Minimum Effective Dose (MED) & Epidural Bupivacaine

Study Overview
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Brief Summary
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Local anaesthetics are highly toxic drugs. They can cause toxicity by an absolute overdose, accidental injection in a blood vessel or slow absorption from the area of injection. The risk of toxicity when performing regional anaesthesia can be reduced significantly by injecting the optimal dose of local anaesthetic at the correct site. To date most of the local anaesthetic dose finding studies for epidural labour analgesia has focused on ED50 ( the dose effective in 50% of patients). The purpose of this research study is to find out the ED95 dose (the dose effective in 95% of patients) of local anaesthetic for epidural analgesia in labour. The dose determined from this research trial will guide the anaesthetists to the optimal starting dose of the local anaesthetics for epidural analgesia in labour. This would lead to decreased chances of toxicity and will improve patient safety. We aim to recruit a total of 100 pregnant patients in early labour (cervical dilatation ≤ 5 cm) requesting epidural analgesia to answer the research question based on the continual reassessment method. Patients will be recruited according to well-defined criteria. They will be fully informed about the study and have the choice of not participating or opting out at any time during the study. It is not going to affect the kind of treatment they receive. The experts in the field with full safety precautions will perform this study at St James' Hospitals, Leeds.

Official Title
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Comparison of the ED95 Dose of 0.075% and 0.1% Bupivacaine for Labour Analgesia in Primigravida.

Conditions
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Labour, Pregnancy, Primigravida Labour, Epidural Block

Intervention / Treatment
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* Drug: 0.1% bupivacaine
* Drug: 0.075% bupivacaine
* Drug: 40 µg fentanyl


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anaesthesiologists (ASA) 1-3 patients Primigravida (1st pregnancy) patients requesting epidural analgesia in early labour (≤ 5 cm cervical dilatation. Exclusion Criteria: Primigravida (1st pregnancy) patients requesting epidural analgesia in late labour (> 5 cm cervical dilatation) Multigravida patients ( ≥ 2nd pregnancy) ASA > 3 Allergy to Bupivacaine Unable to give written informed consent BMI >35 Abnormal blood coagulation profile Patients taking any medication that are indicated in the Summary of Product Characteristics (SPC) as not recommended

Ages Eligible for Study
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Minimum Age: 18 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: 0.075% bupivacaine<br>Consenting patients randomised to receive 0.075% bupivacaine and 40 µg fentanyl. | Drug: 0.075% bupivacaine<br>* Epidural block in early labour.<br>Drug: 40 µg fentanyl<br>* Given with different doses of bupivacaine in epidural block.<br>|
| Experimental: 0.1% bupivacaine<br>Consenting patients randomised to receive 0.1% bupivacaine and 40 µg fentanyl. | Drug: 0.1% bupivacaine<br>* Epidural block in early labour.<br>Drug: 40 µg fentanyl<br>* Given with different doses of bupivacaine in epidural block.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effective dose in 95% of patients (ED95) dose of bupivacaine for a primigravida in early labour. | To find out the ED95 dose of bupivacaine 0.075% and 0.1% for epidural analgesia for a primigravida in early labour . | up to 30 minutes |