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Dural Sac Area-Guided Spinal Anesthesia Dosing for TURP

26. august 2026 opdateret af: Ezgi Budak Ozyalcın, Istanbul University

Clinical Effects of Individualized Spinal Anesthesia Dosing Based on Ultrasound-Measured Dural Sac Cross-Sectional Area in Patients Undergoing Transurethral Resection of the Prostate: A Prospective, Randomized Controlled Trial

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.

Studieoversigt

Detaljeret beskrivelse

This prospective, randomized controlled study compares two routinely used approaches to determining the intrathecal bupivacaine dose for spinal anesthesia in patients undergoing transurethral resection of the prostate (TURP). No new drug, new indication, or experimental treatment will be introduced. Both dosing approaches are currently used in routine clinical practice; the study will prospectively and randomly compare their clinical effects.

Participants will be randomly assigned to either a dural sac cross-sectional area (DSCSA)-guided individualized dosing group or a fixed-dose control group.

Before spinal anesthesia, the anteroposterior diameter of the dural sac will be measured by ultrasound at the L3-L4 intervertebral level. DSCSA will be calculated using the formula A = π × (D/2)².

In the individualized-dose group, a DSCSA of 150 mm² will be used as the reference value corresponding to 10 mg of intrathecal bupivacaine. The bupivacaine dose will be adjusted proportionally according to the participant's calculated DSCSA and limited to a minimum of 6 mg and a maximum of 12.5 mg. Fentanyl 25 micrograms will be added intrathecally.

In the fixed-dose group, participants will receive 10 mg (2 mL of 0.5%) intrathecal bupivacaine together with fentanyl 25 micrograms.

Spinal anesthesia will be performed at the L3-L4 intervertebral space using a 27-gauge Quincke needle. Standard intraoperative monitoring will be performed according to the study protocol. Sensory and motor block characteristics and hemodynamic variables will be recorded prospectively for comparison between the two dosing strategies.

Undersøgelsestype

Interventionel

Tilmelding (Anslået)

60

Fase

  • Ikke anvendelig

Kontakter og lokationer

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Studiekontakt

Studiesteder

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

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Beskrivelse

Inclusion Criteria:

  • Male participants aged 40 years or older
  • American Society of Anesthesiologists (ASA) physical status I-III
  • Scheduled to undergo transurethral resection of the prostate (TURP) for prostate cancer

Exclusion Criteria:

  • Refusal of spinal anesthesia
  • Local infection or wound at the planned puncture site
  • Current anticoagulant therapy
  • Neurological disease, including multiple sclerosis, myelopathy, or peripheral neuropathy
  • Known allergy to any of the study medications
  • Inability to maintain the required position during ultrasound measurement or spinal puncture

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Støttende pleje
  • Tildeling: Randomiseret
  • Interventionel model: Parallel tildeling
  • Maskning: Dobbelt

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: DSCSA-Guided Individualized Dose
The dural sac cross-sectional area (DSCSA) will be estimated from the ultrasound-measured anteroposterior dural sac diameter at the L3-L4 level. The intrathecal bupivacaine dose will be individualized according to the DSCSA, using 150 mm² as the reference area corresponding to 10 mg bupivacaine. The calculated bupivacaine dose will be limited to 6-12.5 mg. Fentanyl 25 micrograms will also be administered intrathecally.
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.
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 25 micrograms is administered intrathecally together with bupivacaine in both study groups.
Aktiv komparator: Fixed Dose
Participants will receive a fixed intrathecal dose of 10 mg (2 mL of 0.5%) bupivacaine together with fentanyl 25 micrograms.
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 25 micrograms is administered intrathecally together with bupivacaine in both study groups.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Incidence of Intraoperative Hypotension
Tidsramme: 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.
During surgery (from completion of spinal anesthesia until the end of surgery)

