Training for HALO procedures. Part 1: Background and psychomotor skills. St Emlyn’s

Estimated reading time: 13 minutes

This week I am delighted to be travelling to Florence to join the Third National Urgent and Emergency conference. I’ll be meeting old friends and hopefully making some new ones in a beautiful setting. The topic I’ve been given is ‘how to train for HALO procedures’. HALO stands for High Acuity, Low Occurrence. Originally I thought this was about parachuting as in the military HALO stands for High Altitude, Low Opening. A technique used by special forces and others to covertly enter enemy territory. It has risk, uncertainty, time pressure and the stakes are high. So perhaps there are some comparisons to be made with the complex resuscitation procedures that we will consider here.

Although there is some international variance around what exactly constitutes a HALO procedure most systems would agree that the following are relevant to emergency and prehospital emergency medicine.

  • Surgical Airway/Front of neck access
  • Thoracotomy +/- chest drain insertion
  • Thoracotomy
  • Resuscitative hysterotomy
  • Advanced Vascular Access (IO/Central/Arterial)
  • Lateral Canthotomy
  • (in some health regions you might add ECMO, REBOA, Eschartomy etc. but we don’t do those in my system at the moment

These are all practical procedures which we don’t do every day, but which we may be required to perform under a significant degree of pressure. They are usually performed when our patients are in extremis, but they are also risky in themselves to patients with a number of complications. They are also potentially risky to the operators, both physically and psychologically. As educators we want our colleagues to be able to perform these competently at the time when they are required. They need to be able to do this quickly as it is highly likely that there will be time pressure to do so. It is vital that we take note that our aim is to train people to be able to deliver the procedure in practice. What this means is that the preparation for HALO techniques is not just about psychomotor skills. Our goal is that they are done quickly and competently when required, and that requires much more than psychomotor proficiency.

This blog is based on what I have learned from some incredible teachers and organisations over the years. At the moment I’m delighted to work and teach some of these skills with the ATACC group, the MATT charity, the NWPCC charity and then NW Air Ambulance charity, all of whom do amazing work. Having developed my own skills before surgical skill courses, high fidelity mannequins or even half decent debriefing models, I can assure the readers that the current opportunities for learning are now much better, but they still have very significant challenges.

The triumvirate of training for HALO procedures.

For a HALO technique to be successful in practice we need three elements to work in harmony.

  1. Psychomotor skills
  2. Personal cognitive skills
  3. Team skills

Firstly, and most obviously we need the operators to be proficient in the task itself (psychomotor skills). Secondly we need ourselves to be optimally mentally prepared and focused (self skills). Thirdly, we need a team around us that understand what is going on and who are able to support the procedure (team skills). My experience and belief is that all three of these have to function well for a procedure to be optimised. They all require different types of preparation and training as discussed below.

Stage 1: Psychomotor skills.

The principle problem with learning the psychomotor skills in normal clinical practice is the rarity of these procedures. After many years in an MTC and prehospital care I’ve done more than my fair share of these procedures, but it’s still relatively small numbers for many of them. For some HALO procedures it is entirely possible for a clinician to only perform them once or twice (perhaps never) in an entire career. In contrast when learning many other procedures in medicine we will often have seen the procedure done in practice before we go on a course or perform any practical training. HALO procedures will rarely have been witnessed live before someone is required to perform them. This is clearly a significant educational challenge.

There are number of strategies and opportunities to develop psychomotor skills and we have a hierachy of opportunity, complexity and cost which flows from knowledge/awareness through to teaching on all types of model. Roughly speaking it looks a little like this.

Awareness and understanding through reading, online videos, podcasts and blogs is obviously something that is widely available but still underpins how we perform these procedures. It is essential that participants understand the relevant anatomy, pathology and physiology linked to the procedure. Surprisingly, this is not widely appreciated. A recent example being a course where several participants advocated bilateral open thoracotomies for awake, spontaneously breathing patients with chest injury (not a great plan unless followed up by further intervention in the form of a chest tube, or at the very least a chest seal). This perhaps identifies the need to understand the anatomical issues (in that case making a hole in the chest), together with the physiological impact of such a treatment.

Part task trainers.

