Determination of the ED50 and ED90 of Prophylactic Phenylephrine Infusion for the Prevention of Spinal Anesthesia-Induced Hypotension During Elective Cesarean Delivery in the Supine and Left-Lateral-Tilt 15° Positions: A Randomized, Concentration-Blinded, Parallel-Group Dose-Response Study
试验速览
- 阶段
- 4 期
- 状态
- 尚未招募
- 入组人数
- 200
- 试验地点
- 1
- 主要终点
- hypotension incidence of hypotension from completion of intrathecal injection to delivery of the infant
研究概览
简要总结
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
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)
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 否
入选标准
- •Singleton term pregnancy scheduled for elective cesarean delivery
- •Height 150-180 cm
- •ASA physical status II-III
- •Body mass index < 35 kg/m2
排除标准
- •Transverse lie or suspected macrosomia
- •Uterine abnormalities (e.g., large uterine fibroids, bicornuate uterus)
- •Polyhydramnios
- •Ruptured membranes or oligohydramnios
- •Fetal growth restriction
- •Gestational or pregestational hypertension, diabetes mellitus, or preeclampsia
- •Diseases associated with autonomic neuropathy (e.g., diabetes mellitus > 10 years) or renal failure
- •Contraindications to spinal anesthesia
- •Refusal to provide written informed consent-
研究组 & 干预措施
Supine Position - Phenylephrine 0.2 μg/kg/min
Participants in the supine position (maintained from completion of spinal anesthesia until delivery) receiving prophylactic phenylephrine infusion 0.2 μg/kg/min (pump rate 0.6 mL/kg/h, concentration-blinded solution 20 μg/mL) from completion of spinal anesthesia until delivery.
干预措施: Phenylephrine hydrochloride infusion (Drug)
Supine Position - Phenylephrine 0.4 μg/kg/min
Supine position as Arm 1; phenylephrine infusion 0.4 μg/kg/min (concentration-blinded solution 40 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Supine Position - Phenylephrine 0.6 μg/kg/min
Supine position as Arm 1; phenylephrine infusion 0.6 μg/kg/min (concentration-blinded solution 60 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Supine Position - Phenylephrine 0.8 μg/kg/min
Supine position as Arm 1; phenylephrine infusion 0.8 μg/kg/min (concentration-blinded solution 80 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Left-Tilt 15° - Phenylephrine 0.2 μg/kg/min
Participants in the left-lateral-tilt 15° position (sponge wedge 7.5 × 28 × 50 cm under the thoracolumbar region, maintained from completion of spinal anesthesia until delivery) receiving prophylactic phenylephrine infusion 0.2 μg/kg/min (pump rate 0.6 mL/kg/h, concentration-blinded solution 20 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Left-Tilt 15° - Phenylephrine 0.4 μg/kg/min
Left-tilt 15° position as Arm 5; phenylephrine infusion 0.4 μg/kg/min (concentration-blinded solution 40 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Left-Tilt 15° - Phenylephrine 0.6 μg/kg/min
Left-tilt 15° position as Arm 5; phenylephrine infusion 0.6 μg/kg/min (concentration-blinded solution 60 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
Left-Tilt 15° - Phenylephrine 0.8 μg/kg/min
Left-tilt 15° position as Arm 5; phenylephrine infusion 0.8 μg/kg/min (concentration-blinded solution 80 μg/mL).
干预措施: Phenylephrine hydrochloride infusion (Drug)
结局指标
主要结局
hypotension incidence of hypotension from completion of intrathecal injection to delivery of the infant
时间窗: 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
次要结局
- Umbilical artery and umbilical vein blood gas values(At delivery)
- 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)
研究者
Yi Feng, MD
Director of Anesthesiology
Peking University People's Hospital