Tag Archives: top end

The Remote Bad Stuff

Last time Jodie Martin, Flight Nurse extraordinaire dropped by she shared one of our most popular posts ever. Jodie returns with a little on the Top End experience of sepsis. 

Time for a look at some remote medicine again.

CareFlight provides the aeromedical service for the top half of the Northern Territory (NT) in Australia.  The area covered by the service is the same size as France but has only 160,000 people.  And less vineyards.

As 115,000 of this population are in Darwin which is serviced by road ambulance services this leaves CareFlight to provide services to about 45,000 people in very remote and widely scattered centres, most of which are small Indigenous communities.  The catchment area has only two rural hospitals which are non-referral centres with care otherwise provided in remote health clinics. Even then not everyone lives close to a rural hospital or remote health clinic. Some rural folk still have to drive several hours or even a few days to any level of health care. Access to health care is a real challenge when someone becomes sick.

The Top End of the Northern Territory may be sparsely populated with 0.2 persons per square km, but it has the highest incidence of sepsis in Australia and five times higher rates than those recorded in the US and Europe 1,2. It has been suggested that one of the reasons for the high incidence of sepsis is related to the higher Indigenous population in the Top End 2. The incidence of sepsis requiring ICU admission in the Top End of the NT for Indigenous people is reported to be 4.7 per 1,000. In the non-Indigenous population there are 1.3 admissions per 1000 people. When compared to the rest of Australia, the rate of admission to an ICU for sepsis is 0.77 per 1,000 2  with national 28 day mortality rates of 32.4% 1.

The Top End – Not Just Popular with People

Human-invading bacteria and viruses love the warmth and moisture of the tropics. To make things even harder, the Top End has the highest rate in the world of melioidosis, a very nasty pathogen found in the wet tropics of Australia.  Melioidosis has been classified as a Type B bioterrorism agent by the Centre for Disease Control in the US and kills up to 40% of infected patients often from rapidly fulminant disease.  However most sepsis is of the more common garden variety, but still causes severe, life threatening illness.

A quick editorial note that we have done another story from the Top End and still it’s not about crocodiles. We apologise but it turns out there are other things up there trying to kill you.

When you add the challenges of distance and retrieval times, meeting targets for sepsis treatment which are time-based would seem an impossible task. Given this, we were keen to review the retrieval of septic shock patients in our service to see what the outcomes are like and whether we could improve the process.  The results have just been published in the Air Medical Journal which you can find here.

The patients were sick.  A third of patients required intubation and 89% required inotropes.  Median mission time however was 6 hours and the longest case took 12 hours.  Given the remoteness and time delays inherent in retrieval over such distances with a population known to have worse health outcomes, you would expect mortality to be high.  Surprisingly however the 30 day mortality in this group of 69 patients, which are predominately Indigenous, was only 13%.  This is lower than previous rates described for both sepsis in Australian Indigenous populations and for patients in Australian and New Zealand intensive care units.

That’s Excellent, But Why?

It is interesting to speculate on the possible reasons for such good outcomes.  Reasons might include:

  • The relatively young age of the patients compared with many series. Perhaps the better physiological reserves of younger patients are still a key factor despite the higher rates of co-morbidities.
  • Early antibiotics – these are almost always given by the end of the referral call. Good clinical coordination has a role to play in this too.
  • Early aggressive fluid resuscitation – the median volume of crystalloid administered was 3L during the retrieval process.
  • Inotropes administered following fluid resuscitation occurred in the vast majority of patients.
  • Early referral – recognising when a patient is sick. This is something we’d like to gather more data on. We didn’t record how long a patient was in a remote health centre before a referral call was made, but we have a suspicion early referral might have played a part here.

It is also interesting to note the good outcomes that were achieved without invasive monitoring in approximately half the patients retrieved.  Perhaps there are shades of the findings of the ARISE study here where fancy haemodynamic monitoring really did not seem to make much difference either – what matters in the retrieval context is early antibiotics, aggressive fluid resuscitation and early intubation when indicated.

We did not randomise patients to invasive versus non-invasive monitoring and it is possible that the sicker patients and those with longer transport times received the invasive version.  But it is also possible that we get too hung up on this stuff and it is the basics that really matter whether you are in the city or a really remote health clinic.

