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Dural Sac Area-Guided Spinal Anesthesia Dosing for TURP

26 de agosto de 2026 atualizado por: 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.

Visão geral do estudo

Descrição detalhada

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.

Tipo de estudo

Intervencional

Inscrição (Estimado)

60

Estágio

  • Não aplicável

Contactos e Locais

Esta seção fornece os detalhes de contato para aqueles que conduzem o estudo e informações sobre onde este estudo está sendo realizado.

Contato de estudo

Locais de estudo

      • Istanbul, Turquia (Türkiye), 34360
        • Istanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine
        • Contato:

Critérios de participação

Os pesquisadores procuram pessoas que se encaixem em uma determinada descrição, chamada de critérios de elegibilidade. Alguns exemplos desses critérios são a condição geral de saúde de uma pessoa ou tratamentos anteriores.

Critérios de elegibilidade

Idades elegíveis para estudo

  • Adulto
  • Adulto mais velho

Aceita Voluntários Saudáveis

Não

Descrição

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

Plano de estudo

Esta seção fornece detalhes do plano de estudo, incluindo como o estudo é projetado e o que o estudo está medindo.

Como o estudo é projetado?

Detalhes do projeto

  • Finalidade Principal: Cuidados de suporte
  • Alocação: Randomizado
  • Modelo Intervencional: Atribuição Paralela
  • Mascaramento: Dobro

Armas e Intervenções

Grupo de Participantes / Braço
Intervenção / Tratamento
Experimental: 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.
Comparador Ativo: 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.

O que o estudo está medindo?

Medidas de resultados primários

Medida de resultado
Descrição da medida
Prazo
Incidence of Intraoperative Hypotension
Prazo: 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)

Medidas de resultados secundários

Medida de resultado
Descrição da medida
Prazo
Number of Intraoperative Hypotension Episodes
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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
Prazo: 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)

Outras medidas de resultado

Medida de resultado
Descrição da medida
Prazo
Mean Left Regional Cerebral Oxygen Saturation During the First 60 Minutes
Prazo: 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
Prazo: 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
Prazo: 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

Colaboradores e Investigadores

É aqui que você encontrará pessoas e organizações envolvidas com este estudo.

Patrocinador

Investigadores

  • Investigador principal: Ezgi Budak Özyalçın, MD, Istanbul University - Cerrahpasa

Datas de registro do estudo

Essas datas acompanham o progresso do registro do estudo e os envios de resumo dos resultados para ClinicalTrials.gov. Os registros do estudo e os resultados relatados são revisados ​​pela National Library of Medicine (NLM) para garantir que atendam aos padrões específicos de controle de qualidade antes de serem publicados no site público.

Datas Principais do Estudo

Início do estudo (Estimado)

24 de agosto de 2026

Conclusão Primária (Estimado)

24 de novembro de 2026

Conclusão do estudo (Estimado)

10 de dezembro de 2026

Datas de inscrição no estudo

Enviado pela primeira vez

23 de agosto de 2026

Enviado pela primeira vez que atendeu aos critérios de CQ

26 de agosto de 2026

Primeira postagem (Real)

31 de agosto de 2026

Atualizações de registro de estudo

Última Atualização Postada (Real)

31 de agosto de 2026

Última atualização enviada que atendeu aos critérios de controle de qualidade

26 de agosto de 2026

Última verificação

1 de agosto de 2026

Mais Informações

Termos relacionados a este estudo

Plano para dados de participantes individuais (IPD)

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NÃO

Informações sobre medicamentos e dispositivos, documentos de estudo

Estuda um medicamento regulamentado pela FDA dos EUA

Não

Estuda um produto de dispositivo regulamentado pela FDA dos EUA

Não

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