Sekundære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Number of Intraoperative Hypotension Episodes
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Number of intraoperative hypotension episodes recorded for each participant. Hypotension is defined as a decrease in mean arterial pressure (MAP) of ≥20% from baseline or an MAP <65 mmHg.
During surgery (from completion of spinal anesthesia until the end of surgery)
Minimum Intraoperative Mean Arterial Pressure
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Lowest mean arterial pressure (MAP), measured in mmHg, recorded during the intraoperative period.
During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of Participants With a ≥30% Decrease in Mean Arterial Pressure
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of participants experiencing at least one decrease in mean arterial pressure (MAP) of ≥30% from baseline during surgery.
During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of Participants Requiring Ephedrine
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of participants receiving at least one intravenous dose of ephedrine for treatment of intraoperative hypotension.
During surgery (from completion of spinal anesthesia until the end of surgery)
Total Ephedrine Dose
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Total intravenous ephedrine dose, measured in milligrams (mg), administered to each participant during surgery.
During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of Participants Requiring Atropine
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of participants receiving intravenous atropine for treatment of intraoperative bradycardia.
During surgery (from completion of spinal anesthesia until the end of surgery)
Total Atropine Dose
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Total intravenous atropine dose, measured in milligrams (mg), administered to each participant during surgery.
During surgery (from completion of spinal anesthesia until the end of surgery)
Maximum Sensory Block Level
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Highest cephalad sensory block level achieved after spinal anesthesia, assessed by the pin-prick test and recorded as the corresponding dermatomal level.
During surgery (from completion of spinal anesthesia until the end of surgery)
Time to Achieve T10 Sensory Block
Tidsramme: Up to 30 minutes after spinal anesthesia
Time, measured in minutes, from completion of intrathecal injection to achievement of a T10 sensory block, assessed using the pin-prick test.
Up to 30 minutes after spinal anesthesia
Time to Two-Dermatome Sensory Regression
Tidsramme: From maximum sensory block until two-dermatome regression, assessed up to 3 hours after spinal anesthesia
Time, measured in minutes, from the maximum sensory block level to regression of the sensory block by two dermatomes, assessed using the pin-prick test.
From maximum sensory block until two-dermatome regression, assessed up to 3 hours after spinal anesthesia
Time to Recovery to Modified Bromage Score 0
Tidsramme: From completion of spinal anesthesia until recovery to Modified Bromage score 0, assessed up to 3 hours after spinal anesthesia
Time, measured in minutes, from completion of intrathecal injection until recovery to a Modified Bromage score of 0, indicating complete recovery of lower-extremity motor function.
From completion of spinal anesthesia until recovery to Modified Bromage score 0, assessed up to 3 hours after spinal anesthesia
Number of Integrated Pulmonary Index ≤4 Episodes
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Number of episodes in which the Integrated Pulmonary Index (IPI) is ≤4. The IPI is a composite score ranging from 1 to 10 based on end-tidal carbon dioxide, respiratory rate, oxygen saturation, and pulse rate; lower scores indicate greater respiratory compromise.
During surgery (from completion of spinal anesthesia until the end of surgery)
Incidence of Adverse Events
Tidsramme: During surgery (from completion of spinal anesthesia until the end of surgery)
Percentage of participants experiencing at least one adverse event recorded during the intraoperative study period.
During surgery (from completion of spinal anesthesia until the end of surgery)

Andre resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Mean Left Regional Cerebral Oxygen Saturation During the First 60 Minutes
Tidsramme: During the first 60 minutes after spinal anesthesia
Mean left regional cerebral oxygen saturation (rSO₂), measured continuously by frontal near-infrared spectroscopy (NIRS) during the first 60 minutes after spinal anesthesia. The outcome will be reported as the mean rSO₂ value.
During the first 60 minutes after spinal anesthesia
Minimum Regional Cerebral Oxygen Saturation
Tidsramme: During the first 60 minutes after spinal anesthesia
Lowest regional cerebral oxygen saturation (rSO₂) value recorded by frontal near-infrared spectroscopy (NIRS) during the first 60 minutes after spinal anesthesia.
During the first 60 minutes after spinal anesthesia
Maximum Relative Decrease in Regional Cerebral Oxygen Saturation
Tidsramme: During the first 60 minutes after spinal anesthesia
Maximum relative decrease in regional cerebral oxygen saturation (ΔrSO₂max) from the baseline value during the first 60 minutes after spinal anesthesia, measured by frontal near-infrared spectroscopy (NIRS).
During the first 60 minutes after spinal anesthesia

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Efterforskere

  • Ledende efterforsker: Ezgi Budak Özyalçın, MD, Istanbul University - Cerrahpasa

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Anslået)

24. august 2026

Primær færdiggørelse (Anslået)

24. november 2026

Studieafslutning (Anslået)

10. december 2026

Datoer for studieregistrering

Først indsendt

23. august 2026

Først indsendt, der opfyldte QC-kriterier

26. august 2026

Først opslået (Faktiske)

31. august 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

31. august 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

26. august 2026

Sidst verificeret

1. august 2026

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