Case Based Learning in the New Year: pneumothorax & lung ultrasound

Last week we ran another case-based learning session. The session consisted of a short discussion based around a case that we were tasked that involved a patient with a suspected pneumothorax.

We discussed the issues and challenges of managing a patient on the ground and in-flight with a pneumothorax. In addition, we discussed then practiced how we can use ultrasound as an added tool in the diagnosis of a pneumothorax in the prehospital setting.

To briefly summarize, I’ve divided up some discussion points


  • Both paramedics and doctors discussed the most important aspect in the patient with a pneumothorax in the pre-hospital setting was the clinical status
  • The ultrasound was noted to be extremely helpful for diagnosis however, presence of pneumothorax didn’t necessarily warrant intervention
  • Clinical condition was the overwhelming driver for intervention. The question arose regarding the role of ultrasound – “if the presence of pneumothorax did not necessarily mean intervention required, why use it?” In general, clinicians felt that knowledge about the condition would help make subsequent decisions in the case of deterioration
  • One theoretical approach was proposed – in a patient with pneumothorax that was reasonably stable, consider anesthesitizing & exposing the site for a chest drain then proceed with finger thoracostomy if deterioration. Several clinicians felt that it there was such concern to proceed with local anesthesia then probably a drain should just be placed.
  • In the patient with a left sided pneumothorax, there was strong agreement that loading the patient feet first such that the clinicians would have access to the left side (of our typically starboard loaded patient)
  • The likelihood of needle decompression success is only 50% – brief discussion about an anterior approach vs. a lateral approach


  • Knowledge regarding pneumothorax is key depending on the location of the patient. In situations on the east coast of the Coromandel then altitude becomes extremely important.
  • The early rule out diagnosis that the ultrasound can provide is very useful for managing flight plans
  • Weather was decided as a key factor that would alter management and it would impact possibly both medical decision making and flight operations
  • Placement of ultrasound in the machine: crewman/paramedic at the head of patient holding the machine with doctor on the patient’s right side
A little in-situ training. Enabled us to figure out optimal ergonomics and positioning for in-flight ultrasound. In case you're wondering, I donated my chest to science for this ultrasound to be done

A little in-situ training. Enabled us to figure out optimal ergonomics and positioning for in-flight ultrasound.
In case you’re wondering, I donated my chest for this ultrasound to be done (free of charge!)


  • Overall based on our evaluations of the process, it was a successful event with more case-based learning sessions planned
  • Clinicians reluctant to intervene for pre-hospital pneumothorax unless unstable
  • Strong communication among the team about the presence of a pneumothorax is essential and ultrasound greatly aids with this – affects both medical & operational decision making
  • Ergonomics are important but dependent on each setting; however a standard approach in the machine might be appropriate for positioning of the ultrasound


Cognitive elements of prehospital intubation


Prehospital intubation has been (arguably!) the most important skill the addition of doctors to the Auckland Westpac Rescue Helicopter has brought to helicopter prehospital care in our region.  While the paramedics in our team are highly skilled and very experienced, none of them are currently RSI qualified. St John Ambulance (the ambulance service provider for most of New Zealand, including Auckland) does have RSI-qualified paramedics, some of whom have worked on the helicopter in past years, but currently the helicopter team cannot perform an RSI without a doctor present. Intubations can be performed by paramedics without drugs however in certain circumstances, usually in cardiac arrest or severely obtunded patients.

With the addition of doctors, we have had a heavy training focus on RSI, including introducing an RSI checklist and actively involving the crewman in the RSI procedure.

This paper, from Prehospital and Emergency Care in 2007, provides an interesting insight into the cognitive processes around prehospital intubation, and the implications for training.

Rasmussen’s ‘Skills-Rules-Knowledge’ framework is a concept that can be applied to many difficult/complex processes. The elements are:

Skills-based processing – task performance that can become ingrained, and performed without conciously thinking about it (for example chest compressions in CPR)

Rules-based processing – when an action or series of actions is executed in response to a certain situation, for example ‘if the patient has no pulse – start CPR’. Rules based processing requires explicit knowledge, and can become difficult if the cues for a certain action are unclear.

Knowledge-based processing – a process that can be applied when rules-based processing fails or is not appropriate. For example, in the setting of cardiac arrest – rules-based processing instructs CPR to begin, knowledge-based processing might allow a decision like “the down-time is over 30 minutes, CPR is inappropriate’.

These three elements are highly inter-related – frequently used knowledge-based and rules-based process may, with experience, become skills-based processes.