The Wrap

The Australian Indigenous population have poorer health outcomes than the general community. Outcomes are even worse for those residing in remote areas than those in urban areas. In our small study it is pleasing to see such good outcomes despite remoteness and long retrieval times. Our young patient cohort recovered well considering how sick they were but what would be even better is preventing sepsis in the first instance. The incidence and burden of sepsis in young Indigenous people requires preventative strategies and appropriate and timely health care resources. Improving access to health care, improved housing and decreasing overcrowding, decreasing co-morbidities and decreasing rates of alcohol and tobacco use are hopefully just some of ways we can possibly decrease the incidence of sepsis and contribute to closing the gap.


That croc with almost enough teeth came from flickr’s Creative Commons area and is unchanged from Jurgen Otto’s original post.

Here’s the link to the paper that’s just been published:

Joynes EL, Martin J, Ross M. Management of Septic Shock in the Remote Prehospital Setting. Air Med Journal. 2016;35:235-8. 

The two references with the actual superscript numbers above are here:

  1. Finfer S, Bellomo R, Lipman, J, et al. Adult population incidence of severe sepsis in Australian and New Zealand intensive care units. Intensive Care Med. 2004; 30: 589-596.
  2. Davis J, Cheng A, Humphrey A, Stephens D, Anstey N. Sepsis in the tropical Top End of Australia’s Northern Territory: Disease burden and impact on Indigenous Australians. Med J Aust. 2011; 194: 519-524.

Here’s a bit on melioidosis from the CDC website and here’s a review in the NEJM.

If you want to look more at the government’s Closing the Gap stuff, you could go here.

A Bit Early and A Bit Far Away

We welcome another new contributor to the site with this post. Jodie Martin is a clinical educator and flight nurse working in the Top End of Australia. She has just finished up a Masters which included looking at a big retrieval challenge – preterm births in the wild reaches of the Northern Territory. 

Which retrieval taskings scare you the most? Is it the paediatric trauma patient in the prehospital setting, a long way away from the nearest trauma setting? Or perhaps the critically unwell and septic neonate in a remote clinic, which you know will take you 6 hours to retrieve to a hospital?

For me, it’s the women in preterm labour. Even after 10 years of flight nursing, it’s the women in preterm labour that make me nervous.  And before I became a flight nurse I’d been a midwife for several years, working in rural and remote settings where I became fairly comfortable caring for obstetric patients in an isolated setting, because you had to be really. Aeromedical retrieval teams are rarely as quick as you’d like out there.

So even after a lot of exposure to obstetric patients in isolated areas, it is the preterm labour cases which make me sit on the edge of my seat. These are the cases I really want that crystal ball so we can foresee what is going to happen; is this woman going to deliver before we get there? Do we need to spend time on the ground to wait for birth or can we risk it and transfer her in labour and get her to hospital in time to allow preterm birth in a tertiary health centre? How will I manage an unexpected birth of a preterm baby during flight? Do I need to take all of the 100kg+ neonatal equipment to care for a preterm neonate? Do we need a paediatrician, just in case?

A Brief History of Stopping Labour in the Top End

In 2009 or there about, obstetric services in the Top End of the NT moved away from using IV salbutamol and started using nifedipine as the tocolytic of choice.  This was because nifedipine was seen as a safer tocolytic with less adverse maternal side effects. In particular, there is a high incidence of rheumatic heart disease in the NT and we now had a better option of avoiding the negative effects IV salbutamol can have on cardiac function.

We already knew that facilitating in utero transfer of preterm babies improves their outcomes so that was still our aim. 1 However, I was yet to be convinced nifedipine was a superior choice for the aeromedical transfer of women in preterm labour.

