Minimum Effective Dose of Ropivacaine for Spinal Anesthesia for Cesarean Delivery

NCT ID: NCT02565303

Last Updated: 2018-03-01

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 60 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-09-30
• Study Completion Date: 2017-06-30

Brief Summary

Ropivacaine is one of commonly used anesthetics for spinal anesthesia. Usually L2-3 or L3-4 intervertebral space is chosen for spinal anesthesia. The efficacy of ropivacaine injected into subarachnoid space depends on the given dose and the chosen intervertebral space. Appropriate dose could satisfy the requirement of operation and reduce incidence of the adverse reaction. But it is not certain about the minimum effective dose of ropivacaine in cesarean section through the two intervertebral spaces, respectively. This study is being conducted to find the minimum effective doses for L2-3 and L3-4 spinal anesthesia in cesarean section.

Detailed Description

Some unexpected adverse reactions such as respiratory depression, vomiting, especially supine hypotensive syndrome could caused by a high dose of anesthetic in cesarean section. The investigators assumed that there be a minimum effective dose that will be associated with the best possible performance of ropivacaine for different intervertebral spaces(L2-3 and L3-4 in usual). That maybe enhance the comfort of parturient and safety of fetus.

This study is conducted as a prospective, randomized, up-down sequential dose of isobaric ropivacaine in 3 mL that will provide effective analgesia for 50% of parturients in cesarean section. The investigators use the combined spinal-epidural anesthesia(CSEA) technique in the study. The initial dose of ropivacaine is chosen as 12 mg in L2-3 group and 15 mg in L3-4 group, and the testing interval is 0.5 mg with subsequent doses being determined by the outcome of the previous injection in the same group. If the previous response is ineffective, the next patient will receive 0.5 mg more than the last patient. If the response of the previous patient is effective, the next patient decrease 0.5mg.

The visual analogue scale (VAS) is used to rate the pain, where 0 is no pain and 10 is the worst pain imaginable. Criteria for evaluation:(1) effective: after spinal anesthesia finish, a dose that provide adequate sensory dermatomal anesthesia to pinprick to T6 or higher within 10 minutes, and the VAS is lower than or equal to 3 within 60minutes after skin incision; (2) ineffective: if the initial plane of sensory dermatomal anesthesia is lower than T6 or VAS is greater than 3 within 60 minutes after skin incision, the dose of ropivacaine is considered inadequate and additional lidocaine is given through epidural catheter.

Motor assessments are performed at the start of operation. Motor block in the lower limb is assessed by a modified Bromage scale (0=no paralysis, 1=unable to raise extended leg, 2=unable to flex knee,3=unable to flex ankle). All of the assessments are made by an anesthetist who is blinded to the group assignment as well as to the dose injected.

On the other hand, the investigators will compare the incidence of adverse reaction between the L2-3 and L3-4 group.

Using the Dixon and Massey up-and-down method study design, 60 patients scheduled for elective cesarean section will be included in the study, 30 for each group.

Conditions

Spinal Anesthesia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

L2-3 intervertebral group

The initial dose of ropivacaine for subarachnoid is chosen as 12 mg in L2-3 intervertebral space group.

Group Type: EXPERIMENTAL

Intervertebral space

Intervention Type: PROCEDURE

Ropivacaine

Intervention Type: DRUG

The initial dose of ropivacaine is chosen as 12 mg in L2-3 group and 15 mg in L3-4 group with the volume of 3 mL in both groups. The testing interval is 0.5 mg with subsequent doses being determined by the outcome of the previous injection in the same group.If the previous response is ineffective, the next patient will receive 0.5 mg more than the last patient. If the response of the previous patient is effective, the next patient decrease 0.5mg.

L3-4 intervertebral group

The initial dose of ropivacaine for subarachnoid is chosen as 15 mg in L3-4 group.

Group Type: EXPERIMENTAL

Intervertebral space

Intervention Type: PROCEDURE

Ropivacaine

Intervention Type: DRUG

The initial dose of ropivacaine is chosen as 12 mg in L2-3 group and 15 mg in L3-4 group with the volume of 3 mL in both groups. The testing interval is 0.5 mg with subsequent doses being determined by the outcome of the previous injection in the same group.If the previous response is ineffective, the next patient will receive 0.5 mg more than the last patient. If the response of the previous patient is effective, the next patient decrease 0.5mg.

Interventions

Intervertebral space

Intervention Type: PROCEDURE

Ropivacaine

The initial dose of ropivacaine is chosen as 12 mg in L2-3 group and 15 mg in L3-4 group with the volume of 3 mL in both groups. The testing interval is 0.5 mg with subsequent doses being determined by the outcome of the previous injection in the same group.If the previous response is ineffective, the next patient will receive 0.5 mg more than the last patient. If the response of the previous patient is effective, the next patient decrease 0.5mg.

Intervention Type: DRUG

Other Intervention Names

Naropin

Eligibility Criteria

Inclusion Criteria

• Full term parturient(> 37 and <42 weeks gestation)
• Above 20 years and below 35 years
• American Society of Anesthetists(ASA) I to II
• Singleton pregnancy
• Elective cesarean section
• Body weight during 60-85kg, height during 150-170cm

Exclusion Criteria

• Patient refusal
• Hypertension
• Diabetes mellitus
• Heart diseases
• Asthma
• Abnormal fetus or placenta
• Contraindications to combined spinal-epidural anesthesia(CSEA)
• Allergy to ropivacaine

• Minimum Eligible Age: 20 Years
• Maximum Eligible Age: 35 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: Yes

Sponsors

Shanghai 6th People's Hospital

OTHER

Sponsor Role: lead

Responsible Party

Xiaofeng WANG

physician

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Shanghai Sixth People's Hospital

Shanghai, Shanghai Municipality, China

Countries

China

Other Identifiers

2015-35-(1)

Identifier Type: -

Identifier Source: org_study_id