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Transauricular Vagus Nerve Stimulation Frequencies for Postoperative Pain (TVNS-PAIN)

7 de junio de 2026 actualizado por: Joao Paulo Aureliano de Carvalho, Federal University of Bahia

Effects of Different Frequencies of Transauricular Vagus Nerve Stimulation on Postoperative Pain: A Randomized, Double-Blind, Sham-Controlled Trial With Preoperative and Postoperative Sessions

The goal of this clinical trial is to learn whether different frequencies of transauricular vagus nerve stimulation (tVNS) can reduce postoperative pain and opioid consumption in adults undergoing abdominal or urologic surgery. It will also evaluate the effects of tVNS on recovery quality, autonomic function, and treatment safety. The main questions it aims to answer are:

Does transauricular vagus nerve stimulation reduce postoperative opioid consumption during the first 24 hours after surgery? Do different stimulation frequencies (high-frequency and low-frequency tVNS) produce different effects on postoperative pain and autonomic responses? Is transauricular vagus nerve stimulation safe and well tolerated in surgical patients?

Researchers will compare high-frequency tVNS, low-frequency tVNS, and sham stimulation (inactive stimulation) to determine their effects on postoperative pain and opioid requirements.

Participants will:

Be randomly assigned to receive high-frequency tVNS, low-frequency tVNS, or sham stimulation.

Receive two 30-minute stimulation sessions, one before anesthesia and one after surgery in the post-anesthesia care unit.

Undergo assessments of postoperative pain, opioid consumption, need for rescue analgesics, postoperative nausea and vomiting, heart rate changes, and quality of recovery.

Be monitored for adverse events related to the intervention during the study period.

A total of 174 participants will be enrolled in this single-center, randomized, double-blind, sham-controlled clinical trial.

Descripción general del estudio

Estado

Reclutamiento

Condiciones

Intervención / Tratamiento

Descripción detallada

Postoperative pain remains a major challenge in perioperative care and is associated with delayed recovery, increased healthcare utilization, and greater opioid consumption. Despite advances in multimodal analgesia, opioid medications continue to play a central role in postoperative pain management and may be associated with adverse effects such as nausea, vomiting, respiratory depression, and prolonged recovery. Therefore, the development of effective non-pharmacological adjunctive strategies is of considerable clinical interest.

Transauricular vagus nerve stimulation (tVNS) is a non-invasive neuromodulation technique that stimulates the auricular branch of the vagus nerve through the external ear. Experimental and clinical studies suggest that vagal stimulation may modulate pain perception through activation of central autonomic pathways, enhancement of descending inhibitory pain mechanisms, and regulation of inflammatory responses. Previous clinical trials have demonstrated promising effects of tVNS on acute and chronic pain conditions, including reductions in postoperative pain scores.

However, the optimal stimulation parameters for perioperative analgesia remain uncertain. In particular, the influence of stimulation frequency on clinical outcomes and autonomic responses has not been adequately investigated. Different stimulation frequencies may activate distinct neural pathways and produce different effects on pain modulation and autonomic regulation.

This study is designed to evaluate the effects of different frequencies of transauricular vagus nerve stimulation applied before and after surgery in adult patients undergoing elective surgical procedures. In addition to assessing postoperative opioid requirements, the study will explore the relationship between autonomic responses and postoperative recovery. The findings may contribute to the optimization of non-pharmacological analgesic strategies and support the incorporation of transauricular vagus nerve stimulation into multimodal perioperative pain management protocols.

Tipo de estudio

Intervencionista

Inscripción (Estimado)

174

Fase

  • No aplica

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Estudio Contacto

  • Nombre: Rodrigo L Alves, MD, PhD
  • Número de teléfono: 71 99961-9818
  • Correo electrónico: rlalves@ufba.br

Copia de seguridad de contactos de estudio

  • Nombre: João Paulo A de Carvalho
  • Número de teléfono: 75 98295-3834
  • Correo electrónico: joaoaureliano@ufba.br

Ubicaciones de estudio

  • Brasil
    • Estado de Bahia
      • Salvador, Estado de Bahia, Brasil, 40170-110
        • Reclutamiento
        • Hospital Universitário Professor Edgard Santos, Federal University of Bahia (HUPES-UFBA)
        • Contacto:

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Adulto

Acepta Voluntarios Saludables

No

Descripción

Inclusion Criteria:

  • Adults aged 18 to 59 years.
  • Undergoing elective abdominal or urologic surgery.
  • American Society of Anesthesiologists (ASA) physical status I-III.
  • Able and willing to provide written informed consent.

Exclusion Criteria:

  • History of neurological disorders.
  • History of psychiatric disorders.
  • Inability to understand study procedures.
  • Pregnancy.
  • Cognitive impairment.
  • Communication difficulties that interfere with study assessments.
  • Auricular dermatitis or skin lesions at the stimulation site.
  • Pre-existing cardiac arrhythmia.
  • Chronic opioid use.
  • Implanted electronic medical devices, including pacemakers.

