Abstract
We studied neural input to and force output of the diaphragm in 7 anesthetized neonatal piglets (wt. 2.45-3.06 kg, age 13-21 days) spontaneously breathing against a respiratory load (13× normal pulmonary resistance). Costal diaphragmatic EMG, transdiaphragmatic pressure (Pdi), VE, Ti, and Te were measured at baseline (BL) and during one hour of inspiratory loading. VE (cc/min) fell significantly below BL by 5'(BL: 523±187, 5':250±110 p<.001) and did not change thereafter (60':288±139). Concomitantly, Pdi(cmH2O) increased by 5'(BL: 7.8±3.2, 5':35.9±20 p<.001) and remained unchanged at 60'(41±12). Despite the constancy of VE and Pdi after 5', peak EMG activity, rate of EMG activity (EMG/Ti), and slope moving average EMG progressively increased throughout the loading period. This failure to increase diaphragmatic force output in the presence of increasing neural drive suggested peripheral fatigue. This was confirmed by generating force-frequency curves of the diaphragm via phrenic stimulation at BL and 60' on load in 3 piglets. We found marked decreases in force output (Pdi) on load compared to BL throughout the range of frequencies tested (10-100Hz, p<.05). We conclude that diaphragmatic muscle fatigue is responsible for the decrease in diaphragm efficiency noted during resistive loading in the neonatal piglet.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
