OBJECTIVES The primary objective is to compare if the addition of a needle guide can reduce the number of central venous catheter (CVC) insertions with >1 skin puncture in ultrasound-guided catheterization of the subclavian vein using the long-axis approach with an in-plane needling technique.

Secondary objectives include if this addition 1) decreases the frequency of mechanical complications (defined as bleeding, arterial puncture, arterial catheterization, nerve injury, pneumothorax), 2) increases the time when the needle is visible, 3) decreases the time until successful vessel punction, 4) decreases the number of needle redirections during the insertion, and 5) a comparison between the two groups regarding number of failed catheterizations.

DESIGN This is a prospective, randomised, controlled, parallel intervention study. Patients will be enrolled at Skåne University Hospital in Lund, Sweden. The trial is investigator-initiated and non-commercial.

POPULATION AND INTERVENTION Adults (18 years of age or older) in need of a subclavian CVC for any reason and able to give written informed consent will be included in the study provided no exclusion criteria is fulfilled.

OUTCOMES Primary outcome will be number of CVC insertions with >1 skin puncture. Secondary outcomes include comparison between the two groups regarding 1) the frequency of mechanical complications, 2) proportion of the insertion-time when the needle is visible on the ultrasound (US) screen, 3) time to successful vessel punction, 4) the number of needle redirections during the insertion, 5) number of failed catheterisations, 6) Feasibility of the needle guide evaluated with a questionair to the operators at the end of the study.

Inclusion Criteria:

• Patients in need of a central venous catheter .
• Clinical indication for the subclavian route which includes expected time of use >5 days.
• Signed informed consent.

Exclusion Criteria:

• Patient is deemed unsuitable for cannulation of the subclavian vein, based on a pre-procedural US examination by the operator, or due to unacceptable patient risk in case of mechanical complication (e.g., severe respiratory failure).

Individual participant data that underlie the results reported in this study, will be made available on reasonable request and after deidentification.

Data will be available beginning 3 months and ending 5 years following article publication.

Access will be given to researchers who provide a methodologically sound proposal. Proposals should be directed to the research group Clinical Research in Anaesthesia and Intensive Care Medicine, C/O Thomas Kander, Dept. of Clinical Sciences, Lund, Lund University, Sweden. To gain access, data requestors will need to sign a data access agreement.

The researcher who will review the documented ultrasound movies and assess the secondary outcomes will be blinded. However, given the nature of the study neither the Care Provider or Investigators will be blinded for the group affiliation or the primary outcome