With regards to prehospital intubation (paramedic performed), the authors then make the following points:

  • although intubation is often taught as a skills-based process, on closer examination it relies heavily on knowledge-based processing
  • recognition of the need for intubation should theoretically be rules based, however some of the cues involved (assessment of respiratory effort, degree of compromise etc) are challenging and the interpretation may vary between individuals, and there are few clear ‘rules’ for intubation in the prehospital setting, hence it is a knowledge-based process
  • identifying a difficult airway is a knowledge-based process
  • selection of intubation technique (position, equipment) are knowledge-based, the only clear ‘rules’ apply to the sizing of paediatric endotracheal tubes
  • techniques for assessing whether intubation has been successful all aim to provide a rules-based ‘yes/no’ answer as to whether the tube is in the trachea, but all are fallible under certain circumstances. Confirmation of tube position is therefore also knowledge based

Amongst other conclusions (including the need for developing pre-defined “action rules” for common clinical scenarios; developing training that places intubation in the wider context of airway management; and further examining the cognitive processes around paramedic intubation), the authors also ask whether intubation is too cognitively difficult for a paramedic in the prehospital environment, and whether less complex devices would be more appropriate.

So how does this relate to our service?

Given our three clinician model (doctor, paramedic, medically-trained crewman), plus often other ambulance staff, it would be (hopefully!) difficult to argue that a pre-hospital RSI is too cognitively difficult for us.

Thinking about an RSI in terms of skills-based/rules-based/knowledge-based processes is useful however.

The most common way we practise RSI is currently some sort of ‘RSI drill’, involving a team of three. It includes running through our checklist, following by executing the RSI procedure as a simulation. This most closely represents a skills-based procedure. Individual elements of the sequence (laryngoscopy, passing a tube over the bougie etc) also represent skills-based processes. With our simulation lab now up and running (plus 3 new mannequins) we have the opportunity to practise skills-based elements of RSI as often as we wish.

Based on collective experience however (both from clinical practice and training) the most difficult elements of RSI are likely to be the knowledge-based processes – whether an RSI is indicated in certain situations, whether modifications to a standard RSI are required (for example DSI or neuroprotective RSI), and contingencies in the event of difficulties or failure. Given a distinct lack of evidence in many of these areas decisions rely heavily on clinician judgement and experience.

For me, the most important thing to come out of reading the paper above was the idea that we can and should be generating specific rules-based processes tailored to the clinical scenario we are dealing with. In the setting of an RSI, this is crucial for when things are not going to plan. The NAP4 audit of airway failures from the UK found that one of the main contributing factors to ED airway failures was ‘a failure to plan for failure’.

While we have a standard RSI checklist and a sequence of events to follow in the event of a failed airway, we need to (and hopefully already do) go beyond this to consider patient specific elements (for example ‘this patient’s airway burns means a higher chance of failed laryngoscopy and need for surgical airway, I will declare failure after x seconds’, or ‘I expect this patient to desaturate very fast, actions when saturations reach 90% will be x,y,z..)

Anticipating and voicing patient-specific elements and (using the terminology from the study) actively regarding them as rules-based processes should, provided they are generated PRIOR to the proverbial hitting the fan, provide an extra level of safety and decisiveness whan an RSI is not going to plan. With a failing RSI and an increasingly unwell patient, I suspect we would all find it easier to follow a clear, pre-defined, and overtly stated rule or two (that we and our team had tailored for the specific scenario) rather than trying desperately to apply knowledge-based processing too late and under extremely stressful circumstances…

What 'rules' would you generate for intubating this child?

What ‘rules’ would you generate for intubating this child?

The full text pdf for this article is here (secure area limited to ADHB staff – ADHB has subscription access to this journal via the Philson Library at the University of Auckland School of Medicine)

A simulation update: Latest session at the ARHT base

This week we ran an in-situ simulation with our duty crew (crewman, paramedic and doctor). We had great participation in a challenging scenario of massive hemorrhage in a blunt trauma patient.

As our simulation experience continues to grow we are always trialling new things. This past week we integrated several techniques that helped enhance the scenarios fidelity.

The scenario was a patient who had fallen off his motorbike at highspeed. There was a paramedic already on scene when our team arrived. The patient was in shock: BP 95/60, 130bpm, RR 28, 87% on room air, GCS 15.

Here’s a brief outline of what we did and why!

