Flow controlled expiration does not impair pedal power during physical exercise on a bicycle ergometer

Area of Science:

• Critical Care Medicine
• Respiratory Physiology
• Mechanical Ventilation

Background:

• Flow Controlled Expiration (FLEX) is a lung-protective ventilation strategy during controlled mechanical ventilation.
• Modern critical care ventilation often incorporates spontaneous breathing, necessitating evaluation of FLEX under these conditions.

Purpose of the Study:

• To investigate breathing discomfort and physical performance constraints of FLEX in healthy individuals under increased ventilation demand.
• To assess the feasibility of FLEX during spontaneous breathing in critical care settings.

Main Methods:

• 24 healthy subjects performed cycling exercise at 20, 50, and 100 W.
• Breathing discomfort was rated on a 0-10 scale with and without FLEX.
• Subjects estimated maintainable power for 30 minutes with and without FLEX.

Main Results:

• Tidal volume increased and respiratory rate decreased with FLEX.
• Breathing discomfort was slightly elevated with FLEX (2.2 to 3.2, p=0.002).
• Estimated maintainable power was similar with and without FLEX (p=0.986).

Conclusions:

• FLEX does not cause intolerable breathing discomfort.
• FLEX does not impair physical performance during spontaneous breathing with increased ventilation demand.
• FLEX may be a viable option in critical care settings involving spontaneous breathing.