High-flow oxygen delivery system and oxygen reserve index-guided apnoeic oxygenation versus low-tidal-volume ventilation during robotic flexible ureteroscopy: A retrospective cohort study.

BACKGROUND AND AIMS: Robotic flexible ureteroscopy often requires intermittent apnoeic periods to minimise kidney movement and improve surgical conditions. This study evaluated the effectiveness of high-flow oxygenation (HFO) in maintaining oxygenation and preventing desaturation during retrograde flexible ureteroscopy (RFU).

METHODS

This retrospective cohort study included 62 male patients undergoing robotic RFU: 28 received HFO and 34 served as controls. The HFO group underwent repeated 5-minute apnoeic periods with 100% oxygen delivered at up to 80 L/min. Vital parameters were recorded before and after each apnoeic period. In the control group, the tidal volume was reduced to 250 mL with a respiratory rate of 20 cycles per minute during the robotic phase, and these settings were maintained throughout. Wilcoxon rank-sum test, T-tests, and Fisher's exact test were used to compare the groups. Durbin-Conover test was used for pairwise comparisons.

RESULTS

Compared to the HFO group, overall, the control group had slightly higher median end-tidal carbon dioxide (EtCO2) levels (43.3 vs 41.6, P = 0.021), heart rate (71.6 vs 65.1, P = 0.001), mean arterial pressure (83 vs 70.6, P < 0.001), and temperature (36.5 vs 35.6, P < 0.001). No desaturation events or haemodynamic instability occurred in the HFO group. ORI and PI remained stable, and no postoperative complications were reported.

CONCLUSION

HFO during robotic ureteroscopy appears effective in maintaining oxygenation and haemodynamic stability while providing a still surgical field. These findings support its integration into clinical practice for procedures requiring controlled apnoea.