Keywords: obesity, shock, blood pressure (PubMed Search)
Blood pressure cuffs tend to OVERESTIMATE true blood pressure in obese patients. Even larger cuffs tend to do this as well. While low blood pressures are often reliable in diagnosing shock, be wary of assuming a "normal" blood pressure (e.g. SBP 100-120s) rules out shock in an obese patient who is sick. A-lines might be necessary to accurately assess the blood pressure.
[adapted from ACEP talk by Dr. Tiffany Osborn]