Bronchiolitis 2017: Winter is Coming

The bronchiolitis season is here! Well it is in Broome anyway.  Winter in the southern hemisphere is on the way and we are all ready for the coughing, coryzal, crackly chickens that will crowd into our cubicles soon.  Bronchiolitis is the bread ‘n butter of Paeds Emergency care – this is something we need to do well and know backwards to deliver great care.  Recent years have seen quite a bit of flux in the state of the evidence for managing our little wheezers.  If you live below the equator then you may be aware of the PREDICT crew [Paediatric Research in Emergency Department International Collaborative network].  This is an Aussie / NZ research group who put out evidence-based clinical guidelines and carry out research in kids ED practice.

Their 2016 AUSTRALASIAN BRONCHIOLITIS GUIDELINES were put out recently, just in time for the silly season.  [PDF version is here].  You can read either the long version, or the shorter practical version if you like your EBM spoonfed!

I thought it might be interseting to run throught he recommendations and see what is new, what is controversial and what we may need to change. So please do NOT consider this a cook book for the management of bronchiolitis – it is really just what I found interesting and may influence my practice.

CLINICAL EXAM & DIAGNOSIS: Bronchiolitis remains a clinical diagnosis.  It starts with upper respiratory symptoms and progresses to the lower tract on day 2-3.  These include cough, tachypnoea, increased work of breathing, recessions and the presence of crackles and wheezing.

Hot tip: I have developed a new test to clinically confirm bronchiolitis: THE TBA (Triple Blind Auscultation) All you need is 3 medical students / JMOs or other eager young Paeds learners.  You send them one at a time, at 5 minute intervals into the bay to listen to the babe’s chest.  You then sit them all down and ask them what they heard… if a heated debate breaks out about where the crackles were eg : left upper lung, right lower, both bases…. then it MUST be bronchiolitis!  This is how mucus behaves.  However, if they all agree the creps were only in the left base… think again.  [If you only have one student available – you can just send them back in 3 times, it is amusing to watch them debate their own findings with themself.!! ]  Sorry, cruel – but crucial to learn.

RISK FACTORS FOR SEVERE DISEASE:

• Preterm (gestational age < 37 weeks) – though some folk like to measure “age since conception < 48 weeks”. So if you were born at 36 weeks and are now 11 weeks old you are 36 + 11  = 47 weeks “post conception”.
• Age less than 10 weeks (which is similar to Post-conception age < 48 weeks.
• Failure to thrive
• Known congenital heart disease
• Chronic lung disease ( eg. bronchopulmonry dyplasia, lung disease of prematurity..)
• Congenital neurological disease ( I would include genetic disease such as Down’s etc)
• Cigarette exposure
• Being Aboriginal – though this is a crude risk factor in my opinion..

In Broome we tend to see quite a lot of kids with prematurity, FTT, cigarette exposure and being Aboriginal, so our threshold for admission may need to be set low.  Though I think we are best to do this assessment on an individual basis.

CHEST X-RAY:  Just DON’T DO IT!  If youthink the diagnosis is bronchiolitis after taking a history and examining the kid.  You do not think that the kid is overtly septic, and in need of source localisation. The please do not Xray them.  Sure – its just one Xray, hardly any radiation right?  Well there are 2 arguments against that logic.

1. As a policy, for the whole population we need to limit radiation exposure – and this is prime territory for achieving that goal without a loss in safety.
2. Several studies have shown that doing a chest Xray, leads to the domino effect of:  CXR = subtle consolidation = “maybe this is pneumonia?” = IV ABs = harm and unnecessary AB use.

So when is a CXR useful? Well pretty much never in the ED.  Sure some kids will ahve something else going on, but that is usually detected when they fail to follow the expected course on day 4 – 6.  This is best left to the inpatient team.  CXR up front is low yield and confuses the picture.

LUNG ULTRASOUND

No, you guessed right! It was not mentioned in the guidelines.  So this is my opinion! I love lung US in kids – it was what I spoke on at SMACC Mini last year.  However, the first rule of POCUS is this: have a clear question you can answer.  Ruling out pneumonia – LUS is pretty darn good.  Ruling in bronchiolitis, not so good.  There is a bit of data out there to show it is accurate [Basile et al BMC Paeds 2015].  However, it doesn’t add too much to our clinical exam and history. Remember LUS is very sensitive – you will see tiny subpleural consolidations in bronch – it would be easy to interpret these as “pneumonic consolidation” if your brain wanted to see that!  Same as CXR, there is a slippery slope into overtreatent here.  So you question should be one of “ruling out a proper pneumonia” if you feel the need to scan.

OTHER INVESTIGATIONS:

• Bloods: FBP, Blood cultures and EVEN the much hallowed CRP have NO role in bronchiolitis.
• Viral tessting: PNA, NPA, PCR…. these are not useful. However, we are often asked to do them to allow our wards to group inmates by species.  The new guidelines state clearly that we should not be “cohorting” kids based on PNAs [Grade C rec] so I think we can stop doing this unless the teaam really want it for other reasons / research.
• URINE MICRO:  this is a tricky one.  An oft asked, but rarely answered question.  The guidelines say we MAY consider it in infants < 2 months with a fever  > 38 degress. This is the same group I am stil doing a septic work up for anyway, so do it for that reason.  Be aware that there is a reasonably high rate of “false positive” urine cultures in kids with clear URTI and bronchiolitis.  Catching that golden fluid may be simply confusing the picture in kids with clinical bronchiolitis over 2 months of age.

OXYGEN… 92%.

