DR. AARTHI. C,DR. LAKSHMI
DOI: https://doi.org/Background: Hypoxemia during induction of general anaesthesia is one of the leading causes of anaesthesia-related morbidity and mortality. Preoxygenation before induction increases alveolar oxygen reserves by denitrogenation, prolonging safe apnoea time and reducing hypoxemia risk. The standard method uses a tight-fitting facemask with oxygen flow at 10 L/min for at least 3 minutes. High-flow nasal cannula (HFNC) delivers heated, humidified oxygen at up to 60 L/min, with potential advantages such as continuous oxygen delivery during laryngoscopy. This study was conducted to compare HFNC and conventional facemask preoxygenation in prolonging safe apnoea time and maintaining arterial oxygen tension (PaO₂) during intubation.
Methods: This prospective, single-blinded, randomized controlled trial included 40 ASA I–II adult patients (18–50 years) with normal airway anatomy scheduled for elective surgery under general anaesthesia with orotracheal intubation. Patients were randomized to HFNC (60 L/min, FiO2 (1.0, 3 min) or facemask (10 L/min, FiO2 1.0, 3 min) preoxygenation. PaO2 was measured by arterial blood gas immediately after preoxygenation and immediately post-intubation.
Results: Mean post-intubation PaO₂ was significantly higher in the HFNC group (454.2 ± 37.3 mmHg) than in the facemask group (370.7 ± 37.0 mmHg, p = 0.002). Safe apnoea time was also significantly longer with HFNC (288 ± 40 s) than facemask (210 ± 35 s, p < 0.001). No episodes of hypoxemia (SpO₂ < 90%) occurred in either group. Conclusion: HFNC is an effective alternative to conventional facemask preoxygenation in elective surgical patients, providing higher post-intubation PaO₂ and prolonging safe apnoea time.
