Hypotension After Spinal Anesthesia
Conditions
Keywords
Hypotension, Cesarean Delivery, Phenylephrine
Brief summary
The purpose of this study is to determine the 50% and 90% effective doses (ED50 and ED90) of prophylactic phenylephrine infusion for preventing spinal anesthesia-induced hypotension during elective cesarean delivery, in the supine position and in the left-lateral-tilt 15° position, respectively. Two hundred parturients with singleton term pregnancies will be randomized 1:1 to the supine group or the left-tilt 15° group, and within each position 1:1:1:1 to one of four fixed phenylephrine infusion rates (0.2, 0.4, 0.6, or 0.8 μg/kg/min; 25 per group), with the rate allocation masked by concentration blinding (identical pump rate, different solution concentrations). Spinal anesthesia consists of hyperbaric bupivacaine 12 mg plus morphine 0.15 mg. The primary outcome is the incidence of hypotension (systolic blood pressure \< 80% of baseline or \< 90 mmHg) from completion of the intrathecal injection to delivery. ED50 and ED90 will be estimated by probit regression within each position.
Interventions
Prophylactic fixed-rate IV infusion (pump rate 0.6 mL/kg/h, concentration-blinded), from completion of spinal anesthesia until delivery
Sponsors
Peking University People's Hospital
XuZhouHeJia hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
Position allocation was open label; rate allocation was masked by concentration blinding (identical pump rate 0.6 mL/kg/h; solution concentrations 20/40/60/80 μg/mL prepared in identical syringes)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Singleton term pregnancy scheduled for elective cesarean delivery 2. Height 150-180 cm 3. ASA physical status II-III 4. Body mass index \< 35 kg/m2
Exclusion criteria
1. Transverse lie or suspected macrosomia 2. Uterine abnormalities (e.g., large uterine fibroids, bicornuate uterus) 3. Polyhydramnios 4. Ruptured membranes or oligohydramnios 5. Fetal growth restriction 6. Gestational or pregestational hypertension, diabetes mellitus, or preeclampsia 7. Diseases associated with autonomic neuropathy (e.g., diabetes mellitus \> 10 years) or renal failure 8. Contraindications to spinal anesthesia 9. Refusal to provide written informed consent-
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| hypotension incidence of hypotension from completion of intrathecal injection to delivery of the infant | From completion of spinal anesthesia to fetal delivery | Hypotension defined as systolic blood pressure \< 80% of baseline (measured in the assigned study position) or \< 90 mmHg |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Umbilical artery and umbilical vein blood gas values | At delivery | Umbilical artery and umbilical vein blood gas values (pH, PCO2, PO2, base excess, lactate) |
| Apgar scores at 1 and 5 minutes after delivery | From fetal delivery to 5 minutes after delivery | — |
| Time to first rescue vasopressor | From completion of intrathecal injection to delivery | — |
| Serial systolic blood pressure values within 12 minutes after intrathecal injection | From completion of spinal anesthesia to 12 minutes after completion of spinal anesthesia | — |
| Incidence of hypertension before delivery | From completion of intrathecal injection to delivery | Incidence of hypertension (systolic blood pressure ≥ 120% of baseline) before delivery |
Countries
China
Contacts
CONTACTFeng Feng, Dr.
Outcome results
None listed