Randomized trial of pressure controlled versus volume controlled ventilation during robot assisted urological surgery in the clasp knife position

Abstract Background The combination of CO₂ pneumoperitoneum and clasp-knife position imposes substantial respiratory and hemodynamic challenges in Da Vinci robot-assisted urological surgery. Although volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) are widely used, their comparative effects under these specific surgical conditions remain unclear. We hypothesized that PCV could reduce peak inspiratory pressure (Ppeak) and improve dynamic lung compliance (Cdyn) without compromising hemodynamic stability. Method Sixty ASA I–II patients undergoing Da Vinci robot-assisted laparoscopic urological surgery in the clasp-knife position were randomized to receive VCV or PCV. Ventilatory parameters, hemodynamic variables, and arterial blood gas values were recorded at five time points: T1 (15 min after induction), T2 (15 min after clasp-knife positioning), T3 (30 min after CO₂ pneumoperitoneum), T4 (60 min after CO₂ pneumoperitoneum), and T5 (15 min after pneumoperitoneum removal). Result Ppeak was significantly lower in the PCV group compared with the VCV group at T2 (P = 0.0076), T3–T4 (P < 0.0001), and T5 (P = 0.0059). Cdyn was significantly higher in the PCV group at T2 (P = 0.0154), and T5 (P = 0.0038). Patients in the PCV group had higher blood pH levels than those in the VCV group (T1, P = 0.0079; T2, P = 0.0132; T3, P = 0.0072; T4, P = 0.0015; T5, P = 0.0258). No severe postoperative complications were observed. Conclusion PCV reduces Ppeak and improves Cdyn compared with VCV during Da Vinci robot-assisted laparoscopic urological surgery in the clasp-knife position, without adversely affecting hemodynamic stability. Therefore, PCV may represent a preferable ventilation strategy in this surgical context.