Comparative study of the non-dependent continuous positive pressure ventilation and high-frequency positive-pressure ventilation during one-lung ventilation for video-assisted thoracoscopic surgery.

The application of volume controlled high-frequency positive-pressure ventilation (HFPPV) to the non-dependent lung (NL) may have comparable effects to continuous positive-airway pressure (CPAP) on the surgical conditions during one-lung ventilation (OLV) for video-assisted thoracoscopic surgery (VATS). After local Ethics Committee approval and informed consent, we randomly allocated 30 patients scheduled for elective VATS after the first 15 min of OLV to ventilate the NL with CPAP of 2 cm H(2)O (NL-CPAP(2)) and HFPPV using tidal volume 2 ml/kg, inspiratory to expiratory ratio <0.3 and respiratory rate 60/min (NL-HFPPV) for 30 min, each in a randomized crossover order. Intraoperative adequacy of surgical conditions was evaluated using a visual analog scale and the changes in hemodynamic and arterial oxygen were recorded. The application of NL-CPAP(2) and NL-HFPPV resulted in more improved arterial oxygenation than during OLV for VATS (P<0.001). The operative field was much better during the application of NL-CPAP(2) than during NL-HFPPV (P<0.001). We concluded that the application of CPAP to the NL during OLV offers good quality of operative field and improved arterial oxygenation for VATS.