Hemodynamic Effects of Low Dose Spinal Anesthesia for Cesarean Section

November 4, 2016 updated by: University of Manitoba

We propose to study the effects on hemodynamics (blood pressure, cardiac output, and central venous pressure) of two doses of bupivacaine for spinal anesthesia during cesarean section: a higher dose of 12 mg to a lower dose of 4.5 mg. We will examine recovery times, incidence of hypotension, and compare pain control and maternal satisfaction during and after cesarean section.

We hypothesize that low dose bupivacaine spinal anesthesia will provide equivalent anesthesia for cesarean section compared to conventional dose bupivacaine, with less hypotension, faster recovery time, and enhanced maternal satisfaction. Maternal satisfaction will be assessed by self-reported pain scores, incidence of nausea and vomiting, shivering, and ability to interact with baby in the OR.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Terminated

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Hypothesis

It is hypothesized that low dose spinal anesthesia can provide equivalent anesthesia for cesarean section as higher conventional dose spinal anesthesia, with less hypotension, faster recovery and enhanced maternal satisfaction.

Patient Population

Adult females having elective, repeat cesarean sections who have given informed consent.

Exclusion Criteria

  • Contraindications to dural puncture
  • BMI >40
  • Elective C/S presenting in labour or with rupture of membranes
  • Placenta previa or accrete

Methodology

Patients will be screened in the antenatal clinic at Women's Hospital, Health Sciences Centre (HSC), Winnipeg during one of their regularly scheduled visits. If patients are scheduled at another antenatal clinic in the city, we will ask the obstetrician to briefly mention the study to potential study patients, and if they are interested give them the consent form to take home and read. We will then phone patients, obtain verbal consent and discuss any questions they may have. On the morning of their procedure we will obtain written consent, and answer any additional questions they may have. Alternatively, patients will be approached by their obstetrician in clinic, and if interested will be given the option to go to the Pre-Anesthesia Clinic at HSC where a member of our study team will discuss the study with them and obtain written consent.

Potential patients will be provided with information regarding the study and consent will be obtained prior to their enrollment in the study. Forty patients will be randomized into two groups: 1. Conventional dose spinal anesthesia 2. Low dose spinal anesthesia. Randomization will occur via sealed envelope prior to their scheduled cesarean section. The patient will be blinded to the randomization.

All women will have standard monitors. In addition, a radial arterial line will be inserted for continuous blood pressure measurement and cardiac output measurements using the FloTrac sensor and Vigileo monitor(cardiac output monitor using arterial waveform analysis, Edwards Life Sciences). All women will receive a preload of 500ml of Ringers Lactate solution intravenously.

The conventional dose control group will receive a spinal anesthetic consisting of hyperbaric bupivacaine 1.2cc (9mg) with fentanyl 15mg and preservative free morphine 150mcg. The patient will be in the sitting position for the dural puncture and then positioned supine, in the left lateral tilt position after the anesthetic solution has been given. Once block height has been established the patient will be placed in 20-30 degrees trendelenberg for the cesarean section.

The low-dose spinal group will receive a spinal anesthetic consisting of hyperbaric bupivacaine 4.5mg with fentanyl 15mg and preservative free morphine 150mcg. The patient will be positioned on her side, right side down and head down 20-30 degrees for the dural puncture and then positioned supine in the left lateral tilt position after the anesthetic solution has been given. The OR table will be kept in 20-30 degrees head down for the cesarean section.

Blood pressure will be monitored continuously. Cardiac output measurement will be done immediately prior to administering the spinal and immediately after positioning in a left lateral tilt position and then every five minutes until the end of the operation.

All women will be instructed in the use of a patient controlled analgesia (PCA) remifentanil infusion which they can use during the cesarean section if they experience any discomfort. If this is not adequate, 60-70% nitrous oxide will be attempted. If adequate pain control cannot be established and the cesarean section is not near completion, conversion to a general anesthetic will be the next step. All women will receive rectal naproxen at the conclusion of the surgery unless there is a contraindication or bleeding is a concern. All women will receive prophylactic ondansetron intraoperatively unless there is a contraindication.

Decreases in mean blood pressure greater than 20% from baseline or less than 90 mm Hg will be defined as hypotension and will be treated with incremental doses of phenylephrine (50-100mcg IV) or ephedrine (5mg) if maternal heart rate is less than 60 bpm. A 500cc lactated ringers bolus will be co-administered with initiation of the spinal anesthetic. Further fluids will be administered with a goal of approximately 1-1.5 liters intraoperatively. Each patient will in addition receive 20 units Oxytocin in 500cc saline. Additional fluid or uterotonics will be given as necessary for bleeding or hypotension and will be taken into account at the end.

Levels of sensory and motor blockade will be recorded just prior to skin prep, following arrival in recovery room and then every 30 minutes thereafter. Sensory block will be monitored by dermatome level at which there is a loss of sensation to ice. Motor blockade will be checked using the modified Bromage score (0 = no impairment, 1 = unable to raise extended legs but able to move knees and ankles, 2 = unable to raise extended legs or to flex knees but able to move feet, 3 = unable to flex ankles, knees or hips).

