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Flight after a pneumothorax

August 10, 2016

There have been a number of incidents at motorsport events that have resulted in a blunt chest injury mechanism with the competitor presenting to the event medical centre for assessment and while no major injuries were found they have subsequently been diagnosed with a pneumothorax. Usually it has been a small one, associated with one or more fractured ribs, diagnosed on a CT. Some of the more high profile incidents include:

  • Fernando Alonso's horrifying rollover at the Melbourne F1GP where having been cleared of significant injury at the circuit medical centre, he later had a CT which showed a single rib fracture and a tiny associated pnuemothorax.
  • A WRC competitor at the 2015 Rally Australia event was referred to the nearby hospital from the service park medical centre following a collision during recce and was found to have several rib fractures and again a very small pneumothorax.
  • James Courtney was struck in the chest by a large placard while standing in the pit lane watching a military helicopter display and again a CT performed at the referral hospital demonstrated a few cracked ribs and a small pneumothorax.

The CT has usually been performed at a hospital later in the day, either as a result of a referral from the circuit medical centre or after a follow up check by a team or series doctor for ongoing chest wall pain. The rib fractures have often been suspected on clinical examination and in the absence of any associated significant injury or physiological derrangement, have been managed appropriately with basic analgesia and follow up advice.

But what about the pneumothorax?

If it is a large one, that's easy. An intercostal catheter goes in. Pneumothorax sorted!

If it is relatively small, as would be reasonably common practice, the pneumothorax is left to resolve by itself, with or without supplementary oxygen and with appropriate follow up. Again, job done!

However, Australia is a big country and most people get between major cities by flying. And this includes race car competitors. International competitors attend races in Australia too.

So a question that often comes up is "Can I get on my flight tomorrow?"


This seems to be a bit of a wooly area. The response from most authorities seems to be to defer flight until two weeks after the resolution of the pneumothorax, whether spontaneously or by chest drain. But that could mean a total of up to three weeks which is inconvenient, potentially expensive and may result in missing out on the next scheduled competition. So what to do? And where do the numbers come from?

Here's the problem. According to Boyle's Law a gas volume will increase as the surrounding pressure decreases. As a plane ascends, the cabin pressure drops and the fear is that a small pneumothorax will become a bigger one causing clinical decompensation. However, don't panic just yet. All commercial passenger jets have cabin pressures maintained at between 1,200 and 2,500m, depending upon their actual cruising altitude. So when you do the calculations it falls out that a volume of gas will increase by about 20-30%. If the pneumothorax has been adequately drained or was too small to be worth placing a drain to begin with, then that 20-30% increase is unlikely to result in a volume increase that is going to cause any problems; especially if the person's lungs and chest are otherwise normal.

Chartered helicopters don't fly much above 2,500m. Unfortunately I haven't had the chance to travel on any private jets, so I'm a bit unsure about these but I think if it is a jet rather than a propellor-driven plane (e.g. Cessna) the cabin is still pressurized.

A trial in 1999 by Cheatham and Safczak showed no respiratory symptom deterioration in 10 of 12 patients flying commercially more than 14 days after CXR resolution of a motor vehicle collision (MVC) associated pneumothorax. One of the two patients who flew earlier than 14 days after resolution experienced respiratory symptoms that were attributed to recurrence of a pneumothorax. That's an n=12 study! And it used a chest x-ray (CXR) to determine pneumothorax resolution, an imaging modality with known false positive and negative issues that can miss up to 30% of pneumothoraces depending upon their size, the image taken and the patient's position. If you really want to exclude a pneumothorax you should probably be using a CT (radiation lifetime risk and expense) or chest ultrasound (bedside, no radiation, and good sensitivity and sepcificity numbers)

An interesting paper by Sacco and Calero in 2014 looked at 80 trauma patients who had either a pneumothorax not requiring a chest drain, a pneumothorax drained by intercostal catheter or a haemothorax requiring a chest drain at their hospital in Anchorage who were all due to fly out subsequently. All of the patients had either a clearance CXR prior to hospital discharge or a follow up CXR within 48 hours of discharge. The age range was 2 to 60 years old (mean 32yo) and most were male. The mean delay to flight after discharge was 6 days and for the 10 patients with a known residual small pneumothorax it ranged from 0 to 15 days with all but one patient flying within 9 days. Not one complication was reported for any of these patients, including the 5 patients who's small pneumothoraces were diagnosed on CT only. The authors appropriately acknowledge the limitations of this single centre study and that this went against the aeronautical agencies guidelines of the time.

The 2011 British Thoracic Society (BTS) Guidelines recommend that patients with a spontaneous pneumothorax defer flight until at least 7 days after CXR-confirmed pneumothorax resolution. For patients with a traumatic pneumothorax a deferral of 2 weeks is recommended. It seems that the Cheatham and Safczak paper form at least part of the evidence base for these recommendations.

It also seems that the majority of world aviation agencies take their cue on commercial passenger transport from the BTS guidelines and apply the same recommendations. Here are some examples:

As an example of a specific airline's guidelines, the Qantas Group Medical Travel Clearance Guidelines state that a person is "not suitable to fly for 7 days or less after full lung expansion" and a Travel Clearance Form completed by a doctor is required for commercial passenger flight "within 8 - 21 days after full lung expansion".


