Death in the vast majority of cases entails general ischemia due to the cessation of circulation, trauma or no. How sensitive your brain is to a lack of oxygen is easily tested by having someone compress both your carotid arteries for 60 seconds. (The exception to the death-ischemia link would be brain death with circulation upheld for a variety of reasons, most commonly viability for organ transplantation.)
The killer consideration with fatal traumatic injuries is their unpredictability. Such an event will most probably drastically prolong the time to cryopreservation, at least by hours. Where are you? Which hospital are you announced dead in? Where's the nearest cryopreservation team? When in the process are they notified? How long is their travel time? How much damage is done while you're not yet announced dead?
The delay, hours of ischemia (while being dead), is what will degrade your brain tissue to a microscopically garbled mess, regardless of the specific type of trauma.
It bears repeating: Even the penumbra of neurons = the peripheral neurons that after a stroke still get some measure of oxygen are given up upon after 4-5 hours (no benefit from further treatment). The central neurons most affected by an ischemic event are considered lost within an hour.
Saw this on reddit.
http://www.reddit.com/r/atheism/comments/ydsy5/reddit_help_me_find_some_peace_in_dying_young_im/
I couldn't help be moved by this. I felt a very strong sense that she is one of us, whoever "us" is. Looking at some of the negative comments and worst of all bad arguments people are using as reasons not to donate made me more upset.
I hope some here might join me in dismantling them. I'd also encourage those like me for who this buys a lot of warm fuzzies to donate. Though it might be wise to wait until we hear from CI or some other third party on the matter.
Edit: She has since made a comment on LW! The provided information has made me pretty much certain that this is a genuine plight.
redditors where willing to give her money to go skydiving, they don't want to give her money to buy cryonics. Sometimes I can only weep.
I think it pretty clear that promoting efficient charity in that particular thread is very unlikely to result in people giving money to better causes. Also I just plain want her to be rewarded in some small way! Note the part starting in the second paragraph that I bolded, not only did she realized what she really was, but she stepped over the entire set of pro-death rationalizations and faced the social pressure people she loved exerted on her because they think she might go to heaven ... its not her fault that a few cells in her brain went haywire before she could afford an insurance policy, I just don't want people like that not having something to show after getting so much stuff right.
2n Edit:
For anyone who just realized the universe sucks and wishes to do something about that whole people dying thing, they are welcome to engage in some optimal death defeating philanthropy by donating to The Brain Preservation Prize that has been endorsed by both Robin Hanson and Eliezer Yudkowsky.