Cesarean Section Complications
Conditions
Keywords
cesarean-20% hyperbaric bupivacaine
Brief summary
Effect of a 20% Reduction in Hyperbaric Bupivacaine Dose on High Spinal Block Incidence in Cesarean Delivery: A Risk-Stratified Randomized Controlled Trial.
Detailed description
Study OverviewThis prospective, randomized, double-blind, active-controlled trial investigates the clinical efficacy of a 20% dose reduction of intrathecal hyperbaric bupivacaine (10 mg vs. 12.5 mg) in reducing the incidence of high spinal block (HSB) among parturients undergoing elective or emergency cesarean delivery under spinal anesthesia. Participants are stratified preoperatively using an adapted risk-prediction model to evaluate the predictive validity of dose-blind versus dose-aware scoring frameworks.Study Arms and InterventionsArm A: Reduced-Dose Group (Intervention)Intrathecal Regimen: 10 mg hyperbaric bupivacaine 0.5% (2.0 mL) combined with 25 µg preservative-free fentanyl (0.5 mL of 50 µg/mL solution).Total Injectate Volume: 2.5 mL.Arm B: Standard-Dose Group (Active Comparator)Intrathecal Regimen: 12.5 mg hyperbaric bupivacaine 0.5% (2.5 mL) combined with 25 µg preservative-free fentanyl (0.5 mL of 50 µg/mL solution).Total Injectate Volume: 3.0 mL.Procedural Workflow and MethodologyStep 1: Risk-Prediction Scoring FrameworkPrior to randomization, each participant's risk profile is quantified using a 7-factor model adapted from Benjhawaleemas et al. (2024):Risk FactorCriterionBaseline WeightGestational age\< 35 weeks8 pointsMaternal height\< 150 cm8 pointsPost-pregnancy BMI\> 27.5 kg/m²10 pointsOperator experienceFirst-year resident4 pointsSurgical historyPrevious cesarean delivery during labor6 pointsSurgical indicationElective cesarean delivery9 pointsBupivacaine dose\> 11 mgVariable (see below)Timepoint 1 (Pre-randomization / Dose-Blind): The six non-dose variables are scored based on clinical assessment. The dose parameter is provisionally assigned a neutral weight of 5 points (reflecting the expected mean contribution under 1:1 allocation) to allow unbiased baseline stratification into low (score ≤ 14), intermediate (15-21), or high (\> 21) risk tiers.Timepoint 2 (Post-randomization / Dose-Aware): Following unmasking of the syringe preparation, the score is recalculated with the actual dose parameter weighted as 0 points (≤ 11 mg, Group A) or 9 points (\> 11 mg, Group B). Comparative discrimination metrics (ROC/AUC) assess the diagnostic utility of the pre-randomization model.Step 2: Anesthetic TechniqueAdministration: Performed by supervised 2nd- or 3rd-year anesthesia residents with the patient in the sitting position with maximal lumbar flexion.Access & Equipment: L3-L4 or L4-L5 interspace identified via Tuffier's line; 25-gauge Whitacre (pencil-point) needle via midline approach with free-flowing clear CSF confirmation.Injection Rate: Intrathecal injection over 15-20 seconds using identical, prefilled syringes prepared by an unblinded pharmacist/anesthetist not involved in outcome assessment.Post-Injection Positioning: Immediate supine positioning with ≥ 15° left uterine displacement (wedge or table tilt).Block Assessment: Bilateral sensory level to cold sensation (ice/alcohol) and motor blockade via the Modified Bromage Scale. Surgical incision proceeds once bilateral sensory block achieves the T6 dermatome.Step 3: Hemodynamic and Safety ProtocolCo-loading: Intravenous balanced crystalloid (Ringer's lactate) at 10-15 mL/kg administered over 15-20 minutes starting at spinal injection.Prophylaxis: Routine prophylactic vasopressor infusions are withheld to prevent pharmacodynamic confounding of the primary endpoint.Monitoring Regimen: Continuous ECG, pulse oximetry ($SpO\_2$), and heart rate. Non-invasive blood pressure (NIBP) measured every 2-3 minutes for the first 15 minutes post-injection, and every 5 minutes thereafter until surgery completion.Study Design and Administration DetailsTarget Enrollment: 666 participants (333 per arm; powered at 80%, $\\alpha = 0.05$ to detect a reduction in HSB incidence from 5% to 1%, accounting for continuity corrections and attrition).Randomization & Allocation Concealment: 1:1 computer-generated block randomization managed through sequentially numbered, opaque, sealed envelopes opened solely by the drug preparation team.Blinding Model: Double-blind (participants, clinical care providers, and outcome assessors remain masked).Study Setting: Single-center tertiary academic hospital (Operating Theaters, Aswan University Hospital, Egypt).
Interventions
DRUGHyperbaric Bupivacaine HCl 0.5% 12.5 mg
1- Standard dose group: receiving the typical dose of hyperbaric bupivacaine (12.5 mg hyperbaric bupivacaine + 25 mcg fentanyl).
DRUGHyperbaric Bupivacaine HCl 0.5% 10 mg
2- Reduced dose group: receiving a20% reduced dose of hyperbaric bupivacaine (10 mg hyperbaric bupivacaine + 25 mcg fentanyl).