So we turned to the literature to find out about the incidence of inflight births and to determine what happens to the women in preterm labour transported by aeromedical retrieval. Some studies reported no births occur in flight.2 However these studies utilise different types of tocolytics than our aeromedical retrieval service. A Canadian aeromedical retrieval service did report inflight births. 4 of these births occurred despite tocolysis but that tocolytic was not a calcium channel blocker such as nifedipine and the other births received no tocolysis at all 3. Anecdotally we knew at CareFlight NT we’d had 3 inflight preterm births despite nifedipine being administered. In three different Australian based studies which reviewed the transfer of rural and remote women, approximately 50% are in fact discharged.2,4,5

So what about the risks for pregnant women in the Northern Territory? Unfortunately, the news is not good. The NT has the highest rate of preterm births in Australia with 10% of all births occurring before arrival to hospital.6 Indigenous women and newborns do worst on some birth outcomes if they live in a remote area of the Top End of the NT7 and the NT has the highest maternal death rate in Australia.8 So being an Indigenous pregnant woman in a rural remote area of the NT is a combination of a lot of significant risk factors.

Let Me Paint You a Picture of Where We Work

The Top End is a geographical area twice the size of the UK & a just a little smaller than Texas, so around 400,000km2. There are two small rural hospitals which undertake planned low risk, term births. Both hospitals have emergency obstetric and caesarean capability along with the ability to provide immediate neonatal emergency care, but have limited resources to care for a preterm newborn for any extensive period of time.

There are over 35 small remote health centres we service. These health centres have no inpatient facilities and do not perform planned births. These centres can sometimes manage an unexpected normal birth but have no theatre or neonatal nursery care resources. Sometimes there is a remote area midwife available.

There’s only one NICU, which is located at Royal Darwin Hospital. The next closest NICU is 3,027km away in Adelaide. So when a woman presents in preterm labour in a rural or remote area in the Top End of the NT there is a natural level of anxiety as resources are limited, retrieval times can be long and we know we have a high risk obstetric population.

So I thought it was worth looking at our own data on the women we transport in preterm labour to find out more about their outcomes. Plus I needed to do a research project to complete a Masters’ degree.

The aim of our 3 year retrospective study was to determine the outcomes of women in preterm labour transported by aeromedical retrieval. We reviewed all the cases of preterm labour referred to CareFlight NT. Preterm labour was defined as 23+6 to 36+6 weeks gestation with a viable pregnancy. We excluded those women who had been referred after a preterm birth had already occurred. After exclusions for missing & incomplete data, we ended up with a sample of 304 women referred in preterm labour. We examined discharge data at Royal Darwin Hospital to review the outcomes.

What we found

Demographics and retrieval times
The average gestation was 32+2 week and 90% of the women we transferred were Indigenous (there’s that high risk obstetric factor again I mentioned previously).

Retrieval time was taken from time of referral to our logistics coordination unit (LCU) to time of handover at the receiving hospital. Average retrieval time was 5.55hrs. Those women who proceeded to a preterm birth had an average time of birth following referral as 5hrs. Therefore there will be times when a preterm birth occurs before we can get to our destination.

Where preterm birth occurred
The places where women did give birth to a preterm baby:

16% in a remote health clinic

7% in a rural hospital

73% in RDH – the only tertiary health centre in the Top End with neonatal intensive care capabilities

4% elsewhere -3 births occurred in flight, 1 on the tarmac of a remote airstrip and 1 interstate.

Preterm birth remote airstrip-2
Yes of course, this is exactly where we’d like to be setting up for a preterm delivery.

Nearly half of all preterm births which occurred in a rural hospital had been transferred from a remote community to a rural hospital instead of the tertiary centre. It is thought the rural hospital may have been chosen as a destination on occasions it was closer than Royal Darwin Hospital from the referral site and the long transfer was thought likely to end with an inflight birth. This reflects the decision making clinical crews have to be able to make on the run. Detailed midwifery and obstetric assessments and sound judgement are vital skills that the teams have to deploy when faced with the aeromedical retrieval of pregnant women in preterm labour.

Who went on the flights
79% of all retrievals in this cohort were conducted by a flight nurse/midwife alone; 15 (or 44%) of all preterm births occurred outside of any hospital (being a rural or tertiary hospital) with a flight nurse/midwife only crew. This certainly highlights the importance and requirements for ongoing education and training in midwifery, obstetric emergencies and neonatal resuscitation for our flight nurse/midwives plus our rural and remote health colleagues.

