Flow-controlled versus pressure-controlled ventilation in thoracic surgery with one-lung ventilation – A randomized controlled trial

Comparison of flow-controlled ventilation (FCV) to standard of pressure-controlled ventilation (PCV) in thoracic surgery procedures requiring one-lung ventilation. Prospective, non-blinded, randomized, controlled trial. Operating theater at a university hospital, Austria. Patients scheduled for elective, thoracic surgery. Participants received ventilation randomly either with FCV or PCV per-protocol for the duration of anesthesia. The primary endpoint was oxygenation assessed by paO 2 / FiO 2 ratio 30 min after the start of OLV. Secondary endpoints included the required minute volume for CO 2 removal, applied mechanical power and incidence of postoperative pulmonary complications. A total of 46 patients were enrolled and 43 included in the primary analysis. The primary endpoint paO 2 / FiO 2 ratio was significantly higher in the FCV group ( n = 21) compared to the control group (PCV n = 22) (187 vs 136 mmHg, MD 39 (95 % CI 1 to 75); p = 0.047). The required respiratory minute volume to obtain comparable mild hypercapnia during OLV was significantly lower in FCV (3.0 vs 4.5 l/min, MD -1.3 (95 % CI -1.9 to −0.8); p < 0.001). The applied mechanical power was also significantly lower (3.5 versus 7.6 J/min, MD -3.8 (95 % CI -5.3 to −2.7); p < 0.001). In this single-center randomized controlled trial, flow-controlled ventilation improved gas exchange parameters in terms of oxygenation and carbon dioxide removal during one-lung ventilation in patients undergoing thoracic surgery and reduced the mechanical impact of artificial ventilation. • Flow-controlled ventilation lowers mechanic impact by a constant gas flow. • During one-lung ventilation this strategy improved gas exchange compared to control. • In addition, the applied mechanical power of ventilation was reduced to half. • This may indicate a novel lung protective strategy in thoracic surgery.