Ultrasound-guided central venous catheterization: what is the evidence? Acesso venoso central guiado por ultrassom: qual a evidência? REVIEW ARTICLE INTRODUCTION Central venous puncture is extremely frequent in intensive care units (ICU). (1,2) It is estimated that more than 5 million central venous catheters (CVCs) are inserted yearly in the United States of America. (3) Despite its frequency, this procedure has risks and may be associated with severe complications, including death. The complication rate is estimated to be 15%, with 750,000 adverse events anticipated yearly, according to American data. (1,2,4) Therefore, routine measures to prevent these complications should be adopted to improve the quality of care in ICUs. (5,6) Traditionally, CVC cannulation is based on anatomical landmarks. However, since 2001, the Agency for Healthcare Research and Quality (AHRQ) has been recommending 11 fundamental practices to improve the safety of this procedure for hospitalized and/or surgical patients, including