The technique will be performed by applying transcutaneous neuromuscular electrical stimulation to the phrenic nerve pathway in the cervical region.

The technique will be performed by applying transcutaneous neuromuscular electrical stimulation with the electrodes positioned bilaterally in the parasternal region adjacent to the xiphoid process, and the other electrode placed in the intercostal space.

The characteristics of the electrical current: biphasic waves, set at a stimulation frequency of 10 Hz, pulse width of 200 μs, rise time of 1.0 second, on time of 1.0 second, fall time of 1.0 second, and off time of 2 seconds, resulting in 12 stimuli per minute. The application of "TEPNS" will initially be performed by defining the trajectory of the phrenic nerve in the cervical region. The negative pole (active point), a stick with a spherical tip for micro-current of 2 mm will be positioned with slight pressure in the region of the phrenic nerve pathway between the two heads of the sternocleidomastoid muscle. Additionally, at the positive pole (passive point), a self-adhesive electrode sized (2.0 x 2.0 cm) will be positioned on the skin in the shoulder region. The intensity, measured in milliamperes (mA), will be adjusted to the maximum tolerated by the patient. The total stimulation time will be 10 minutes, applied continuously in a single session.

The assessment of diaphragmatic mobility will use a "convex" type transducer (2-6 MHz), positioned in the right subcostal space, at the midclavicular line, tilted in the cephalic direction. The B-mode visualization window will initially be used to locate the diaphragmatic hemi-dome. Upon acquiring a good quality image, respiratory excursions will be measured in M-mode, using the inferior vena cava and the gallbladder as anatomical parameters. Diaphragmatic mobility measurement will be considered as the distance, in centimeters, between the baseline at expiration and its greatest vertical displacement at inspiration produced by diaphragmatic movement.

Diaphragm thickness (Tdi) will be obtained using a high-frequency "linear" type transducer (7-13 MHz), positioned over the zone of apposition (ZA) of the diaphragm muscle. The approximate location is between the 8th and 9th intercostal space, between the anterior axillary line and the midaxillary line, 0.5 to 2.0 cm below the costophrenic angle. The depth will be 1.5 to 3.0 cm, and the diaphragm muscle will be identified as the innermost portion of the hypoechoic muscular layer bounded by two hyperechoic membranes, the pleura - superficial line, and the peritoneum - deeper line. "Tdi" will be measured from the inner edge of the pleural line to the inner edge of the peritoneal line at the end of expiration (Tdi-exp); and at the end of inspiration (Tdi-insp).

The thickening fraction will be obtained using a high-frequency "linear" type transducer (7-13 MHz), positioned over the zone of apposition (ZA) of the diaphragm muscle. The approximate location is between the 8th and 9th intercostal space, between the anterior axillary line and the midaxillary line, 0.5 to 2.0 cm below the costophrenic angle. The depth will be 1.5 to 3.0 cm, and the diaphragm muscle will be identified as the innermost portion of the hypoechoic muscular layer bounded by two hyperechoic membranes, the pleura - superficial line, and the peritoneum - deeper line. The localization of structures and measurements will be performed in B-mode. The diaphragm thickening fraction will be calculated as the percentage of thickness increment during inspiration relative to the thickness at the end of expiration.

The assessment of reported sensory discomfort will be measured through the application of the horizontal numerical scale of sensory discomfort. The numerical scale will be presented to participants in its printed version, on standardized paper measuring 10 centimeters in length. The value "0" (zero) will be assigned to the concept of "absence of discomfort," and the value "10" (ten) will be assigned to the concept of "greatest imaginable discomfort."