Time to adequate preoxygenation when using flush rate oxygen.

Area of Science:

• Emergency Medicine
• Respiratory Physiology

Background:

• Non-rebreather (NRB) mask preoxygenation at maximal flow rate is common in emergency airway management.
• Current guidance for 3-minute preoxygenation is based on devices not typical in emergency settings.

Purpose of the Study:

• To determine the median time to adequate preoxygenation using an NRB mask with flush rate oxygen.
• To evaluate the efficacy of NRB mask preoxygenation in a simulated emergency setting.

Main Methods:

• Healthy volunteers underwent 5-minute preoxygenation trials with an NRB mask and flush rate oxygen.
• End-tidal oxygen (EtO2) was measured every 15 seconds, with adequate preoxygenation defined as EtO2 ≥ 85%.

Main Results:

• The median time to achieve an EtO2 of 85% was 90 seconds (IQR 60-135s).
• All 50 participants achieved EtO2 > 80%, with a median maximum EtO2 of 87%.
• At 3 minutes, 86% of participants reached adequate preoxygenation levels.

Conclusions:

• The median time to adequate preoxygenation using an NRB mask with flush rate oxygen is 90 seconds.
• 86% of healthy participants achieved adequate preoxygenation by 3 minutes.
• Three minutes appears to be a reasonable preoxygenation target time with this method.