Lateral decubitus: its influence on hemodynamic and respiratory function during retroperitoneal robotic assisted laparoscopic pyeloplasty (R-RALP) in children.

Retroperitoneal robotic-assisted laparoscopic pyeloplasty (R-RALP) is the commonest urologic procedure performed in children, entailing retroperitoneal CO2 insufflation and lateral decubitus, whose effects on cardiopulmonary variables are poorly known. We, therefore, studied hemodynamic and respiratory changes due to CO2 insufflation and lateral decubitus in children undergoing R-RALP and their effects on regional tissue oxygenation. Between 1/2021 and 7/2024, children affected by ureteropelvic joint obstruction (UPJO) underwent a pyeloplasty by R-RALP at Necker Enfants Malades Hospital (Paris, France), using a standardized surgical technique and a lung-protecting anesthetic protocol aimed to prevent hypercarbia. Cerebral and renal Near InfraRed Spectroscopy (NIRS) were added to standard monitoring. Mean monitoring parameters and NIRS values were derived from the prospectively kept continuous reading at eight preset points and analyzed. 37 patients were prospectively included (21 males), with a mean age of 6.0 ± 3.9 years, and mean body weight of 22.5 ± 11.3 kg; 15 patients were operated on in Left Lateral Decubitus (LLD) and 22  in Right Lateral Decubitus (RLD). No different LLD/RLD time trends were observed for standard monitoring parameters and NIRS measurements. Conversely, EtCO2 was higher in the RLD group at trocars insertion (T4, + 3.3 mmHg), beginning of CO2 insufflation (T5, + 2.9), and 45 min after the start of the procedure (T6, + 3.1). At the same time points, Pplat was higher in the LLD group at T4 (+ 3.0 cmH2O); T5, (+ 3.4) and T6 (+ 4.7). During R-RALP, the combination of RLD and CO2 insufflation promotes hypercarbia, while LLD requires increasing Pplat pressures, potentially favoring lung injury and hemodynamic instability during prolonged procedures.