Age related differences in diaphragm muscle fiber response to mid/long term controlled mechanical ventilation

This study shows an unexpected response of the diaphragm fibers to 5 days CMV, demonstrating an increased CSA (p < 0.001) in both young and old animals. Furthermore, an observed decreased maximum force of 39.8-45.2% (p < 0.001) in both young and old animals compared with controls resulted in a dramatic loss of specific force. We suggest that this increase in CSA and decrease in specific force observed in both the young and old diaphragm fibers is an ineffective compensatory hypertrophy in response to the CMV. These results demonstrate an important mechanism of significant importance for the weaning problems associated with mechanical ventilation.