  • In-situ simulation: Make the most of the availability of your team. On the job training during a work day is a great way of maximizing educational opportunities. It doesn’t require that people come in on their day off and they still get paid while at work except their learning. We don’t use any expensive simulation centre – instead only using our training packs and equipment we were able to run this scenario at NO COST!
Mid way through a resus. We have all hands on deck, even getting our cameraman Matt to hold the IV!

Mid way through a resus. We have all hands on deck, even getting our cameraman Matt to hold the IV!

  • Set the scene with a video: using footage from the TV show Rescue 1 (filmed on our helicopters) we were able to begin the simulation with our team watching 2 minutes of a scenario to help them better picture the scene and envision the challenges of the local surroundings
  • Live patient actor: in scenarios that don’t require intubation this is especially powerful since we were able to capture our team’s ability to communicate with a live patient. Our patient had multiple traumatic injuries that was causing considerable pain. The team used managed the pain with ketamine and small doses of fentanyl. It was especially helpful to have a live patient since participants would receive real-time feedback if their pain regimen was working.
Having a live patient actor is a great asset and can add extra fidelity to the scenario. Definitely alters the way clinicians approach and speak with the patient.

Having a live patient actor is a great asset and can add extra fidelity to the scenario. Definitely alters the way clinicians approach and speak with the patient.

  • SimMon: I highly recommend this for anyone interested in doing in-situ simulation. Using an iPad and an iPhone, linked by Bluetooth (no Wifi needed) we are able to have a patient monitor with fully adjustable and modifiable vital signs! I have no relationship with the company that makes the app but we use it regularly and it’s must have for any educator running in-situ simulation. Available for download for less than $20NZD.
  • Ultrasound images for eFAST: Our doctor (Alana) performed a pre-hospital FAST and lung ultrasound. We had images and video downloaded ahead of time on a computer to show her the findings. This provided more realistic visual feedback that closely mimics a real clinical setting.
Alana checking out the eFAST findings on the laptop. Diagnosing pneumothorax & positive FAST

Alana checking out the eFAST findings on the laptop. Diagnosing pneumothorax & positive FAST

  • Integration of new medication: We are in the process of integrating a Tranexamic Acid protocol for trauma patients with suspected hemorrhage. This was our first time trialling the medication in a simulation setting. Great discussion around timing and especially helpful for our clinical team that we have clear guidelines when it can be administered.
  • Observation/Feedback by an industrial engineer: Tammy Bryan, is an industrial engineer from Auckland District Health Board, who joined us to observe our work with an interest in the ergonomics of scene set up. This was useful for a current state analysis and the beginning to work towards any changes that can make us more efficient!

Huge thanks to Bruce Kerr, Greg Brownson and Alana Harper who participated as our clinical and operational crew for the scenario. Also a huge thanks to Alice who was our live patient for the scenario. She did an outstanding job acting as a patient in pain with multiple injuries! Don’t worry, our team took care of her with lots of pain meds administered! And Chris was our paramedic who provided outstanding pre-hospital care before the team arrived

Tranexamic acid podcast and resources

In this post Andrew Petrosoniak discussed the use of tranexamic acid in the prehospital trauma setting, and  Auckland HEMS is currently developing a prehospital protocol its use in our service.

About a year ago, Scott Weingart from interviewed Dr Tim Coats, one of the lead authors of the CRASH 2 trial. The interview, which covers a lot of practical territory, became a podcast on in early 2012.

The podcast is here.

Dr Weingart’s ‘show notes’, which include a link to a draft protocol by Minh Le Cong for tranexamic acid in the prehospital setting, are here.




Sim and Choppers

I have written about checklists in medicine before, but in light of a recent publication in the New England Journal of Medicine, I was inspired again to write about it.

One of the leading advocates for checklists in medicine is Atul Gawande. His book “The Checklist Manifesto” is an excellent read for anyone interested in the topic and definitely well written for the lay-person. Notably he’s also the senior author on this randomized trial just published in NEJM. And while the NEJM is often busy publishing some questionably biased and often pharma-funded studies, this one deserves attention. But before I discuss more about the trial…I digress…

Just this week, while we were flying I observed something quite interesting. Typically when we fly in the helicopters, our pilots ask our crewman for landing checks. At which point the crewman will go through the checklist with the pilot answering appropriately. We…

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New clinical simulation lab at ARHT and our newest team member!

Over the past few months at ARHT, we’ve been working to secure a location that can be used as our clinical sim lab. While most of our sim is done outside, this will allow for a “think tank” and location to keep all of our supplies. A spot like this will have a huge positive impact on improving our ability to run effective in-situ simulation.

