This prospective, multicenter observational registry systematically captures all emergency department tracheal intubations across participating hospitals in Taiwan. The registry focuses on process quality indicators, including first-pass success, and patient-safety outcomes, including hypoxemia, hypotension, and peri-intubation cardiac arrest within 30 minutes of intubation. Routinely generated laboratory and physiologic variables are also collected to improve risk stratification and identify predictors of major adverse events. The study is non-interventional and does not alter clinical care.

Inclusion Criteria:

• Undergoing tracheal intubation in the emergency department during the study period

Exclusion Criteria:

• Prehospital intubation; intubation performed solely for elective anesthesia/procedural sedation outside emergency indications

Consecutive adult emergency department patients undergoing tracheal intubation at participating hospitals in Taiwan.

De-identified data will be retained under institutional governance and are not currently planned for public individual participant data sharing.