Effect of High-Flow Nasal Cannula vs. Facemask on Arterial Oxygenation During Liver Radiofrequency Ablation: A Randomized Controlled Trial

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 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 HFNC (30 L/min) or a facemask (6 L/min). Arterial blood gases were collected at baseline and 5 minutes after oxygenation. Primary outcome was arterial partial pressure of oxygen (PaO₂). Secondary outcomes included hypoxia incidence (SpO₂ <95%), difference in the ratio of arterial partial pressure of oxygen to the fraction of inspired oxygen concentration (ΔP/F ratio), difference in arterial partial pressure of carbon dioxide (ΔPaCO2), respiratory rate (RR) changes, and patient satisfaction. Results: After adjustment for baseline PaO₂, the HFNC group showed significantly higher intra-procedural PaO₂ compared to the facemask group (299 ± 18.6 vs. 194 ± 19.0 mmHg, p < 0.001). No significant differences were found in ΔP/F ratio, ΔPaCO₂, or patient satisfaction. Among secondary outcomes, RR was more stable in the HFNC group throughout the procedure (Group × Time interaction, p = 0.003). Conclusions: HFNC significantly improved intra-procedural PaO₂ 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 HFNC may reflect a physiological advantage, though further studies are needed to determine its clinical relevance.