Resusitation -- Life Support

For a Person in Cardiac Arrest

In a person whose heart is healthy, the functioning of the heart is intricately timed and orchestrated to supply the brain, lungs, body tissues, and organs with blood. When a person's heart stops beating (cardiac arrest), or beats so ineffectively that blood circulation is not sufficient to supply the brain with oxygen and nutrients, the brain is irreversibly damaged within as little as 3 minutes, spontaneous breathing cannot be recovered, and death follows within 4 to 5 minutes. Resuscitation offers a way to reverse the imminent threat to life.

Although most people who suffer cardiac arrest are elderly, the nature and underlying causes of their arrest vary widely. Cardiac arrest frequently results from a loss of blood supply to the heart (myocardial infraction--commonly known as heart attack), but can result from a variety of other conditions, including kidney failure, hemorrhage, and metabolic disorders.

Any one of various heart disturbances--abnormal heartbeats (arrhythmias), absence of a heart beat (asytole), or failure of a normal electrical impulse to cause contraction (electromechanical dissociation)--may proceed or initiate cardiac arrest. The most serious of the cardiac arrfhythmias is ventricular fibrillation, in which the ventricles (lower chambers) of the heart twitch or beat in an uncoordinated pattern without contraction and cardiac output.

Ventricular fibrillation is the most frequent cause of death prior to hospital admission. Other abnormal heartbeats associated with cardiac arrest are ventricular tachycardia, which is characterized by rapid regular or slightly irregular beats; and bradycardia, or abnormally slow heartbeats.

Asystole and electromechanical dissociation cause fewer cardiac arrests than arrhythmias. Arrhythmias, asystole, and electromechanical dissociation can be diagnosed with the aid of an electrocardiograph (EKG) machine.

Cardiopulmonary resuscitation
Cardiopulmonary resuscitation (CPR) refers to a range of technologies that restore heartbeat and maintain blood flow and breathing following cardiac or respiratory arrest. Many people think of resuscitation as it is portrayed on television--a bystander, a paramedic, or an emergency room physician pumping on a person's chest until the person either dies or is revived.

However, resuscitation consists of a wide array of procedures, often involving sophisticated and specialized techniques and equipment. These procedures range from basic life support, which uses manual external cardiac massage and mouth-to-mouth ventilation (see article on CPR on pages 000 and 000), to advanced life support, which may include application of:

• Drugs -- either intravenously, by direct injection into the heart, or via endrotracheal tube (through the windpipe).

• An electrical defibrillator -- used to deliver a high-voltage current averaging 4,000 volts, which is delivered over 4 to 12 milliseconds via two paddles placed externally on the patients chest, on either side of the heart.

• A temporary cardiac pacemaker -- used to regulate heart rhythm. There are three basic approaches: external (using skin electrodes to send electrical impulses through the chest wall), transthoracic (the insertion of a pacing electrode through the chest into the heart muscle), and transvenous (insertion of a pacing electrode through a large vein near the collarbone and into the heart).

• Open-chest cardiac massage -- is the most drastic means of attempting to restore circulation. This procedure involves surgically opening the patient's chest and breaking the ribs so that the heart can be directly massaged.

Yet, some resuscitative procedures for elderly persons can be complicated by age-associated illness or physiological changes such as osteoporosis, cataracts, arthritis, and altered metabolism and may increase risk of complications.

The purpose of cardiopulmonary resuscitation is the prevention of sudden, unexpected death. Still, CPR is not indicated in certain situations, such as in cases of terminal, irreversible illness where death is not unexpected or where prolonged cardiac arrest dictates the futility of resuscitation efforts. Resuscitation decisions vary from individual to individual, factors that are frequently involved include the clinical indicators of the chance of success, as well as the patient's mental status.

Resuscitation can deliver a person from the brink of death. It can restore a person to his or her prior lifestyle within a few weeks, with only bruises and soreness as reminders of the ordeal. However, for most patients, the outcome of CPR is not so positive. Most patients who die following resuscitation do so within the first few days. Some patients die despite repeated resuscitation over a period of hours. Some who are successfully resuscitated face a long, difficult recovery, and some never resume their normal daily activities. Others survive with serious physical impairment or brain damage.

With varied and often conflicting attitudes about the role and responsibilities of the patient's physician, staff physicians, nurses, patients, families, and overall about the goal of treatment itself, there has developed a need for a mechanism by which decisions about resuscitation can be made. In response to this need, some hospitals, nursing homes, and hospices have developed guidelines and policies governing decisions about resuscitation--many have not. These are called DNR (decision not to resuscitate) orders. Recent legal developments such as living wills and Durable Power of Attorney for Healthcare complicate further the decision making process.

When cardiac arrest occurs unexpectedly or there has been no advance deliberation of the appropriateness of resuscitation, CPR is almost always attempted because the alternative for the patient is death. Yet, resuscitation may represent a positive violation of an individual's right to die with dignity.

In general, only a physician may decide to withhold CPR. Emergency rescue teams have standing orders to initiate CPR as quickly as possible. In hospitals, staff members are generally required to initiate CPR unless there is a physician's order not to resuscitate a particular patient. In the event of a sudden and unexpected cardiac arrest, a patient cannot participate in the decision whether to resuscitate, and the involvement of the patient's family is severely limited by time constraints. In the great majority of cases, however, advance deliberation is possible, and patients, families, and surrogates can be involved in decisionmaking.