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ED50/ED90 of Phenylephrine Infusion for Preventing Spinal Anesthesia-Induced Hypotension: Supine vs Left-Tilt 15°

ConditionHypotension After Spinal Anesthesia
Trial statusNot yet recruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexFemale
Age18+
SponsorPeking University People's Hospital

About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

Singleton term pregnancy scheduled for elective cesarean delivery

Height 150-180 cm

ASA physical status II-III

Body mass index < 35 kg/m2

Disqualifiers

Transverse lie or suspected macrosomia

Uterine abnormalities (e.g., large uterine fibroids, bicornuate uterus)

Polyhydramnios

Ruptured membranes or oligohydramnios

Trial design

Design model

Parallel

Treatments tested in this trial

  • Phenylephrine hydrochloride infusion

    Drug

    Prophylactic fixed-rate IV infusion (pump rate 0.6 mL/kg/h, concentration-blinded), from completion of spinal anesthesia until delivery

Treatment groups

200 Participants
are divided into 8 treatment groups

8

Treatment groups

See each treatment group below.

Group A: Supine Position - Phenylephrine 0.2 μg/kg/minExperimental treatment 1 intervention
Group B: Supine Position - Phenylephrine 0.4 μg/kg/minExperimental treatment 1 intervention
Group C: Supine Position - Phenylephrine 0.6 μg/kg/minExperimental treatment 1 intervention
Group D: Supine Position - Phenylephrine 0.8 μg/kg/minExperimental treatment 1 intervention
Group E: Left-Tilt 15° - Phenylephrine 0.2 μg/kg/minActive comparator 1 intervention
Group F: Left-Tilt 15° - Phenylephrine 0.4 μg/kg/minExperimental treatment 1 intervention
Group G: Left-Tilt 15° - Phenylephrine 0.6 μg/kg/minActive comparator 1 intervention
Group H: Left-Tilt 15° - Phenylephrine 0.8 μg/kg/minActive comparator 1 intervention

Trial outcomes

Primary outcomes

1

hypotension incidence of hypotension from completion of intrathecal injection to delivery of the infant

Hypotension defined as systolic blood pressure \< 80% of baseline (measured in the assigned study position) or \< 90 mmHg

Time frame
From completion of spinal anesthesia to fetal delivery

Secondary outcomes

1

Umbilical artery and umbilical vein blood gas values

Umbilical artery and umbilical vein blood gas values (pH, PCO2, PO2, base excess, lactate)

Time frame
At delivery
2

Apgar scores at 1 and 5 minutes after delivery

Time frame
From fetal delivery to 5 minutes after delivery
3

Time to first rescue vasopressor

Time frame
From completion of intrathecal injection to delivery
4

Serial systolic blood pressure values within 12 minutes after intrathecal injection

Time frame
From completion of spinal anesthesia to 12 minutes after completion of spinal anesthesia

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Peking University People's Hospital

Lead sponsor

XuZhouHeJia hospital

Collaborator

Source ClinicalTrials.gov

This trial is not recruiting at the moment. You can still explore other options: