Dural Sac Area-Guided Spinal Anesthesia Dosing for TURP

Condition(s) studied

Investigational drug(s) / intervention(s)

DSCSA-Guided Individualized Spinal Anesthesia Dosing: The dural sac cross-sectional area (DSCSA) is calculated from the ultrasound-measured anteroposterior dural sac diameter at the L3-L4 level. The intrathecal bupivacaine dose is individualized according to DSCSA.

Bupivacaine: Hyperbaric bupivacaine is administered intrathecally in both study groups. In the DSCSA-guided group, the dose is individualized according to DSCSA, using 150 mm² as the reference corresponding to 10 mg, with a permitted dose range of 6 to 12.5 mg. In the fixed-dose group, 10 mg (2 mL of 0.5% bupivacaine) is administered.

Fentanyl (FEN): Fentanyl 25 micrograms is administered intrathecally together with bupivacaine in both study groups.

Study summary

This randomized controlled study will evaluate whether individualizing the dose of spinal anesthesia according to the ultrasound-derived dural sac cross-sectional area (DSCSA) can improve hemodynamic stability in patients undergoing transurethral resection of the prostate (TURP).

Participants aged 40 years or older will be randomly assigned to one of two groups. In the individualized-dose group, the anteroposterior diameter of the dural sac will be measured by ultrasound at the L3-L4 level, and DSCSA will be calculated from this measurement. The dose of intrathecal bupivacaine will then be individualized according to the calculated DSCSA. In the control group, participants will receive a fixed dose of intrathecal bupivacaine. Both groups will also receive intrathecal fentanyl.

The main outcome is the incidence of intraoperative hypotension. The study will also evaluate the number of hypotensive episodes, minimum mean arterial pressure, vasopressor and atropine requirements, sensory and motor block characteristics, respiratory monitoring parameters, cerebral oxygenation, and adverse events.

The study aims to determine whether a DSCSA-guided dosing strategy can reduce excessive spinal block and improve hemodynamic stability while maintaining effective spinal anesthesia.

Eligibility

Primary outcome measure(s)

• Incidence of Intraoperative Hypotension — During surgery (from completion of spinal anesthesia until the end of surgery)
  Intraoperative hypotension is defined as a decrease in mean arterial pressure (MAP) of ≥20% from baseline or an MAP \<65 mmHg. Participants meeting either criterion at least once during surgery will be classified as having intraoperative hypotension. The outcome will be reported as the percentage of participants with intraoperative hypotension.

Trial sites (1)

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