Maternal satisfaction will be assessed as self reported pain scores, nausea/vomiting, shivering, ability to interact with baby in the OR.

Outcome measures will include the following

  1. Hemodynamics (BP, heart rate (HR), Cardiac Index)
  2. Time to completion of spinal anesthetic (from skin puncture to positioning in the left lateral tilt position)
  3. Surgical time (skin incision to skin closure)
  4. Total remifentanil administration during the procedure
  5. Total phenylephrine administration during the procedure
  6. Administration of any other sedatives/anti-emetics
  7. Fetal cord blood gases (arterial and venous) and Apgar scores
  8. Maternal satisfaction scores
  9. Bilateral sensory block levels Bromage scores on arrival to PACU and every 30 minutes until the patient is discharge ready
  10. Time to being discharge ready from PACU
  11. Complications (difficult spinal, PDPH)

Outcome 1 to 6 will be recorded intraoperatively (average time 90 to 120 minutes). Outcomes 6 to 10 will be recorded in the post anesthesia care unit (PACU)(average stay 4 to 6 hours). Outcome 11 will be recorded for the duration of the patient's hospital stay.

Patients will be followed for the duration of their hospital stay (estimated three days).

Statistical Analysis

Statistical analysis will be done by the Biostatistical Consulting Unit of the University of Manitoba. It will consist of analysis of variance for repeated measures for continuous variables, student's T-test and Chi square analysis for non-parametric variables. P<0.05 will be considered statistically significant.

We propose to study 20 patients in each group.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Manitoba
      • Winnipeg, Manitoba, Canada, R3E 0W2
        • Health Sciences Centre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 40 years (ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Adult females having elective, repeat cesarean sections who have given informed consent.

Exclusion Criteria:

  • • Contraindications to dural puncture

    • BMI >40
    • Elective C/S presenting in labour or with rupture of membranes
    • Placenta previa or accrete

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Allocation: RANDOMIZED
  • Interventional Model: SINGLE_GROUP
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
EXPERIMENTAL: Low Dose Spinal

Hyperbaric bupivacaine 4.5mg with fentanyl 15mcg and preservative free morphine 150mcg.

The patient will be positioned right side down and head down 20-30 degrees for the dural puncture and then positioned supine in the left lateral tilt position after the anesthetic solution has been given. The OR table will be kept in 20-30 degrees head down for the cesarean section.
Drug: Bupivacaine 4.5
Bupivacaine hyperbaric, 4.5 mg
Drug: Morphine
morphine 150 mcg.
Drug: Fentanyl
15 mcg
ACTIVE_COMPARATOR: Control Spinal Group

Hyperbaric bupivacaine 1.2cc (9mg) with fentanyl 15mcg and preservative free morphine 150mcg.

The patient will be in the sitting position for the dural puncture and then positioned supine, in the left lateral tilt position after the anesthetic solution has been given. Once block height has been established the patient will be placed in 20-30 degrees trendelenberg for the cesarean section.
Drug: Morphine
morphine 150 mcg.
Drug: Fentanyl
15 mcg
Drug: Bupivacaine 9
Bupivacaine hyperbaric, 9 mg

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Recovery room length of stay
Time Frame: Current recovery room average length of stay is 4 hours
The primary endpoint is the expected reduction in the Recovery Room length of stay. Based on a predicted 50-100% reduction in length of stay, alpha 0.05, power of 80%, and given an anticipated drop-out rate of 10%, a sample size of n = 20 study patients per group is required.
Current recovery room average length of stay is 4 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Hemodynamics
Time Frame: Average duration of surgery is 100 minutes
Intraoperative management during Cesarean section, Hemodynamics (BP, HR, Cardiac Index)
Average duration of surgery is 100 minutes

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Maternal satisfaction scores
Time Frame: Average duration of recovery room stay is 4 hours.
Post-operative maternal satisfaction scores, every 30 minutes until the patient is discharge ready from PACU.
Average duration of recovery room stay is 4 hours.
Bromage Scores
Time Frame: Average recovery room length of stay is 4 hours
Bromage Scores every 30 minutes until discharge from PACU.
Average recovery room length of stay is 4 hours
Sensory Levels
Time Frame: Average recovery room length of stay is 4 hours
Sensory levels will be measured every 30 minutes until discharge from PACU.
Average recovery room length of stay is 4 hours
Remifentanil PCA
Time Frame: Intra-operatively. Average OR Time is 100 minutes.
Total Remifentanil PCA dose will be recorded intraoperatively.
Intra-operatively. Average OR Time is 100 minutes.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Manitoba

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Stephen E Kowalski, MD, University of Manitoba

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2013

Primary Completion (ACTUAL)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2014

Study Completion (ACTUAL)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2015

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 26, 2013

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 13, 2014

First Posted (ESTIMATE)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 15, 2014

Study Record Updates

Last Update Posted (ESTIMATE)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 8, 2016

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 4, 2016

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • B2013060

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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