The goal of this interventional study is to assess the feasibility of two bedside techniques for confirming central venous catheter (CVC) placement and detecting complications:

• Intracavity ECG monitoring to confirm internal jugular vein CVC tip position.
• Thoracic point-of-care ultrasound (POCUS) to rule out pneumothorax following CVC insertion.

Participants who require an internal jugular CVC as part of their routine care and meet all inclusion and no exclusion criteria will be randomised to receive either:

• Standard care, or
• The intervention, consisting of intracavity ECG guidance and thoracic POCUS. The CVC will be inserted either on the left or right side of the neck.

All participants will undergo a post-procedure chest X-ray regardless of study arm, to allow comparison of the intervention methods with standard care.

Central venous catheters (CVCs) are commonly inserted in critically ill patients to enable the administration of medications, fluids, and monitoring. Following insertion, it is standard practice to perform a chest X-ray (CXR) to confirm correct catheter tip position and exclude complications such as pneumothorax. However, reliance on post-procedure radiography can delay verification of line position, increase patient radiation exposure, and contribute to workflow inefficiency.

Alternative bedside techniques have been proposed to improve the speed and safety of CVC verification. Intracavity electrocardiography (IC-ECG) uses the patient's cardiac electrical activity to confirm the catheter tip's location in real time. When the catheter tip approaches the cavoatrial junction, a characteristic increase in P-wave amplitude is observed, allowing for accurate placement without the need for immediate imaging. Thoracic point-of-care ultrasound (POCUS) has been shown to be an effective method for detecting pneumothorax following CVC insertion.

This single-centre, prospective, randomised feasibility study will evaluate the combined use of intracavity ECG for tip confirmation and thoracic POCUS for pneumothorax exclusion in patients requiring internal jugular CVC insertion. Eligible participants will be randomised to receive either:

• Standard care (ultrasound-guided insertion with post-procedure CXR), or
• The intervention, consisting of ultrasound-guided insertion supplemented with intracavity ECG confirmation and thoracic POCUS assessment, followed by a post-procedure CXR for comparison.

The primary objective is to determine the feasibility of implementing these combined techniques within a critical care environment, including assessment of recruitment, protocol adherence, and completeness of data acquisition. Secondary outcomes include the accuracy of IC-ECG and POCUS compared to CXR for tip position and pneumothorax detection, and the time required to confirm line placement.

The findings will inform the design of a future multi-centre study to assess diagnostic accuracy, cost-effectiveness, and potential to replace routine post-procedure chest X-ray in appropriate clinical settings.

Inclusion Criteria:

• Adult (aged ≥ 18 years)
• Admitted, or planned for admission, to critical care
• Requiring central venous catheter insertion as a part of their usual care
• Suitable for both right or left internal jugular vein insertion

Exclusion Criteria:

• Previously randomised into CVC-TIP
• Atrial fibrillation on 12-lead ECG
• Cardiovascular instability, defined as
• Noradrenaline dose > 0.5mcg/kg/min
• Rapidly escalating doses of vasopressors / inotropes
• Difficulty in obtaining thoracic ultrasound images due to either
• Weight > 120kg
• Existing pneumothorax (either side)
• Subcutaneous emphysema
• Wounds / dressing over anterior chest wall
• Existing pacemaker
• Non-English speaking participants
• Death perceived as imminent
• Any other reason as determined by treating clinician

Anonymised individual participant data will not be publicly available. Data may be shared on reasonable request with approval from the trial steering committee and subject to a signed data sharing agreement. Shared data will include de-identified procedural and clinical outcome information and may be used for secondary analyses or meta-analyses.

Investigators analysing post-procedure chest x-rays will be blinded