Aseptic technique and peripheral intravenous cannulation

Aseptic technique is a risk assessment and sequence. Identify the key site, such as prepared skin or insertion tract, and key parts, including cannula, disinfected connector, syringe tip and sterile dressing surface. Arrange the field so they are never touched or allowed to contact a non-sterile surface. If contamination occurs, stop and replace the item or reprepare the site.

Prepare a clean trolley with hand-rub, gloves and PPE, tourniquet, approved skin antiseptic, gauze, smallest suitable safety cannula, extension or needle-free connector, prescribed compatible flush, sterile transparent dressing, label, waste bag and sharps bin. Check therapy osmolarity, vesicant status, duration and flow need; peripheral access may be inappropriate for some infusates.

Verify identity, indication, allergies, limb restrictions, skin condition and prior access. Explain discomfort and alternatives and position with the limb supported. Inspect and palpate from distal to proximal, avoiding infection, burns, flexion when possible, fistula, graft, lymphatic-risk or neurologically compromised areas under local policy. Use ultrasound only with training and sterile probe-cover technique.

Choose cannula size for therapy rather than habit. A smaller gauge often reduces vein trauma and is adequate for routine medicines or fluids, while rapid resuscitation, contrast or blood may require a larger validated device and vein. If the planned therapy needs central access, do not repeatedly damage peripheral veins while pretending a small cannula is adequate.

Perform hand hygiene and prepare the field. Apply the tourniquet, identify vein and release if needed while arranging. Reapply, clean the site using the product and local specified friction/contact time and allow it to air dry. Do not fan, blot or repalpate. If the patient touches the site or the operator loses location, repeat preparation.

Anchor the vein below the site without contaminating it. Insert bevel up at a shallow angle until blood enters the flash chamber; lower the device, advance slightly to ensure catheter entry, then thread only the plastic catheter while withdrawing the needle. Never push the needle back into a partly advanced catheter because it can shear the catheter. Release tourniquet.

Occlude the vein only as locally taught without contaminating the key site, activate needle safety and discard directly. Connect the primed extension using non-touch technique. Confirm patency using the prescribed flush and observe the whole site. Pain, blanching, swelling, leakage, resistance or absent expected blood return for a therapy that requires it means stop and reassess; do not force.

Secure without obscuring the site using a sterile transparent semipermeable dressing and approved stabilisation. Do not place tape under the dressing or loop tubing under tension. Label site, gauge, date and time. Restore comfort, dispose of waste, clean the area and perform hand hygiene. Document indication, device, site, number of attempts, flush, complications and review plan.

Accessing the cannula is a new aseptic procedure. Check indication and site, perform hand hygiene, disinfect the needle-free connector with the approved agent and time and let it dry, then keep syringe and connector key parts untouched. Check compatibility and patency. Clamp or use positive-pressure technique only as the specific device/local protocol requires.

Inspect at least at each access and at locally defined intervals for pain, erythema, warmth, swelling, leakage, palpable cord, discharge, dressing integrity and continued indication. Ask the patient to report burning or tightness. Extravasation risk depends on the infusate; stop immediately, disconnect and follow the drug-specific extravasation protocol, often leaving the device temporarily for aspiration or antidote rather than automatically removing it.

Remove when no longer needed or with complication. Explain, hand hygiene and gloves, stop infusion, remove dressing and withdraw the cannula smoothly. Apply pressure, especially with bleeding risk, inspect that the catheter is intact and dress. If a fragment is missing, immobilise the limb and obtain urgent senior/vascular help; do not probe. Document removal and site condition.

Suspected local infection or bloodstream infection requires assessment, culture strategy and antimicrobial action under local policy. Do not routinely replace a well-functioning adult peripheral cannula solely at an arbitrary interval if the current organisational policy uses clinically indicated replacement; equally, do not keep one because the dressing looks clean when the indication has ended.

Cannulation competence includes knowing when not to continue. Follow the local maximum-attempt rule, seek ultrasound or specialist access early, and obtain direct supervision until formally assessed. In children, fragile veins, emergency large-bore access, intraosseous access, midlines, PICCs and vesicant administration require additional training and governance.

After needlestick, follow immediate first aid and exposure reporting. After extravasation or nerve symptoms, provide ongoing review. Communicate the line’s limitations at handover, such as positional flow, unverified high-pressure compatibility or difficult access. The person receiving handover must know what may and may not safely pass through it.