RCPs’ Role in Defibrillation

d02b.JPG (14016 bytes)With well-honed assessment skills and the ability to work in a variety of settings, RCPs are ideal candidates to provide rapid defibrillation for patients in cardiac arrest.

Sudden cardiac death (SCD) takes a tremendous toll on the North American public, killing more than 450,000 people annually.1 SCD, the nation’s number one health problem, is unequaled in its ability to kill. The myocardial infarction continues to destroy heart muscle and leads to complications of congestive heart failure, cardiogenic shock, and dysrhythmias, even in patients who survive. It decreases a person’s life performance through cardiac dysfunction, and brings about numerous physical limitations. There is an obvious need for a strategy to counter this problem.

Defibrillation is the only effective treatment for the majority of initial electrocardiograph rhythms in sudden cardiac arrest. Currently, a person who suffers sudden cardiac arrest outside of a hospital has only about a 5% chance of surviving; 90% of cardiac arrest victims who are treated with a defibrillator within 1 minute of arrest can be saved, and every minute after the initial event that they go without treatment decreases their chance of survival by 10%.2

Time Is Critical
The target rapid defibrillation interval from the time a resuscitation team arrives at the patient’s side to the time of the initial defibrillation attempt should be less than 1 minute. This rapid response time improves the potential for cerebral performance following SCD; however, unlike other significant health problems of this magnitude, sudden cardiac arrest is treatable. Immediate treatment with a defibrillator shocks the heart out of a fatal rhythm, allowing a normal, healthy rhythm to resume. Unfortunately, although science and industry have developed a safe and effective cure that works, few victims of sudden cardiac arrest have immediate access to this treatment. RCPs must develop strategies to ensure that a defibrillator reaches every victim of sudden cardiac arrest within minutes of collapse.

Successful resuscitation programs include the rapid defibrillation component. An automated external defibrillator (AED) monitors, assesses, and automatically treats patients with life-threatening heart rhythms. The AED, following application by a trained individual, identifies sudden cardiac arrest and immediately administers life-saving defibrillation without further human intervention. In a recent study,3 people who suffer cardiac arrest outside the hospital had a 33% increase in survival when first-response teams had a defibrillator at the scene within 8 minutes.

RCPs play a major role in the response to cardiac arrest in health care environments. They use well-honed skills to manage the patient’s airway and ventilate and oxygenate the patient. RCPs who have frequent patient contact and excellent assessment skills, and work in a variety of clinical settings, are in an ideal position to provide rapid defibrillation for patients in cardiac arrest. It does not really matter who brings the defibrillator to the victim’s side; the critical activity is to confirm that a defibrillator is readily available and there is an action plan to ensure the device and trained clinicians, including RCPs, reach the patient in time. AEDs have a very high success rate in terminating ventricular fibrillation (VF), yet not all RCPs have access to such a device in certain health care settings. RCPs must ensure that their health care facilities provide timely access to a defibrillator. Rapid access to and implementation of defibrillation improves patient outcomes. According to a study conducted in casinos in Las Vegas,4 74% of gamblers who suffered sudden cardiac arrest survived after getting defibrillated within 3 minutes. Many major airports have installed AED units at 1-minute walking intervals. Can your health care facility deliver this critical intervention within the same time frame as a casino or airport?

The implementation of defibrillation therapy when there is significant delay prior to treatment often proves to be of little value. There is little doubt that the speed in providing care represents a major determinant of survival for patients with cardiac arrest. Although defibrillation is recognized as an effective treatment of VF, it is also clear that defibrillation alone does not ensure survival. The skills and knowledge of the RCP in managing the airway and ensuring adequate ventilation and oxygenation are critical to the restoration of circulation and maintaining homeostasis. The termination of VF or pulseless ventricular tachycardia (VT) with defibrillation and the return of an organized cardiac rhythm move the patient toward a successful outcome.

Cardiopulmonary resuscitation, including airway management, chest compressions, and the administration of medications, must be implemented with defibrillation. But defibrillation is the only intervention that has been clearly demonstrated to improve long-term survival for cardiac arrest. RCPs should encourage the diffusion of defibrillator technology into all health care environments and the community.

RCPs are comfortable with the interaction between technology and patients, and defibrillator technology has advanced significantly and rapidly in the past few years. External defibrillators have been available since the 1960s, and the current use of high-energy shocks to treat VF or VT has not changed. Standard defibrillators of the past have delivered a dampened sine wave monophasic shock. This electrical pulse flows one way between two electrodes on the external chest wall. The theory of transthoracic impedance and timing of shocks has resulted in today’s standard practice of sequential or stacked shocks. The key has been the sequential increase in delivered energy from 200 joules to a maximum of 360 joules. In relation to energy, there have been many studies to evaluate the effect of multiple high-energy shocks on the heart muscle itself. These studies have shown that initially there are significant ST segment changes associated with high-energy defibrillation, which can last up to several months.

The new biphasic waveform, in which the polarity is reversed partway through the pulse, has been used in internal pacemaker/defibrillators for many years. Research has shown that early defibrillation can save lives, but that biphasic waveform defibrillators use less energy to achieve the same result. The consequence of reduced energy is a reduction in myocardial damage during defibrillation and may have an impact following resuscitation. Some of the research has also shown that the same success rates can be achieved with consistent and reduced energy when delivering a biphasic shock.

The location for each cardiac arrest is vital to understanding the impact of successful defibrillation. The level of care provided in health care settings must not fall below that provided in other public areas such as sporting arenas and shopping malls. All too often we see an initial focus on the ABCs of resuscitation and critical elements to the successful outcome of cardiac arrest with a delay in the application of the most effective therapy for VF. When working in an emergency situation, RCPs must not only use standard airway skills and equipment readily at hand, but also ensure that a defibrillator arrives at the patient’s side in a timely manner. The importance of this strategy and the move to bring it about in a changing health care environment will undoubtedly emphasize new expectations for RCPs, but RCPs are critical to the success of this strategy. The presence, knowledge, and influence of RCPs in an emergency setting are crucial to the outcome. At the same time, RCPs are able to provide comfort, care, and skillful intervention to patients with cardiac arrest and cardiogenic shock.

Dan Hatlestad is a speaker, author, and trainer in Littleton, Colo, and a member of RT’s Editorial Advisory Board.

1. State-specific mortality from sudden cardiac death—United States 1999. MMWR Morb Mortal Wkly Rep. 2002;15:123-126.
2. American Heart Association. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: International Consensus on Science. Hagerstown, Md: Lippincott Williams & Wilkins; 2000.
3. Ho J, Held T, Heegaard W, Crimmins T. Automatic external defibrillation and its effects on neurologic outcome in cardiac arrest patients in an urban, two-tiered EMS system. Resuscitation. 2001;49:9-14.
4. Valenzuela TD, Roe DJ, Nichol G, Clark LL, Spaite DW, Hardman RG. Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med. 2000;343:1206-1209.