High-Level Pressure Support Ventilation Attenuates Ventilator-Induced Diaphragm Dysfunction in Rabbits.

Area of Science:

• Respiratory Physiology
• Critical Care Medicine
• Diaphragm Function

Background:

• Mechanical ventilation can lead to ventilator-induced diaphragm dysfunction (VIDD).
• Different ventilation modes may impact VIDD onset differently.
• Assessing VIDD in healthy animal models is crucial for understanding human respiratory physiology.

Purpose of the Study:

• To evaluate the effects of distinct mechanical ventilation modes on diaphragm dysfunction in healthy rabbits.
• To compare ventilator-induced diaphragm dysfunction across controlled mechanical ventilation (CMV), assist/control (A/C), and high-level pressure support ventilation (PSV) modes.

Main Methods:

• Twenty healthy New Zealand rabbits were divided into four groups: no ventilation, CMV, A/C, and PSV for 24 hours.
• Physiological parameters (heart rate, blood pressure, blood gases) and diaphragm electrical activity were monitored.
• Caspase-3 activation and diaphragm ultrastructure were analyzed using protein analysis and electron microscopy.

Main Results:

• All ventilation modes (CMV, A/C, PSV) reduced diaphragm myoelectric activity and centroid frequency.
• PSV demonstrated significantly less reduction in centroid frequency compared to CMV and A/C.
• PSV group showed attenuated caspase-3 activation and minimal mitochondrial injury compared to CMV and A/C groups.

Conclusions:

• High-level pressure support ventilation (PSV) mode minimized diaphragm injury in rabbits compared to CMV and A/C.
• Despite reduced diaphragm electrical activity, PSV retained partial function and reduced oxidative stress.
• PSV may represent a safer mechanical ventilation strategy to mitigate diaphragm injury.