Neonatal resus eduation and training-2
Slightly less pressure here.

14% (n=42) of all preterm labour referrals included a CareFlight flight doctor + flight nurse/midwife mix, with 12 preterm births occurring prior to arrival to a tertiary health centre. A paediatrician/paediatric registrar went on 23 taskings (7%) and their skills were required in 5 cases where a preterm birth occurred whilst another 6 of these cases with a paediatrician/paediatric registrar resulted in the woman being discharged with no preterm birth occurring.

What about the transfer of women in labour after they’d had nifedipine? About half of the women were still contracting upon handover at the receiving hospital whilst 42% had stopped contracting upon handover. 13% of referrals of women in preterm labour delivered a preterm baby prior to arrival at a tertiary health centre despite tocolysis, which could reflect women presenting late in labour & nifedipine not being useful in these and other instances.

Birth outcomes
In aiming to facilitate preterm birth in a tertiary hospital, there will always be a proportion of women who are subsequently transferred and do not go onto give preterm birth. We had a discharge rate of 49% where no preterm birth occurred. Our findings are comparable to other Australian studies. One previous study reported 53% of women in Western Australia transferred by aeromedical retrieval were discharged without birth occurring2 and another study reported 46% of women from rural areas in New South Wales were discharged following transfer to a tertiary centre.5

Yet another study reported 42% of women were discharged without birth occurring following transfer and the authors suggested that remoteness was associated with increasing rates of antenatal transfer.4  This is evident in the results of our study as we found 4% of women were transferred two or more times during a current pregnancy, reflecting the remote nature of the area we service and the high risk obstetric population. We need to expect that in the interest of maximising outcomes for mothers and babies from rural and remote areas, facilitating preterm birth in a tertiary hospital will result in some unnecessary yet costly aeromedical retrievals.

Triage and priority coding

The majority of women were triaged and retrieved appropriately to facilitate aeromedical retrieval in a timely fashion to enable a preterm birth in a tertiary hospital (73%). Five out of the 11 preterm births in a rural hospital were initially planned for retrieval from a remote health centre to the tertiary hospital but were transferred to a rural hospital instead. This may have occurred as the aeromedical crew found the woman was in more advanced labour than anticipated and elected to choose the closer rural hospital. Other aviation factors such as adverse weather may also play a role in these decisions.

Thus triage and priority coding for women in preterm labour reflects accuracy in the need for prompt retrieval, but also sometimes later decisions by the retrieval team who are required to make judgements upon arrival as to whether to allow birth to proceed in an environment with limited resources or risk inflight birth. Decision making on triage and priority coding will always revolve around the facilities and skill of personnel at the referring site, distance, gestational age, cervical dilation, labour advancement and maternal and fetal risk factors.

Stuff this bit of research didn’t tell us

There were several limitations in our study, namely the small sample size and lack of stratification of obstetric risk factors. It was intended at the commencement of this study to report on the doses of nifedipine administered. However, due to lack of documentation and ability to clarify the doses administered, it was decided early in the data collection process to discontinue recording the doses. Thus it has been assumed the dose administered is in accordance with local clinical guidelines (oral nifedipine 20mg given 20-minutely to a maximum of 3 doses in 1 hour then 20mg 3 hourly)10. The doses of nifedipine actually administered may be different to that recommended and therefore the success of in-utero transfer may be dependent on the dose of nifedipine administered.

The Bit for the Fridge Magnet

So, the take home points when it comes to the aeromedical retrieval of women in preterm labour:

  • Prompt retrieval of women in preterm labour is vital to facilitate preterm birth in a tertiary health centre with neonatal intensive care facilities to improve neonatal outcomes or at least get the neonatal intensive care unit to the neonate in a timely manner;
  • Early and aggressive management of preterm labour with nifedipine improves the success of an in-utero transfer;
  • We have a high risk obstetric population in the NT – remember the importance of other preterm labour clinical guidelines such as the administration of steroids and IV antibiotics;
  • Send the right team at the right time. One member of the aeromedical retrieval should have an obstetric/midwifery background. It’s the detailed obstetric assessment which will assist a crew to make that decision of whether to stay and play or scoop and run, hopefully avoiding inflight birth and facilitating a successful inutero transfer to a hospital;
  • Ongoing regular education and training in neonatal resuscitation, neonatal care and obstetric emergencies is paramount for our flight nurses and flight doctors;
  • In the interests of improving maternal and neonatal outcomes, we have to accept that there will be some retrievals of women in preterm labour which weren’t required as a half of them will end up being discharged;
  • Flight crews and retrieval consultants make some tough decisions when it comes to the aeromedical retrieval of women in preterm labour…if only we could have that crystal ball. But at least we know we’re making the right decisions regarding flight crew mix, triage and whether to put a woman in preterm labour on an aircraft or wait on the ground for birth to occur.

