One-lung anesthesia offers advantages during thoracic surgery, but has the disadvantage of causing hypoxemia and affects the respiratory mechanics.

We investigated the peak inspiratory airway pressure(PIP) and compliance during one-lung ventilation using different tubes.

In healthy 12 patients undergoing thoracic surgery, left-sided double lumen endobronchial tube was inserted. In 10 patients, Univent tube was inserted and fixed the blocker using the bronchofiberscope. The PIP, compliance, end-tidal CO₂ and SpO₂ were measured using a Capnomac Ultima® during two-lung and right one-lung ventilation.

During two-lung ventilation, there was no difference between the two groups During one-lung ventilation PIP increased and compliance decreased significantly than two-lung ventilation. In the double lumen tube group, PIP increased significantly and compliance decreased significantly than Univent tube group. There was no significant changes in the end-tidal PCO₂ and SpO₂.

Univent tube provide lesser changes of PIP and compliance during one-lung anesthesia in supine position than double lumen endobronchial tube.