Peripheral IV therapy is one of the most common interventions in healthcare, and two of its most common complications remain widely under-recognised: infiltration and extravasation. Both involve fluid or medication leaking from a vein into the surrounding tissue, yet both can go unnoticed until a patient is already uncomfortable or harmed. The NIVAS Infiltration and Extravasation Toolkit, published in February 2024, together with an NHS national patient-safety campaign in 2023, put these complications squarely back on the agenda for anyone inserting or managing a peripheral cannula. For nurses, HCAs and clinical educators, that means revisiting some basics with fresh eyes, not because practice has failed, but because recognition can always be sharpened.

Two words, two different problems

Infiltration and extravasation are often used loosely, even interchangeably, but they describe different risks. Infiltration is the leakage of a non-vesicant fluid, one that will not cause tissue damage, into the surrounding tissue. Extravasation is the leakage of a vesicant, a substance capable of causing blistering or tissue injury, and it is therefore the more serious of the two. Knowing which one you are dealing with shapes everything that follows: how urgently you act, who you escalate to and what your organisation's policy requires. The NIVAS Toolkit's five-stage framework, prevention, recognition, treatment, follow-up and reporting, gives UK teams a shared structure for thinking through both, supported by the NIVAS grading scale that puts a number on severity rather than leaving it to a subjective sense of "somewhat swollen."

Prevention

Prevention starts before the needle goes in: careful insertion-site selection, secure dressing and device fixation, and a structured, ongoing assessment rather than a one-off check at the start of an infusion. Care-bundle approaches, where these elements are combined into a consistent routine, are associated with fewer complications. One quality-improvement study recorded a drop in complications from 15.1% to 9.4% after a bundle was introduced. It is worth being honest about the strength of this evidence: it comes from quality-improvement data, not randomised trials, so it points us in a sensible direction rather than proving cause and effect. That is still a useful steer for practice.

Recognising it early

Some infusions carry more inherent risk than others. Crystalloids, analgesics and, by definition, any vesicant medication all carry a raised risk of infiltration or extravasation, and patient factors such as age also play a part. This is where a graded assessment tool earns its keep. A binary judgement of "swollen or not swollen" misses the early, more treatable stages, while a recognised grading scale, such as the one in the NIVAS Toolkit, encourages practitioners to look for the earlier, subtler signs: change in skin texture, temperature, or the patient's report of discomfort, before things progress. Building the habit of grading rather than guessing is one of the simplest ways to catch a problem early.

What to do in the moment

If infiltration or extravasation is suspected, the broad teaching sequence is: stop the infusion, disconnect the giving set, aspirate if your local policy directs it, elevate the limb, grade the severity, then escalate, document and report. The Thames Valley Cancer Network guidelines are one useful local exemplar of how this sequence gets translated into a real-world protocol. It is worth being clear that decisions about antidotes or thermal treatment, such as GTN paste or phentolamine, sit at prescriber level. The role of general IV training is to build awareness of why these exist and when they might be considered, not to teach administration. Whatever the situation, every step defers to your own organisation's policy: always act under your organisation's own policy, escalating to the right person rather than improvising.

The oncology boundary

Cytotoxic extravasation deserves its own mention, because it is a specialist pathway rather than an extension of general practice. Where a vesicant chemotherapy agent is involved, the guidance is to recognise the signs, stop the infusion and escalate immediately according to UKONS acute oncology guidance. This is a clear boundary line: general IV competence includes knowing when a situation has moved into this specialist territory and needs to be handed over promptly.

Practising safely before it is real

Simulation has a genuine role to play here, precisely because it lets practitioners make and learn from mistakes somewhere safe. In a 2022 study using mixed-reality training for peripheral IV cannulation, 17.7% of first attempts caused extravasation on the simulator. That figure is not a criticism of the learners; it is a demonstration of how easily this complication can occur, and why a simulated first attempt is a far better place for it to happen than a real one. The field is still developing: recognition-focused simulation trials are currently registered and under way in 2026, with results awaited. There is more to learn here, and it is being actively studied.

How VeinTrain connects this to learning

VeinTrain's role is to connect this kind of evidence to structured learning and assessment, giving practitioners repeated, low-stakes opportunities to build the judgement needed to recognise infiltration and extravasation early, rather than after the fact. How that learning is then applied, in terms of protocols, escalation routes, supervision and sign-off, remains entirely a matter for each organisation's own local policy and governance arrangements. Training builds the eye; local policy decides what happens next.

Sources

NIVAS Infiltration & Extravasation Toolkit, Feb 2024: read the toolkit.

NHS national patient-safety campaign on infiltration and extravasation, 2023.

Association of Anaesthetists guidelines: safe vascular access 2025. Anaesthesia 80(11):1381-1396. DOI: 10.1111/anae.16727.

PIVC care-bundle quality-improvement study, 2023.

Journal of Infusion Nursing, 2024, PIVC complication risk-factor study.

Thames Valley Cancer Network Extravasation Guidelines, v5.1a, 2025 (local exemplar).

ONS/ASCO Guideline on the Management of Antineoplastic Extravasation, 2025.

UKONS Acute Oncology Initial Management Guidelines, Guideline 34: Extravasation, 2023.

Rochlen et al., Mixed reality simulation for peripheral intravenous catheter placement training. BMC Medical Education, 2022. DOI: 10.1186/s12909-022-03946-y.

ClinicalTrials.gov NCT07514247 (registered 2026 trial, results awaited).