Peacocks: Pharmacokinetics of Oxytocin at Cesarean Delivery

• Sponsor: Washington University School of Medicine (Other)
• Overall Status: Completed
• CT.gov ID: NCT03898882
• Collaborator: (none)
• Enrollment: 30
• Location: 1
• Actual Duration (Months): 9.2
• Patients Per Site Per Month: 3.3

Study Details

Study Description

Brief Summary

The primary objective is to obtain data to inform the design of a population pharmacokinetic study of oxytocin after administration at CD as per standard institutional practice.

Condition or Disease	Intervention/Treatment	Phase
Postpartum Hemorrhage	Drug: oxytocin; Device: Shore durometer

Detailed Description

In this pilot study the investigators will compare plasma oxytocin concentrations measured in arterial and venous blood, after oxytocin administration at cesarean delivery, in order to assess the validity of venous samples. They will also measure oxytocinase to explore how levels vary around the time of delivery of the placenta and to assess the effect that this may have on the metabolism of oxytocin.

Study Design

• Study Type: Observational
• Actual Enrollment: 30 participants
• Observational Model: Cohort
• Time Perspective: Prospective
• Official Title: The Pharmacokinetics of Oxytocin in Pregnant Women Undergoing Cesarean Delivery - a Feasibility Pilot Study
• Actual Study Start Date: May 24, 2019
• Actual Primary Completion Date: Feb 28, 2020
• Actual Study Completion Date: Feb 28, 2020

Arms and Interventions

Arm	Intervention/Treatment
BMI 20 - 29.9 kg/m2	Drug: oxytocin; PK measurements of oxytocin; Device: Shore durometer; The investigators will take serial readings from a digital durometer at the uterine fundus at 3, 6, 9 and 12 minutes following OXT administration to provide data that will inform an estimate of the timing of peak effect. Shore durometers measure the hardness of materials on a scale of 0-100 Shore Units (SU). Preliminary (unpublished) data provided a range of 10-56 SU after oxytocin administration at cesarean delivery. Durometer readings were also shown to correlate positively with the obstetrician's manual assessment of uterine contractility, which is traditionally used to determine the success or failure of uterotonic therapy.
BMI > 30 kg/m2	Drug: oxytocin; PK measurements of oxytocin; Device: Shore durometer; The investigators will take serial readings from a digital durometer at the uterine fundus at 3, 6, 9 and 12 minutes following OXT administration to provide data that will inform an estimate of the timing of peak effect. Shore durometers measure the hardness of materials on a scale of 0-100 Shore Units (SU). Preliminary (unpublished) data provided a range of 10-56 SU after oxytocin administration at cesarean delivery. Durometer readings were also shown to correlate positively with the obstetrician's manual assessment of uterine contractility, which is traditionally used to determine the success or failure of uterotonic therapy.

Outcome Measures

Primary Outcome Measures

1. Arterial [OXT] [Scheduled samples during the first 30 minutes after oxytocin administration]

   Concentration of oxytocin in arterial samples

2. Venous [OXT] [Scheduled samples during the first 30 minutes after oxytocin administration]

   Concentration of oxytocin in venous samples

Secondary Outcome Measures

1. Arterial [OXTase] [Scheduled samples during the first 30 minutes after oxytocin administration]

   Concentration of oxytocinase in arterial samples

2. Uterine tone [Scheduled measurements during the first 30 minutes after oxytocin administration]

   Uterine tone measured using a Shore Durometer or assessed by obstetrician using numerical rating score (NRS, 0-10)

3. Hypotension [Measured intraoperatively]

   Incidence of systolic BP reduced by 20% from baseline

4. Nausea & Vomiting [Recorded intraoperatively]

   Incidence of nausea and vomiting

5. EBL [Estimated at the end of surgery]

   Estimated blood loss in milliliters

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 45 Years
• Sexes Eligible for Study: Female
• Accepts Healthy Volunteers: Yes

Inclusion Criteria:

• Term singleton pregnancy

• Age 18-45 years of age

• ASA classification 2 or 3

• Scheduled cesarean delivery under neuraxial anaesthesia

Exclusion Criteria:

• Age or ASA classification outside of inclusion criteria

• Need for general anaesthesia

• Absence of consent

• Inability to communicate in English or other barrier to providing informed consent

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Washington University in St. Louis	Saint Louis	Missouri	United States	63110

Sponsors and Collaborators

• Washington University School of Medicine

Investigators

• Principal Investigator: David T Monks, MBChB, Washington University School of Medicine

Study Documents (Full-Text)

None provided.

More Information

Publications

• Attilakos G, Psaroudakis D, Ash J, Buchanan R, Winter C, Donald F, Hunt LP, Draycott T. Carbetocin versus oxytocin for the prevention of postpartum haemorrhage following caesarean section: the results of a double-blind randomised trial. BJOG. 2010 Jul;117(8):929-36. doi: 10.1111/j.1471-0528.2010.02585.x. Epub 2010 May 19.
• Chiou WL. The phenomenon and rationale of marked dependence of drug concentration on blood sampling site. Implications in pharmacokinetics, pharmacodynamics, toxicology and therapeutics (Part I). Clin Pharmacokinet. 1989 Sep;17(3):175-99. Review.
• Chiou WL. The phenomenon and rationale of marked dependence of drug concentration on blood sampling site. Implications in pharmacokinetics, pharmacodynamics, toxicology and therapeutics (Part II). Clin Pharmacokinet. 1989 Oct;17(4):275-90. Review.
• Say L, Chou D, Gemmill A, Tunçalp Ö, Moller AB, Daniels J, Gülmezoglu AM, Temmerman M, Alkema L. Global causes of maternal death: a WHO systematic analysis. Lancet Glob Health. 2014 Jun;2(6):e323-33. doi: 10.1016/S2214-109X(14)70227-X. Epub 2014 May 5. Review.

• Responsible Party: Washington University School of Medicine
• ClinicalTrials.gov Identifier: NCT03898882
• Other Study ID Numbers: 201810134
• First Posted: Apr 2, 2019
• Last Update Posted: May 7, 2020
• Last Verified: May 1, 2020

• Individual Participant Data (IPD) Sharing Statement: No
• Plan to Share IPD: No
• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: Yes
• Product Manufactured in and Exported from the U.S.: No
• Additional relevant MeSH terms: Postpartum Hemorrhage; Hemorrhage; Oxytocin

Study Results

No Results Posted as of May 7, 2020