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

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.