However, it has been shown that many of the critically ill are less likely to choose resuscitation when given accurate information about its limitations.In the event that cardiopulmonary resuscitation is successful, complete recovery is not guaranteed as many survivors experience an array of disability including partial paralysis, seizures, difficulty with walking, speaking, or memory, limited consciousness, or persistent vegetative state and brain death. Signs and symptoms
Cardiac arrest is not preceded by any warning symptoms in approximately 50 percent of people. For individuals who do experience symptoms, the symptoms are usually nonspecific to the cardiac arrest. This can present in the form of new or worsening:

chest pain
fatigue
blackouts
dizziness
shortness of breath
weakness
vomitingWhen cardiac arrest is suspected due to signs of unconsciousness or abnormal breathing, a bystander should attempt to feel a pulse for 10 seconds; if no pulse is felt, it should be assumed the victim is in cardiac arrest. As a result of loss of cerebral perfusion (blood flow to the brain), the person will rapidly lose consciousness and can stop breathing. Near-death experiences are reported by 10 to 20 percent of people who survived cardiac arrest, which demonstrates a certain level of cognitive processes that are still active during resuscitation. Risk factors
The risk factors for sudden cardiac arrest (SCA) are similar to those of coronary artery disease and include age, cigarette smoking, high blood pressure, high cholesterol, lack of physical exercise, obesity, diabetes, and family history of cardiac disease. A prior episode of sudden cardiac arrest also increases the likelihood of future episodes.
A trisomy is a type of polysomy in which there are three instances of a particular chromosome, instead of the normal two. A trisomy is a type of aneuploidy (an abnormal number of chromosomes). Description and causes
Most organisms that reproduce sexually have pairs of chromosomes in each cell, with one chromosome inherited from each parent. In such organisms, a process called meiosis creates cells called gametes (eggs or sperm) that have only one set of chromosomes. The number of chromosomes is different for different species. Humans have 46 chromosomes (i.e. 23 pairs of chromosomes). Human gametes have only 23 chromosomes. If the chromosome pairs fail to separate properly during cell division, the egg or sperm may end up with a second copy of one of the chromosomes. (See non-disjunction.) If such a gamete results in fertilization and an embryo, the resulting embryo may also have an entire copy of the extra chromosome. Terminology
The number of chromosomes in the cell where trisomy occurs is represented as, for example, 2n+1 if one chromosome shows trisomy, 2n+1+1 if two show trisomy, etc. "Full trisomy", also called "primary trisomy", means that an entire extra chromosome has been copied. "Partial trisomy" means that there is an extra copy of part of a chromosome. "Secondary trisomy" - the extra chromosome has quadruplicated arms (the arms are identical; it is an "isochromosome").