Teaching Arterial Puncture and IM Injection on the HS5 Arm Trainer

Two of the most common needle procedures in hospital care are also two of the most frequently performed incorrectly: arterial blood sampling and intramuscular injection. Both fail for the same reason — the learner has the theory but has never felt the resistance of a vessel wall or the depth of a muscle belly. The HS5 is an arm trainer built for those two procedures, so a student can practise the angle and the feel before touching a patient.

This guide sets out what to teach on the model, in what order, and what the model cannot tell the student.

What the trainer supports

Procedure	Skill being trained	Common learner error
Arterial puncture	Locating the artery, needle angle, aspiration technique	Angle too shallow, probe instead of puncture
Intramuscular injection	Site selection, needle depth, aspiration and withdrawal	Injecting too high or too lateral on the arm
Site marking	Identifying landmarks before needle contact	Skipping palpation entirely
Hand hygiene and asepsis	Full procedure sequence	Starting with the needle, not the prep

Teach the landmarks before the needle

The most common failure in both procedures is not needle technique — it is landmark identification. A student who cannot find the artery by palpation will not find it with a needle.

Run the session in this order:

1. Landmark drill without equipment (8 min). Each student identifies the arterial path and the deltoid injection site on the model by palpation and describes them aloud.
2. Asepsis sequence (5 min). Gloves, antiseptic, drape. The student states each step before doing it.
3. Arterial puncture (12 min). Practise the angle and the advance; discuss what a flash of blood means and what to do if there is none.
4. Intramuscular injection (12 min). Site, depth, aspiration, withdrawal, disposal.
5. Complication briefing (8 min). Haematoma, nerve injury, infection, and what the student would report.

WHO guidance on drawing blood is explicit that the procedure is only as safe as its preparation and disposal steps, not only its puncture [1]. Assess the whole sequence, not only the moment of needle entry.

Depth and angle: what the model can and cannot teach

The model gives the learner a realistic arm contour and a target vessel, which is enough to correct gross errors: approaching at 45 degrees instead of a shallower arterial angle, or aiming too distal. It cannot teach the subtle feedback of a vessel that rolls, a patient who moves, or a haematoma forming under the skin.

The honest framing for students is that the model teaches the sequence and the geometry. Real tissue response comes later, under supervision. Simulation research consistently shows that physical models improve procedural learning but do not replace supervised clinical practice [2].

Assessment that actually discriminates

Do not grade on "did the needle go in". Grade on observable behaviours:

• Landmarks identified by palpation before any equipment is opened.
• Correct angle stated and then demonstrated.
• Asepsis maintained throughout, including glove change if contaminated.
• Sharps disposed of immediately, not at the end of the station.
• Complication recognised and reported in the correct terms.

A checklist of five behaviours is enough for a formative assessment and far more reliable than a global impression.

Procurement and care notes

• Check the replaceable parts. Vessels and skin pads take the wear; ask which components are consumable and their cost per class.
• Confirm the arm can be re-primed. Ask the supplier for the filling and drainage procedure in writing.
• Plan cleaning. PVC skin should be cleaned with a mild agent, not alcohol-based solvents that dry and crack the surface.
• Ask for the tube and needle specification the model was designed for, so the department orders compatible consumables.

Quotation and specification. Current pricing, spare skin and vessel sets for the HS5 are available from chinonmed@adaanatomy.com.

FAQ

Q1. What procedures does the HS5 support? Arterial puncture for blood sampling and intramuscular injection, practised on a lifelike arm.

Q2. Is it a full-body manikin? No. It is an arm trainer focused on injection and puncture skills.

Q3. Can students practise on it without supervision? It is suitable for supervised practice and self-directed repetition of the sequence, but clinical competency still requires supervised patient contact.

Q4. What wears out first? The puncture sites and vessel tubing. Ask the supplier for replacement parts and their cost before purchase.

Q5. Is it suitable for phlebotomy training too? The model is specified for arterial puncture and IM injection. Confirm with the supplier whether venous access is also supported before designing a phlebotomy station around it.

Q6. How many students can one arm serve? Two to three per station, rotating roles of operator and observer, keeps the queue short and the assessment honest.

Product page: Teaching Arterial Puncture and IM Injection on the HS5 Arm Trainer — specification, packing data and a quotation request form.

References

1. World Health Organization. WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. Geneva: WHO; 2010.
2. Motola I, et al. Simulation in healthcare education: a best evidence practical guide. AMEE Guide No. 82. Med Teach. 2013;35(10):e1511–e1530.
3. INACSL Standards Committee. Healthcare Simulation Standards of Best Practice: Facilitation. Clin Simul Nurs. 2021;58:22–26.

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For a quotation on the HS5 with replacement vessels and skin pads, write to chinonmed@adaanatomy.com with your annual student intake.