Dead Space in Mechanical Ventilation With Constant Expiratory Flow

What this Trial Is About

Researchers are studying mechanical ventilation methods used during surgery, focusing on two types: conventional volume-controlled ventilation (VCV) and flow-controlled ventilation (FCV). FCV is a newer ventilation mode that controls the expiratory flow constantly, unlike conventional ventilation that relies on natural chest recoil. This trial aims to compare the amount of dead space ventilation, or "wasted ventilation," between these two methods, as dead space relates to lung function and patient outcomes during mechanical ventilation. Participants will receive both ventilation methods in a randomized order during surgery under general anesthesia. After setting baseline ventilation with VCV, participants will receive 20 minutes of FCV followed by 20 minutes of VCV, or vice versa. FCV will be delivered using the Evone ventilator, while VCV will use standard ventilators like the Aisys CS3 or Flow-i. This crossover design allows direct comparison of ventilation effects within the same participant. During the trial, researchers will measure various lung function and ventilation parameters, including different types of dead space ventilation, airway pressures, lung volumes, blood gas levels, and cardiac output. These measurements will be taken during each 20-minute ventilation period. Participants are expected to be under general anesthesia with standard monitoring lines in place, and the study will last for the duration of the controlled mechanical ventilation during surgery. Safety and ventilation efficiency will be closely monitored throughout.

Dead Space in Mechanical Ventilation With Constant Expiratory Flow