These are the classic specific skill trainer models that you will be familiar with on life support courses. In this category I refer to small models that may be plastic manufactured or in some cases animal parts (e.g. sheep larynx) to practice the general approach to a practical skill. The advantage is cost and availability, but this is at the expense of realistic feedback from the tissues. They are generally useful at teaching and practicing the sequencing of a procedure.

For example, when training to put in rapid access, large flow subclavian lines, you might use a plastic torso to practice the technique. Although the model lacks real skin, lacks the feel of tissues, has no arms and does not move, it is still a useful tool to teach a rough approximation of positioning and placement. Most importantly (perhaps), it allows multiple attempts at the procedure at low cost. Learners can practice where to put their hands, how to hold the device/scalpel/introducer, how to prepare the equipment, how it feels in their hands, perhaps even where they would place it practice etc. Although the overall learning experience is not ‘realistic’ the ability to familiarise with the touch and feel of the equipment is really important. Such familiarity will lead to more available cognitive bandwidth in the event of a real case. Some clinicians call this ‘micro-skill’ teaching, but in reality it’s about optimising your technique in such as all the marginal gains by gaining familiarity and flow add up to making the whole procedure much easier. An example would be knowing that the introducer wire for an arterial line has a bendy end and stiff end (again it’s surprising how few people know this).

NOTE: there are some amazing plastic models that can be used for training with very realistic features, we will return to these when we talk about team preparation. For focused psychomotor skills training we focus here on part task trainers similar to the one above, or something like a 3D printed larynx.

Animal cadaver models

Animal models can be used to deliver a greater degree of authenticity to training. Regulations vary around the world with regard to animal models, but in the UK we are talking about cadaveric models rather than live anaesthetised training models that are used in other countries. There is a lot that you can gain in using animal models, particularly around enhancing the look and feel of the tissues. Locally colleagues in Salford and Preston have developed pig models for chest procedures, lateral canthotomy and resuscitative hysterotomy that allow learners to handle tissues in a realistic way to both gain access to the relevant body cavity, and also to practice procedures within them. This latter point is really important and extends into human cadaver courses.

A pig thorax is a reasonable model for thoracotomy training. A pig’s head can be used to simulate retrobulbar bleeding that requires a lateral canthotomy by placing a foley catheter balloon behind the orbit. The images below show a resuscitative hysterotomy model developed by colleagues that allows a layered approach through skin, soft tissue, uterus, amniotic sac and then the delivery of a baby connected to an artificial umbilical cord. It’s not the same as a human but you can clearly see this can be used to gain familiarity with the technique and the experience of cutting through tissues.

There are some significant differences as compared to human anatomy which detracts from the learning. For example the sternum is wider and tougher in pigs, and the heart is central and not rotated as it is in humans (and it is smaller), but it is still possible to replicate the experience of procedures on humans if the faculty are sufficiently experienced to discuss the differences.

HALO procedures when done for real are resuscitative procedures. There is simply no time to pause and discuss how the procedure is done, to argue different approaches or to try different techniques in the heat of the moment. Similarly it is difficult to do this with part task trainers. The animal models allow these discussions and practice to take place in a non-time pressured environment. They can also address any latent technical problems such as instrument handling, packing techniques and suturing.

In the NW these courses are targeted at senior EMv trainees/consultants. The main advantage of these courses is cost. They are relatively cheap to provide (as long as your instructors offer their time for free). Courses typically involve PHEM, anaesthetic, surgical and obstetric colleagues who can add additional expertise to the faculty and learners.

Human Cadaver courses

The highest fidelity training environments are arguably the surgical skills courses using donated human cadavers. These courses allow participants to learn techniques with the correct anatomy. In the NW these run once or twice a year and are aimed at Senior trainees and consultants from trauma specialities. They are expensive and administratively much more complex, but they are very valuable in familiarising and exploring the HALO techniques. Courses typically take place over 1-2 days. A program can be seen on the MATT website here (other courses are available of course).

For many reasons it is vital that these courses are optimised to get the best out of the day(s). Locally we believe that a multidisciplinary faculty with surgeons (CT/Ortho/Gen), anaesthetists, EM, PHEM etc. is essential. Specialist input from teams such as ophthalmology is incredibly valuable. Interestingly, a welcome side effect of training together has been an increasingly better relationships and understanding between these specialities in clinical practice).

