Postpartum Hemorrhage
Conditions
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.
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.
Interventions
DRUGoxytocin
PK measurements of oxytocin
DEVICEShore 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 Preliminary (unpublished) data provided a range of 10-56 SU after oxytocin administration at cesarean delivery.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.
Sponsors
Washington University School of Medicine
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 45 Years
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Arterial [OXT] | Scheduled samples during the first 30 minutes after oxytocin administration | Concentration of oxytocin in arterial samples |
| Venous [OXT] | Scheduled samples during the first 30 minutes after oxytocin administration | Concentration of oxytocin in venous samples |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Hypotension | Measured intraoperatively | Incidence of systolic BP reduced by 20% from baseline |
| Arterial [OXTase] | Scheduled samples during the first 30 minutes after oxytocin administration | Concentration of oxytocinase in arterial samples |
| EBL | Estimated at the end of surgery | Estimated blood loss in milliliters |
| Nausea & Vomiting | Recorded intraoperatively | Incidence of nausea and vomiting |
| 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) |
Countries
United States
Outcome results
None listed