Rossi, our Emergency Medicine award winning medical student (and newest team member) While it may not be the exact replica of the EM's pretty close!

Rossi, our Emergency Medicine award winning medical student (and newest team member) While it may not be the exact replica of the EM award…it’s pretty close!

In addition, we plan to use this site for task training and trialling new equipment. While it has taken some time to get it organized, we’ve made huge progress recently. One of the main reasons we’ve had such success can be attributed to our newest education team member, Rossi, who is a senior medical student at the University of Auckland. She has a keen interest in emergency medicine, retrieval medicine and trauma. Her enthusiasm has been crucial to getting us up and running with a fully functional sim lab. We should also acknowledge her recent achievement as the recipient of a special mention in Emergency Medicine for dedication & teamwork at U of Auckland Medical school. Welcome Rossi, and we look forward to all that you bring!

I also felt it would be great to show the progress we’ve made with the sim lab. This will be an outstanding location to think, work and practice. We’ll be able to re-pack packs for simulations and engage in task training modules.

Here’s a few pics of the progress…and completion!

Sim lab: the beginning

Sim lab: the beginning

Rossi doing her best Vanna White impersonation

Rossi doing her best Vanna White impersonation

Sim Lab: the current state! Ready for use!

Sim Lab: the current state! Ready for use!

Sim Lab: airway task trainers...clearly needing a cric to be performed!

Sim Lab: airway task trainers…clearly needing a cric to be performed!


An inadvertent leader in trauma research..!

An inadvertent leader in trauma research..!

There have been significant changes in the delivery of acute trauma care as a result of the military conflicts in Iraq and Afghanistan. One of the recent advances has been the advent of haemostatic dressings for haemorrhage control, which are now being used in the civilian as well as the military setting.

Auckland HEMS carries a product called Quikclot Gauze. This is an inert mixture of oxides of silica, sodium, magnesium, aluminium, and quartz. The compounds absorb water in a physical (not chemical) reaction, which concentrates platelets and clotting factors at the site of administration.

In 2008 the Journal of Trauma published a case series of the first 103 documented uses of Quikclot, including uses in military and civilian prehospital and hospital settings. The majority of uses involved extremity haemorrhage, often when direct pressure and tourniquets and direct pressure had failed. First responders found Quikclot to be 100% effective. Quikclot was ineffective in a handful of hospital cases, which involved moribund coagulopathic massively-injured patients. Heat generation from the physical reaction was an issue, with 3 patients sustaining burns, and a quarter of concious patients reporting ‘moderate to severe’ pain.

Wound from helicopter rotor blade, with Quikclot applied

Wound from helicopter rotor blade, with Quikclot applied

There is also evidence from an animal model that Quikclot may allow sufficient haemostasis to reduce tourniquet time. This study involved a pig model of extremity haemorrhage and found that after haemostasis of a bleeding extremity had been acheived with a tourniquet and Quikclot, bleeding occurred only 20% of the time after tourniquet release, compared to a 100% failure rate with standard gauze dressings.

A systematic review of literature regarding haemostatic dressings was published in Injury in 2011, and can be found here. Overall data is scant and mostly observational/retrospective, but what is available suggests that haemostatic dressings like Quikclot should be a useful tool for controlling significant haemorrhage in our prehospital setting.

Full text pdfs for this post are here (secure area limited to ADHB staff only – ADHB has online subscription access to these journals through the Philson Library at the University of Auckland School of Medicine)

Predisposing factors for difficult physician-performed pre-hospital intubation

Warning: Grade IV

Warning: Grade IV!

This German study, published in Resuscitation in 2011, collected data regarding prehospital endotracheal intubations performed by physicians from a variety of specialties in both helicopter and ground EMS.

Of 276 patients analyzed, 86.9% were intubated on the first pass, 9.8% required 2 attempts, 1.1% required 3 attempts, and 1.4% could not be intubated.

The factors most commonly associated with difficult intubation were obesity, short neck, and limited space on scene. Limited space on scene more than doubled the probability of difficult intubation.