Sponsors
Aswan University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Masking description
Masking Description A double-blind design is maintained throughout the trial to minimize performance and detection bias. Drug Preparation & Allocation Concealment: An independent anesthetist not involved in patient management, intraoperative care, or postoperative data collection prepares all study medications in identical, unmarked, prefilled syringes according to the sequentially numbered, sealed opaque envelopes. Participant Blinding: Parturients remain masked to group allocation and syringe volume throughout their hospital stay. Care Provider Blinding: The anesthesia residents performing the subarachnoid block and the operating surgical team are blinded to the allocated dose. Syringes are visually indistinguishable (clear, colorless solutions). Outcomes Assessor Blinding: Independent outcome assessors who record sensory dermatome levels, motor blockade (Modified Bromage Scale), hemodynamic parameters, and incidence of high spinal block (HSB) remain strictly masked
Intervention model description
Prospective, randomized, active-controlled, parallel-group trial stratified preoperatively using a 7-parameter weighted risk-prediction tool.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* • Pregnant women aged 18-45 years. * ASA physical status II-III.
Exclusion criteria
* • Twin pregnancies. * Contraindications to spinal anesthesia (e.g., coagulopathy, infection). * Patients with incomplete preoperative data for risk stratification.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of high spinal block (HSB) | Within 15 minutes after intrathecal drug administration (assessed at 5, 10, and 15 minutes) | The incidence of high spinal block (HSB), defined as the presence of both of the following criteria within 15 minutes of intrathecal drug administration: 1. Sensory block exceeding the T4 dermatome: * Assessed bilaterally using the pinprick test (with a 25-gauge blunt needle) and cold sensation (using an alcohol swab) * The upper sensory level was recorded as the most cephalad dermatome with complete loss of sensation to both pinprick and cold * A block was considered to have exceeded T4 if the loss of sensation was documented above the T4 dermatome (i.e., ≥ T3 or higher) on at least one side 2. Hemodynamic instability, defined as any of the following (thresholds informed by Klöhr et al., 2010, and Kinsella et al., 2018): * A decrease in systolic blood pressure (SBP) exceeding 30% below baseline (baseline SBP was defined as the mean of three preoperative measurements taken in the supine position with left uterine displacement) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Predictive Performance of the Risk-Prediction Score | From pre-randomization up to the end of the intraoperative observation period for high spinal block (HSB) (e.g., from baseline prior to spinal injection through discharge from the Post-Anesthesia Care Unit [PACU] / ~2 hours post-anesthesia). | The predictive performance of the risk-prediction score for the primary outcome (HSB) was assessed at both timepoints described in Step 1 (pre-randomization, dose-blind score; and post-randomization, dose-aware score). For each score version, the following were calculated against the observed incidence of HSB: * Area under the receiver operating characteristic curve (AUC) * Sensitivity, specificity, and Youden's index at the pre-specified risk-category cutoffs (≤ 14, 15-21, and \> 21 points) * Agreement between the pre- and post-randomization risk categories This secondary outcome was pre-specified to determine whether the dose-blind (pre-randomization) score retains adequate predictive accuracy relative to the dose-aware (post-randomization) score, in order to establish whether the tool can be applied prospectively - before the anesthetic dose is chosen - for preoperative prediction of the risk of high spinal block. The statistical methods used to evaluate this outcome are detailed in |
| Neonatal Outcomes | 1 minute and 5 minutes after delivery | Neonatal outcomes were assessed using Apgar scores (Apgar, 1953) recorded at 1 minute and 5 minutes after delivery by the attending neonatologist or pediatrician, who was blinded to group allocation. The Apgar score was assessed based on five parameters: heart rate, respiratory effort, muscle tone, reflex irritability, and color, each scored from 0 to 2, giving a total score ranging from 0 to 10. |
| Maternal Satisfaction | 4 to 6 hours postoperatively | Maternal satisfaction was assessed postoperatively using a validated five-point Likert scale questionnaire, administered by a blinded research assistant 4-6 hours after surgery (once the patient was fully recovered from the neuraxial block and able to provide informed responses). The Likert Scale: Participants were asked to respond to the following statement: "Overall, how satisfied were you with your anesthetic experience during the cesarean delivery?" |
| Hemodynamic Stability | Intraoperatively, from spinal injection ($T_0$) through surgical completion (monitored at 1, 3, 5, 7, 10, 12, 15 minutes, and every 5 minutes thereafter; up to approximately 2 hours). | Hemodynamic stability was evaluated intraoperatively by monitoring predefined cardiovascular endpoints and therapeutic interventions. Hypotension was defined as a decrease in systolic blood pressure (SBP) greater than 30% from baseline, an absolute SBP below 90 mmHg, or a mean arterial pressure (MAP) below 65 mmHg at any point during the procedure. Bradycardia was defined as a heart rate below 50 beats per minute. Pharmacological and fluid interventions were quantified as the total intraoperative requirements of vasopressors (cumulative doses of ephedrine in milligrams and/or phenylephrine in micrograms), anticholinergics (cumulative dose of atropine in milligrams), and intravenous fluids (total volume of crystalloid infused in milliliters). All physiological parameters were recorded at baseline (preoperative), immediately following spinal injection ($T\_0$), at 1, 3, 5, 7, 10, 12, and 15 minutes post-injection, and subsequently every 5 minutes until the completion of surgery. |
Countries
Egypt
Contacts
CONTACTEman Mahmoud Ismail, Resident
CONTACTSoudy Salah Hammad, consultant
STUDY_DIRECTORAyman Mohamdy Eldemerdash, consultant
Aswan University
Outcome results
None listed