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.
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.
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.
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.
- 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
- 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
- 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
- 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
- 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.
- 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.
- 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.
- 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.
- 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.
- Alukura C. Minymaku Kutju Tjukurpa – Women’s Business Manual (6th Ed). Alice Springs: Centre for Remote Health; 2015