High-flow nasal cannula improves pulmonary gas exchange during endoscopic retrograde cholangiopancreatography: A single-center randomized controlled trial.

BACKGROUND

Sedation during endoscopic retrograde cholangiopancreatography procedures (ERCP) increases the risk of hypoxemia and the need for respiratory support in high-risk patients. High flow nasal cannula (HFNC) provides humidified gas at high flow rates, improving alveolar ventilation. We aim to assess whether ventilatory support with HFNC improves gas exchange compared to standard low-flow nasal cannula (NC).

METHODS

Single-center, randomized controlled trial, in adults undergoing ERCP. After providing informed consent, participants were randomized in a 1:1 ratio following obstructive sleep apnea (OSA) stratification to receive ventilatory support with HFNC (60 L·min-1, Fi02 0.4) or NC (6 L·min-1). All procedures were performed under deep sedation. We collected clinical data, ECG, pulse oximetry (SpO2), blood pressure, Bispectral index, rescue airway maneuvers, and transcutaneous carbon dioxide (PtCO2). The primary outcome was the incidence of hypoxemic events defined as SpO2 < 90% lasting ≥15 s; the secondary outcome was PtCO2, and the exploratory was need for airway rescue maneuvers. Post-hoc analyses explored the HFNC effect on the severity and duration of hypoxemia using the area under a threshold (AUC) for SpO₂ < 90%.

RESULTS

191 patients were included (38% female, median age 67 years, 59% ASA III-IV, and 38% with OSA). A total of 92 patients were randomized to HFNC and 99 to NC. Sixteen (8%) patients presented hypoxemic events (SpO₂ < 90%) and 64 (33%) needed airway rescue maneuvers. HFNC did not significantly reduce the incidence of hypoxemic events (3 vs. 13; p = 0.05). However, HFNC significantly reduced hypercapnia with lower PtCO₂ (HFNC, 51 [44-59] vs. NC, 56 [45-75] mmHg; p < 0.005), and the AUC for SpO₂ < 90% (HFNC, 175[167-226] vs. NC, 268[241-342] %·min; p < 0.001).

CONCLUSIONS

HFNC did not reduce the incidence of hypoxemic events. However, it resulted in a reduction of hypercapnic events.