Anesthesia
Conditions
Brief summary
Oxytocin is normally administered following delivery in pregnant patients to reduce postpartum bleeding by increasing uterine tone. It is unclear whether the use of intravenous oxytocin alters coagulation in pregnant patients. The purpose of the in-vitro study is to assess the coagulation changes of oxytocin in blood samples from pregnant patients using thromboelastrography (TEG). TEG is a point-of-care device which measures the viscoelastic properties of clot formation, and can provide rapid and detailed information about coagulation changes. We aim to collect blood samples from pregnant patients to assess the in-vitro effects of synthetic oxytocin on coagulation using TEG.
Detailed description
All obstetric patients presenting for elective induction of labor or elective Cesarean delivery will be informed about the study prior to and on admission to the labor and delivery unit. Admission blood sampling will take place by venepuncture for the following analysis:TEG, PT, PTT, INR, Hct, Platelet count.The results of oxytocin influence on thromboelastogram parameters will be compared to a control. The control is an aliquot of parturient blood with no added oxytocin. Thromboelastography will be used to assess coagulation changes between control samples and blood samples with added oxytocin. The results will not be used to influence clinical management of any case.
Interventions
DRUGFinal exogenous oxytocin concentration=22.5 μU/mL
Citrated whole blood 1mL + 23μU oxytocin. After mixing by inversion 8-10 times, 360μL kaolin-activated blood of each study solution was pipetted into a plastic cup in a prewarmed Thromboelastograph® (37°C). Each sample was recalcified in a plastic cup with 10μL of CaCl2 6.45%, and TEG® analysis was commenced within 1 minute of reconstituted sample preparation.
DRUGFinal exogenous oxytocin concentration=30.1μU/mL
Citrated whole blood 1mL + 31μU oxytocin. After mixing by inversion 8-10 times, 360μL kaolin-activated blood of each study solution was pipetted into a plastic cup in a prewarmed Thromboelastograph® (37°C). Each sample was recalcified in a plastic cup with 10μL of CaCl2 6.45%, and TEG® analysis was commenced within 1 minute of reconstituted sample preparation.
DRUGFinal exogenous oxytocin concentration=32.9μU/mL
Citrated whole blood 1mL + 34μU oxytocin. After mixing by inversion 8-10 times, 360μL kaolin-activated blood of each study solution was pipetted into a plastic cup in a prewarmed Thromboelastograph® (37°C). Each sample was recalcified in a plastic cup with 10μL of CaCl2 6.45%, and TEG® analysis was commenced within 1 minute of reconstituted sample preparation.
Sponsors
Stanford University
Study design
Observational model
CASE_ONLY
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
All obstetric patients with singleton pregnancies admitted to the labor and delivery unit at Lucile Packard Childrens Hospital awaiting elective induction of labor or elective Cesarean delivery. We will select 25 healthy ASA 1 patients with singleton pregnancies who are scheduled for uncomplicated elective induction of labor. Gestational age equal to or greater than 37 weeks.
Exclusion criteria
Patients with underlying coagulation disorders. Patients with thrombocytopenia. Patients with pregnancy-induced hypertension, pre-eclampsia. Patients admitted for non-elective cesarean section. Patients in active labor. Patients requiring the following medications prior to surgery: NSAIDS, aspirin, anticoagulants. Patients with significant obstetric or medical disease. No patients \<18 years of age will be recruited.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| r Time | 6 months | thromboelastographic indices - reaction time (normal range, 5-10 min) |
| k Time | 6 months | thromboelastographic indices - clot formation time (normal range, 1-3 min) |
| Alpha Angle | 6 months | thromboelastographic - alpha angle = clot formation rate (normal range, 53 degress to 72 degrees) |
| MA | 6 months | thromboelastographic indices - maximum amplitude (normal range, 50-70 mm) |
| MRTG | 6 months | thromboelastographic indices - maximum rate of thrombus generation (normal range, 5-17 mm/min) |
| Tmax | 6 months | thromboelastographic indices - time to initiation of clot formation plus time to achieve maximum rate of clot strength development (normal range, 6-12 min) |
| TTG | 6 months | thromboelastographic indices - total thrombus generation (normal range, 584-796 mm) |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| All Participants For each patient, 1 solution with citrated whole blood (control) and 3 solutions with citrated whole blood and exogenous oxytocin were prepared in separate vials using micropipettes as follows:
