There are interesting iPhone apps that are fun to play around with, and then there are iPhone apps that serve a clear clinical purpose. Vigilance is the latter. The Vigilance app, developed at Vanderbilt University Medical Center and marketed by Birmingham, Ala.-based Acuitec, tracks patient vital signs, transmits live video from exam and operating rooms, and sends alerts when patients are in distress so doctors can respond even before nurses page them. FierceMobileHealthcare