The aim of the study is to evaluate the interest of Local Anesthesia (lidocaïne/prilocaïne versus placebo)before arterial puncture for Blood Gas Analysis. The pain is measured with a numeric Pain Intensity for all patients included.

In an approach of continuous improvement of the quality of the care, this project joins logically after a reflection on the treatment of pain generated by the care in the department of Pneumology 1 / septic Thoracic and vascular Cardiac Surgery.

The arterial puncture for blood gas analysis is an act with aim diagnosis which allows to study gases of the arterial blood to watch the hematosis of the patient. This act appears at the top of the anticipated care as painful by the nursing teams.

In the literature, we find no study carried out with the eutectic mixture lidocaïne prilocaïne. Other local anesthetics and other local ways of administration were estimated and the results diverge as for the efficiency of a local anesthetic for the arterial blood sample at the level radial nerve. Finally authors showed a correlation between certain factors(mailmen) and the painful character of the arterial blood sample, without defining really of population.

In this context, it is necessary to estimate the interest of a local anesthetic before arterial sampling of blood by a study randomized in insu double and versus placebo.

Inclusion Criteria:

• Patients aged more than 18 years old, having signed an enlightened consent, who have an indication of gazometry by taking radial nerve
• Patients capable of estimating the pain felt with numeric pain intensity scale
• Patients with numeric pain intensity scale = 0 before sample of blood
• Patients with no contraindication or no allergy of an anesthetic such as lidocaine

Exclusion Criteria:

• Patients aged less than 18 years old
• Patients incapable of estimating the pain felt with numeric pain intensity scale
• Patients with numeric pain intensity scale > 0 before sample of blood
• Patients for whom the arterial taking is impossible for the level radial nerve
• Hypersensibility to local anesthetics of the amide-type or other component of lidocaïne/prilocaïne cream
• Porphyries known
• Pregnant woman