Full-text pdf for this article is available here (secure area limited to ADHB staff only – ADHB has online subscription access to this journal via the Philson Library at The University of Auckland School of Medicine)

Prehospital Ultrasound – a new tool for our HEMS community

Several months ago, our HEMS service introduced a portable ultrasound machine onto our helicopters and so far it has been a great success!  While this blog post won’t be presenting the data we’re collecting, our physicians have reported it to be extremely useful. Most often we use it in the evaluation of a trauma patient to perform an eFAST (extended focused assessment with sonography in trauma) that includes assessment for free fluid in the abdomen but also importantly, lung ultrasound for the diagnosis of pneumothorax. Recently, I was part of a mission to transport a patient who had suffered a fall and there was question of a pneumothorax as reported by the ambulance team on scene. We were quickly able to perform an ultrasound of the lungs which ruled out pneumothorax. This enabled our pilot to fly at normal altitude rather than having to fly lower. Furthermore, as a clinician, it helped with decision making during transport as the patient still required treatment in hospital for other injuries. Knowledge that a pneumothorax was virtually unlikely allowed me to focus on other treatment priorities.

Picture of a similar model portable ultrasound that is being used at ARHT by HEMS physicians

We’re using a similar model of portable ultrasound as pictured above at ARHT 

More recently, one of our physicians performed an ultrasound guided femoral nerve block to assist with pain management of a patient with a femur fracture. It worked brilliantly and the patient was transported with considerably less pain!

In the spirit of our new technology, I’ve reviewed what’s out there in the literature regarding prehospital ultrasound (and emphasis on HEMS). There’s very little but this is definitely a growing field!

A recent review of HEMS pre-hospital ultrasound feasibility was published with good results. They performed 144 pre-hospital scans. On average scans took less than 2 minutes with a symptom based approach to what region to scan. While there are some limitations in their methodology, they reported no false-positives compared with available clinical data which is important. In addition, overall sensitivity was 85% (though it should probably be reported for each indication). Nonetheless, this study adds support to the feasibility of prehospital HEMS ultrasound and documents what findings may be value in the field. In several cases, management was altered, for example when pneumothorax was diagnosed then chest drains were placed.

Another study just published, prospectively evaluated the utility of lung ultrasound in non-trauma patients with dyspnea in a pre-hospital setting. They used a focused approach (as pictured below) to specifically identify potential causes of dyspnea. In 68% of cases, physicians reported lung US as a useful tool.

Imaging sites for rapid assessment of lung using ultrasound in dyspneic patients in prehospital setting

Imaging sites for rapid assessment of lung using ultrasound in dyspneic patients in prehospital setting

They required physicians to complete the exam within 5 minutes as not to delay scene times. Pneumothorax was accurately ruled out in all cases, while a large pericardial effusion causing hemodynamic instability was properly diagnosed though it was only drained once in hospital. You might imagine however that if the patient deteriorated en route that emergent pericardiocentesis would probably be the next intervention so identification would be important.

Algorithm for evaluation of dyspneic patient in the prehospital setting with ultrasound

Algorithm for evaluation of dyspneic patient in the prehospital setting with ultrasound in conjunction with imaging sites of above picture. 

I’m not sure how to interpret their results when they reported that additional management approaches were taken in 25% of cases as a result of US. Primarily diuretics were administered after US given the diagnosis of pulmonary edema. In our setting, we don’t carry furosemide so this doesn’t directly apply though if perhaps properly delineating between pulmonary edema and COPD would be useful as nitroglycerin vs. nebulizers could be emphasized in subsequent therapy.

I believe that most of the benefit of prehospital ultrasound is in the injured patient however, as we see, there is growing evidence that it can be used similarly to how it’s used within the emergency department and ICU.


1.  Eur J Emerg Med. 2010 Oct;17(5):254-9. doi: 10.1097/MEJ.0b013e328336ae9e. Prehospital ultrasound in emergency medicine: incidence, feasibility, indications and diagnoses. Hoyer HX et al.

2. Eur J Emerg Med 2012 Jun;19(3):161-6. doi: 10.1097/MEJ.0b013e328349edcc. Prehospital chest emergency sonography trial in Germany: a prospective study. Neesse A et al.

Sim and Choppers

Recently, we had an elderly patient brought into the ED after being involved in a fairly substantial motor vehicle collision. As we began treating her, I asked the trauma surgeon who was taking over the patient’s care whether he wanted tranexamic acid given (TXA). As she was relatively hemodynamically stable (despite several  transient hypotensive episodes), he declined providing her with TXA without elaborating.


In my view, this patient was definitely someone who would have benefited from TXA especially after later imaging revealed retroperitoneal bleeding. I also wondered, whether this patient could have been given TXA in the pre-hospital setting? At ARHT, we’re not currently using TXA but there’s some question as to whether the pre-hospital setting may be an optimal place for initiation of therapy.

In 2010, the Crash-2 study was published. It was an unbelievably impressive undertaking that randomized trauma patients (a very broad cohort) to TXA or placebo…

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