Abstract:Objective To investigate the effects of different inspiratory flow rates on respiratory function in patients undergoing one-lung ventilation (OLV) with pressure controlled and volume guaranteed. Methods A total of 75 patients undergoing unilateral lung lesion resection in general anesthesia with one-lung ventilation were randomly divided into three groups: group A (Insp Flow 30?L/min, n?=?25), group B (Insp Flow 50?L/min, n?=?25) and group C (Insp Flow 70?L/min, n?=?25). Peak airway pressure (Ppeak), plateau airway pressure (Pplat) arterial and central venous blood were collected at 5 minutes before one lung ventilation (T0), 30 minutes (T1), 60 minutes (T2) and 120 minutes (T3) after one lung ventilation, respectively. Then we calculated and analyzed the pulmonary dynamic compliance (Cdyn), dead space rate (VD/VT), PaO2/FiO2 and Qs/Qt. Results Three groups of PaCO2, PaO2, SaO2, ScvO2, Ppeak, Pplat, PEEP, VD/VT, Cdyn, PaO2/FiO2 and Qs/Qt at different time points were significantly different (P?0.05). PaCO2, Ppeak, Pplat, PEEP, VD/VT and Cdyn among the three groups were significantly different (P?0.05). The trends of PaCO2, Ppeak, Pplat, PEEP and VD/VT were different among the three groups (P?0.05). Conclusions In one-lung ventilation with pressure controlled and volume guaranteed, properly increasing the inspiratory flow rate can reduce airway pressure and promote more effective gas diffusion, reduce the rate of dead space and improve pulmonary dynamic compliance.