The algorithm is divided into a primary and secondary survey. The thought behind this was that immediate threats to life must be identified and managed within minutes. Once an acute hypoxic event is identified, the patient should instantly be hand ventilated with a high flow manual resuscitator (> 20 L/M of O flow). The goal is to identify an airway occlusion that must be reversed immedi­ately. Difficult bagging is suggestive and further addressed by passage of a section catheter. Inability to pass the catheter pin points to the problem which must be rectified without delay. Artificial airway leaks while problematic can usually be troubled-shot by an experienced therapist, thereby preventing unneces­sary reintubation. Clearly, if the patient responds to bagging with an increase in oxygen saturation then attention should be turned to the ventilator looking for circuit or settings that are inappropriate. Once the airway is eliminated as a primary concern (this should take < 60 seconds) and the patient remains unstable, tension pneumothorax must be considered. When in doubt and in the face of life­threatening hypoxemia, the chest should be vent prior to obtaining a chest X-ray. Once oxygenation has stabilized but the etiology remains unclear, performance of the secondary survey should commence. Clearly, a recent intervention i.e. new medication, transport etc. may have been responsible. Likewise, complications from procedures must be recognized as well as the possibility for progression of the underlying disease process. A common mistake is to attribute an acute hypoxic event to a pulmonary embolism when a portable chest X-ray reveals a new infil­trative or collapse. The last place you want to be is in a dark, cold radiology room at two in the morning with a hypoxic patient who more likely has a much more common problem like mucous plugging or atelectasis!