Oxytocin Maintenance Infusion in Labouring Women Undergoing Cesarean Delivery: an Up-down Sequential Allocation Study

Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Status: Enrolling

Conditions: Postpartum Hemorrhage

Treatments: Drug: Oxytocin

Study type: Interventional

Funder types: Other

Identifiers

NCT05290129

22-02

Details and patient eligibility

About

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.

Full 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.

Enrollment: 40 estimated patients

Sex: Female

Ages: 18 to 50 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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40 participants in 10 patient groups

Oxytocin infusion rate 4 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 4 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 6 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 6 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 10 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 10 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 14 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 14 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 18 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 18 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 22 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 22 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 26 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 26 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 30 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 30 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 34 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 34 IU/h.

Treatment:

Drug: Oxytocin

Oxytocin infusion rate 36 IU/h

Experimental group

Description:

The maintenance infusion rate of oxytocin will be 36 IU/h.

Treatment:

Drug: Oxytocin