Medium-Flow Oxygenation Through Facial Mask and Nasal Cannula in a Limited Resource Setting

Introduction: In centers with limited resources, a high flow nasal cannula is not available, thus we assess if preoxygenation with 15L flow of O2 available from anesthesia machines can prolong the safety period of induction of anesthesia before intubation and provide more time for securing the airway. Moreover, we compared the preoxygenation with standard 6L vs. 15L O2 through a facemask or a nasal cannula.

Material and methods: Patients were allocated into four groups. Group I patients were preoxygenated with a nasal cannula on 6L of oxygen, patients in group II were preoxygenated with a nasal cannula on 15L of oxygen, patients in group III were preoxygenated with a facemask on 6L of oxygen, and patients in group IV were preoxygenated with a facemask on 15L of oxygen. The primary endpoint was time to desaturation and intubation. The secondary endpoints were PaO2, PaCO2, Sat% and ETCO2.

Results: The groups with 15L preoxygenation had a statistically significant prolonged time to desaturation and intubation. Patients allocated to group II have a statistically significant greater PaO2 and lesser ETCO2 compered with group I. However, between patients in group III and IV there is a difference only in PaCO2, and although this effect is significant, both groups have values within the normal range.

Conclusion: In centers with limited resources, preoxygenation with the maximum available oxygen flow from anesthesia machines (15L/min) are useful. This prolongs the safety period for securing the airway. We suggest the use of the maximum available amount of oxygen flow from anesthesia machines in clinical settings.