Exploring the Optimal Concentration of Lidocaine Test Dose for Labor Analgesia

N/AActive Not RecruitingNCT06819579

The Second Affiliated Hospital of Chongqing Medical University99 enrolled

Overview

This study aims to compare the analgesia effects and side effects of different concentrations of test dose lidocaine (1.5% lidocaine 3 ml, 1.0% lidocaine 5 ml, 0.5% lidocaine 10 ml) in labor analgesia, so as to provide a scientific basis for the clinic al practice of labor analgesia.

Epidural analgesia is the most effective and widely used analgesic method for relieving labor pain in clinical practice. However, inadvertent insertion of an epidural catheter into a blood vessel or subarachnoid space may result in local anesthesia or total spinal anesthesia, which can be life-threatening. Therefore, a low-concentration, low-volume dose of local anesthetic is usually injected as a test dose before injecting a large dose of local anesthetic through the epidural catheter to ensure that the catheter is within the epidural space. At present, the guidelines recommend 3 ml of 1.5% lidocaine as the test dose, but in clinical practice and the study of Chen et al., it was found that the test dose of 1.5% lidocaine 3ml still has a high incidence of lower limb motor block of 57.1%, which affects maternal activity and labor progression. In addition, Liu Henry et al. found that the incidence of 0.5% lidocaine 10 ml test dose-induced motor block was 0%, and the analgesic effect could be quickly achieved. Therefore, it is uncertain which concentration of lidocaine has the fastest onset of analgesia and the fewest side effects in labor analgesia. Therefore, this study aims to compare the effects of different concentrations of lidocaine (1.5% lidocaine 3 ml, 1.0% lidocaine 5 ml, 0.5% lidocaine 10 ml) in labor analgesia, so as to provide a scientific basis for the clinical practice of labor analgesia.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Labor Pain

Interventions

1.5% LidocaineDRUG

After successful epidural puncture, 3ml of 1.5% lidocaine was injected as a test dose

1.0% LidocaineDRUG

After successful epidural puncture, 5ml of 1% lidocaine was injected as a test dose

0.5% LidocaineDRUG

After successful epidural puncture, 10ml of 0.5% lidocaine was injected as a test dose

Eligibility

Sex: FEMALEMin age: 20 YearsMax age: 40 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Singleton primipara 2. Aged 20-40 years 3. Pre-assessed as eligible for vaginal delivery 4. Height between 155-170 cm, BMI between 18.5-35 kg/m² 5. Cervical dilation between 2-6 cm 6. No significant history of cardiopulmonary disease 7. No history of surgical trauma 8. American Society of Anesthesiologists (ASA) Grades I-III 9. Patients are willing to participate and be able to understand and sign an informed consent form Exclusion Criteria: 1. Contraindications for spinal anesthesia, such as coagulopathy or ongoing anticoagulant therapy, infection at the puncture site, bacteremia, epidural abscess, increased intracranial pressure, severe hypovolemia 2. Physical or mental disabilities, such as scoliosis and depression, alcohol or drug abuse 3. Major organ diseases, such as hyperthyroidism, cardiopulmonary diseases, diabetes treated with insulin, and neuromuscular diseases 4. Numerical Pain Rating Scale (NPRS) \< 5 5. Refusal to participate in the study

Locations (1)

The Second Affiliated Hospital of Chongqing Medical University

Chongqing, Chongqing Municipality, China

Outcomes

Primary Outcomes

The incidence of motor block

Bromage Scores were used to grade movement block: I free movement of legs and feet, II free movement of feet with only bent knees, III free movement of feet without bending knees, IV no movement of legs and feet, with scores of II, III and IV considered as movement block.

Time frame: 3,5,7,9,11,13,15,20,25,30 minutes after lidocaine administration

Secondary Outcomes

Pain scores

Pain scores is assessed by the Numerical Pain Rating Scale (NPRS, where 0 means no pain and 10 means no pain tolerance)

Time frame: 3,5,7,9,11,13,15,20,25,30 minutes after lidocaine administration

Time of analgesia onset

Pain scores is assessed by the Numerical Pain Rating Scale (NPRS, where 0 means no pain and 10 means no pain tolerance). Analgesia is considered effective when NPRS is ≤3 or NPRS is reduced by ≥ 50% of the baseline value.

Time frame: 3,5,7,9,11,13,15,20,25,30 minutes after lidocaine administration

Sensory block level

Midabdominal line acupuncture was used to assess the sensory block level

Time frame: 3,5,7,9,11,13,15,20,25,30 minutes after lidocaine administration

Incidence of complications related to labor analgesia

Ask the patient if they have discomfort such as leg warmth, leg numbness, trembling, itching, headache, tinnitus, etc.

Time frame: 30 minutes after lidocaine administration

frequency and intensity of uterine contractions

A contraction monitor is used to monitor the intensity and frequency of contractions

Time frame: 30 minutes after lidocaine administration

Data from ClinicalTrials.gov

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