Inspiratory Training in Children After Fontan

The mobility and thickness of the diaphragm muscle were assessed using ultrasound in M mode. Both variables were analyzed during spontaneous, relaxed breathing in terms of both tidal volume and deep breathing at vital capacity. Muscle mobility was examined along the right and left mid-axillary and parasternal lines with volunteers in both the supine and sitting positions. Muscle thickness was measured while the patients were in the supine position along the mid-axillary lines during both natural, relaxed and deep breathing. Measurements were taken in centimeters, with the largest value selected from at least three reproducible measurements.

Respiratory muscle strength was measured using maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) with a digital manometer calibrated beforehand. The MIP was determined by the maximal inspiratory effort from the residual volume (RV), and the MEP was determined by the maximal expiratory effort from the total lung capacity (TLC). At least three reproducible maneuvers were performed, with the largest value used unless it did not exceed the previous value by more than 20%.

Pulmonary volume and capacity were evaluated using the spirometer protocol as recommended by the American Thoracic Society guidelines. For spirometry, at least three acceptable and reproducible maneuvers at each stage were performed using encouragement and positive reinforcement to obtain maximum values. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and the FEV1/FVC ratio were studied, and the predicted values were calculated from previously reported equations

A submaximal analysis of physical capacity was conducted using the six-minute walk test (6MWT), following the protocol of the American Thoracic Society[16]. The patients were instructed to walk as quickly as possible without running for six minutes, while the distance covered was recorded. Breaks during the walk were allowed if needed. The data analyzed included the distance covered in meters, heart rate, respiratory rate, peripheral oxygen saturation, blood pressure, and the Modified Borg Scale for Fatigue. These measurements were taken at rest one minute before the test, immediately after the test, two minutes after the test if there was an interruption, and five minutes after the test.

The evaluation of quality of life was conducted using the Self-imaginary Questionnaire on Children's Quality of Life (Autoquestionnaire Qualité de Vie Enfant Imagé). This scale consists of closed questions about the point of view for children aged 4 to 12 years, and their answers are directed toward 'very happy', 'happy', 'unhappy', or 'very unhappy', supported by an image of a child in these emotional states. The survey included 26 analysis items related to socialization, family relationships, activities, health, isolation, and other functions. The items were divided into factors such as autonomy, leisure, functions, family, and the legal value of the answers. The sum of all the questions generates a score with a maximum of 78. Scores less than 48 are considered to indicate a loss in quality of life. The questionnaire was validated and translated by Assumpçao et al.

Change in functional capacity will be performed by cardiopulmonary exercise test and will be expressed by Peak VO2 and Predicted Peak VO2 (%). After the training program, an increase in the peak VO2(mL/kg/min) value between 10 to 15% is expected in relation to the baseline value.