HESI is an exam that many schools are using as an midcuricular and exit exam. The exam is written by health education systems incorporated (HESI) and it is supposed to test whether or not a student will succeed on the NCLEX. Truman requires students to take the exam after the first year. If you get less than an 840, you have to take a summer course. The midcurricular HESI is written according to what the school gives HESI to test. In other words, on what they taught you so far. However, the exit HESI exam is everything. Even if Truman didn't cover it, it might be on there. If you get less than an 870 on the exit HESI, you get one more chance to pass it. If you fail twice, you have to repeat your second year of school.
I highly recommend getting disks to do practice questions throughout school. Now that I've purchased Saunder's Comprehensive Review (comes with a disk with over 4,000 questions), I am finding questions that appeared on our exams at Truman. Also, HESI sells a disk and study guide... http://portals2.elsevier.com/portal/portal/hesi
I hope this helps and good luck to you!
P.S. Are you waiting on a decsion for this Fall? Have you considered RUSH?