Effects of transcutaneous auricular vagus nerve stimulation on inflammation, cardiac autonomic modulation, and clinical evolution of patients with COVID-19: protocol for a clinical, controlled, randomized, and blind trial

Abstract

This study aims to evaluate the effect of
transcutaneous auricular vagus nerve stimulation (taVNS) on
inflammation, cardiac autonomic modulation, and clinical evolution
of patients with COVID-19. This is a clinical, sham-controlled,
randomized, and blind trial, in which 52 hospitalized individuals
diagnosed with COVID-19 will participate. They will be randomized
into: experimental group (usual medical treatment associated
with active taVNS) and control group (usual medical treatment
associated with sham taVNS). The taVNS will be performed
by a neuromuscular electric stimulator (Dualpex model 071
of Quark Medical Products), with the stimulation electrode
positioned on the left tragus, with alternating current, at a 30Hz
frequency with 50% variation. Intensity will be adjusted to the
patient’s sensory threshold, with 90-minutes-long stimulation
sessions, happening twice per day for seven consecutive days,
totaling 14 sessions. Interleukin-6 (IL-6) and interleukin-10 (IL-10),
cortisol and C-reactive protein (CRP), blood pressure, heart rate
variability (HRV) by low frequency (LF), high frequency (HF)
and low and high frequency ratio (LF/HF) parameters will be
evaluated before and after the intervention, as well as patients’
clinical evolution—including anxiety and depression levels—
whose data will be obtained through medical records and
questionnaires. A follow-up will also be performed seven and
14 days after the end of the interventions to verify the clinical
evolution, including anxiety and depression levels. Memory and
attention levels will be evaluated for six months.