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

  • Propósito principal: Tratamiento
  • Asignación: Aleatorizado
  • Modelo Intervencionista: Asignación paralela
  • Enmascaramiento: Triple

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Experimental: High-Frequency tVNS
Participants will receive active transauricular vagus nerve stimulation (tVNS) at a frequency of 60-120 Hz. Stimulation will be applied bilaterally to the auricular branch of the vagus nerve for 30 minutes before anesthesia and for 30 minutes after surgery. Current intensity will be adjusted between 2 and 6 mA according to participant tolerance.
Dispositivo: Transauricular Vagus Nerve Stimulation (tVNS)
Non-invasive electrical stimulation of the auricular branch of the vagus nerve applied bilaterally through ear electrodes. Stimulation is delivered before anesthesia and after surgery using predefined frequency settings.
Experimental: Low-Frequency tVNS
Participants will receive active transauricular vagus nerve stimulation (tVNS) at a frequency of 10-20 Hz. Stimulation will be applied bilaterally to the auricular branch of the vagus nerve for 30 minutes before anesthesia and for 30 minutes after surgery. Current intensity will be adjusted between 2 and 6 mA according to participant tolerance.
Dispositivo: Transauricular Vagus Nerve Stimulation (tVNS)
Non-invasive electrical stimulation of the auricular branch of the vagus nerve applied bilaterally through ear electrodes. Stimulation is delivered before anesthesia and after surgery using predefined frequency settings.
Comparador falso: Sham tVNS
Participants will receive sham transauricular vagus nerve stimulation. The device will be positioned and activated to mimic active treatment, but stimulation will be discontinued shortly after initiation. Participants will undergo two 30-minute sessions, one before anesthesia and one after surgery, while maintaining blinding to treatment allocation.
Dispositivo: Sham Transauricular Vagus Nerve Stimulation (sham tVNS)
Sham stimulation delivered using the same device and electrode placement as active stimulation. The device is activated to mimic treatment but does not deliver therapeutic electrical stimulation.

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Total postoperative opioid consumption during the first 24 hours after surgery
Periodo de tiempo: 24 hours after surgery
Total opioid consumption during the first 24 postoperative hours, recorded according to the institutional postoperative analgesia protocol.
24 hours after surgery

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Postoperative pain intensity (VAS)
Periodo de tiempo: Before stimulation in the post-anesthesia care unit, immediately after stimulation, 2 hours after surgery, and 24 hours after surgery
Pain intensity measured using a 100-mm Visual Analog Scale (VAS). Pain scores will be assessed at predefined postoperative time points and compared among study groups.
Before stimulation in the post-anesthesia care unit, immediately after stimulation, 2 hours after surgery, and 24 hours after surgery
Rescue analgesic use
Periodo de tiempo: Within 24 hours after surgery
Number of participants requiring rescue analgesics and total rescue analgesic administration during the first 24 postoperative hours.
Within 24 hours after surgery
Postoperative nausea and vomiting (PONV)
Periodo de tiempo: Within 24 hours after surgery
Incidence of postoperative nausea and/or vomiting and use of rescue antiemetic medication during the postoperative period.
Within 24 hours after surgery
Heart rate changes
Periodo de tiempo: Immediately before and immediately after each stimulation session (preoperative and postoperative).
Changes in heart rate measured immediately before and immediately after transauricular vagus nerve stimulation sessions as an indicator of autonomic nervous system activity.
Immediately before and immediately after each stimulation session (preoperative and postoperative).
Quality of Recovery (QoR-15 Score)
Periodo de tiempo: Baseline (preoperative) and 24 hours after surgery.
Quality of postoperative recovery assessed using the 15-item Quality of Recovery questionnaire (QoR-15). Higher scores indicate better recovery.
Baseline (preoperative) and 24 hours after surgery.
Adverse events related to transauricular Vagus Nerve Stimulation
Periodo de tiempo: From the first stimulation session until 24 hours after surgery.
Incidence of adverse events potentially related to the intervention, including auricular discomfort, skin irritation, headache, bradycardia, hypotension, bronchospasm, or other treatment-related events.
From the first stimulation session until 24 hours after surgery.

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Federal University of Bahia

Colaboradores

Faculdade de Medicina de Botucatu, UNESP, Botucatu, Brasil

Investigadores

  • Investigador principal: Rodrigo M Vieira, MD, Botucatu Medical School, São Paulo State University (UNESP)

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Estimado)

1 de junio de 2026

Finalización primaria (Estimado)

30 de noviembre de 2026

Finalización del estudio (Estimado)

4 de diciembre de 2026

Fechas de registro del estudio

Enviado por primera vez

2 de junio de 2026

Primero enviado que cumplió con los criterios de control de calidad

2 de junio de 2026

Publicado por primera vez (Actual)

8 de junio de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

10 de junio de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

7 de junio de 2026

Última verificación

1 de mayo de 2026

Más información

Términos relacionados con este estudio

Palabras clave

Términos MeSH relevantes adicionales

Otros números de identificación del estudio

  • 96691226.0.0000.0049 (Identificador de registro: 8.416.413)

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

SÍ

Descripción del plan IPD

De-identified individual participant data underlying the results reported in publications arising from this study will be made available, including demographic characteristics, intervention allocation, primary and secondary outcome measures, and adverse event data. Data will be shared only after removal of all direct identifiers to protect participant confidentiality.

Marco de tiempo para compartir IPD

De-identified individual participant data and supporting study documents will be available beginning 3 months after publication of the primary study results and will remain available indefinitely, with no end date.

Criterios de acceso compartido de IPD

De-identified data will be available to qualified researchers who provide a methodologically sound research proposal. Requests should be submitted to the principal investigator. Access will be granted following review and approval of the proposed use and execution of a data-sharing agreement.

Información sobre medicamentos y dispositivos, documentos del estudio

Estudia un producto farmacéutico regulado por la FDA de EE. UU.

No

Estudia un producto de dispositivo regulado por la FDA de EE. UU.

No

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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