Mark's site is excellent. I would recommend as a reference book that you can carry to work with you Fast Facts for Adult Critical Care by Kathy White.It's available at
www.kathywhite.com . For a larger reference text, I'd suggest Thelan's Critical Care Nursing, Diagnosis and Management by Urden, et al. ISBN 0-323-01461-5.
For Hemodynamics, theres a great little handbook out there called, Handbook of Hemodynamic Monitoring by Gloria Darovic.
Good luck!
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