the international recommendations don't explain the place of the intraosseous infusion in the reanimation of adult cardiac arrest; the goal of this preliminary study is to inform the delay for obtaining a vascular access by evaluation of a current strategy (using intraosseous infusion after one peripheral venous access failure) and to determine the potential failure risk factors of venous access.

In 2010, the European Resuscitation Council and the International Liaison Commitee on Resuscitation have made new recommendations about management of cardiac arrest. The intraosseous infusion was described as an alternative to the peripheral venous access, before the intra tracheal way for adrenaline administration. But this work doesn't specify the delay and the circumstance for this use: time to obtain a vascular access, number of failure, difficulty to obtain a venous access. Furthermore the recent improvements in intraosseous devices may make it relevant to compare intra osseous infusion and venous access in first intention in adult's cardiac arrest in view of the significant number of venous failures and of the subsequent delay of adrenaline administration.

The goal of this preliminary study is to inform the delay to obtain a vascular access by evaluation of a current care (using intravenous infusion after one peripheral venous access failure) and to determine the potential failure's risk factors of venous access.

Main objective: estimate the delay to obtain an effective vascular access (peripheral venous access, intra osseous infusion, central venous access) in resuscitation of adult's cardiac arrest by out of hospital care unit according to the international recommendations.

Study design: monocentric prospective cohort of consecutive patients presenting with out-of-hospital cardiac arrest.

Inclusion Criteria:

• 18 years old or over
• patients insured by social security
• cardiac arrest (all causes) with mobilisation of a intensive mobile care unit in primary intervention
• medical resuscitation indicated

Exclusion Criteria:

• pregnancy
• contraindication osseous infusion