So it would seem that the actual risk of significant decompensation from a small, undrained traumatic pneumothorax in the absence of associated significant injury with a CXR demonstrating resolution is miniscule. It would further seem that a small pneumothorax detected only on CT would be of similar low risk, though this represents only 5 of the patients in the Alaskan paper. And there is no evidence for what to do with the ultrasound detected pneumothorax, though one could extrapolate to requesting a follow-up CXR or CT. However, the established guidelines for commercial passenger air travel continue to recommend a 2 week post resolution by CXR deferal.

Now what is your answer to the competitor?

Update 15/08/2016

So, within minutes of publishing this post, the omni-present Dr Minh Le Cong (@ketaminh) got stuck into me on Twitter. His comments were completely fair, so I'm posting up our conversation below. So of it is a little out of sequence because of how Twitter collates conversation replies, but you'll get the gist of it.








References and Resources





 

How to do simulation training well

August 9, 2016
The previous blog post covered a recent session that I ran for some Australian Rally Championship competitors which covered First On Scene Response training. The aim of the session was to give the competitors some basic skills so that should they be the first to arrive at a rally accident where someone has been seriously injured they have a framework to get help and provide some potentially life or limb saving assistance, buying time for the medical team. The session was deliberately practica...

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An untapped rescue resource for rally and off-road events

June 2, 2016
Last week I finished up a clinical week in the ICU and went home. Just like this time last year, I packed my bags after putting my kids to bed and early on Friday morning, before they woke up, I got into my car and drove three hours to Canberra for the National Capital Rally. This time, however, I had a few extra bags and boxes.

There is a requirement for motorsports, like many other events, to have medical cover in case of illness or injury. At circuit races a medical crew can be at a crash...


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Protecting yer noggin'

April 1, 2016


There is a lot made of safety at motorsport events. Competitors sign a waiver acknowledging that motorsport is dangerous and the same statement is printed on every ticket sold. Crashes such as Fernando Alonso's in Melbourne a few weeks ago, Robert Kubica's hand injuring rally crash in 2011 or Simone De Silvestra's 2010 IndyCar inferno amongst many others serve to reinforce that message.



It is not surprising then that safety is emphasized for those officials working at a motorsport event, whet...

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Australian Resuscitation Council Guidelines 2016 update

February 26, 2016


The Australian Resuscitation Council, in co-operation with the New Zealand Resuscitation Council have at last published their local take on the recently released ILCOR 2015 guideline update for adult, paediatric and neonatal basic and advanced resuscitation. Released in mid January, the combined Australian and New Zealand update makes recommendations for how resuscitation should be conducted here based on the evidence and guidelines issued by the central body, ILCOR.

You can read my summary of...

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Pearls from FOAMed

November 18, 2015
Many of you reading this post will be familiar with the term FOAMed, which is an acronym for Free Open Access Meducation. (If it is new to you, find out more about this concept on these blog posts and articles - LITFL - FOAM / The Short Coat - What is FOAM?EMA - Free Open Access Medical education (FOAM) for the emergency physician). There are subsets of FOAMed, such as FOAMcc (critical care), FOAMped (paeds), FOAMlit (literature review and research) and FOAM4GP (general practice) which ca...

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ILCOR 2015 - Does it matter for motorsports?

November 9, 2015


Every five years the International Liason Committee On Resuscitation reviews the currently available evidence and updates its recommendations regarding resuscitation. The review board is large and made up of resuscitation experts from all over the world and from several specialty areas, including emergency medicine, prehospital medicine and critical care. The recommendations that they write carry a lot of weight and are in turn taken by the lead resuscitation bodies in the various countries a...

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Apnoeic oxygenation by nasal cannulae during RSI

October 22, 2015
Apnoeic oxygenation has been around for a while and the NODESAT (Nasal Oxygen During Efforts Securing A Tube) application has become a fixture on many ED, ICU and Prehospital RSI checklists since the publication of Weingart and Levitan's 2011 article in the Annals of Emergency Medicine,

Preoxygenation and prevention of desaturation during emergency airway management.
Weingart SD1, Levitan RM. Ann Emerg Med. 2012 Mar;59(3):165-75.e1. doi: 10.1016/j.annemergmed.2011.10.002.
Epub 2011 Nov 3.

Desp...

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Medicine in Motorsport App

October 21, 2015
The FIA publication, "Medicine in Motorsport", was published in January 2011. It was intended as a primer for all things that related to providing medical care at (FIA-sanctioned) motorsport events; from how the various roles and organisations fit togther to explanations of race car safety structures to resuscitation topics, all in the context of a motorsport environment. Edited by Dr Gary Hartstein, it was released in digital format through Amazon and could be read on Kindle devices or as a ...

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A medical publication from the FIA Institute (and a survey)

September 4, 2015
It's been an interesting and busy few months and I'll get into all that has been happening in due course. But let's start off with this.

The FIA (Federation International d'Automobile), like any organisation that sets itself up as the prime authority in a given field, cops a fair bit of criticism for many things. That said, within and around the organisation there are plenty of smart, progressive individuals. (I say "around" because not everyone who works with the FIA is necessarily an FIA em...

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