Unexpected cardiac arrest involves approximately 0.5 to 5% of patients admitted in Intensive Care Unit (ICU). Even if they have a technical environment conducive to prompt diagnosis and prompt treatment, patients hospitalized in ICU suffer from chronic illnesses and organ failure(s) that obscure the prognosis of cardiac arrest. Although extra cardiac arrhythmias or intra-hospital arrests are the subject of numerous publications, few studies specifically focus on unexpected cardiac arrest in ICU (none in France). The objective of our work is to produce a prospective epidemiological description of unexpected cardiac arrest in in French ICUs.

Unexpected cardiac arrest in ICU corresponds to cardiovascular arrest leading to at least one cardiopulmonary resuscitation technique (external cardiac massage and / or electric shock). They account for about 0.5 to 5% of admissions to intensive care units. Even if they benefit from a technical environment conducive to prompt diagnosis and rapid management, Resuscitated patients suffer from chronic diseases and organ failure (s) that darken the prognosis. Etiologies of unexpected cardiac arrest in ICU are rarely described in the literature. Their specificity comes from the fact that they can be related to patient's medical characteristics, but also to deleterious effects of supportive techniques in place at the time of circulatory arrest (respiratory assistance, vasopressor drugs, extracorporeal circulation ...). These same techniques may also reduce the effectiveness of cardiopulmonary resuscitation (cardiorespiratory interactions of respiratory assistance, pro-arrhythmogenic effect of vasopressor drugs, haemodynamic repercussion of extracorporeal circulation). Although cardiac arrests have been published extensively out of or in-hospital, there are few studies specifically concerning unexpected cardiac arrest in ICU (none in France). The prognosis is different: after an unexpected cardiac arrest in ICU, 50% of the patients recover a spontaneous cardiac activity but only 15% leave alive from the hospital (3 to 4% with a good functional autonomy). A prospective description of risk factors, circumstances and consequences in the medium term would identify (and prevent) risky situations and identify, among those at risk for unexpected cardiac arrest, those for whom a cardiopulmonary resuscitation is justified.

Inclusion Criteria:

• Patient with unexpected cardiac arrest during his / her hospitalization in the ICU
• Patients who have benefited from at least one basic cardiopulmonary resuscitation technique by the ICU team to treat this circulatory arrest (external electric shock, external cardiac massage, adrenaline injection ...)
• Patients with multiple unexpected cardiac arrest during hospitalization will be included only for the first circulatory arrest.

Exclusion Criteria:

• Patients with unexpected cardiac that have not been resuscitated.
• Patients in cardiac arrest at admission to ICU

Patients admitted in intensive care unit during the study period and presenting an unexpected cardiac arrest will be included