92% oxygen sats is the magic number.  This is lower than I see a lot of our team accepting before we commence oxygen.  The 92% is qualified as “persistently below 92%” – given how often these kids plug & unplug airways.  They are saying that we should wait n see, rather than react to momentary desaturations.  They also recommend stopping oxygen if SpO2 is higher than 92% – this would require frequent attempts to wean the O2.  IN short I think there is a growing acknowledgement in Medicine that OXYGEN is not benign.  We should use it sparingly.

Now how should we deliver this oxygen?  well the old standard is simple “nasal prong O2” … but there is a new kid on the block.  I will dive a little deeper into HFNCs [heated, humidified, high flow nasal cannulae.. HHHFNC]

HHHFNC OXYGEN

I have noticed a trend over the years with bronchiolitis… nothing works.  Every now and then a new hero is put forward, we want it to work, we expect it to work, we hate to see thse poor little tikes suffering away as we stand by the bedside with not an arrow in our quiver other than the passage of time…. this last season’s hero was HHHFNC.  Quite an acromyn!  Recently I haev seen this started in the ED for kids with increased work of breating despite normal oxygenation on traditional NCs.  Is this the right thing to do?

The guidelines are clear, sorta… “HFNC CAN be CONSIDERED in INPATIENTS with HYPOXIA (SpO2 < 92%).  Do not use it in kids with higher sats.”  That sentence contains a few qualifiers!  Basically there is very little good quality data to support the routine use of HFNCs for any clinically / patient-centred outcome.  BEWARE – there is also little safety data on these devices.  So we just don’t have the evidence either way.

Here is how I think we should practice (pure opinion): give oxygen via traditional NC – these are cheap and easy, can be used in a wide range of settings, training is not too onerous. I don’t think we should be using HFNC in the ED ever really, unless we are en route to ICU otherwise.  If a kid has clearly failed on traditional NC after a decent duration (hours, not minutes) on the ward -then it may be worth a go on the HFNC.  If they are clinically deteriorating to the point where invasive ventilation is being considered – then HFNC may save a few, but don’t relax just yet!

I think each department needs clear parameters to trigger the use of HFNC – I really don’t enjoy debating each case at the end of the bed.  This is simply not good medicine when we are dealing with such a common problem.

HYDRATION:  NG vs. IV

Hydration is one of the key principles of successful management in bronchiolitis.  We are dealing with little people, breathing fast, working hard and with limited capacity to increase oral fluids. The best hydration strategy is the one which works!  In mild cases – smaller, frequent feeds are fine. However, in the kids who need our help should we go with the NGT or IV as first line?

When we think about acute gastroenteritis we tend to go with NGT.  There is good data around its safety and efficacy.  However, for bronchiolitis IV seems to be more entrenched in practice.. at least it is where I work.  The evidence suggests that they are equally good. But… remember that these are often chubby tots, IV access is tricky at times.  Oakley et al [Lancet 2012] found “first pass success” was 85% for NGT  vs. 56% for IV. So I reckon that unless there is another indication to place an IV, NGT seems like a good opening gambit for kids with clear bronchiolitis.

There is a specific recommendation to AVOID any hypotonic fluids if you are using an IV hydration strategy.  And the goal is somewhere between 60 – 100% of maintenence rate.

JUST SAY “NO” TO DRUGS

I will run through this list in quick time, as the data and recommendations are pretty clear.

• Steroids – NOT indicated
• Adrenaline – IV, IM or nebulised… no, no, no
• Hypertonic saline – probably not. This remains an open question. Watch this space. Not for prime time.
• Antibiotics (any kind) – no. Resist the urge to treat the perihilar consolidation that turned up on the CXR that you should not have ordered!
• Antivirals – not helpful, expensive and not available where I work.

Beta2 AGONISTS

This is a bit more murky for me.  The guidelines are very clear that salbutamol / albuterol offer no benefit and possible harms to children under 12 months of age.  That is fair, makes sense and is consistent with current practice.

But what about the older kids?  The second year, particularly kids aged > 18 months are starting to get into the territory of asthma, viral-wheeze and the benefit starts to potentially increase.  There is a real dearth of good data in this age group.  Studies are underpowered, heterogenous and conflicting.

My practice has been to try them, at a decent dose, as a “trial” in the ED and watch them closely for any signs of improvement.  This IS NOT supported by the literature it would seem.  I sense a change coming!

SUCTIONING

A lot of the Paeds ED folk that I have learned from swear by nasal suctioning!  The drainage of boogers seems to provide good relief, facilitate feeding and decrease work of breathing. However, the trial data is not so clear.  Superficial suctioing seemed benign, however there was evidence of harms from deep nasopharyngeal suctioning.   So if you are a “sucker” – be a superficial one!

NORMAL SALINE NOSE DROPS

I have been writing this up as a routine since I was a PAeds RMO around the turn of the millenium.  NEver really questioned it.  I tell parents to do it to “clear a passage” prior to feeding in the obligate nose breathers full of crusty boogers.  The data is essentially non-existen in either direction.  So should we do it?  Well, it does give us something to do & amuse us whilst Nature takes care of the cure.. [Candide] Or to put it another way: “suck it and see” – if it helps, carry on.

WASH YOUR BLOODY HANDS – this is how we spread this disease… and others. You do not need evidence, just soap!

That is a wrap.  All the guidelines are of course – guidelines.  These are a prescription for how to run an ED or ward.  The patient and family in front of you all come with specific quirks and questions. We are clinicians – we need to treat them as individuals.

This disease is one where the social background is crucial to the management.  The single mum with 3 kids and a sick infant needs more help than the professional primip with grandparents on autodial.

Be prepared to do the best we can in the face of the winter tide of mucous.

If you prefer your Bronchiolitis education in an audio format and have yet to check out the excellent PEM Playbook podcast by Dr Tim Horeczko then do yourself a favour – pop over to the blog and listen.

Comments, queries and concerns are always welcome

Casey