Ambulance

Researchers at Duke University Medical Center have been using wireless connectivity to transmit ECGs from ambulances to hospital located cardiologists in an effort to bypass the emergency department and take patients straight to the cath lab. The defibrillator/patient monitor in the ambulance is connected to a gateway device (usually a PDA) that transmits the patient's ECG over a wireless carriers' cellular network to a PDA/phone carried by an on duty cardiologist.

The cardiologists are looking for a specific kind of heart attack called an ST-segment elevation myocardial infarction (MI). This type of MI is noted by a major elevation of the ST portion of an ECG. With ST-segment elevation MIs, there is little question that patient is having a heart attack. These patients can bypass the emergency department (where other suspected heart attack victims must first undergo testing before receiving treatment) and go right into the cath lab.

While the American College of Cardiology and the American Heart
Association recommend that heart attack patients have their arteries
opened within 90 minutes of arriving at the hospital, the NorthEast
Medical Center team was able to cut that time to 50 minutes. The
national average is about 100 minutes, the researchers said.

"We found that the pre-hospital wireless transmission of an
ECG directly to a cardiologist's hand-device significantly reduced the
time," said the lead researcher, George Adams, M.D. "When the
cardiologist can directly see an ECG, it clarifies the decision to
mobilize all the personnel necessary for the cath lab to be ready to go
when the patient arrives."

This is a great connectivity application with tangible medical benefits. First let's describe the solution. The defibrillator vendors are coming out with defibs with wireless connectivity to a hospital based device (either a PDA or workstation). Here's the page for Medtronic's product in this category. So, the ECG goes from the defibrillator to a gateway, the gateway "dials" the appropriate hospital, and transmits a snapshot of the ECG to the hospital. The received waveform is read by a cardiologist and a determination is made regarding the diagnostic confidence of a heart attack - hence Duke's interest in ST-elevated MIs. Just this simple remote review has benefit. There are additional requirements though for taking that early data and integrating it into an EMR - now things get more complicated.

Why isn't this done everywhere? Most hospitals are served by more than one EMS service; and certainly each EMS serves numerous independent and unaffiliated hospitals. Because the wireless connectivity at the debfib/monitor end and the PDA/phone cardiologist end are part of the same system, both the EMS services and all the hospitals they serve have to agree on a single vendor who will provide new defibrillators with this wireless option. Yes, all the ambulances in the area have to replace their defibrillators, and the hospitals have to buy and install their end of things. Even a modest sized market like Durham, NC, has a couple dozen defibs riding around in various ambulances. Few markets have the cash to replace perfectly good defebs with wireless models, and incremental implementation just doesn't seem all that compelling.

So, if the defibs presently in use are nearing their end of life, and if there's money to replace them, and if all or most of the hospitals in the area agree to both buy into the solution and can agree among themselves and the EMS folks as to which solution, then you might be seeing this in your area soon.

This sort of ties into the ambulance based wireless gateway stories that have been going around.