A cardiac arrest is the cessation of normal
circulation of the blood due to failure of the ventricles of the heart to contract
effectively during systole. The resulting lack of blood supply results in
cell death from oxygen starvation. Cerebral hypoxia, or lack of oxygen
supply to the brain, causes victims to immediately lose consciousness and
Cardiac arrest is a medical
emergency that, if left untreated, invariably leads to death within
minutes. The primary first-aid treatment for cardiac arrest is
Coronary artery disease (CAD)
is the predominant disease process associated with sudden cardiac death in
the United States. The incidence of CAD in individuals who suffer sudden
cardiac death is between 64 and 90%.
In apparently healthy adults,
cardiac arrest is often caused by ventricular fibrillation during
myocardial infarction (heart attack).
In children, cardiac arrest
is typically caused by hypoxia from other causes such as near-drowning.
With prompt treatment survival rates are high.
The state of cardiac arrest
is diagnosed in an unconscious (unresponsive to vigorous stimulation)
person who does not have a pulse.
An ECG clarifies the exact
diagnosis and guides treatment. but treatment should begin without awaiting
an ECG. The ECG may reveal:
· asystole (known colloquially as a flatline),
· ventricular fibrillation,
· ventricular tachycardia
· severe bradycardia,
· complete heart block with a slow ventricular escape
· or even normal electrical activity (pulseless
electrical activity, formerly called electromechanical dissociation).
Potentially treatable causes
of pulseless electrical activity and some other arrhythmias include:
· cardiac tamponade
· tension pneumothorax
· toxins or drug overdoses
· thromboembolism or other mechanical obstruction
· lack of oxygen (hypoxia)
· potassium disturbance (hypokalemia or hyperkalemia)
· decreased blood volume (hypovolemia) due to
haemorrhage or dehydration
Seconds count. Call for help
immediately or send someone for help. Begin cardiopulmonary resuscitation
(CPR) immediately. CPR only buys time for advanced responders to arrive and
does not restart the heart. If an automated external defibrillator is available,
use it at once.
personnel apply advanced cardiac life support protocols as soon as they
arrive, unless there is a valid do not resuscitate order or advance health
directive. If so, it is ethically appropriate to permit natural death to
occur in accordance with the wishes of the patient.
In many hospitals, cardiac
arrest results in one of the carers announcing a "Code Blue" for
immediate response by a trained team of nurses and doctors. The resuscitating
team continues advanced cardiac life support until the patient recovers or
a doctor declares the patients death.
and advanced cardiac life support are not always in a persons best
interest. This is particularly during terminal illness when resuscitation
will not alter the outcome of the disease. Properly performed CPR often
fractures the rib cage. Defibrillation, especially repeated several times
as called for by ACLS protocols, may also cause electrical burns. Internal
cardiac massage, an ACLS procedure performed by emergency medicine
physicians in requires splitting open the rib cage, which is painful during
the weeks of recovery. While such treatment is worthwhile when it saves a
life, it is undignified and simply adds to the suffering of a victim with a
terminal illness who wishes to die peacefully.
It is not surprising that
most people with a terminal illness choose to avoid such "heroic"
measures and die peacefully.
People with views on the
treatment they wish to receive in event of a cardiac arrest to should
discuss these views with both their doctor and with their family.
It is also important that
these views are written down somewhere in the medical record. In the event
of cardiac arrest, health professionals need to act quickly on the
information that is available to them. As cardiac arrest often happens out
of regular hours, the resuscitation team rarely includes anybody who
actually knows the patient.
A patient may ask their
doctor to record a do not resuscitate (DNR) order in the medical record.
Alternatively, in many jurisdictions, a person may formally state their
wishes in an "advance directive" or "advance health