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The Case

You have a 50-year-old male with bad bilateral pneumonia; BP 108/70, HR 96, RR 28. He is delirious, agitated, and looks sick, sick, sick! Saturation is 70% on a nasal cannula; when you try to place the patient on a non-rebreather (NRB), he just swats your hand away and rips off the mask.

It is obvious to everyone in the room that this patient needs intubation—but the question is, how are you going to do it?

Your first impulse may be to perform rapid sequence intubation (RSI), maybe with some bagging during the paralysis period. This is essentially a gamble.

If you have first-pass success with RSI, you (and your patient) may just luck out, allowing you to get the tube in and start ventilation before critical desaturation and the resultant hemo­dynamic instability.

However, the odds are against you: Bagging during RSI predisposes to aspiration; conventional bag valve mask (BVM) without a positive end expiratory pressure (PEEP) valve is unlikely to raise the saturation in this shunted patient; and if there is any difficulty in first-pass tube placement, your patient will be in a very bad place.

A Better Way

Sometimes patients such as this one who desperately require preoxygenation will impede its provision.

Hypoxia and hypercapnia can lead to a state of delirium, causing these patients to rip off their NRB or noninvasive ­ventilation (NIV) masks.

This delirium, combined with the low oxygen desaturation on the monitor, often leads to precipitous attempts at ­intubation without adequate pre­oxygenation.

Standard RSI consists of the simultaneous administration of a sedative and a paralytic agent and the provision of no ventilations until after endo­tracheal intubation.¹ This sequence can be broken to allow for adequate preoxygenation without risking gastric insufflation or aspiration; we call this method “delayed sequence intubation” (DSI).

DSI consists of the administration of specific sedative agents, which do not blunt spontaneous ventilations or airway reflexes, followed by a period of preoxygenation before the administration of a paralytic agent.²

Another way of thinking about the DSI method is to view it as a procedural sedation—with the procedure in this case being effective preoxygenation.