Guidelines following the 2000 International Liaison Committee on Resuscitation (ILCOR) recommendations were for rescuers to look for "signs of circulation", but not specifically the pulse. These signs included coughing, gasping, colour, twitching, and movement. However, in face of evidence that these guidelines were ineffective, the current recommendation of ILCOR is that cardiac arrest should be diagnosed in all casualties who are unconscious and not breathing normally, a similar protocol that of which the European Resuscitation Council has adopted. In a non-acute setting where the patient is expired, diagnosis of cardiac arrest can be done via molecular autopsy or postmortem molecular testing which uses a set of molecular techniques to find the ion channels that are cardiac defective. This could help elucidate the cause of death in the patient. Other physical signs or symptoms can help determine the potential cause of the cardiac arrest. Below is a chart of the clinical findings and signs/symptoms a person may have and a potential cause associated with it. Classifications
Clinicians classify cardiac arrest into "shockable" versus "non-shockable", as determined by the EKG rhythm. This refers to whether a particular class of cardiac dysrhythmia is treatable using defibrillation. The two "shockable" rhythms are ventricular fibrillation and pulseless ventricular tachycardia, while the two "non-shockable" rhythms are asystole and pulseless electrical activity. Prevention
With the lack of positive outcomes following cardiac arrest, efforts have been spent finding effective strategies to prevent cardiac arrest.
Causes
Typical causes of microcytic anemia include:

Childhood
Iron deficiency anemia by far the most common cause of anemia in general and of microcytic anemia in particular
Thalassemia
Adulthood
Iron deficiency anemia
Thalassemia
Anemia of chronic diseaseRare hereditary causes of microcytic anemia include sideroblastic anemia and other X-linked anemias, hereditary hypotransferrinemia, hereditary aceruloplasminemia, erythropoietic protoporphyria, iron-refractory iron deficiency anemia, and other thalassemic mutations (such as hemoglobin E and hemoglobin Lepore syndrome).Rare acquired causes of microcytic anemia include lead poisoning, zinc deficiency, copper deficiency, alcohol, and certain medications.Other causes that are typically thought of as causing normocytic anemia or macrocytic anemia must also be considered, as the presence of two or more causes of anemia can distort the typical picture. Iron Deficiency Anemia
Nearly half of all anemia cases are due to iron deficiency as it is the most common nutritional disorder. Although it is a common nutritional disorder, most causes of iron deficiency anemia (IDA) are due to blood loss. It is also more common to occur among children and females who are menstruating but can occur to any individual of any age. As well as a low MCV, diagnostic criteria includes low serum ferritin levels and transferrin saturation may also be used. Non-pharmacological measures to treat IDA include increasing sources of dietary iron, especially from heme sources such are liver, seafood, and red meats. However, these measures often take a great deal of time longer to replete iron stores compared to pharmacological agents such as iron supplements which are the mainstay of treatment.