TY - JOUR
T1 - Altered diaphragm contractile properties with controlled mechanical ventilation
AU - Sassoon, Catherine S.H.
AU - Caiozzo, Vincent J.
AU - Manka, Albana
AU - Sieck, Gary C.
PY - 2002
Y1 - 2002
N2 - This study shows that, over time, diaphragm inactivity with controlled mechanical ventilation (CMV) decreases diaphragm force and produces myofibril damage contributing to the reduced force. We measured in vivo and in vitro diaphragm contractile and morphological properties in 30 sedated rabbits grouped (n = 6) as follows: 1 or 3 days of CMV, 1 or 3 days of 0 cmH2O continuous positive airway pressure, and control. The CMV rate was set sufficient to suppress diaphragm electrical activity. Compared with the control group, phrenic-stimulated maximum transdiaphragmatic pressure did not decrease with continuous positive airway pressure but decreased to 63% after 1 day of CMV and to 49% after 3 days of CMV. The in vitro tetanic force decreased to 86% after 1 day of CMV and to 44% after 3 days of CMV. After 3 days of CMV, significant myofibril damage occurred in the diaphragm but not in the soleus. The decrease in tetanic force correlated with the volume density of abnormal myofibrils. We conclude that CMV had a detrimental effect on diaphragm contractile properties.
AB - This study shows that, over time, diaphragm inactivity with controlled mechanical ventilation (CMV) decreases diaphragm force and produces myofibril damage contributing to the reduced force. We measured in vivo and in vitro diaphragm contractile and morphological properties in 30 sedated rabbits grouped (n = 6) as follows: 1 or 3 days of CMV, 1 or 3 days of 0 cmH2O continuous positive airway pressure, and control. The CMV rate was set sufficient to suppress diaphragm electrical activity. Compared with the control group, phrenic-stimulated maximum transdiaphragmatic pressure did not decrease with continuous positive airway pressure but decreased to 63% after 1 day of CMV and to 49% after 3 days of CMV. The in vitro tetanic force decreased to 86% after 1 day of CMV and to 44% after 3 days of CMV. After 3 days of CMV, significant myofibril damage occurred in the diaphragm but not in the soleus. The decrease in tetanic force correlated with the volume density of abnormal myofibrils. We conclude that CMV had a detrimental effect on diaphragm contractile properties.
KW - Diaphragm inactivity
KW - Diaphragm muscle force
KW - Force-frequency relationship
KW - Myosin heavy chain isoform expression
KW - Passive ventilation
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U2 - 10.1152/japplphysiol.01213.2001
DO - 10.1152/japplphysiol.01213.2001
M3 - Article
C2 - 12015377
AN - SCOPUS:0036082131
SN - 8750-7587
VL - 92
SP - 2585
EP - 2595
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 6
ER -