This is a prospective randomized clinical trial aiming to compare the success rate, complications, and insertion time between ultrasound-guided brachiocephalic vein (BCV) and internal jugular vein (IJV) cannulation in mechanically ventilated patients in the intensive care unit (ICU). The goal is to determine whether BCV access offers a safer or more effective alternative in critically ill patients requiring central venous catheter placement.

Central venous cannulation is a common and essential procedure in the management of critically ill patients, especially those requiring mechanical ventilation. Traditionally, the internal jugular vein (IJV) has been the preferred site. However, the brachiocephalic vein (BCV) has recently gained attention due to its potentially favorable anatomical location and reduced complication rates.

This study is designed to compare the outcomes of ultrasound-guided cannulation of the BCV versus the IJV, focusing on parameters such as success rate of insertion on first attempt, total cannulation time, and incidence of complications such as arterial puncture, pneumothorax, or hematoma formation. The study will be conducted on adult patients admitted to the ICU and undergoing mechanical ventilation

Inclusion Criteria:

100 patients with age between ( 18 - 50 years old ) ventilated in ICU with need central venous access , with physical status II or III according to ASA classification .

Exclusion Criteria:

• refusal of relatives of patients
• Any contraindication of Central venous line insertion as thrombocytopenia , coagulopathy …. Etc
• any suspected or documented thrombus inside vein
• any congenital or acquired musculo-skeletal deformities of neck or clavicle
• any active infections or signs of inflammation over insertion site
• any previous procedures performed at the cannulation site