Comparison of Three Pre-oxygenation Strategies

Study objective: Comparing the efficacy of three different preoxygenation strategies, i.e. non-rebreather face mask (NRM), bag-valve-mask (BVM) with and BVM without additional positive end-expiratory pressure (PEEP) in three subgroups of spontaneously breathing volunteers. Study endpoints Primary Endpoint: Difference in expiratory oxygen concentration (FeO2) at the end of the 3 min preoxygenation sessions. Secondary endpoints: * Difference in Oxygen Reserve Index (ORi) at the end of the 3 min preoxygenation sessions. * Changes in regional ventilation from baseline to 1.5 min and 3 min into the preoxygenation sessions, assessed using electrical impedance tomography (EIT) * Time to reaching an Oxygen Reserve Index (ORi) ≥ 0.5 * Time to reaching an Oxygen Reserve Index (ORi) =1 * Time to Oxygen Reserve Index (ORi) back to baseline after the 3 min preoxygenation sessions. Number of participants 15 participants per subgroup, i.e. 45 participants in total. Inclusion criteria * Normal-weight adults (body mass index, BMI 18.5-24.9 kg/m2) with an "American Society of Anesthesiologists Physical Status Classification System (ASA) " score of I or II * Adults with a BMI 25-39.9 kg/m2 with and ASA score \<3 * Healthy (ASA I) children aged 6-12 years Exclusion criteria ASA 3, Age \< 6 and age 12-18, pregnant women, missing informed consent, signs and symptoms of an acute respiratory illness on the study day. After informed consent and a medical check-up, baseline measurements will be done for 10 minutes (peripheral oxygen saturation SpO2, ORI, regional ventilation). Then the participants will undergo 3 different preoxygenation sessions with the 3 interfaces (i.e. non-rebreather facemask with reservoir and a bag-valve-mask with and without PEEP) in a randomized order and a 20 min washout between the sessions. Each preoxygenation session is conducted in a supine position and will be proceeded until the measured FeO2 (end expiratory O2 fraction) reaches 90% or up to a maximum time of 3 min. Afterwards 10 min of SpO2, ORI and regional ventilation measurements will follow.

NCT Number	NCT06370689
Lead Sponsor	Institute of Mountain Emergency Medicine
Conditions	Emergencies, Anesthesia
Enrollment	45 participants
Start Date	2024-05-23
Primary Completion	2024-12-31 (estimated)
Study Completion	2025-07-30 (estimated)
Updated on ClinicalTrials.gov	2025-03-28