Effects of Ventilatory Mode During One-Lung Ventilation on Intraoperative and Postoperative Arterial Oxygenation in Thoracic Surgery

Objective

The purpose of this study was to investigate the relationship between the ventilatory mode used during one-lung ventilation (OLV) and intraoperative and early postoperative arterial oxygenation in patients undergoing thoracic surgery.

Methods

A prospective, randomized clinical trial.

Setting

A tertiary care university hospital single institution.

Participants

One hundred ten patients scheduled for thoracic surgery with at least 1 hour of OLV.

Interventions

Patients were prospectively randomized into 2 groups depending on the ventilatory mode used during OLV: volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV). In VCV, the authors used a tidal volume (Vt) of 8 mL/kg and in the PCV group an inspiratory pressure to provide a tidal volume of 8 mL/kg.

Measurements and Main Results

Airway pressures and arterial blood gases were obtained at 20, 30, and 40 minutes after OLV. The authors recorded the ratio of arterial oxygen tension to inspired oxygen fraction (PaO₂/F_IO₂) at 4 hours (RU1) and 24 hours (RU2) after surgery. During OLV, there were no differences in arterial oxygenation, airway plateau pressure, and mean pressure between groups, although peak pressure was higher in the VCV group (p < 0.01). The PaO₂/F_IO₂ ratio at RU1 was 312.6 ± 106 in the VCV group and 322.1 ± 104. In the PCV group at RU2, it was 402.4 ± 105 and 389.6 ± 114, respectively, and there were no significant differences between the groups.

Conclusions

In patients undergoing thoracic surgery, the use of PCV compared with VCV during OLV with the same Vt of 8 mL/kg does not affect arterial oxygenation during OLV or early postoperative oxygenation.

Key Words: one-lung ventilation, volume-controlled ventilation, pressure-controlled ventilation, arterial oxygenation, thoracic surgery