs result in reduced local anaesthetic consumption, less motor block, fewer instrumental and cesarean deliveries and improved maternal satisfaction – however these have often occured in research environments and with equipment not representative of typical clinical practice.
What did they do?
This Duke University team randomized 120 parturients to epidural ropivacaine 0.1% + fentanyl 2 mcg/mL delivered either as PIEB (6mL q45min) or continuous infusion (8 mL/h). All subjects had access to patient controlled epidural analgesia (PCEA) for breakthrough pain, used as the marker of analgesia efficacy. The study used the commercially-available CADD Solis pump.
And they found...
There was no difference in PCEA volume between groups, or in any secondary outcome (physician interventions, hypotension, pain scores, satisfaction, duration, or delivery mode), EXCEPT for a greater motor block seen with the continuous infusion group (50% vs 28% Bromage < 5).
Bottom-line
This (relatively small) study did not find significant improvement in labor experience or outcome with PIEB using commercially available epidural pumps, although the reduction in motor blockade may
Pause for thought...
The big challenge with identifying benefit from PIEB techniques is that it introduces even more epidural variables (pump type, bolus volume, frequency, concentration & flow rate, lockouts, background infusions...) making it very difficult to compare the conlficting results of PIEB studies.
Read more in the growing Programmed Intermittent Epidural Bolus for Labour Analgesia article collection.
Daniel Jolley
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