Lidocaine topicalization?

I've seen it done only once. It was a patient who had a trach, then was decannulated. A few days later, they went into resp distress. So he used lidocaine through the trach stoma, then intubated orally. I'm not sure for the reasoning behind this.... It was my first intubation at the time, so I wasn't sure of the "norms". Looking back on it, I think it's so he didn't have to paralyze the patient. He just gave a large dose of Morphine, and then the lidocaine.

But of all the other intubations I've seen, no one else has used lidocaine

The reason for giving topical xylocaine is not about ICP, it is to prevent post operative coughing and other potential complications associated with intubation such as laryngeospasm. Generally, you want to apply xylocaine to the glottic area (to include the vocal cord area). Topical xylocaine is also used for awake intubation. I haven seen a cricoid puncture and injection into the glottic area through the cricoid membrane.

When considering xylocaine as a pre-medication agent in head injury, the IV route is typically endorsed; however, there exists limited and weak evidence to even support the efficacy of using xylocaine to "blunt" ICP spikes during laryngoscopy. I am not aware of any papers that definitively state xylocaine leads to significant outcome improvements. However, nothing in the literature says xylocaine is particularly harmful.