Abstract
Background and Objectives: Percutaneous liver radiofrequency ablation (RFA) under monitored anesthesia care (MAC) carries a risk of hypoxia due to respiratory depression. Ensuring adequate oxygenation during such procedures is essential for patient safety. This study aimed to evaluate whether a high-flow nasal cannula (HFNC) improves oxygenation compared to a simple facemask during RFA. Materials and Methods: In this prospective, randomized controlled trial, 51 patients undergoing ultrasound-guided RFA under MAC were allocated to receive oxygen via an HFNC (30 L/min) or a facemask (6 L/min). Arterial blood gases were collected at the baseline and 5 min after oxygenation. The primary outcome was the arterial partial pressure of oxygen (PaO(2)). Secondary outcomes included hypoxia incidence (SpO(2) < 95%), the difference in the ratio of the arterial partial pressure of oxygen to the fraction of inspired oxygen concentration (ΔP/F ratio), the difference in the arterial partial pressure of carbon dioxide (ΔPaCO(2)), respiratory rate (RR) changes, and patient satisfaction. Results: After adjustment for the baseline PaO(2), the HFNC group showed significantly higher intra-procedural PaO(2) compared to the facemask group (299 ± 18.6 vs. 194 ± 19.0 mmHg, p < 0.001). No significant differences were found in the ΔP/F ratio, ΔPaCO(2), or patient satisfaction. Among the secondary outcomes, RR was more stable in the HFNC group throughout the procedure (Group × Time interaction, p = 0.003). Conclusions: The HFNC significantly improved intra-procedural PaO(2) during RFA under MAC but did not reduce hypoxia incidence or improve other clinical outcomes compared to facemask oxygenation. The stability of RR observed with the HFNC may reflect a physiological advantage, though further studies are needed to determine its clinical relevance.