And for more details I’ll just have to let you know when the publication hits the journals (very soon I hope …)



The staff in those photos are OK with those being shared.

The image of MKT airstrip is a Creative Commons one from flickr and is unchanged from the original Ken Hodge posting.


  1. Tara P, Thornton S. Current medical therapy in the prevention and treatment of preterm labour. Seminars in Fetal and Neonatal Medicine. 2004;9(6):481-489. doi:10.1016/j.siny.2004.08.005
  2. Akl N, Coghlan E, Nathan EA, Langford SA, Newnham J. Aeromedical transfer of women at risk of preterm delivery in remote and rural Western Australia: Why are there no births in flight? Australian and New Zealand Journal of Obstetrics and Gynaecology. 2012;52(4):327-333. doi: 10.1111/j.1479-828X.2012.01426.x
  3. McCubbin K, Moore S, MacDonald R, Vaillancourt C. Medical transfer of patients in preterm labour: Treatments and tocolytics. Prehospital Emergency Care. 2015;19(1):103-109. doi:10.3109/10903127.2014.942475
  4. Hutchinson F, Davies M. Time-to-delivery after maternal transfer to a tertiary perinatal centre. Biomed Res Int. January 2014:1-6. doi: 10.1155/2014/325919
  5. Badgery-Parker T, Ford J, Jenkins M, G. Morris J, Roberts C. Patterns and outcomes of preterm hospital admissions during pregnancy in NSW, 2001-2008. Med J Aust. 2012; 196(4):261-265.
  6. Barclay L, Kruske S, Bar-Zeev S, Steenkamp M, Josif C, Narjic C, Kildea S. Improving Aboriginal maternal and infant health services in the ‘Top End’ of Australia; synthesis of the findings of a health services research program aimed at engaging stakeholders, developing research capacity and embedding change. BMC Health Services Research. 2014; 14(1):241.
  7. Steenkamp M, Rumbold A, Barclay L, Kildea S. A population-based investigation into inequalities amongst Indigenous mothers and newborns by place of residence in the Northern territory, Australia. BMC Pregnancy and Childbirth. 2012;12(44): doi:10.1186/1471-2393-12-44. http://www.biomedcentral.com/1471-2393/12/44. Accessed August 13, 2015.
  8. Li Z, Zeki R, Hilder L, Sullivan E. Australia’s mothers and babies 2011 Perinatal statistics series no. 28. 2013. http://www.aihw.gov.au/publication-detail/?id=60129545702. Accessed August 10, 2015.
  9. Roberts C, Henderson-Smart D, Ellwood D. Antenatal transfer of rural women to perinatal centres. High Risk Obstetric and Perinatal Advisory Working Group. Aust N Z J Obstet Gynaecol. 2000;40(4):377-384.
  10. Alukura C. Minymaku Kutju Tjukurpa – Women’s Business Manual (6th Ed). Alice Springs: Centre for Remote Health; 2015

Once Bitten, When to Fly?

It is very exciting to introduce Tim Wallace, flight nurse from the Top End, on a topic sorely neglected for a website coming from Australia – animals that can kill you. Actually, perhaps Tim can introduce Tim. 

“When I was a researcher working for a haematologist, I wanted to be a paramedic, but I ended up as a pedantic number chaser driving ventilators (ICU nurse). So I went to uni again so I could be a paramedic. Then I got this job and now I’m studying midwifery (I’ve been a uni student for 9 of the last 15 years). I came to Darwin then left after a couple of years and went rock climbing for a year with my now wifey. I thought the grass was greener down south. It wasn’t. I like Darwin. Finally, I think cats are the only malicious animal.

