Midline catheters offer an alternative to central venous access, providing vascular access in a larger peripheral vein without entering central venous circulation. They are available in various sizes and for various durations of treatment, and are inserted peripherally in the upper arm, with the tip terminating proximal to the axillary vein. Benefits to the patient include reduction in repeated peripheral venous cannulations, and a subsequent reduction in associated venous trauma. The dwell time of midline catheters is up to 29 days.

Drugs that can be administered via a midline are restricted to those that are suitable for peripheral administration, and a midline is not an alternative to a central venous catheter or peripherally inserted central catheter (PICC) line in situations where centrally administered therapies are required (i.e. total parenteral nutrition (TPN)).

The aim of this guideline is to inform practitioners of the recommended procedure for inserting midline catheters.

Please be aware that this guideline does not deem you competent in using these devices.

Purpose of this guideline

This guideline has been developed to inform nurse practitioners and medical staff of the recommended procedure for inserting midline catheters.

Midline catheters should only be inserted by staff that have demonstrated competence in the insertion of midline catheters, as per the competency framework (appendix 1)

Scope of this guideline

This guideline should enable any competent registered nurse, or doctor, to safely insert midline catheters within NHS Ayrshire & Arran.

Definition of terms

Aseptic technique:

This is a sterile procedure performed to prevent contamination and risk of contracting infection.

Chlorhexidine 2% in 70% alcohol sponge applicator:

e.g. Chloraprep.

Chlorhexidine 2% in 70% alcohol wipe:

e.g. Clinell wipe (green).

Extravasation:

The infiltration of a drug into the surrounding tissue.

Lumen:

The cavity of tube within an organ.

Needle free device:

Vygon TKO should be used on all midlines.

Securement device:

GripLoks should be used to secure all midlines.

Sterile transparent semi-permeable dressing:

e.g. IV Tegaderm Advance or IV3000 dressing.

Midlines are non-tunnelled peripherally-inserted vascular access devices which are inserted through a peripheral vein in the arm. Midlines can be used for a longer period of time than conventional peripheral cannulas, and should be considered when patients require intravenous therapy for more than seven days. The tip of a midline does not terminate centrally in the superior vena cava and instead typically terminates before entering the axillary vein at the shoulder. Since the catheter tip is of a much shorter length, a follow-up chest x-ray is not required to confirm catheter placement. Midlines do not enter the central system and therefore have the same limitations as a peripheral cannula.

Vygon offers three types of midline catheter:

• Smartmidline is indicated for up to 29 days of treatment.
• Leaderflex is indicated for up to 29 days of treatment.
• Lifecath Midline™ comes in a range of sizes and can be used for the duration of therapy.

Indications

• Patients undergoing IV therapy (eg antibiotics) for more than seven days. (IV therapy must be suitable for peripheral administration. If central administration is required (i.e. total parenteral nutrition (TPN)) then central venous catheter (CVC) or peripherally inserted central catheter (PICC) line should be considered)
• Patients who have poor venous access in the lower arm where using central access would be contraindicated or not in the best interests of the patient.

Contraindications

• Mastectomy on same side of midline insertion
• Arterio-venous fistula on insertion side
• Parenteral nutrition
• Vesicant medications
• Systemic anti-cancer therapies
• Solutions with pH<5 or >9
• Solutions with osmolarity>500mOsm/l.

Vessel identification and selection identification

Identification

• A vein is a non-pulsatile vessel and easily compresses with the ultrasound probe.
• An artery is a pulsatile structure that is difficult to compress with the ultrasound probe.

Once the vessel has been accessed, the practitioner must observe the flow of blood from the needle to ascertain if the vessel is a vein or an artery. Blood flow from an artery will pulsate, be excessive and may be bright red in colour.

Vein selection

The veins of choice for the placement of a midline when using ultrasound guidance are the basilic and the brachial veins in the upper arm. The cephalic vein should only be used if the aforementioned veins are unsuitable. Midlines should not be placed in a small cephalic vein. Care must be taken when cannulating. If veins are easily identified by simple examination of the patient’s arm then ultrasound may not be required.

