Cumulative validitys of Aging and ...

Cumulative validitys of Aging and Mechanical Ventilation forward In Vitro Diaphragm Function. Criswell D Shanely RA, Betters JJ McKenzie MJ Sellman JE Van Gammeren DL Powers SK Reprinted with permission from Chest. 2003;124:2302-2308 ?© 2003 American college edifice [i]or[/i] building of Chest Physicians.

Study Objective: Unloading the diaphragm, via mechanical ventilation (MV)7 inferences in significant diaphragmatic atrophy, contractile dysfunction, and oxidative stres in young adult animals. Since aging increases skeletal muscle susceptibility to atrophy and injury, we exampleed the hypothesis that MV-induced diaphragmatic contractile dysfunction would be exacerbated in aging rats. Methods: Fisher 344/Brown Norway hybrid rats (4 month antique [young] and 30 months ancient [old]) were assigned to either repress or MV groups. MV rats were anesthetized, tracheostomized, and ventilated with 21 % O2 for 12 h Arterial BP pH and vital fluid gas homeostasis were maintained in the MV animals in every part the experimental period. Animals in the restrain group were acutely anesthetized, and the diaphragms were immediately remov Muscle strips from the mid-costal diaphragm were remov from each experimental animal, and contractile properties were studied in vitro. Results: Compared to young have charge of animals, aging (old control animals) was associated with a 13% decrease in maximal isometric tension (245 N/cm^sup 2^ v 213 N/cm^sup 2^) Although, MV induced similar relative losse (24%) in diaphragmatic isometric tension in the couple young and old animals receiving MV the combined events of aging and MV comeed in a 34% decrement in diaphragmatic isometric tension compared to young superintendence animals (24.5 N/cm^sup 2^ v 161 N/cm^sup 2^) Conclusions: These data do not support the hypothesis that aging exacerbates the relative MV-induced impairment in diaphragmatic isometric tension. Nonetheless, the additive results of aging and MV have dramatic purports on diaphragmatic force reserve. This could exacerbate weaning difficulties in older individuals receiving MV

Copyright Cardiopulmonary Physical Therapy Journal Mar 2004

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