Patients will receive preoxygenation via face mask with oxygen at 6-8 L•min-¹. Spontaneous breathing will be maintained until induction, and manual ventilation will be performed at the discretion of the attending anesthesiologist without predefined EtCO₂ targets.

Patients will receive identical preoxygenation. Following induction, gentle assisted ventilation will be initiated to maintain EtCO₂ between 35 and 40 mmHg, avoiding hyperventilation.

Patients will receive face mask preoxygenation as above. A low-flow nasal cannula delivering oxygen at 5 L•min-¹ will be maintained during laryngoscopy. Manual ventilation will be adjusted to achieve an EtCO₂ target of 40-45 mmHg, representing mild permissive hypercapnia.

By employing multi-wavelength technology on the forehead, the O3 device provides clinicians with crucial insights into the balance between cerebral oxygen demand and supply. This monitoring is especially valuable for high-risk patient populations, such as those undergoing cardiac surgery, and patients in the intensive care unit (ICU), which provides a continuous, non-invasive assessment of rSO₂ enabling the prompt detection of critical desaturation events. Crucially, changes in rSO₂ during induction correlate with factors directly relevant to spinal cord safety, such as hypotension, hypocapnia, and reduced cardiac output.

Maximum percentage decrease in MAP from baseline between induction and intubation

≥20% decrease in rSO₂ from baseline