TY - JOUR T1 - Acute inspiratory load effects on chest wall volumes distribuition and inspiratory muscles activation JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p2119 AU - Alana da Gama AU - Larissa Carvalho AU - Larissa Feitosa AU - Jasiel Nascimento, Jr. AU - Rafaela Sa AU - Ana Gabriela Cavalcanti AU - Guilherme Fregonezi AU - Andrea Aliverti AU - Marco Aurelio Rodrigues AU - Armele Dornelas de Andrade Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p2119.abstract N2 - Inspiratory loads can induce changes on the ventilatory pattern. In order to analyze the acute effect of the imposition of inspiratory load (IL) on the ventilatory pattern and inspiratory muscle action, 39 healthy subjects (19M, 20F) were analyzed. Characteristics of male and female subjects respectively were: age,25.50±0.86 and 22.70±0.45 years, FEV1/FVC, 95.05±2,27 and 105.06±1.97%pred; maximal inspiratory pressure, 123.6±43.7 and 98.2±37.4 cmH2O. During IL, total and compartmental volumes were measured by Opto-Electronic Pletysmography (OEP) simultaneously with the activity of bilateral sternocleidomastoid (STMD) and Diaphragm (DI) measured by Surface Electromyography (SEMG). For diaphragm SEMG, electrodes were positioned on the 7th e 8th intercostal spaces on anterior axillary line. For STMD SEMG, electrodes were positioned 5 cm below the mastoid process. IL was performed using Threshold®, with 2 minutes of breathing at different levels (initial load=10 cmH2O, then increments of 5 cmH2O, up to 40 cmH2O or exhaustion). Inspiratory time increased during IL compared to Quite Breathing (QB) (p=0.004). Tidal volumes of the total chest wall (Vcw) and pulmonary rib cage (VRcp) increased for loads ≥20 cmH2O (p= 0.000). Tidal volume of the abdomen increased only for loads ≥at 30 cmH2O (p= 0.03) in males and ≥20cmH2O in females. Median frequency of STMD started to decrease for loads ≥30 cmH2O (p=0.02), while that of the DI decreased only for loads ≥40 cmH2O (p=0.049). In conclusion, the acute effects of IL in healthy subjects occur before and are more intense on inspiratory rib cage muscles than the diaphragm This behavior should be considered when IL treatments are given to patients. ER -