Trial Information

The Effect of Different I:E Ratio on Gas Exchange of Patients Undergoing One-lung Ventilation for Lung Surgery

Pulmonary gas exchange disturbance is a common anesthetic problem during one-lung
ventilation (OLV) for thoracic surgery. Continuous positive airway pressure or positive
end-expiratory pressure are usually applied to improve this disorder including hypoxia, but
these methods are not enough. The inverse-ratio ventilation (IRV), which prolongs the
inspiratory time greater than expiratory time, can be applied for adult respiratory distress
syndrome. The effect of IRV is to improve gas-exchange status by increasing mean airway
pressure and alveolar recruitment. The application of IRV during OLV has not been performed
to our knowledge, and there is a possibility of IRV to improve oxygenation during OLV. There
is a possibility of increase of auto-PEEP, or air trapping in subjects with chronic
obstructive pulmonary disease, but this kind of auto-PEEP can be overcome by external PEEP.
Therefore, we tried to evaluate the effect of IRV during OLV with lung protective strategy.