A 20-year-old patient took 50 sleeping pills, attempting to commit suicide. Objectively, the patient's condition is severe, the pupils are dilated and unresponsive to light. The patient's breathing is hoarse, noisy at a distance, respiratory rate 48/min, auxiliary muscles are involved in the act of breathing. Marked cyanosis is observed. Auscultation detects numerous wet crackles in the lungs. Pulse 126/min, shallow, blood pressure 85/45 mm Hg. What aid must be provided to the patient first?