Physical Medicine Interventions for Duchenne Muscular Dystrophy, the Including Avoiding Invasive Airway Tubes

14 Figure 5. Manual Assisted Cough. Air stacking via oronasal interface to deep air volume held by glottis, then abdominal thrust with cough flows measu- red by peak flow meter. *(Figure taken from the book: Huerta-Armijo A, Prado F, Valdebenito C. Distrofia muscular de Duchenne: Abordaje res- piratorio y cuidados res- piratorios como estrategia de cuidados humanizados (1era edición). Santiago, 2025.) B. Mechanical Insufflation-Exsufflation (MIE) MIE is the delivery of deep insufflations followed immediately by deep exsufflations. The insufflation and exsufflation pressures, as well as delivery times, are independently adjustable. The former, approximately 2.5 seconds, is the time required for complete distension of the chest, and about 1.5 seconds the time required for full chest retraction but can be different for each patient. Insufflation and exsufflation pressures of ±50 a ±60 cm H2O in and out are the most effective for DMD. They are used via mouthpiece or oronasal interface while ±60 to ±70 cm H2O in and out are used via invasive airway tubes. A treatment consists of about five cycles of MIE followed by a short period of normal breathing or ventilator use to avoid hyperventilation. This i s continued until no further secretions are expulsed and any secretion- or mu- cus-induced oxyhemoglobin desaturations are reversed. Although initially the O2 sat may decrease for 2 minutes, it then returns to the baseline or higher in am- bient air, that is, without use of O2. During respiratory infections, MIE may be required as much as every 20 minutes around the clock. The use of MIE via the upper airway can be effective in children as young as 11 months of age so it should