Without a doubt, one of the most readable, yet informative is: Notes on ICU Nursing: Critical Care FAQ Files From the MICU
It is written by Mark Hammerschmidt and Jayne Mulholland and can be ordered on icufaqs.org. The website has all the FAQ files, also.
Oops!! Sorry, I didn't read your post carefully!! I'm sure you already know about their book!!
And, BTW, the Fast Facts series by Kathy White is good, and I got the iPhone version, but I find that I never refer to it.