When we talk about surviving cardiac arrest, we mean the patient was discharged from the hospital alive. More than 95 percent of the survivors of cardiac arrest are resuscitated (regain a pulse and respiration) on the scene. In addition, 97 to 99 percent of the survivors are found in V Fib; a few are in pulseless V Tach. V Fib is chaotic, unorganized electrical activity without cardiac output; V Tach is defined as three or more beats of ventricular origin in succession at a rate greater than 100 beats per minute.
Photo by Jack Jordan Using author Tim Simmons as a "victim," Phoenix firefighters demonstrate how an automatic external defibrillator (AED) is used.
For all practical purposes, the patients who survive cardiac arrest are those found in V Fib by rescuers and who regain a pulse and breathing on the scene. The treatment for V Fib is early defibrillation. The earlier defibrillation is delivered, the more patients survive. A study of adult medical cardiac arrest in Phoenix was completed in 1993. What follows are some of the results of that study.
Slightly more than half of our patients were in V Fib when paramedics arrived on the scene. Our survival rate from V Fib was 19.2 percent (a very good number when compared to published survival rates). Looking at two subsets of patients, those in an advanced life support (ALS) company's first-due area and those in a basic life support (BLS) company's first-due area (ALS responds as second-due unit), gave some interesting insights into improving patient survival. Survival with an ALS company as first unit on scene was 25.6 percent; with a BLS company first on scene, survival fell to 12.8 percent.
The main reason for the difference in survival rates was the delay in defibrillation when ALS was the second unit on the scene. Most experts agree that delaying defibrillation beyond eight minutes from the onset of V Fib results in markedly decreased survival. When an ALS company is first on scene, defibrillation is available within six minutes, 44 seconds from receipt of the call by 911. When BLS is the first unit on scene, defibrillation is delayed over nine minutes from the time of collapse.
The American Heart Association (AHA) has identified a series of four critical interventions, the "Chain of Survival," that must occur rapidly if patients are to survive cardiac arrest. The links in the Chain of Survival are early access to EMS, early cardiopulmonary resuscitation (CPR), early defibrillation and early advanced cardiac life support (ACLS). While all links must be strong for the patient to have the best chance of survival, early defibrillation is the single most important factor in determining survival from cardiac arrest. So how do we extend early defibrillation to more patients and increase survival from cardiac arrest? Automatic external defibrillators (AEDs).
The use of defibrillators has traditionally been reserved for ACLS providers such as paramedics. Medical studies have shown that early defibrillation unquestionably saves lives. The studies led to the development of AEDs. These devices use "computers" to interpret the heart's rhythm and, when needed, prompt the user to defibrillate the patient. The devices are easy to use and extremely reliable.
Photo by Jack Jordan The devices extend early defibrillation to more patients and increase survival from cardiac arrest.
Experience in numerous EMS systems has shown that defibrillation by EMTs using AEDs is the most effective way to expand early defibrillation capabilities. The Arizona Department of Health Services says that EMTs who have completed a five-hour training program and passed a state certification test may use AEDs. The AHA's position on early defibrillation is that every emergency vehicle that may respond to a cardiac arrest be equipped with a defibrillator and that all personnel be trained to operate the device. And the International Association of Fire Chiefs (IAFC) has endorsed equipping every fire suppression unit in the United States with an AED.
AEDs have been in use for about 10 years. Research suggests that one life per year is saved for every defibrillator placed in service and that the cost per year of life saved is $452.
Two published studies have particular interest to the Phoenix Fire Department. The studies examined the effect of adding AEDs to existing paramedic systems: the San Francisco and Seattle fire departments. Both studies showed significant improvements in survival rates from V Fib after AEDs became a part of patient care. San Francisco increased survival from 9.5 to 15.3 percent after integration of AEDs, a 61 percent increase in patient survival. Seattle went from 17 percent to 30 percent patient survival after implementation of an AED program, a gain of 76.5 percent.
Phoenix has a modified two-tiered EMS response system. We have both ALS and BLS units respond to incidents the closest available unit is dispatched.
AEDs became a regular part of the Phoenix Fire Department EMS system with our firefighters, who are also EMTs, receiving thorough training. All BLS engines and ladder trucks were equipped with AEDs. One week after we had our AEDs out in the field, we had our first save. It took place on Feb. 23, 1996. A 69-year-old man was taking a walk when he had a heart attack. The crew from Ladder 37, a BLS unit, defibrillated the man and brought him back to life before any ALS unit could reach the scene. He was released from the hospital only days later.
On March 22, 1996, a 48-year-old man went down with cardiac arrest. A Phoenix Fire Department unit responded with an AED and saved his life. Later, then man talked out it: "The doctor was telling me the things that happened and said, 'By the way, you were dead.' I'm appreciative of all the things that happened. I lost one-third of the capacity of my heart. The muscle died. But I'm here. I get to spend time with my family and enjoy the blessings every day … I've been given a gift that a lot of other people haven't been given … I understand the reality of budgets in today's economic environment … but if our investment in equipment will allow the manpower to perform miracles and save lives, what better investment can you make … From what I understand, the paramedics were not on that truck. It was firefighters trained in the use of that machine that saved my life."
The Phoenix Fire Department has 37 ALS companies and 29 BLS companies providing early defibrillation. Our overall survival rate from V Fib/V Tach is 31 percent. When you look at ALS first-on-the-scene vs. BLS first-on-the-scene, the change really hits you. ALS first-on-the-scene survival rates are unchanged, 25 or 26 percent. The survival rate for BLS first-on-the-scene is now 36 percent, up from 12.8 percent. The meaning of these numbers in human terms is that 45 to 50 people per year who would have died before this program was in place will now survive.
Chuck Rockyvich is a 16-year veteran of the Phoenix Fire Department. He has been a paramedic for 14 years and is currently assigned to the Emergency Medical Services Section. Tim Simmons has been with the Phoenix Fire Department's Division of Corporate Communications for 11 years. He is also a captain in the Nogales, Mexico, Fire Department.
