High flow nasal cannula oxygen versus bag-valve-mask for preoxygenation before intubation in patients with hypoxemic respiratory failure – a randomized controlled trial

Introduction: Critically ill patients with respiratory failure undergoing intubation have an increased risk of hypoxemia-related complications. An increasingly used means of oxygen delivery with theoretical advantages is its application via high flow nasal cannula (HFNC). This study was therefore conducted to compare HFNC with bag-valve-mask (BVM) for preoxygenation in patients with hypoxemic respiratory failure.

Methods: Randomized controlled trial randomizing 40 critically ill patients with hypoxemic respiratory failure to receive either HFNC or BVM for preoxygenation before intubation in the intensive care unit.

Results: Mean PaO₂/FiO₂ at baseline was 200 ± 57 mmHg in the HFNC group and 205 ± 59 mmHg in the BVM group (p = 0.76). Mean oxygen saturation measured by pulse oximetry (SpO₂) at baseline was 96 ± 3% in the HFNC group and 94 ± 4% in the BVM group (p = 0.24). The mean lowest SpO₂ during intubation was 89 ± 18% in the HFNC group and 86 ± 11% in the BVM group (p = 0.56). During the one minute of apnea after the induction of anesthesia, SpO₂ dropped significantly in the BVM group (p = 0.001), while there was no significant difference in the HFNC group (p = 0.17). There were no significant differences between the two groups at any of the pre-defined time points concerning SpO₂, PaO₂/FiO₂, PaCO₂, heart rate, and mean arterial pressure.

Conclusions: Preoxygenation using HFNC prior to intubation was feasible and safe in critically ill patients with acute hypoxemic respiratory failure. There were no significant differences in gas exchange before and after intubation between the two groups. However, in contrast to the BVM group there was no significant decrease in SpO₂ during the apnea phase prior to intubation within the HFNC group.