Maintenance Infusion of Oxytocin Following Elective Cesarean Deliveries

Sponsor

Samuel Lunenfeld Research Institute, Mount Sinai Hospital (Other)

Overall Status

Completed

CT.gov ID

NCT04946006

Collaborator

(none)

Enrollment

Location

Arms

8.2

Actual Duration (Months)

4.9

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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).

Condition or Disease	Intervention/Treatment	Phase
Postpartum Hemorrhage	Drug: Oxytocin	N/A

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 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.

Study Design

Study Type:

Interventional

Actual Enrollment :

40 participants

Allocation:

Non-Randomized

Intervention Model:

Parallel Assignment

Intervention Model Description:

Biased coin up-and-down design.Biased coin up-and-down design.

Masking:

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

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

Actual Study Start Date :

Jul 26, 2021

Actual Primary Completion Date :

Apr 1, 2022

Actual Study Completion Date :

Apr 2, 2022

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Oxytocin infusion rate 2 IU/h The maintenance infusion rate of oxytocin will be 2 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 4 IU/h The maintenance infusion rate of oxytocin will be 4 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 6 IU/h The maintenance infusion rate of oxytocin will be 6 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 8 IU/h The maintenance infusion rate of oxytocin will be 8 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 10 IU/h The maintenance infusion rate of oxytocin will be 10 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 12 IU/h The maintenance infusion rate of oxytocin will be 12 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 14 IU/h The maintenance infusion rate of oxytocin will be 14 IU/h.	Drug: Oxytocin 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
Experimental: Oxytocin infusion rate 16 IU/h The maintenance infusion rate of oxytocin will be 16 IU/h.	Drug: Oxytocin 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

Outcome Measures

Primary Outcome Measures

Uterine tone upon discharge from the post anesthetic care unit (PACU): questionnaire [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 Outcome Measures

Calculated blood loss [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.
Incidence of post partum hemorrhage [24 hours]
Incidence of post partum hemorrhage defined as a calculated blood loss >1L.
Need for blood transfusion [24 hours]
Blood product administered.
Episodes of bleeding postpartum [24 hours]
Number of episodes of bleeding postpartum up to 24 hours post delivery.
Intraoperative requirement for additional uterotonic medication [2 hours]
A request made by the obstetrician performing the cesarean delivery for additional uterotonic medication, due to bleeding or poor uterine tone.
Requirement for additional uterotonic medication in the PACU [2 hours]
Any uterotonic medication administered while the patient is in PACU
Requirement for additional uterotonic medication from discharge from the PACU until 24 hours postpartum. [24 hours]
Any uterotonic medication administered after the patient is discharged from PACU until 24 hours postpartum.
Postoperative uterine position in the PACU [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.
Hypotension: systolic blood pressure less than 80% of baseline [2 hours]
Systolic blood pressure < 80% of baseline, from drug administration until end of surgery
Hypertension: systolic blood pressure greater than 120% of baseline [2 hours]
Systolic blood pressure > 120% of baseline, from drug administration until end of surgery
Tachycardia: heart rate greater than 130% of baseline [2 hours]
Heart rate > 130% of baseline, from drug administration until end of surgery
Bradycardia: heart rate less than 70% of baseline [2 hours]
Heart rate < 70% of baseline or a heart rate < 50bpm, from drug administration until end of surgery
Presence of ventricular tachycardia: ECG [2 hours]
Presence of ventricular tachycardia as recorded by ECG, from drug administration until end of surgery
Presence of atrial fibrillation: ECG [2 hours]
Presence of atrial fibrillation as recorded by ECG, from drug administration until end of surgery
Presence of atrial flutter: ECG [2 hours]
Presence of atrial flutter as recorded by ECG, from drug administration until end of surgery
Presence of nausea: questionnaire [2 hours]
The presence of nausea and number of episodes, from drug administration until end of surgery, as reported by the patient
Presence of vomiting: questionnaire [2 hours]
The presence of vomiting and number of episodes, from drug administration until end of surgery
Presence of chest pain: questionnaire [2 hours]
Any presence of chest pain, from drug administration until end of surgery, as reported by the patient
Presence of shortness of breath: questionnaire [2 hours]
Any presence of shortness of breath, from drug administration until end of surgery, as reported by the patient
Presence of headache: questionnaire [2 hours]
Any presence of headache, from drug administration until end of surgery, as reported by the patient

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 50 Years

Sexes Eligible for Study:

Female

Accepts Healthy Volunteers:

Yes

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.