Sensory Block Onset: Epidural vs Dural Puncture Epidural in Cesarean Section

• Dural Puncture Epidural (DPE) Anesthesia (Procedure): Dural puncture epidural (DPE) is a combined neuraxial technique that integrates spinal and epidural approaches to enhance the quality of sensory and motor blockade. The procedure begins with dural puncture using a 26-gauge Spinocan spinal needle at the L3-L4 lumbar interspace until cerebrospinal fluid (CSF) is observed, indicating a micro-dural lesion, after which the spinal needle is withdrawn. Subsequently, an epidural catheter is inserted using an 18-gauge Tuohy needle with the loss-of-resistance (LOR) technique using saline, and advanced 4-5 cm into the epidural space. The anesthetic agents administered are the same as those used in conventional epidural anesthesia. This DPE technique is operationalized to accelerate sensory block onset, improve motor block quality, and minimize complications compared with conventional epidural anesthesia.
• epidural anesthesia (Procedure): Conventional epidural technique for elective cesarean delivery. Epidural anesthesia is a neuraxial technique used for analgesia or anesthesia during cesarean delivery by administering local anesthetic agents through a catheter placed in the epidural space without penetrating the dura mater. In this study, epidural anesthesia is operationalized by inserting an 18-gauge Tuohy needle at the L3-L4 lumbar interspace, advancing the epidural catheter 4-5 cm into the epidural space, followed by administration of 0.5% isobaric bupivacaine combined with 50 µg fentanyl. Parameters recorded include sensory and motor block onset, mean arterial pressure (MAP), heart rate, and procedure- and surgery-related adverse events. In this study, epidural anesthetic dosing is adjusted for patients with very short stature (height <150 cm), with dose reduction based on published literature (10-20%).

Primary outcomes

• Time (minutes) to achieve bilateral T6 sensory block [From an anesthetic injection to the achievement of sensory and motor block during surgery (intraoperative period).]: Sensory block onset is defined as the time from anesthetic injection until the achievement of sensory block at the T6 dermatome on both the left and right sides. The measurement is recorded in minutes using a stopwatch.
• Time (minutes) to achieve Bromage grade 3 motor block [From an anesthetic injection to the achievement of sensory and motor block during surgery (intraoperative period)]: Motor block onset is defined as the time from anesthetic injection until the achievement of Bromage grade 3 motor block (inability to raise the straight leg). The measurement is recorded in minutes using a stopwatch.

Secondary outcomes

• Mean Arterial Pressure (MAP) [From baseline (minute 0) to 20 minutes after anesthetic administration during surgery]: Mean arterial pressure (MAP) is defined as the average arterial blood pressure during a single cardiac cycle and is monitored non-invasively using an automated blood pressure monitor. This parameter is recorded at baseline (minute 0) and subsequently measured every 3 minutes during the first 20 minutes following anesthetic administration.
• Heart Rate (HR) [From baseline (minute 0) to 20 minutes after anesthetic administration during surgery]: Heart rate is defined as the number of heartbeats per minute and is measured automatically via standard patient monitoring. Heart rate is recorded at baseline (minute 0) and subsequently measured every 3 minutes during the first 20 minutes following anesthetic administration.
• Number of participants with Post-dural Puncture Headache (PDPH) [Within 72 hours after neuraxial anesthesia]: Post-dural puncture headache (PDPH) is assessed as part of the side effect evaluation. PDPH is defined as a postural headache that worsens when the patient is sitting or standing and improves in the supine position, occurring within 48-72 hours after dural penetration. PDPH is evaluated as a secondary outcome as a potential complication following neuraxial anesthesia, including epidural and dural puncture epidural (DPE) techniques.
• Number of participants with nausea and/or vomiting [During anesthetic administration and surgery]: Nausea and vomiting are assessed as part of the side effect evaluation. These outcomes are defined as subjective complaints of nausea and/or observed episodes of vomiting occurring during anesthetic administration and throughout the cesarean delivery procedure. Events are assessed through direct observation and patient self-reporting.
• APGAR Score [At 1 and 5 minutes after birth]: APGAR Score is assessed as part of the side effect evaluation. Neonatal outcome is assessed using the Apgar score at 1 and 5 minutes after birth. The Apgar score evaluates five parameters: skin color, heart rate, reflex irritability, muscle tone, and respiration, with a total score ranging from 0 to 10. Apgar scores are recorded by trained healthcare personnel and used as an indicator of immediate neonatal clinical condition.
• Number of participants with hypotension [From anesthetic administration until the end of surgery]: Hypotension is assessed as part of the side effect evaluation and defined as a decrease in blood pressure of ≥20% from baseline or a mean arterial pressure (MAP) <65 mmHg following neuraxial anesthesia.

Sex: Female

Inclusion Criteria:

* Pregnant women scheduled to undergo cesarean delivery
* American Society of Anesthesiologists (ASA) physical status II-III
* Willing to participate in the study by providing written informed consent

Exclusion Criteria:

* Patients with absolute contraindications to neuraxial anesthesia
* Patients with known allergy or history of allergy to medications used in the study
* Patients with psychiatric disorders or who are uncooperative
* Patients with accidental dural puncture

Dropout Criteria:

* Patients who require conversion to general anesthesia during the procedure
* Patients who experience major intraoperative complications (massive hemorrhage, shock, or cardiac arrest)