Comparison of Three Techniques for Ultrasound-guided Internal Jugular Cannulation

Inclusion Criteria: * Patients aged 18 or older * Indication for internal jugular venous cannulation, previously established by the doctor responsible for the patient´s hospital diagnosis and treatment * Informed consent for trial participation has been obtained from the patient Exclusion Criteria: * Infection signs at or close to puncture site * Cutaneous erosions or subcutaneous haematoma at or close to puncture site * History of internal jugular venous cannulation during the past 72 hours (in the same side in which the present cannulation is taking place) * History of previous surgical interventions on the cannulation site * Recent cervical trauma with present neck immobilization and without having ruled out eventual cervical spinal injury * Severe coagulopathy (altered coagulation parameters and active bleeding) which cannot be promptly corrected by platelet, fresh frozen plasma or pharmacologic intervention * Subcutaneous emphysema with cervical extension * Agitated or uncooperative patient (including deep sedation) * Inability to obtain formal informed consent from the patient or his legally authorized representative (in case the patient is legally incompetent to give informed consent) * Cannulation being performed outside the surgical area or the post-anesthesia care unit