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NCT Number: NCT04946006

Maintenance Infusion of Oxytocin Following Elective Cesarean Deliveries

This study is designed to determine the minimal effective oxytocin maintenance dose required during cesarean delivery to achieve the best effect. Oxytocin is a drug which is routinely used to help contract the uterus and keep it contracted after the delivery of the baby and placenta. The aim of oxytocin is to reduce the amount of blood that might be lost. In order to determine the minimal effective dose, the investigators will conduct a dose-finding study. The first patient will receive a set oxytocin infusion. If the uterus contracts well, this is considered satisfactory and the next patient will receive the same dose. If the uterus does not contract well, this is considered unsatisfactory and the next patient will receive a higher dose. The dose for the next patient will be determined based on the results of the uterine contraction of the previous patient.

The investigators hypothesize that the ED90 of an oxytocin infusion rate to maintain a satisfactory uterine tone during a cesarean delivery in non-laboring women, would be lower than that found in previous studies without an initial bolus (less than 16 IU/h).

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Key information

Conditions

Postpartum Hemorrhage Female Urogenital Diseases and Pregnancy Complications Hemorrhage Obstetric Labor Complications Pathologic Processes Pathological Conditions, Signs and Symptoms Pregnancy Complications Puerperal Disorders Urogenital Diseases Uterine Hemorrhage

Age range

18 year–50 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Mount Sinai Hospital

Toronto, Ontario, M5G1X5, Canada

About this study

This study will be conducted as a prospective, double blinded clinical trial (patient, anesthesiologist and obstetrician blinded to the oxytocin dose), in an up-down sequential allocation fashion. The objective of the study is to determine the minimum effective dose of oxytocin infusion required to produce appropriate uterine contraction during and after cesarean delivery under neuraxial anesthesia in non-laboring women. For the purpose of this study, the minimum effective dose is defined to be that at which adequate response occurs in 90% of patients, i.e. ED90.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Elective uncomplicated cesarean delivery under neuraxial anesthesia
  • >18 year-old with ASA status II or III, with a singleton gestation and a gestational age between 37 to 42 weeks Informed consent to participate in this study

Exclusion criteria

  • Refusal to give written informed consent
  • Allergy or hypersensitivity to oxytocin
  • Body mass index ≥ 40 kg/m2on the day of admission
  • A history of hypertension and/ or severe cardiac disease(s)
  • Contra-indications for neuraxial anesthesia
  • Conditions that predispose to uterine atony and postpartum hemorrhage such as placenta previa, multiple gestation, preeclampsia, macrosomia (≥ 4 kg), polyhydramnios, uterine fibroids in and near operating field, previous history of uterine atony and postpartum bleeding, or bleeding diathesis.

Treatment and study plan

Oxytocin

Drug

Oxytocin will be prepared in a 1L bag of Ringer's lactate, to be infused at a rate of 125 ml/h.

Other names: Pitocin

Primary outcomes

  1. Uterine tone upon discharge from the post anesthetic care unit (PACU): questionnaire

    Time frame: 2 hours

    Uterine tone will be evaluated as satisfactory or unsatisfactory by the obstetrician throughout the surgery, starting at 5 minutes after the oxytocin infusion. It will also be measured at 10 minutes following the oxytocin infusion and every 10 minutes following that for the duration of the surgery. Unsatisfactory uterine tone at any time until discharge from the PACU will be considered a failure of the maintenance infusion.

Secondary outcomes

  1. Calculated blood loss

    Time frame: 24 hours

    Estimated blood loss will be calculated using the difference in hematocrit values prior to surgery and 24 hours post surgery, using the following formula:

    Calculated blood loss (mL) = EBV ((Pre-op Htc-Post-op Htc)/pre-op Htc) EBV (estimated blood volume) in ml: patient's weight in kg x 85.

  2. Incidence of post partum hemorrhage

    Time frame: 24 hours

    Incidence of post partum hemorrhage defined as a calculated blood loss >1L.

  3. Need for blood transfusion

    Time frame: 24 hours

    Blood product administered.

  4. Episodes of bleeding postpartum

    Time frame: 24 hours

    Number of episodes of bleeding postpartum up to 24 hours post delivery.

  5. Intraoperative requirement for additional uterotonic medication

    Time frame: 2 hours

    A request made by the obstetrician performing the cesarean delivery for additional uterotonic medication, due to bleeding or poor uterine tone.

  6. Requirement for additional uterotonic medication in the PACU

    Time frame: 2 hours

    Any uterotonic medication administered while the patient is in PACU

  7. Requirement for additional uterotonic medication from discharge from the PACU until 24 hours postpartum.

    Time frame: 24 hours

    Any uterotonic medication administered after the patient is discharged from PACU until 24 hours postpartum.

  8. Postoperative uterine position in the PACU

    Time frame: 3 hours

    Postoperative uterine position (below or above the umbilicus) as determined by the PACU nurse. This is measured every 15 minutes for the first hour and then hourly until discharge to the postpartum unit.

  9. Hypotension: systolic blood pressure less than 80% of baseline

    Time frame: 2 hours

    Systolic blood pressure < 80% of baseline, from drug administration until end of surgery

  10. Hypertension: systolic blood pressure greater than 120% of baseline

    Time frame: 2 hours

    Systolic blood pressure > 120% of baseline, from drug administration until end of surgery

  11. Tachycardia: heart rate greater than 130% of baseline

    Time frame: 2 hours

    Heart rate > 130% of baseline, from drug administration until end of surgery

  12. Bradycardia: heart rate less than 70% of baseline

    Time frame: 2 hours

    Heart rate < 70% of baseline or a heart rate < 50bpm, from drug administration until end of surgery

  13. Presence of ventricular tachycardia: ECG

    Time frame: 2 hours

    Presence of ventricular tachycardia as recorded by ECG, from drug administration until end of surgery

  14. Presence of atrial fibrillation: ECG

    Time frame: 2 hours

    Presence of atrial fibrillation as recorded by ECG, from drug administration until end of surgery

  15. Presence of atrial flutter: ECG

    Time frame: 2 hours

    Presence of atrial flutter as recorded by ECG, from drug administration until end of surgery

  16. Presence of nausea: questionnaire

    Time frame: 2 hours

    The presence of nausea and number of episodes, from drug administration until end of surgery, as reported by the patient

  17. Presence of vomiting: questionnaire

    Time frame: 2 hours

    The presence of vomiting and number of episodes, from drug administration until end of surgery

  18. Presence of chest pain: questionnaire

    Time frame: 2 hours

    Any presence of chest pain, from drug administration until end of surgery, as reported by the patient

  19. Presence of shortness of breath: questionnaire

    Time frame: 2 hours

    Any presence of shortness of breath, from drug administration until end of surgery, as reported by the patient

  20. Presence of headache: questionnaire

    Time frame: 2 hours

    Any presence of headache, from drug administration until end of surgery, as reported by the patient

Sponsors and collaborators

Lead sponsor

Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Other

Registry information

Official study title

Maintenance Infusion of Oxytocin Following Elective Cesarean Deliveries: an Up-down Sequential Allocation Dose-response Study

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Jun 30, 2021
Registry last updated
Jun 7, 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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