try:
#trigger {~<(%d)hp ~[(%d)*~]~>} {#echo %1;echo %2}

I think it should echo:
277
2

or #trigger {~<(%d)hp ~[(*)~]~>} {#echo %1;echo %2}

to echo:
277
2pm

I'm not at a computer with a CMUD client though so I can't exactly confirm this.

There is actually a command within CMUD to have it automatically set up triggers to grab all sorts of variables from your prompt too. I've not used it personally but I saw it in a helpfile once (I think the command is #setprompt