January 30, 2009

EMS’ heart attack protocols boost response times, outcomes

Doctors and nurses working on patients as they come into the ER
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The ability of Emergency Medical Services personnel to diagnose heart attacks on the scene is saving time and improving outcomes. (photo by Mary Donaldson)

EMS’ heart attack protocols boost response times, outcomes

On Jan. 12, the Nashville Fire Department EMS responded to a call from a 38-year-old male who complained of chest pain. When paramedics arrived at the patient's home, they performed a 12-lead electrocardiogram (ECG) and determined he was having a heart attack.

The ability of EMS to diagnose heart attacks at the scene of an emergency is a recently new phenomenon, but it is proving to be key in saving lives in Metro Davidson County.
The city's EMS team, under the direction of Corey Slovis, M.D., chair of Vanderbilt's Department of Emergency Medicine, has been trained to perform an ECG on anyone at risk for having a heart attack, including people who complain of chest pain, shortness of breath, sudden weakness or nausea, fainting or acute unexplained sweating.

Corey Slovis, M.D.

Corey Slovis, M.D.

The paramedics download the ECG into a computerized medical record that automatically dials the Emergency Department (ED) and sends a fax to the medical receptionist who hands it to an ED physician.

Once the physician confirms the heart attack, he activates the cardiac cath lab, which means that an interventional cardiologist is waiting when the patient arrives.

The protocol of “transmit then transport” saves valuable time, which results in saved cardiac muscle and lives. The time from when the paramedics arrive at the scene of a heart attack to when the blocked artery is opened by a balloon catheter in the hospital cath lab is known as EMS-to-balloon time, or E2B.

This patient had an E2B of 64 minutes.

The American College of Cardiology recommends a door-to-balloon (D2B) time of 90 minutes or less for 75 percent of heart attack victims. Vanderbilt's median door-to-balloon time for all cases in 2008 was 60.5 minutes with 100 percent within 90 minutes. If the EMS brings the patient, the median D2B drops to 47 minutes.

Slovis said these numbers drive home the point that it is important for people who suspect they may be having a heart attack to call 911 rather than try to get to the hospital by car.

“There has been a dramatic change in how quickly we can get patients to the cath lab,” Slovis said.

“About 10 or 20 minutes prior to the patient's arrival in the ED, we know it's a heart attack. We're in a critical period the first hour when you can make the most impact. If you can get someone from symptoms and into lab in under an hour, you can abort many heart attacks before there is significant damage to the heart.”

Key to improving E2B and D2B times is a collaborative relationship among EMS, the ED and the cardiologists who staff the cath lab.

Joseph Fredi, M.D., a Vanderbilt Heart & Vascular Institute interventional cardiologist, oversees the STEMI Network, a program to get heart attack victims who live outside of Davidson County to Vanderbilt as quickly as possible.

Many of those cases are transfers from outlying hospitals and are not labeled as D2B or E2B.

“We have seen an improvement in times for patients who were transferred to Vanderbilt from other hospitals, and we are in the process of compiling our 2008 data to compare the times for those patients who came through the STEMI Network to those who did not,” Fredi said.

Vanderbilt's cath lab does about 250 balloon catheter cases a year on heart attack victims.

“We have been able to achieve these incredible E2B and D2B times because everyone is functioning as a team. There is a shared responsibility to see how we can care for heart attack patients better,” Fredi said.