Development of Variable Volume Automated Mandatory Boluses for Patient-controlled Epidural Analgesia During Labour

Study Overview
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Brief Summary
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A novel epidural delivery regimen was developed: Variable volume automated mandatory bolus (AMB) (VVAMB) will advance individualisation of labour epidural analgesia, by which a larger volume of bolus may contribute to better spread of the local anaesthetics within brief period and thereby reduces the chances of motor blockade that could reduce instrumental deliveries.

Detailed Description
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Epidural analgesia is the gold standard of pain relief for labour pain. Despite this, up to 50% of parturients continue to experience pain leading to suffering and increased caregiver workload. There is also higher risk of motor blockade found in those receiving epidural analgesia, and these factors is associated with dysfunctional labour requiring obstetric intervention (instrumental delivery). Automated mandatory bolus (AMB) of variable-frequency (VAMB) has been shown to provide better pain relief as compared with conventional patient-controlled epidural analgesia (PCEA) with basal infusion, however its long lockout time per hour is associated with unsuccessful patient bolus requests, with similar motor block to conventional regimens. The investigators therefore proposes to develop a novel epidural delivery regimen: Variable volume AMB (VVAMB) will advance individualisation of labour epidural analgesia, by which a larger volume of bolus may contribute to better spread of the local anaesthetics within brief period and thereby reduces the chances of motor blockade that could reduce instrumental deliveries. This algorithm development including pilot and clinical trial will compare VVAMB with VAMB regimens, in reducing the incidence of motor block in 216 term women requesting for labour epidural analgesia.

Official Title
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Development of Variable Volume Automated Mandatory Boluses (VVAMB) for Patient-controlled Epidural Analgesia During Labour and Delivery

Conditions
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Labor Pain, Breakthrough Pain

Intervention / Treatment
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* Device: Epidural infusion pump
* Drug: Ropivacaine
* Drug: Fentanyl


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy (American Society of Anesthesiologists (ASA) physical status 1 and 2) primiparous parturient at term (≥36 weeks gestation); Singleton fetus; In early labor stage (cervical dilation ≤5cm); Request labor epidural analgesia and able to administer combined spinal epidural analgesia (CSEA) according to protocol. Exclusion Criteria: Non-cephalic fetal presentation; Obstetric (e.g. pre-eclampsia, premature rupture of amniotic membranes for more than 48 hours, gestational diabetes on insulin, pregnancy-induced hypertension on medication) and uncontrolled medical (e.g. cardiac disease) complications; Have contraindications to neuraxial blockade or have received parenteral opioids within last 2 hours; Dural puncture/ suspected dural puncture at initiation of CSEA.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Variable volume Automated Mandatory Bolus (VVAMB)<br>The anaesthetic drug and pain medication are prepared in an epidural infusion pump with the VVAMB programme. The programme uses higher doses with lower frequency of medication (ropivacaine and fentanyl), and a patient control button for the patient to control the additional pain relief demands depending on the requirements during labour. | Device: Epidural infusion pump<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Epidural delivery system;Drug: Ropivacaine<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Amide local anaesthetic;Drug: Fentanyl<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Opioid;|
| Active Comparator: Automated mandatory bolus (AMB) of variable-frequency (VAMB)<br>The anaesthetic drug and pain medication are prepared in an epidural infusion pump with the VAMB programme. The programme uses lower doses with more frequency of medication (ropivacaine and fentanyl), and a patient control button for the patient to control the additional pain relief demands depending on the requirements during labour. | Device: Epidural infusion pump<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Epidural delivery system;Drug: Ropivacaine<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Amide local anaesthetic;Drug: Fentanyl<br>* Epidural delivery system for maintenance of labour epidural analgesia using 0.1% ropivacaine (amide local anaesthetic) with 2mcg/ml fentanyl (opioid) as maintenance solution.<br>* Other names: Opioid;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of motor block in each group | The number of event of motor block throughout the labour. Previous studies have shown that epidural analgesia using high concentrations of local anaesthetics could lead to decreased motor functions, and are subsequently associated with an increased incidence of instrumented delivery and longer second stage of labour. In this study, the intensity of motor block is assessed by the patient's ability to move their lower extremities via a modified Bromage scale. In the modified version, a scoring of 0 implies no motor block (Free movement of both legs and feet), scoring of 1 implies partial block (Just able to flex knees with free movement of feet), 2 implies almost complete block (Unable to flex knees but with free movement of feet) and 3 implies a full block (Unable to move legs/ feet). | During labour (1 day) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of subjects with Instrumental delivery | The number of subjects in each group having instrumental delivery (forceps, vacuum delivery) | During labour (1 day) | 
| Number of subjects with Breakthrough pain | The number of subjects in each group having unscheduled epidural supplementation by anaesthetist due to labor pain | During labour (1 day) | 
| APGAR score | The Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score is a test given to newborns soon after birth. In the test, five are being evaluated: Appearance (skin color), Pulse (heart rate), Grimace response (reflexes), Activity (muscle tone) and Respiration (breathing rate and effort). Each is scored on a scale of 0 to 2, with 2 being the best score; a total score of ten represents the best possible condition. | After delivery (1 day) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Labor Pain, Breakthrough Pain, Infusion pump