Impact of Low Tidal Volumes During One-Lung Ventilation. A Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES

The link between ventilation strategies and perioperative outcomes remains one of the fundamental paradigms of thoracic anaesthesia. During one-lung ventilation (OLV), one lung is excluded from gas exchange and ventilation is directed at the dependent lung. The authors hypothesised that the use of low tidal volumes (V) during OLV provides adequate gas exchange and improves postoperative outcome.

DESIGN

Meta-analysis of randomized clinical trials.

SETTING

Thoracic surgery.

PARTICIPANTS

Patients undergoing OLV.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors performed a meta-analysis of all randomized trials on low versus high V during OLV in patients undergoing thoracic surgery. Outcomes of the study were gas exchange and airway pressures during and after OLV, postoperative pulmonary complications (PPCs), and hospital stay (HLOS). Fourteen randomized trials were selected, but only a few of them contained one outcome of interest. Low V was associated with lower arterial oxygen tension, lower airway pressures, and higher arterial carbon dioxide tension at specific time points during OLV. Low V was associated with preserved gas exchange after OLV, lower incidence of pulmonary infiltrations, and acute respiratory distress syndrome. Incidences of PPCs and HLOS were similar.

CONCLUSIONS

The use of low V reduces airway pressure but worsens gas exchange during OLV. Preservation of postoperative oxygenation and reduction in infiltrates suggest a lung-protective modality with no demonstrable impact on PPCs and HLOS.