After receiving an e-mail asking whether there is a federal law requiring an agency to be on scene within so many minutes, I realized there is some confusion about response time standards.
First, there is no federal law regarding response times, and, after doing thorough research, I cannot find any state laws that pertain to response times. There are some contractual agreements between EMS providers and political subdivisions that stipulate response times, and some political subdivisions enter and ratify these contractual agreements into ordinances. But most of the contractual agreements or ordinances are directed toward private EMS providers. Most of these communities have established standards of eight minutes or less 90% of the time for ALS service. Some municipalities, especially in California, have even moved response time standards to 12 or 15 minutes for private EMS providers 90% of the time, but these are usually coordinated with ALS first response.
What really drives response time philosophy is consensus standards. Consensus standards are developed by specific industries to set forth widely accepted benchmarks for things such as response times. This is an attempt by the EMS industry to self-regulate by establishing minimal operating performance or safety standards.
In most cases, compliance with consensus standards is voluntary. Regardless of whether compliance is voluntary or mandatory, EMS agencies must consider the impact of "voluntary" standards on private litigation. In some states, a department may be liable for negligent performance. Even in states that protect EMS personnel under an immunity statute, most state laws do not protect personnel or their agencies for grossly negligent acts. Essentially, gross negligence involves the violation of a standard with willful intent that results in injury or loss to some individual or organization. In establishing the standard for EMS agencies, the courts frequently look to the "voluntary" standards issued by various organizations. Although "voluntary" in name, these standards can become, in effect, the legally enforceable standard of care or operation for EMS agencies and their personnel. Accordingly, EMS agencies should pay close attention to applicable standards.
One standard that affects EMS deals with cardiac arrest. This is one of the most relevant standards affecting response times.
Most adults who can be saved from cardiac arrest are in ventricular fibrillation (VF) or pulseless ventricular tachycardia. Electrical defibrillation with ALS intervention provides the single most important therapy for the treatment of these patients. Resuscitation science, therefore, places great emphasis on early defibrillation and ALS intervention. The greatest chances of survival result when the interval between the start of VF and the delivery of defibrillation is as brief as possible. The Advanced Life Support Working Group of the International Liaison Committee on Resuscitation (ILCOR) for the American Heart Association recommends that resuscitation personnel be authorized, trained, equipped and directed to operate a defibrillator and provide ALS intervention if their professional responsibilities require them to respond to persons in cardiac arrest.
The American Heart Association's scientific position is that brain death and permanent death start to occur in 4–6 minutes after someone experiences cardiac arrest. Cardiac arrest can be reversible if treated within a few minutes with an electric shock and ALS intervention to restore a normal heartbeat. Verifying this standard are studies showing that a victim's chances of survival are reduced by 7%–10% with every minute that passes without defibrillation and advanced life support intervention. Few attempts at resuscitation succeed after 10 minutes.