The objective of the prospective multicenter observational study consists in defining a difficult intravenous access score in adult, during the preoperative period.

The main objective: the outcome of interest is defined as failure of cannulation on first attempt.

The risk factors of failure of cannulation on first attempt will be described. Adjusted multivariate models will be constructed. A prediction model will be proposed according to the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD)

Objectives:

To define a difficult intravenous access score in adult during the preoperative period Methods Multicenter, Observational prospective study

Patients:

patients >18 years old, undergoing peripheral IV placement just before a surgery in operating room excision criteria: pregnant woman, induction of anesthesia with sevoflurane, Predictor variables include: history of patient (age,BMI, Fitzpatrick skin type, cancer, ICU stay, burn, diabetes, kidney disease, anxiety of patient...) , operator experience characteristics( years since graduation, years of anesthesiology experience, IVs started per month), type of catheter and place of catheterization),and postcatheterization data (success on fist attempt yes or no, number of total attempts until success...)

Inclusion Criteria:

• patients >18 years old, undergoing peripheral IV placement just before a surgery in operating room

Exclusion Criteria:

• patients who refused IV placement; pregnant woman; induction of anesthesia with sevoflurane without venous access in place

Patients undergoing peripheral intravenous placement just before a surgery will be enrolled. (the investigator does not assign specific interventions to the subjects of the study)