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Completed

NCT Number: NCT02635555

The Effects of Height and Weight Adjusted Dose of Local Anesthetic.

At our centre a conventional dose of 12 mg of hyperbaric bupivacaine in combination with a short acting opioid fentanyl (to increase block density) and a long acting opioid morphine (to provide post-operative pain relief ) is used for spinal anesthesia for cesarean section.However, larger doses of local anesthetic drug when used in caesarean section commonly cause low blood pressure and requires drugs (vasopressors) to treat it. In our study the investigators will standardize the doses of both opioids (fentanyl/morphine) and adjust the dose of local anesthetic (bupivacaine) based on the patients height and weight .One of the obvious challenges anesthesiologists face is providing adequate anesthesia to the patient whilst minimizing harmful side effects. Our primary concern is the low blood pressure as an effect of the spinal anesthetic as it is harmful to both mother and the baby. The investigators propose that the extent of surgical anesthetic block, which is dependent on height and weight in our adjusted dose group, will provide adequate anesthesia for surgery and minimise maternal low blood pressure.

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Key information

Conditions

Complications; Cesarean Section Cardiovascular Diseases Hypotension Vascular Diseases

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Victoria Hospital

London, Ontario, N6A 5W9, Canada

About this study

Study design is prospective, randomized, double blind, placebo controlled.

Patients presenting for elective cesarean section under neuraxial block and meeting inclusion criteria will be randomized to two groups:

Group 1: Fixed dose group: Bupivacaine 12 mg, Fentanyl 15 mcg, Morphine 100 mcg Group 2: Height and weight adjusted bupivacaine dose, fentanyl 15 mcg, morphine 100 mcg Patients are fasted as per Canadian guidelines prior to the procedure. All patients have an IV cannula inserted,baseline vitals recorded and routine blood work checked prior to blockade. Routine monitoring (as per Canadian Anesthesia Society (CAS) guidelines) occur during and after the procedure. This includes pulse oximetry (SpO2), ECG and non-invasive blood pressure (NIBP). NIBP monitoring occurs every two minutes for the first 20 minutes post spinal and every 5 minutes thereafter. Oxygen via Hudson mask or nasal prongs is available if required.

Spinal anesthetic is performed with standard doses of drugs and the level of sensory block is tested with ice. Motor block is tested with Bromage scale just before prepping and draping. Once deemed adequate, surgery begins. During surgery, phenylephrine/ephedrine is given to maintain blood pressure as necessary. After surgery, patients are monitored in a recovery area until fit to be transferred to their rooms. If patient reports extreme discomfort or sharp pain during the surgery,conversion to general anesthetic is as per the discretion of the attending anesthesiologist.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

ASA I and II patients aged 18-40 > 37 weeks gestation

  • Scheduled for an elective c-section under spinal anesthetic
  • Singleton pregnancy
  • Patients height between 150-180cm and with a BMI of <35
  • Subject understands the study and consents to participate

Exclusion criteria

Contraindication to neuraxial blockade

  • Local anesthetic allergy
  • Above or below our defined height and BMI criteria
  • Emergency C-Section
  • Complicated pregnancy including severe toxemia, pregnancy induced hypertension, and placenta previa

Treatment and study plan

Phenylephrine

Drug

100 mcg of phenylephrine or 5 mg ephedrine given as deemed necessary for treating episodes of hypotension.

Other names: Ephedrine

Primary outcomes

  1. Maternal hypotension needing vasopressors.

    Time frame: Until the end of surgery

Secondary outcomes

  1. Time to adequate surgical anesthetic block

    Time frame: 24 hours after the surgery

  2. incidence of nausea, vomiting, pruritus, and respiratory depression

    Time frame: 24 hours after the surgery

  3. conversion to general anesthesia due to block failure

    Time frame: 1 hour

Sponsors and collaborators

Lead sponsor

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Other

Registry information

Official study title

The Effects of Height and Weight Adjusted Dose of Local Anesthetic Compared to Standard Dose for Spinal Anesthesia in Elective Cesarean Section

Important dates

Study start
2016
Primary completion
2019
Study completion
2019
First posted
Dec 21, 2015
Registry last updated
Sep 26, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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