Pharmacokinetics of Oxytocin at Cesarean Delivery

Postpartum Hemorrhage Clinical Trial

— Peacocks  

Official title:

The Pharmacokinetics of Oxytocin in Pregnant Women Undergoing Cesarean Delivery - a Feasibility Pilot Study

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03898882
• Other study ID #: 201810134
• Status: Completed
• Start date: May 24, 2019
• Est. completion date: February 28, 2020

Study information

• Verified date: May 2020
• Source: Washington University School of Medicine
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 30
• Est. completion date: February 28, 2020
• Est. primary completion date: February 28, 2020
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Female
• Age group: 18 Years to 45 Years

Eligibility

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

Related Conditions & MeSH terms

• Hemorrhage
• Postpartum Hemorrhage

Intervention

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 Preliminary (unpublished) data provided a range of 10-56 SU after oxytocin administration at cesarean delivery.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.

Locations

Country	Name	City	State
United States	Washington University in St. Louis	Saint Louis	Missouri

Sponsors (1)

Lead Sponsor	Collaborator
Washington University School of Medicine

Country where clinical trial is conducted

United States, 

References & Publications (4)

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. — View Citation

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. — View Citation

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. — View Citation

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. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Arterial [OXT]	Concentration of oxytocin in arterial samples	Scheduled samples during the first 30 minutes after oxytocin administration
Primary	Venous [OXT]	Concentration of oxytocin in venous samples	Scheduled samples during the first 30 minutes after oxytocin administration
Secondary	Arterial [OXTase]	Concentration of oxytocinase in arterial samples	Scheduled samples during the first 30 minutes after oxytocin administration
Secondary	Uterine tone	Uterine tone measured using a Shore Durometer or assessed by obstetrician using numerical rating score (NRS, 0-10)	Scheduled measurements during the first 30 minutes after oxytocin administration
Secondary	Hypotension	Incidence of systolic BP reduced by 20% from baseline	Measured intraoperatively
Secondary	Nausea & Vomiting	Incidence of nausea and vomiting	Recorded intraoperatively
Secondary	EBL	Estimated blood loss in milliliters	Estimated at the end of surgery