Patient preparation and consent

An explanation of the following must be provided prior to obtaining informed consent:

• reason for midline and available alternatives
• explanation of procedure
• time frame of the procedure
• aftercare
• potential complications.

All patients must be verbally consented for midline insertion. If a patient lacks capacity for consent an adults with incapacity form must be completed.

Patients on warfarin therapy should have an INR <3.0 prior to placement. If patient parameters fall below these criteria discuss plan with medical team.

Infection control

Ideally, a dedicated procedure room should always be adopted.

All lines must be placed using strict maximal barrier precautions.
This includes:

• Cleansing the site with chlorhexidine 2% in 70% alcohol (Chloraprep) using a friction scrub with a single use applicator for 3mls for at least 30 seconds in an area of approximately 6cm squared around the proposed exit site and allowed to dry for at least 30 seconds.
• In the event of chlorhexidine allergy, use 70% alcoholic povidone iodine for skin cleansing.
• Full body draping.
• Thorough hand-washing using a surgical scrub technique and drying with sterile towels.
• Wearing hat, mask, sterile gloves and eye protection.
• The use of sterile equipment placed onto a sterile field.

Venepuncture

When inserting the needle into the vein, the probe can be held perpendicular (across) or longitudinal (along) the vein. The needle should be placed slowly into the skin. When the needle approaches the vessel target, the anterior wall will indent. A swift insertion into the vein at this time will prevent excessive collapse of the vein wall. Once venipuncture has taken place, the vessel returns to normal shape. Always observe for a blood return from the needle or cannula.

Inadvertent arterial puncture

The inadvertent puncture of an artery can be avoided by:

• Recognising the position and location of all main and aberrant arteries.
• If the vein accessed is close to an artery, visualize and identify brachial artery with ultrasound.
• During insertion, if the artery is punctured (pulsatile and excessive flow). Remove needle immediately and apply pressure.
• Please note: If line has been placed and brachial vein used and excessive bleeding is noted, blood gas analysis or doppler ultrasound should be considered.
• In the event of inadvertent introducer or line placement in an artery, leave device in place, secure device and seek advice from the medical team.

Inadvertent nerve damage

The inadvertent damage of a nerve can be avoided by:

• Possessing the knowledge of anatomic location of the nerve.
• If brachial vein to be accessed for midline insertion, visualize and identify median nerve with ultrasound.
• During insertion, if the patient reports sudden “electric shock” like pain shooting down the arm or has involuntary and rapid movement of the arm, when nerve is touched. Remove the needle immediately.

The midline placement procedure is a two person procedure.

1. Collect required equipment

• Portable Ultrasound machine
• Ultrasound probe sterile probe cover
• Ultrasound conduction gel
• Disposable tourniquet
• Midline insertion pack (pre-prepared)
• Midline catheter
• Sterile gloves x 2
• 3 ml chlorhexidine 2% in 70% alcohol sponge applicator x 1 (Chloraprep)
• Semipermeable IV transparent dressing
• GripLok securement device
• Sterile 0.9% NaCl for injection
• Lidocaine 1% 5mls.

2. Non-sterile vessel assessment with ultrasound

1. Instruct the patient on the purpose of the ultrasound procedure.
2. Position the patient with the arm supported and apply tourniquet.
3. Ensure that the Ultrasound machine is in a suitable location for optimum visualisation by the placer.
4. Scan the patient with a non-sterile technique to determine the size, location, depth and patency of the veins and location of nerves and arteries.
5. Identify insertion site.
6. Choose appropriate size and length of midline (see appendix 2)

3. Preparation

Prepare the sterile field:

1. Don hat and mask.
2. Wash hands and arms using a surgical scrub technique (see appendix 3)
3. Ensure assistant, after appropriate hand hygiene, has opened midline kit outer pack.
4. Dry hands with sterile towels within the pack.
5. Put on sterile gown & sterile gloves.
6. Prepare the Midline insertion trolley. Your assistant should open remaining sterile items onto the trolley in a manner that maintains strict asepsis.
7. Draw up lidocaine injection and place an orange needle onto the filled syringe – only a 5ml syringe and a 10ml syringe are permitted onto the sterile field in order to clearly distinguish between the lidocaine and the saline.
8. Draw up sterile 0.9% sodium chloride for injection in 10ml syringe.

