Clinical trial NCT05290129: Oxytocin Maintenance Infusion in Labouring Women Undergoing Cesarean Delivery: an Up-down Sequential Allocation Study
Official title: Oxytocin Maintenance Infusion in Labouring Women Undergoing Cesarean Delivery: an Up-down Sequential Allocation Study
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Postpartum Hemorrhage
Keywords: Cesarean delivery
oxytocin
uterotonic
pregnancy
labour
Lead sponsor: Samuel Lunenfeld Research Institute, Mount Sinai Hospital
Sponsor class: OTHER
First posted: 2022-03-22
Enrollment: 40
Sex: FEMALE
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Biased coin up-and-down design.
Primary purpose: TREATMENT

Brief summary: This study is designed to determine the minimal effective oxytocin maintenance infusion required in labouring women undergoing cesarean delivery to achieve the best effect. Oxytocin is a drug that is routinely used to help the uterus to contract and keep it contracted after delivery. Consequently, it will help to reduce blood loss after delivery. 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. The next patient's infusion dose of oxytocin, will either increase or decrease, depending on how the previous patient responds in terms of uterine tone. If the response is satisfactory with the infusion dose used, the next patient will either receive the same infusion dose or it will be decreased depending on a probability of 1:9. If the response is not satisfactory, then the infusion dose will increase for the next patient. The dose for each patient will be determined based on the results of the uterine contraction of the previous patient.

The investigators hypothesize that the ED90 of the oxytocin infusion rate to maintain adequate uterine tone in labouring women with induced or augmented labour undergoing cesarean delivery, following an initial effective bolus dose, would be lower than 0.74 IU/min (44 IU/h), which was found as the ED90 in a previous study, without an initial bolus dose prior to the infusion.

Detailed description: 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 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.

Eligibility criteria: Inclusion Criteria:

• All patients with induced or augmented labour undergoing cesarean delivery under neuraxial anesthesia (at least 3 hours of prior exposure to oxytocin during labour)

Exclusion Criteria:

* All patients who refuse to give written informed consent
* All patients who declare allergy or hypersensitivity to oxytocin
* A history of hypertension and/or severe cardiac disease(s)
* All patients who have contraindications for neuraxial anesthesia
* All patients who will be converted to general anesthesia intraoperatively
* All patients with placenta previa and multiple gestation

Primary outcomes:
measure: Uterine tone up to discharge from the post anesthetic care unit (PACU): questionnaire
timeFrame: 2 hours
Secondary outcomes:
measure: Calculated blood loss
timeFrame: 24 hours
measure: Need for blood transfusion
timeFrame: 24 hours
measure: Episodes of bleeding postpartum
timeFrame: 24 hours
measure: Intraoperative requirement for additional uterotonic medication
timeFrame: 1 hour
measure: Requirement for additional uterotonic medication in the PACU
timeFrame: 2 hours
measure: Requirement for additional uterotonic medication from discharge from the PACU until 24 hours postpartum.
timeFrame: 24 hours
measure: Hypotension: systolic blood pressure less than 80% of baseline
timeFrame: 2 hours
measure: Hypertension: systolic blood pressure greater than 120% of baseline
timeFrame: 2 hours
measure: Tachycardia: heart rate greater than 130% of baseline
timeFrame: 2 hours
measure: Bradycardia: heart rate less than 70% of baseline
timeFrame: 2 hours
measure: Presence of ventricular tachycardia: ECG
timeFrame: 2 hours
measure: Presence of atrial fibrillation: ECG
timeFrame: 2 hours
measure: Presence of atrial flutter: ECG
timeFrame: 2 hours
measure: Presence of nausea: questionnaire
timeFrame: 2 hours
measure: Presence of vomiting: questionnaire
timeFrame: 2 hours
measure: Presence of chest pain: questionnaire
timeFrame: 2 hours
measure: Presence of shortness of breath: questionnaire
timeFrame: 2 hours
measure: Presence of headache: questionnaire
timeFrame: 2 hours
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: Mount Sinai Hospital
state: Ontario
Study officials:
affiliation: MOUNT SINAI HOSPITAL
name: Mrinalini Balki, MD
role: PRINCIPAL_INVESTIGATOR
References: