Effects of Transcutaneous Electrical Phrenic Nerve Stimulation and Transcutaneous Electrical Diaphragmatic Stimulation

Effects of Transcutaneous Electrical Phrenic Nerve Stimulation and Transcutaneous Electrical Diaphragmatic Stimulation: a Randomized Controlled Crossover Trial

Transcutaneous electrical phrenic nerve stimulation (TEPNS) and transcutaneous electrical diaphragm stimulation (TEDS) are modalities that use surface electrodes placed on the patients' skin to generate action potentials and contractions of the muscle fibers of the diaphragm. The primary objective will be to evaluate the efficacy of TEPNS and TEDS in healthy adult individuals. Secondary objectives will be to assess the feasibility, safety, and level of discomfort reported by the individual resulting from the application of TEPNS and TEDS.

This crossover trial, single-blind, bicentric study will be conducted at two hospitals. Adult volunteers aged 18 to 60 years, healthy, with a body mass index between 18.5 and 24.9 kg/m2, without a history of previous respiratory diseases, and without contraindications to undergo evaluation or application of the proposed electrical stimulation modalities will be included. Participants' diaphragm muscle will be assessed using ultrasound for variables such as thickness, thickness fraction, and diaphragm mobility. Patients will be randomized using opaque envelope draw prior to evaluation into two distinct experimental moments: 1) "TEPNS" moment - application of the TEPNS protocol; or 2) "TEDS" moment - application of the TEDS protocol. Additionally, data regarding the feasibility and safety of the application of electrical stimulation modalities will be collected.

Inclusion Criteria:

• Age between 18 and 60 years;
• Normal pulmonary function test, without alterations, assessed through spirometry;
• Body Mass Index (BMI) between 18.5 and 24.9 kg/m2.

Exclusion Criteria:

• Smokers or former smokers;
• Individuals with previously known cardiopulmonary diseases (restrictive lung diseases, chronic obstructive pulmonary disease - COPD, asthma, cystic fibrosis, among other pathologies);
• Presence of implanted electrical devices (pacemaker, implantable cardioverter-defibrillator, among others);
• Individuals who have contraindications to undergo evaluation and/or application of transcutaneous electrical stimulation of the diaphragm muscle, such as: altered sensitivity, wounds at the site of application, deformities, among other conditions.