The cycle and hierarchy of learning the psychomotor skills can be summarised in the flow chart below. The three year cycle is a rough guide and arguably 5 years may be more realistic for expensive courses, but for lower cost training events it should be possible to do more often. Of course, if you’re lucky to be able to instruct on courses then you may well have the opportunity to do these more frequently.

The approach is both cyclical and sequential. Cadaver courses are expensive, but can be excellent. Animal models are cheaper and more accessible (if you have the people to put them on) and ‘part task trainers’ such as 3D printed larynx’s for surgical airway can be used pretty much at any time and with minimal cost and preparation for the basics of the technique.

High fidelity mannequins for specific procedures.

A number of high fidelity models exist for procedures such as thoracotomy, and they are incredible. The one shown below is from the ATACC group simlab and is an amazing teaching resource for teams. However, even something as realistic as this is not quite the same as real tissues and it’s not optimal for teaching the microskills of procedures. However, they do have a really important place in training teams. A topic we will return to in a future post.

Courtesy of the ATACC group

It’s not about the ‘Otomy’

One thought that occured to me when writing this talk is around the words we use to describe these procedures. In most cases the words we use are all about starting a procedure, but not the life saving element itself. For example nobody ever had their life saved on receiving a thoracotomy (unless it was a rather overzealous decompression of a tension pneumothorax). Rather in many cases, it is what we do AFTER we have made the opening that matters.

Ross Fisher uses the analogy of the bonnet on your car. Learning how to open it is pretty easy, the tricky stuff is what to do when it’s open and for many of us that would be a position of ignorance unless we have had training in car mechanics.

A good example is the teaching beyond the ‘otomy’ in thoracotomy. Some of the elements that we have time and opportunity to teach on the animal and even more so on the human cadaver courses would include those below.

  1. Opening pericardium
  2. Avoiding phrenic nerve
  3. How to handle and inspect the heart
  4. Cardiac wound closure pros and cons (we discuss all, but don’t advocate all)
    • Sutures
    • Pledgets
    • Staples
    • Fingers
    • Balloons
    • Closure next to coronary artery techniques
  5. Lung twist
  6. Hilar occlusion
  7. Non-anatomical lung resection
  8. Packing to different areas in chest
  9. Control of mammary/intercostal bleeding
  10. How to avoid needle/bone stick injury

It’s interesting to listen to colleagues discuss what might be the best option might be for cardiac wound closure depending on environment, familiarity and training. These conversations between experts in their relevant specialities really improve the learning for all, and it’s interesting to reflect on how rarely we bring different specialities together to train. There is simply so much we can learn from each other.

Summary to part 1.

HALO procedures present unique challenges for trainers and trainees. In this blog we focus on the acquisition of psychomotor skills for these tasks. Future blogs will address the equally important self and team preparation required to make these happen in practice.

The educationalists amongst you will also notice the nods to social-constructivism and spaced repetition theories in our approach. Some links below on these as well below.


This blog and the associated talk are based on what I have learned from many superb educators and colleagues. In years gone by the SMACC workshops and educators opened my eyes to elements of teaching and simulation that were truly inspiring. In recent years colleagues in ATACC, NWPCCC, NWAA and MATT have all contributed to developing courses in the NW of England. I am indebted to their wisdom and encourage you to support them on the links below. We are also indebted to the organisations that have funded and hosted events. It all counts and ultimately leads to better patient care and outcomes.

References and Links
  1. CEU2023
  2. MATT: Manchester Advanced Trauma Training.
  3. ATACC: Anaesthesia Trauma and Critical Care group.
  4. NWAA: North West Air Ambulance Charity.
  5. NWPCCC: North West Prehospital Critical Care Charity.
  6. Thoracotomy on St Emlyn’s :
  7. Spaced repetition:
  8. Constructivism and Social Constructivism.

Cite this article as: Simon Carley, "Training for HALO procedures. Part 1: Background and psychomotor skills. St Emlyn’s," in St.Emlyn's, April 2, 2023,

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