The Sherlock 3CG Tip Confirmation System for placement of peripherally inserted central catheters

The Sherlock 3CG Tip Confirmation System (TCS; BD) is designed to confirm the correct tip placement of a peripherally inserted central catheter (PICC; that is, a catheter inserted through a large vein in or near the arm rather than the neck or chest). Sherlock 3CG is also available within the Site Rite ultrasound device (version 8). By using magnetic and electrocardiographic (ECG) real‑time tracking of the PICC tip, Sherlock 3CG is intended to allow the person placing the PICC to detect and correct any error in tip positioning. The tip location sensor is only compatible with a Bard PowerPICC SOLO catheter. The Sherlock 3CG TCS is designed to remove the need for a chest X‑ray which is used to confirm tip location after insertion of a PICC in most patients. [2019]

The Sherlock 3CG TCS comprises: a system console, including a control processor with display interface; a tip location sensor; a PowerPICC SOLO catheter with the Sherlock 3CG tip positioning stylet; a remote control; and an optional miniature wireless printer to create a paper record of the ECG. The sensor is positioned on the patient's sternum with 2 leads placed to pick up external ECG waveforms. The catheter is then inserted into a suitable vein in the upper arm with the stylet. During insertion, magnets in the stylet generate a field that is detected by the sensor. This enables clinicians to track the PICC on the display interface in real time, allowing them to see if the PICC is taking the correct path towards the cavoatrial junction. The stylet is removed once the catheter has been appropriately positioned. The display interface also shows real‑time ECG waveforms received from the patient's skin (baseline) and from the tip of the catheter (intravascular, measured by a column of saline which the placer injects into the PICC). The P wave changes on the ECG as the PICC tip moves towards the right atrium and right ventricle. By observing the P wave, a clinician can determine the PICC tip location relative to the chambers of the heart and the superior vena cava.

The Sherlock 3CG TCS is intended for use in any indication in adults where therapy means accessing a vein through a PICC. PICCs have a wide range of applications and are commonly used for intravenous access for drugs and fluids (infusion of irritant drugs, such as in chemotherapy; total parenteral nutrition; or long‑term administration of drugs such as antibiotics) and monitoring or interventions (such as central venous pressure, repeated blood sampling, or when there is poor peripheral access). The instructions for use state that the device should be used with caution in patients with altered cardiac rhythms, specifically those in whom a P wave is not easily detectable, for example patients with atrial fibrillation, rapid tachycardia, or pacemaker‑driven rhythm. Although the Sherlock 3CG TCS can be used in these patients, the company recommends a chest X‑ray to confirm PICC tip location.

The cost of the Sherlock 3CG TCS – comprising the system console, tip location sensor, remote control, stand and printer – is stated in the company's submission as £10,653.97 (excluding VAT). The cost of consumables associated with each insertion is £215.05, comprising primarily the cost of the PICC (including the stylet), sterile barrier and ECG leads. Maintenance costs associated with the technology are £840 per year per system console. [2019]

The claimed benefits of the Sherlock 3CG TCS in the case for adoption presented by the company were as follows:

• Better accuracy of PICC placement (reducing the need for repositioning after insertion).

• Removed need for a chest X‑ray or fluoroscopy to confirm tip location after PICC insertion.

• Intraprocedural verification of the PICC tip position allows the PICC to be used immediately after insertion. This reduces treatment delays, which may be up to 48 hours after PICC insertion.

• A safe method for PICC tip placement with no associated adverse events or complications.

• PICC placement and tip confirmation happen during the same clinical procedure.

• Increased patient confidence in whoever is placing the PICC, because the rate of malpositioning and repositioning is reduced.

• A reduced and more efficient care pathway because no confirmation X‑ray is needed.

• Lower staff requirements (radiologists, radiology nurses, radiographers, radiology healthcare support workers) because the need for an X‑ray to confirm PICC placement is reduced or eliminated. All staff who are freed by the use of the Sherlock 3CG can be redirected to other areas of need.

• Potential reduction of bed occupancy due to reductions in treatment delays post‑PICC insertion and delays caused by repositioning. This may lead to earlier discharge of hospital patients having intravenous therapy, enabling management in the community.

• Reduced costs of consequences of incorrect PICC placement.

• Reduced costs of using resource‑intensive departments such as radiology.

In current NHS clinical practice, there is substantial variation between sites in the ways in which PICCs are inserted. Catheters are typically inserted by nurse‑led or consultant‑led vascular access teams, although PICCs may be inserted by a range of healthcare professionals, including nurse specialists, intensive care consultants, anaesthetists, general physicians, radiologists and radiographers. Clinical settings where PICCs are inserted include operating theatres, emergency rooms, oncology, orthopaedic and other wards, radiology departments, intensive care units, high dependency units and outpatient clinics. Sterility is a major concern, and can best be achieved using a maximum barrier sterile field at the bedside.

Ultrasound is used to identify a suitable vein in the upper arm. The PICC is then inserted using a modified Seldinger technique, which involves inserting a small gauge needle into the vein followed by a wire. A sheath and dilator are used for the catheter to gain access to the vein before the wire is removed. The PICC is advanced to a suitable point using a measurement of the distance between the insertion site and a suitable anatomical landmark indicating the target site for the tip of the PICC (for example, the third right intercostal space below the right clavicular head). This technique is referred to as blind bedside insertion or blind insertion. The position of the PICC is confirmed by chest X‑ray, which typically requires the patient to go to the X‑ray department; the X‑ray then needs to be checked by whoever inserted the PICC, or by a radiologist. Alternatively, fluoroscopy can be used to position the PICC, especially when this is difficult, such as in patients with narrow vessels.