Are you thinking what I’m thinking? – Assessing response to inhalers in the wheezy child

Imagine that you’re in a training post and working in an acute paediatric setting.  A nurse gets your attention and says, “Would you have a listen to this child please?  They are due their salbutamol but I wonder if they are ready to space*.”

* Increase the interval between inhalers.

Most of us have heard those words or something very similar.  I suspect that most of us are never actually taught exactly what we should assess when reviewing a child post salbutamol.  We are making assumptions and reverting to our safe place of “more is more” when it comes to clinical information.  What is also interesting is that a large number of clinicians feel that auscultation is not the most important part of the assessment.  Many feel that the auscultation bit is positively unhelpful when reassessing a wheezy child.

So, what is the deal?  Does the noisiness of the wheeze matter after the initial assessment?

Let’s consider a case.  Three year old Adam has developed a wheeze after four days of having a cold.  He didn’t have any treatment at home.

When you clinically assess Adam, he is snotty but looks well and is hydrated.  He is sat on his parent's knee, playing with his favourite soft toy – a ragged bunny rabbit covered in drool and snot.  You can see from where you sit that he has increased work of breathing and you can hear a quiet wheeze.

On closer physical examination you see moderate intercostal recession and tracheal tug.  On auscultation there is a loud wheeze throughout his chest.  There are no focal signs.  Other than signs of an uncomplicated URTI, examination is normal.

What is the diagnosis?

Adam is too old for bronchiolitis to be a real possibility.  In any case the onset ofthe wheeze very much goes against bronchiolitis as a diagnosis. (1)  Asthma is also very unlikely.  This is his first episode of wheeze, he is three years old and there is a clear viral trigger.  Viral wheeze is the winner of the “what is the likely diagnosis?” competition?

How should Adam be treated?

Viral wheeze is the poor cousin of the childhood wheeze family.  Very little guidance exists compared to Asthma or bronchiolitis.  There are plenty of RCTs but these tend to focus on wheeze in certain age groups and avoid the issue of viral wheeze vs asthma (or multi-trigger wheeze).

The only uncontroversial treatment for viral wheeze is beta-agonist therapy (e.g. salbutamol).  Regardless of you views on steroids and montelukast as rescue therapy for acute viral wheeze, beta-agonists are the only intervention that will have immediate effect.

Oral steroids might be used for a child like Adam but the evidence for this is conflicting and confusing.  The latest research supports a practice of reserving steroid use for more severe cases and those in which response to salbutamol is poor. (2)

There is no consensus on how many puffs of salbutamol you should give a child such as Adam.  10 puffs of salbutamol via a spacer is what many would recommend.  What happens next is the more uncertain element.  The main aims of the game are to make Adam feel better and to make sure he is clinically safe.  How we assess all of that comes back to the original question.

How do we assess response and improvement (in viral induced wheeze) following beta-agonist treatment?

There are actually several ways of doing this.  There is no absolute consensus on what measures should be used and, as usual, in that situation, there is a broad spectrum of practices involved in what gets assessed and what gets particular weight put on it.

Let’s look at each option and think about the pros and cons of each.

The noise

Wheeze is a musical sound like any other.  The bronchial tree happens to be the musical instrument.  Anyone who has ever tried to play a brass or wind musical instrument will tell you that it’s not how hard you blow that matters the most.  Wheeze is subject to the same musical rules.  The amount of air being moved, the constriction of the airways and the pattern of breathing will all have an effect on the loudness of the wheeze.  Wheeze can be absent in children with bronchospasm.  It can be louder as the child improves.  Wheeze can persist even when all other signs and symptoms are resolved.

Wheeze is a hugely valuable clinical finding.  It tells you that you are dealing with a wheezy illness.  That limits the possibilities and it is important to have definite wheeze at some point when diagnosing an illness (e.g. asthma) that has wheeze as a primary symptom.  The significance of what happens to the wheeze once treatment has begun is less certain.

Auscultation can be misleading in other ways.  Focal crackles are very common in viral induced wheeze.  This can create anxieties about the presence of secondary infecton.  The good news is that wheeze is a strong negative predictor of bacterial LRTI. (3)  If the child looks really well, a few crepitations in one zone is a poor indicator of pneumonia.

What is certainly true is that auscultation is essential if there is any sign of deterioration (worsening recession or child becomes more tired) as this could indicate a number of things.  Even then, the wheeze will probably not tell you what you need to know i.e. has something else happened such as a pneumothorax or a collapsed lung.

Another issue with using auscultation findings is that this only happens when a clinician is present.  When the child is at home, this is not part of the assessment.  It could be argued that the implication that auscultation is important undermines the confidence of a parent or carer who is required to make ongoing decisions about whether the child can continue to be treated at home or needs to return for further medical assessment.

The visible signs of abnormal breathing

The visible effort of breathing is a more logical measure of the severity of bronchospasm.  Look at respiratory rate, recession, tracheal tug and use of accessory muscles.  The severity of these signs, regardless of the degree of wheeze, are more likely to indicate what treatment is needed.

There are three important caveats to this.  Firstly, if a child is becoming tired, these signs might become less apparent.  Improvement should be accompanied by an increase in activity if it is to be truly considered a sign of resolution of bronchospasm.  Secondly, the child with neurological or muscular abnormality will have less visible signs.  These children should be treated in the knowledge that what we see may not reflect how bad the problem really is.  Thirdly, the adolescent is more likely to be having a more severe episode with minimal visible signs.

The overall appearance and behaviour of the child

The appearance and behaviour of a child are measures of efficacy of breathing.  Essentially, they tell us about what the problem means for the all-important end organs.  If a child has wheeze but is running around, the end organs are telling you something.  If the child is subdued and inactive, this is important clinical information.

What next for Adam?

After being given salbutamol, Adam is running around and playing.  He has no recession and no use of accessory muscles to breathe.  He chatters away with no signs that he is short of breath.  Do you need to listen to his chest to decide what to do with him next?

The bottom line is that whether or not you auscultate the chest when reassessing a child with viral induced wheeze, you probably shouldn’t put too much emphasis on what you hear if there are visible signs of improvement.  As is so often the case in paediatrics, the take home message is simple: look at the child.

Edward Snelson
Mill Town Keeny

@sailordoctor

Disclaimer: If a wheeze falls in the forest and never causes other signs or symptoms, was it ever there?

References

1. Snelson E., A simple model for understanding the causes of paediatric wheeze, Paediatrics and Child Health, Volume 29, Issue 8, 365 - 368
2. Foster S et al, Oral prednisolone in preschool children with virus-associated wheeze: a prospective, randomised, double-blind, placebo-controlled trial, The Lancet Respiratory, Vol 6, Issue 2, P97-106, Feb 01, 2018
3. Shah SN, Bachur RG, Simel DL, Neuman MI. Does This Child Have Pneumonia? The Rational Clinical Examination Systematic Review. JAMA. 2017;318(5):462–471. doi:10.1001/jama.2017.9039