Minimum Effective Volume of Crystalloid Co-Loading to Prevent Spinal Anesthesia-Induced Hypotension in Cesarean Section
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- What is being studied
- The protocol lists: Intravenous Crystalloid Co-Loading.
- Who it may be relevant to
- Registry conditions: Spinal Induced Hypotension in Cesarean Delivery. Basic parameters: from 19 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Determination of the Minimum Effective Volume of Crystalloid Co-Loading for Preventing Spinal Anesthesia-Induced Hypotension in Cesarean Section: A Biased Coin Design Study
Overview
The goal of this clinical trial is to find the minimum effective volume of IV crystalloid that should be given with phenylephrine to prevent hypotension caused by spinal anesthesia in healthy, term pregnant adults having elective cesarean delivery. The main questions are: What is the minimum effective volume (MEV90, mL/kg) of crystalloid co-loading that prevents spinal-anesthesia-induced hypotension in ≥90% of participants? What maternal side effects and newborn outcomes occur with this strategy (e.g., nausea/vomiting, need for extra vasopressors, total fluids/blood loss, Apgar scores, and umbilical cord blood gases)? There is no separate comparison group; this is a single-arm, adaptive dose-finding study. Participants will: Receive a predefined volume of IV crystalloid over \~10 minutes during spinal anesthesia while phenylephrine is infused. Have blood pressure and symptoms monitored; receive rescue treatment if needed. Allow the next participant's fluid volume to be adjusted based on whether hypotension occurred (biased-coin design). Be followed through postoperative day 2 for maternal and newborn outcomes.
Interventions
- Other Intravenous Crystalloid Co-Loading
Balanced crystalloid is infused intravenously immediately after intrathecal injection as a co-load. A predefined volume (mL/kg) is administered over \~10 minutes. The volume for successive participants is adapted by a biased-coin up-and-down algorithm to estimate the minimum effective volume (MEV90) that prevents spinal-anesthesia-induced hypotension. Rescue fluids are allowed per protocol.
Primary outcome measures
- Minimum Effective Volume (MEV90) of Intravenous Crystalloid Co-Loading (mL/kg) [Time frame: From intrathecal injection (start of spinal anesthesia) to end of surgery]
Secondary outcome measures (12)
- Incidence of intraoperative hypotension (mmHg) [Time frame: From intrathecal injection to end of surgery]
- Incidence of intraoperative hypertension (mmHg) [Time frame: From intrathecal injection to end of surgery]
- Additional bolus phenylephrine requirement [Time frame: From intrathecal injection to end of surgery]
- Total Phenylephrine Dose (µg) [Time frame: From intrathecal injection to end of surgery]
- Estimated blood loss (mL) [Time frame: From skin incision to end of surgery]
- Incidence of Maternal Nausea Associated With Hypotension [Time frame: From intrathecal injection to end of surgery]
- Incidence of Maternal Vomiting Associated With Hypotension [Time frame: From intrathecal injection to end of surgery]
- Incidence of Maternal Dizziness/Lightheadedness Associated With Hypotension [Time frame: From intrathecal injection to end of surgery]
- Neonatal Apgar score at 1Minute [Time frame: At 1 minute after birth]
- Neonatal Apgar Score at 5 Minutes [Time frame: At 5 minutes after birth]
- Umbilical Arterial pH [Time frame: At delivery (immediately after birth)]
- Umbilical Arterial Base Excess (mmol/L) [Time frame: At delivery (immediately after birth)]
Eligibility criteria
Inclusion criteria
- Pregnant adults ≥19 years scheduled for elective cesarean delivery under spinal anesthesia
- Term pregnancy (≥37 weeks' gestation)
Exclusion criteria
- Emergency cesarean delivery
- Hypertensive disorders of pregnancy (preeclampsia/eclampsia) or hypertension
- Multiple gestation
- Body weight <50 kg or BMI >35 kg/m²
- Renal impairment or eGFR ≤90 mL/min/1.73 m²
- Heart failure or other heart disease
- History of bronchial asthma or other pulmonary disease
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Prevention
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07324512 · 2508-038-1665