It’s 11 p.m. one night, in the middle of the wet season and a referral comes in for a suspected snake bite in Bulman. What? You don’t remember where Bulman is? Perhaps refresh your geography here.

Here’s the stuff you find out straight away:

  • A 34 year old male has been bitten by something on the foot.
  • He presented around 1 hour before the phone call with a story of walking along the road and stepping on a snake that then bit him. Bearing in mind that an Indigenous man from a very remote area like this is probably very familiar with the characteristics and behaviours of the local wildlife, this man says he didn’t see the snake, but felt it and has some marks on his left ankle that could be puncture marks.
  • He walked to the clinic (1km) and since then has had the leg immobilised and a pressure bandage applied.
  • His observations are unexciting and he is completely asymptomatic of any of the obvious signs (e.g. bleeding from cannula sites) or often subtle symptoms (e.g. abdominal pain) that might be associated with a snakebite.

So what do you make of a story like this? Well typically in a case like this a lot of emphasis is placed on the story as there are a lot of variables (and ambiguity) associated with confirming a snake bite and predicting the clinical course, including:

  • What first aid has actually happened? Was it immediate or delayed, effective or ineffective?
  • Timing: while a bite from a brown snake can be almost immediately obvious, death adder neurotoxicity may be delayed as long as 24hours.
  • Syndromes of envenomation have very poor specificity in general (see ‘syndromes of envenomation’ table/picture)
  • You often see dry bites where the snake digs in with the fangs but does not inject venom.
  • Then there are stick bites, such as: did not see snake, but felt something while walking in the bush at night.

Let’s Talk Logistics

Back to our patient – how will we get there?

Bulman is ~550km as the Kingair flies and is exceptionally isolated and now has no emergency medical services (as they are all tied up with this case). The strip is unlit and not suitable for night landings. While it is possible to get in using the helicopter, there is a large band of storms between us and Bulman that means a bumpy marathon of a flight in what one of my colleagues calls the ‘vomitron’, stopping for fuel via a detour to the north of Kakadu on the way there and back.

tindal radar copy

Yeah. It’s not going to be easy.


Are the Snakes Dangerous?

Well everything in Australia is designed to kill you and the Top End is the most Australian bit of Australia. We have some awesome elapids (hollow fixed venom injecting fanged snakes) up here and snakebite is an increasingly common emergency presentation (as you will see from our data). Australia sees ~3 fatal snakebites per year + occasional significant morbidity (e.g. mechanical ventilation, neurological sequelae at discharge).

This is the only one I have seen in the Top End in the 5 years I’ve been here.


Most of the mortality is associated with the brown snake family whose victims classically present with a story of early collapse and go on to develop VICC (venom induced consumptive coagulopathy) and occasionally signs and symptoms of neurotoxicity. In the Top End, in addition to the western brown, the other problematic species are the myotoxic king browns (mulga snake), neurotoxic death adders and less commonly the mighty taipan (VICC, neurotoxicity). Many of our retrieval registrars come from countries with boring fauna and this topic is very exciting for them.

syndroms of envenomation copy
Not very specific really. (This table is from the Isbister paper mentioned below.)
playing with snake copy
Fun fact: the bite reflex of some snakes can remain intact for over an hour after death. This is me playing with a dead brown snake brought in by CareFlight (with a patient) before I was familiar with the case reports of envenomation from dead snakes …

Having posed this scenario to a few of the retrieval consultants at CareFlight they all placed significant emphasis on how convincing the story was and all offered varying perspectives on the priority of retrieving this man. Remote clinics use the ‘CARPA Standard Treatment Manual’ protocols for managing emergency presentations, and CARPA is quite clear about snakebite:

CARPA snakebite copy

And we can’t assume the RAN was comfortable by herself with this guy in her clinic.

