Effects of pressure-controlled ventilation targeting end-inspiratory flow rate on pulmonary complications and inflammation levels in patients undergoing spinal surgery in the prone position: a randomized clinical trial

Abstract

Abstract Background This study assessed the impact of pressure-controlled ventilation (PCV) focusing on end-inspiratory flow rate on the incidence of postoperative pulmonary complications (PPCs) and inflammation levels in patients undergoing spinal surgery in the prone position. Methods A total of 187 patients who underwent posterior spinal surgery were enrolled and randomly divided into 3 groups: 61 in the volume-controlled ventilation (VCV) group (group V), 62 in the PCV-volume-guaranteed (VG) group (group P1), and 64 in the PCV-VG end-expiratory zero flow rate group (group P2). Indicators including tidal volume (VT), peak airway pressure (Ppeak), and dynamic lung compliance (Cdyn) were recorded. The Ppeak, Cdyn, PETCO2, and oxygenation index (PaO2/FiO2) after intubation (T0), after prone position (T1), 60 min after prone position (T2), and after supine position at the end of surgery (T3) of the three groups were collected. Results In the within-group comparison, compared with T0, Ppeak increased at T1 − 2 in groups V and P1 (P < 0.01), whereas it decreased at T1 − 3 in group P2 (P < 0.01). Cdyn decreased at T1 − 2 and PaO2/FiO2 increased at T1 − 3 in all three groups (P < 0.01), and PaO2/FiO2 increased at T1 − 3 (P < 0.01). Compared with group V, Ppeak decreased at T0 − 3 in group P1 (P < 0.01) and at T1 − 3 in group P2 (P < 0.01), while Cdyn increased at T0 − 3 in groups P1 and P2 (P < 0.01). Compared with group P1, Ppeak was elevated at T0 (P < 0.01) and decreased at T1 − 3 (P < 0.05), and Cdyn was elevated at T0 − 3 in group P2 (P < 0.01). The total incidence of PPCs in group P2 was lower than that in group V (P < 0.01). Compared with the preoperative period, serum interleukin 6 (IL-6) and C-reactive protein (CRP) levels were increased at 24 and 72 h after surgery in group V (P < 0.01), whereas that was increased at 24 h after surgery in group P1 and group P2 (P < 0.01). Compared with group V, serum IL-6 and CRP levels were reduced at 24 h after surgery in groups P1 and P2 (P < 0.01 or < 0.05). Conclusion In patients undergoing spinal surgery in the prone position, PCV-VG targeting an end-inspiratory zero flow rate lowers the incidence of PPCs and inflammation levels.

Keywords

• End-inspiratory flow rate
• General anesthesia
• Pressure-controlled ventilation
• Prone position
• Spinal surgery