Obstetric Anesthesia, Spinal Anesthesia, Hypotension, Fluid Therapy, Cesarean Section
Conditions
Keywords
Obstetric anesthesia, Spinal anesthesia, Hypotension, Fluid therapy, Cesarean section, phenylephrine, cardiac output
Brief summary
The purpose of this trial is to determine the effective volume of hydroxyethylstarch 130/0.4 which would prevent the occurence of maternal hypotension in 50% of healthy pregnant women undergoing a cesarean section under spinal anesthesia.
Detailed description
The incidence of spinal anesthesia-induced hypotension in pregnant women undergoing a cesarean section is high. A preoperative fluid bolus of undetermined volume is frequently administered to lower the incidence of maternal hypotension, with a somewhat poor efficacy. Recently, several investigations have shown that the use of a phenylephrine infusion after the induction of spinal anesthesia results in a significant reduction in hypotensive episodes. Given the high efficacy of this therapy (incidence of hypotension around 20%), it is possible to determine the effective volume of fluid which would prevent hypotension in 50% of the patients studied (ED50). Healthy term pregnant women undergoing elective cesarean section under spinal anesthesia will be recruited in this trial. The spinal anesthesia regimen will be standardized and all subjects will receive a phenylephrine infusion. The fluid investigated is hydroxyethylstarch (HES) 130/0.4 (Volulyte(R)). The ED50 will be determined using an up-down sequential allocation method initially described by Dixon & Massey. The determination of the HES ED50 will help the anesthesiologist in further treating maternal hypotension appropriately.
Interventions
first patient : 500 mL. Following volumes according to up-down sequential allocation, with increments or decrements of 100 mL. An absence of hypotension will lead to an decrement while a presence of hypotension will result in an increment.
Sponsors
Université de Montréal
Maisonneuve-Rosemont Hospital
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
FEMALE
Healthy volunteers
No
Inclusion criteria
* Healthy pregnant women (ASA I or II) * Normal pregnancy * Term gestation (37 weeks and above) * Elective cesarean section * Spinal anesthesia
Exclusion criteria
* Cardiopathies * Hypertensive disease/ pre-eclampsia / eclampsia * Any contraindication to neuraxial anesthesia * Patient refusal * Body mass index \> 30 at first antenatal visit and \> 32 at cesarean section * Twin pregnancy * Known allergies to HES * Emergency cesarean section
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Volume of HES which will prevent hypotension if 50 % of the subjects. | 4 months |
Secondary
| Measure | Time frame |
|---|---|
| Incidence of hypertensive episodes | 1 hour |
| cardiac output | 1 hour |
| Incidence of hypotension episodes | 1 hour |
| umbilical artery pH | 2 hours |
| additional vasopressors administered | 1 hour |
| Apgar score | 10 minutes |
Countries
Canada
Contacts
Primary ContactChristian Loubert, MD, FRCPC
Backup ContactLouis-Philippe Fortier, MD, FRCPC
Outcome results
None listed