Emergency intubation showdown: which method saves more oxygen?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Aged 18 years or older 2. Presence of spontaneous breathing. 3. No prediction of a difficult airway prior to intubation. 4. Requirement for advanced airway management. 5. Not in cardiac arrest. 6. Decided to intubate due to non-traumatic etiologies. 7. Planned intubation using ketamine for sedation and rocuronium for paralysis. 8. Decision to intubate due to one of the following clinical conditions: 1. Acute Respiratory Failure: Patients with hypoxic or hypercapnic respiratory failure where adequate oxygenation cannot be achieved despite non-invasive ventilation. 2. Inability to Protect the Airway: Altered level of consciousness or increased risk of pulmonary aspiration due to conditions such as upper gastrointestinal bleeding, ileus, volvulus, gastric outlet obstruction, hypersalivation, or hyperemesis. 3. Shock States: Patients in any state of shock (hypovolemic, distributive, cardiogenic, obstructive) exhibiting severe altered mental status or declining respiratory status. 4. Neuroprotection: Need to terminate ongoing seizures resistant to medical therapy (status epilepticus), or situations requiring strict control of arterial carbon dioxide (PaCO₂) levels to manage increased intracranial pressure (ICP) in non-traumatic conditions (such as intracranial hemorrhage or severe encephalopathy). 9. Obtaining informed consent from the patient or their legally authorized representative. Exclusion Criteria: 1. Aged under 18 years. 2. Pregnancy. 3. Refusal to provide informed consent. 4. Cardiac arrest prior to intubation. 5. Anticipated difficult airway. 6. Intubation required due to traumatic etiologies. 7. Missing or incomplete patient data. 8. Patients assigned to the DSI protocol but for whom the decision to intubate was rescinded due to clinical improvement during the preoxygenation phase. 9. Use of a sedative agent other than ketamine for the RSI protocol. 10. Intubations performed by practitioners who have not received study-specific training on DSI and RSI protocols. 11. Duplicate enrollment due to recurrent presentations during the study period.