Prep the patient

1. Cleanse the skin thoroughly using 3ml chlorhexidine 2% in 70% alcohol sponge applicator (Chloraprep) using a friction scrub technique for at least 30 seconds, allowing to air dry for at least 30 seconds.
2. Place sterile full body drape underneath the arm and across the body.
3. Change sterile gloves.
4. Drape the insertion site with fenestrated sterile drape.

Drape the probe for sterile use

1. Allow the assistant to place the probe in the side arm holder on the stand.
2. Apply a layer of sterile ultrasonic gel on the acoustic window of the probe.
3. Place the sheath over the probe head, being careful not to wipe off the gel.
4. Cover the probe and cable with the sheath without contamination.
5. Smooth the sheath over the acoustic window of the probe head and remove any air bubbles.
6. Use a sterile elastic band to hold the sheath in place.
7. Place the probe safely onto the sterile drapes.
8. Ask assistant to apply tourniquet.

4. Insertion of the Midline

1. Apply sterile gel onto the skin at the intended site of cannulation.
2. Locate the site of a suitable vein for venepuncture using the ultrasound machine.
3. Administer intradermal lidocaine at the proposed venepuncture site using the guide described above in key points.
4. Place the probe on the skin at the intended access site and hold the probe perpendicular to the vein. Realign the vein on the centre dot marker (if using, on the ultrasound screen).
5. If the vein is superficial, a longitudinal method can be used to place the needle into the vein.
6. When the vein is successfully accessed blood return will be observed in the needle. (Release tourniquet). If cannulation is unsuccessful after 2 attempts, consider seeking assistance from another equally competent practitioner.
7. Introduce the wire into the needle.
   • The wire should never be forced
   • Take extreme care not to lose the wire into the bloodstream, allow at least 10cm of wire outside the sheath and dilator (if using).
   • The wire should never be removed through the needle, due to the risk of severing the wire on the tip of the needle.
8. Remove the needle over the guide wire.
9. If using 4fr midline thread the introducer over the guide wire, through the subcutaneous tissues and into the vein and remove introducer.
10. Thread midline over guidewire holding midline close to insertion site to prevent kinking of guidewire. Thread midline to position tip in the axillary vein.
11. If using 2fr or 3fr midline, thread midline over guidewire directly into the vein, omitting the introducer step. Thread midline to position tip in the axillary vein.
12. Aspirate blood from the lumen to confirm intravascular placement and flush with 10mls of sterile 0.9% sodium chloride for injection.
13. The Midline must be secured using a skin fixation dressing (recommended method of fixation is Vygon Grip-Lok PICC fixation device).
14. The Midline exit site should be dressed with a transparent semipermeable IV dressing.
15. Connect Vygon TKO Needle free device to luer lock connection at end of midline.
16. Dispose of all waste appropriately as per waste management guidelines including appropriate disposal of sharps.
17. Remove PPE and perform hand hygiene as per the WHO 5 moments for hand hygiene.
18. Document procedure in patient record and complete appropriate care bundle (appendix 4)

5. Confirming satisfactory placement of the Midline

Check that blood can be aspirated freely and flushed from the lumen of the midline.

Midline is a peripheral device and so X-ray confirmation is not required.

Professional accountability

All nurses and doctors are personally accountable for their actions and omissions and are professionally accountable for the patient assessment and treatment, including the care and maintenance of midline catheters.

Continuous professional development

As with any area of practice, every nurse and doctor is responsible for ensuring they maintain their knowledge and skill around their practice. All health professionals are expected to keep themselves up to date with current best practice in the management of midline catheters.

Line manager/professional lead

To ensure safe and effective practice, the line manager is responsible for working closely with the registered nurse or doctor caring for a patient with a midline catheter and ensuring adequate clinical support in relation to supervision.

Midline catheter care and maintenance

The person accepting responsibility for the care and maintenance of midline catheters must ensure that the documentation record of the care is accurate and clear.

G124 Care & maintenance of midline catheters

Midline insertion competency framework

Midline device selection UHC

NHS Ayrshire & Arran midline cannula insertion and maintenance bundle