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

7 de junho de 2026 atualizado 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.

Visão geral do estudo

Status

Recrutamento

Condições

Intervenção / Tratamento

Descrição detalhada

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 estudo

Intervencional

Inscrição (Estimado)

174

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

  • Nome: Rodrigo L Alves, MD, PhD
  • Número de telefone: 71 99961-9818
  • E-mail: rlalves@ufba.br

Estude backup de contato

Locais de estudo

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

Aceita Voluntários Saudáveis

Não

Descrição

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.

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: Tratamento
  • Alocação: Randomizado
  • Modelo Intervencional: Atribuição Paralela
  • Mascaramento: Triplo

Armas e Intervenções

Grupo de Participantes / Braço
Intervenção / Tratamento
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.

O que o estudo está medindo?

Medidas de resultados primários

Medida de resultado
Descrição da medida
Prazo
Total postoperative opioid consumption during the first 24 hours after surgery
Prazo: 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 resultados secundários

Medida de resultado
Descrição da medida
Prazo
Postoperative pain intensity (VAS)
Prazo: 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
Prazo: 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)
Prazo: 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
Prazo: 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)
Prazo: 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
Prazo: 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

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

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)

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)

1 de junho de 2026

Conclusão Primária (Estimado)

30 de novembro de 2026

Conclusão do estudo (Estimado)

4 de dezembro de 2026

Datas de inscrição no estudo

Enviado pela primeira vez

2 de junho de 2026

Enviado pela primeira vez que atendeu aos critérios de CQ

2 de junho de 2026

Primeira postagem (Real)

8 de junho de 2026

Atualizações de registro de estudo

Última Atualização Postada (Real)

10 de junho de 2026

Última atualização enviada que atendeu aos critérios de controle de qualidade

7 de junho de 2026

Última verificação

1 de maio de 2026

Mais Informações

Termos relacionados a este estudo

Palavras-chave

Termos MeSH relevantes adicionais

Outros números de identificação do estudo

  • 96691226.0.0000.0049 (Identificador de registro: 8.416.413)

Plano para dados de participantes individuais (IPD)

Planeja compartilhar dados de participantes individuais (IPD)?

SIM

Descrição do plano 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.

Prazo de Compartilhamento de 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.

Critérios de acesso de compartilhamento 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.

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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