Bulmanclinic copy
It turns out that the capacity to deal with a sick person might be more limited than the hospital …

Despite the rigid proclamations of the CARPA manual, I reckon there are unanswered questions about when (and if) patients who are suspected to have been bitten by a snake should be retrieved. As I have alluded to, confirming a diagnosis over the phone is difficult and a lot hinges on how convincing the story is. With this in mind we decided to try and arm ourselves with some hard facts, undertaking an audit of our retrieval database to quantify the existing situation around suspected snakebite retrievals.

Lane dead snake copy
Maybe there’s another time to take the ex-snakes back to the city? (And the patients, of course.)


Let’s Talk Numbers

Interestingly, the numbers of retrievals have increased somewhat since the last published data:

– Currie (2004) – 8.6 year sample – 13.6 aeromedical retrievals per year

– Our audit – 3.8 year sample – 30.2 aeromedical retrievals per year

Why? We’re just not sure.

When it comes to confirmed envenomation we get to a very select group:

– 3.5% (4 of 115 patients) – we’ve used antivenom twice in this period

The comparison? Well previously published data for northern Australia has quoted 5-23%.

Why are those numbers for confirmed envenomation lower in our stats? We don’t quite know that either.

Then there’s the when – is there any particular time of day when the calls come in? Well ~65% of retrievals occur at night – see the slightly busy plot of night retrieval timings

day v night copy

Of course, the timing also has some implications for our pilots.


Flying High

In the Top End strips vary from well serviced, long, sealed, well lit and fenced in with GPS approaches (eg. Gove, Groote Eyeland) to poorly lit, narrow, occasionally dirt strips that are actually primarily the homes of kangaroos and buffalo and only occasionally used to land aircraft. The lights in many remote strips are solar, so they are great at 11pm but generally a lot less bright by 3am.

Crucially, many of these strips have no GPS approach. Where there is a GPS approach, the avionics aid the pilot in landing. Where there is no GPS approach, the pilots do a ‘visual circling approach’. What does that mean for safety? Well night flying is 3 times more dangerous than the equivalent aviation work  in daylight hours. A visual circling approach is 25 times (!) more dangerous than a GPS approach. 25 times. (As a sidenote, helicopter EMS operations are also more dangerous at night.)

Perhaps the best insight for the aviation lay-person is to watch this video of a visual night time landing filmed by one of my colleagues on an after hours retrieval.

How were you planning to get there again?

Back to the Bitten

Back to our dude in Bulman. The retrieval consultant, in consultation with the logistics coordinator and flight crew decided that the the face of apparent low risk to the patient and massive logistical difficulty in getting to Bulman and risk to the flight crew, it would be reasonable to delay the retrieval until daylight. He was retrieved in the morning to Royal Darwin Hospital where the path lab confirmed that there was no envenomation.

 The Big Questions

So we’re left with questions that really matter (like all the best bits of research). My questions for anyone who wants to chip in:

  • Based on the apparently low morbidity/mortality associated with snakebite and low incidence of envenomation in our data, can we justify the frequently high risk (night) flying associated with retrieving the group of patients without clear evidence of envenomation?
  • Would it be reasonable to delay retrieval of patients of ALL patients with no clinical evidence of envenomation until the morning?

Who is shooting for that runway at night? Who is already planning what they’ll have for breakfast first?

Well the good news is this is an ongoing project, so I’ll be updating when we have a bit more information.



This post arose from work presented at this year’s ASA conference. Here’s a bit more reading so you can go back to the sources.

Allen GE, Brown SGA, Buckley NA, et al. Clinical Effects and Antivenin Dosing in Brown Snake (Pseudonaja app.) Envenoming – Australian Snakebite Project (ASP-14). PLoS One. 2012;7:e53188. doi:10.1371/journal.pone.0053188. 

ATSB. 2012. Visual flight at night accidents: What you can’t see can still hurt you. 

Currie B. Snakebite in tropical Australia: a prospective study in the “Top End” of the Northern Territory. MJA. 2004;81: No. 11/12.

Currie B. Treatment of snakebite in Australia: the current evidence base and questions requiring collaborative multi centre prospective studies. Toxicon 2006;48:941-56.

Isbister G. Snake bite: a current approach to management. Australian Prescriber. 2008;29:5.

Sutherland SK. Deaths from snake bite in Australia, 1981-1991. Med J Aust. 1992;157:740-6.

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