"Intubate and provide assisted ventilation with PEEP" emergency treatment would be appropriate.
Explanation:
Positive end-expiratory pressure (PEEP) preserves the airway pressure of the patient beyond the atmospheric level by exerting pressure which inhibits passive emptying of the lung. It serves as the positive pressure that will persist in the airways at the end of the respiratory process i.e end of exhalation, which in manually ventilated patients is higher than the ambient pressure. While intubation serves to insert a flexible plastic tube into the trachea to retain an open airway or to function as a conduit through which other medications may be administered.