Citrated whole blood 1mL + 23μU oxytocin: final exogenous oxytocin concentration=22.5 μU/mL Citrated whole blood 1mL + 31μU oxytocin: final exogenous oxytocin concentration=30.1μU/mL Citrated whole blood 1mL + 34μU oxytocin: final exogenous oxytocin concentration=32.9μU/mL After mixing by inversion 8-10 times, 360μL kaolin-activated blood of each study solution was pipetted into a plastic cup in a prewarmed Thromboelastograph® (37°C). Each sample was recalcified in a plastic cup with 10μL of CaCl2 6.45%, and TEG® analysis was commenced within 1 minute of reconstituted sample preparation. | 25 |
| Total | 25 |
Baseline characteristics
| Characteristic | All Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 25 Participants |
| Region of Enrollment United States | 25 participants |
| Sex: Female, Male Female | 25 Participants |
| Sex: Female, Male Male | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 25 | 0 / 25 | 0 / 25 | 0 / 25 |
| serious Total, serious adverse events | 0 / 25 | 0 / 25 | 0 / 25 | 0 / 25 |
Outcome results
Primary
Alpha Angle
thromboelastographic - alpha angle = clot formation rate (normal range, 53 degress to 72 degrees)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | Alpha Angle | Exogenous Oxytocin 22.5 | 67.4 degrees | Standard Deviation 4.2 |
| All Participants | Alpha Angle | Exogenous Oxytocin 30.1 | 67.7 degrees | Standard Deviation 3.7 |
| All Participants | Alpha Angle | Exogenous Oxytocin 32.9 | 69.4 degrees | Standard Deviation 4.2 |
| All Participants | Alpha Angle | Exogeneous oxytocin 0 | 66.2 degrees | Standard Deviation 4.4 |
Primary
k Time
thromboelastographic indices - clot formation time (normal range, 1-3 min)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | k Time | Exogenous Oxytocin 22.5 | 1.6 minutes | Standard Deviation 0.4 |
| All Participants | k Time | Exogenous Oxytocin 30.1 | 1.5 minutes | Standard Deviation 0.7 |
| All Participants | k Time | Exogenous Oxytocin 32.9 | 1.4 minutes | Standard Deviation 0.4 |
| All Participants | k Time | Exogenous Oxytocin 0 | 1.7 minutes | Standard Deviation 0.4 |
Primary
MA
thromboelastographic indices - maximum amplitude (normal range, 50-70 mm)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | MA | Exogenous Oxytocin 22.5 | 69.8 mm | Standard Deviation 4.3 |
| All Participants | MA | Exogenous Oxytocin 30.1 | 67.2 mm | Standard Deviation 3.7 |
| All Participants | MA | Exogenous Oxytocin 32.9 | 69.0 mm | Standard Deviation 4.2 |
| All Participants | MA | Exogeneous Oxytocin 0 | 67.2 mm | Standard Deviation 3.9 |
Primary
MRTG
thromboelastographic indices - maximum rate of thrombus generation (normal range, 5-17 mm/min)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | MRTG | Exogenous Oxytocin 22.5 | 13.5 mm/min | Standard Deviation 2.7 |
| All Participants | MRTG | Exogenous Oxytocin 30.1 | 14.9 mm/min | Standard Deviation 3.7 |
| All Participants | MRTG | Exogenous Oxytocin 32.9 | 14.3 mm/min | Standard Deviation 2.8 |
| All Participants | MRTG | Exogeneous Oxytocin 0 | 12.8 mm/min | Standard Deviation 2.5 |
Primary
r Time
thromboelastographic indices - reaction time (normal range, 5-10 min)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | r Time | Exogenous Oxytocin 22.5 | 5.6 minutes | Standard Deviation 1.4 |
| All Participants | r Time | Exogenous Oxytocin 30.1 | 4.2 minutes | Standard Deviation 1.3 |
| All Participants | r Time | Exogenous Oxytocin 32.9 | 3.9 minutes | Standard Deviation 1.3 |
| All Participants | r Time | Exogenous oxytocin 0 | 6 minutes | Standard Deviation 1.5 |
Primary
Tmax
thromboelastographic indices - time to initiation of clot formation plus time to achieve maximum rate of clot strength development (normal range, 6-12 min)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | Tmax | Exogenous Oxytocin 22.5 | 6.9 minutes | Standard Deviation 1.6 |
| All Participants | Tmax | Exogenous Oxytocin 30.1 | 5.4 minutes | Standard Deviation 1.9 |
| All Participants | Tmax | Exogenous Oxytocin 32.9 | 5.0 minutes | Standard Deviation 1.5 |
| All Participants | Tmax | Exogeneous Oxytocin 0 | 7.5 minutes | Standard Deviation 1.7 |
Primary
TTG
thromboelastographic indices - total thrombus generation (normal range, 584-796 mm)
Time frame: 6 months
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| All Participants | TTG | Exogenous Oxytocin 22.5 | 845.9 mm | Standard Deviation 53.9 |
| All Participants | TTG | Exogenous Oxytocin 30.1 | 820 mm | Standard Deviation 45.9 |
| All Participants | TTG | Exogenous Oxytocin 32.9 | 839.7 mm | Standard Deviation 51.8 |
| All Participants | TTG | Exogeneous Oxytocin 0 | 819.4 mm | Standard Deviation 48.9 |