A nationwide shortage of critical care specialists has prompted more than three dozen US hospital systems to implement electronic intensive care units, or eICUs, which use telehealth technology to connect remote doctors with critically ill patients. About five years ago, Phoenix-based Banner Health implemented an eICU network, which is one of the country’s largest telehealth systems used for critical care. The system connects physicians and nurses to about 15 hospitals and 450 beds in Arizona, Colorado and Nebraska. Physicians from Southern California and Tel Aviv, Israel, also recently joined the network. Banner Health’s eICU system, which it calls “iCare,” remotely transmits critical patient information such as heart and breathing rates to remote doctors, allowing them to provide guidance to on-site health care providers. Banner Health offers iCare to all the patients admitted to the ICU, but patients have the ability to opt out. The hospital system estimates that over the past four years, the iCare system has helped prevent 600 deaths by providing access to critical care specialists. So far, Banner Health has invested $11.3 million in equipment to implement its telehealth system, which it is considering expanding to areas other than the ICU. Recent research has drawn attention to the concept of using telehealth technology to improve ICU care. For example, a May study published in the Journal of the American Medical Association found that the patient mortality rate at the University of Massachusetts Memorial Medical Center in Worcester, Mass., dropped from 10.7 percent to 8.6 percent after the hospital implemented a telemedicine program.