In a comatose manner; in the manner of someone who is unconscious or in a coma.
From comatose + -ly (adverb suffix). Comatose derives from Greek kōma, with -ose being a suffix for conditions or states.
You'd almost never hear 'comatosely' in real life because you can't really perform an action while comatose—but someone might write 'he lay comatosely on the hospital bed' to emphasize an appearance of extreme unconsciousness.
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