Background and Goal of Study: Complications concerning invasive procedures are common cause of patient morbimortality. Central venous catheters (CVC) are one of the most common techniques in Intensive Care. Experience, mechanical ventilation or night shifts were proposed as risk factors for CVC failure or complication. The aim of our study was to asses the complication rate and characteristics of them in our Unit.Materials and Methods: Prospective, observational study conducted in a 40-bed ICU during a 3-month period. 15 residents (3 per year during 5 years) and the staff were asked to prospectively fill a survey every invasive procedure they had performed. The items collected were: year of residency, time (day or night), urgency, presence of invasive mechanical ventilation or hemodynamic instability. Also type of procedure, who started and who finally made, supervision, number of attempts and the complications that might have occurred. We classified operators in groups (R1-R3, R4-R5, and staff) and number of attempts (< 3 and u22653).Results and Discussion: 100 CVC were performed: 17 during the night (0-9 hs). 72 were carried out, from the beginning, by young trainees (R1-R3) , 24 by R4-R5 and only 4 by the staff. 33 were not supervised. Median of attempts was 1 (1-7). Complications occurred in 33 (33%). They were not associated with time of day (p=0,41) or supervision (p=0,66), but with u22653 attempts (p< 0,001). R1-R3 had more complication than others groups (38,9%) compared to the other groups, R4-R5 20,8% or staff 0% (p=0,049). Complications were: arterial puncture (n 15), difficulty advancing the guide wire (n 18), hematoma (n 5), malposition (n 2). No pneumothorax was found. In 4 patients more than one complication occurred.In an emergency situation (57%), the most chosen access was femoral vein (47%). Ventilation was not associated to complication (p=0,64) nor the site of catheterization (femoral, subclavian or yugular, p=0,11).Conclusion(s): young trainees should be encouraged to try as many techniques as they can without worrying about the time of day or mechanical ventilation but a limit of 3 attemps is recommended to avoid complications. Although supervision had no statistic significance in this study, probably due to a small sample size, it is fundamental for education and patient safety.References: 1) Roux D et al. Acquiring Procedural Skills in ICUs: A Prospective Multicenter Study. Care Med 2014; 42:886-895.