Thursday, 23 July 2015

Feed histories in refluxy babies

Over feeding?  Is that really a thing?

One of the questions that I asked most often is “where do I start when treating reflux in babies?”  This assumes two things.  The first assumption is that it is reflux that you are dealing with and second is that you want to treat it.  Each of those assumptions is worth articles of their own, so I may come back to those two issues at a later date.  However, if we are going to start our treatment somewhere, let’s start as always, by doing as much nothing as possible.  The place to start is by taking a feeding history.

I would like to say now that I do not like the term over-feeding as I feel it implies blame if it is heard in a critical way.  I don’t have a better term (yet) and it is commonly used so it will have to do.  Over-feeding is the phenomenon seen in many babies which involves them taking considerably more milk than they need or can keep in their stomachs.  As a result of this their stomachs are distended enough to cause them pain and are likely to have distressing regurgitation.

Why does this happen in some cases?  Because: the understanding between a baby and the person feeding them is that if the baby cries, that might be because they are hungry.  As a result, they are offered a feed.  Babies are fairly reflexive about feeding and so may suckle even when not hungry, leading to overfeeding.  Being overfull, they will find that they are not comfortable.  They need to let someone know about this unsatisfactory situation and so they cry, at which point someone may offer them a feed.  This is called the feed-cry cycle.

The NICE guideline ‘gastro-oesophagealreflux disease (GORD) in children and young people’ (NG1) acknowledges the possibility that a reduction in feeds might help in their recommendations:

In formula-fed infants with frequent regurgitation associated with marked distress, use the following stepped-care approach:
  • review the feeding history, then
  • reduce the feed volumes only if excessive for the infant's weight, then
  • offer a trial of smaller, more frequent feeds (while maintaining an appropriate total daily amount of milk) unless the feeds are already small and frequent, then
  • offer a trial of thickened formula (for example, containing rice starch, cornstarch, locust bean gum or carob bean gum). (1)

The devilment is however most definitely in the detail…
If we are going to be scientific about this we need to define our terms.  What is an excessive volume of feed?  Ooh, I know the answer to this one…  Nobody knows.  What we do have is a consensus that approximately 150ml/kg/day is a ‘normal’ amount.  The thing about norms is that they tend to have standard deviations and no one knows what that number is either.  So where does that leave you?

I have read through the detail of the full NICE NG1 guideline in the hopes of finding the answer and there is no centile chart of feed volumes, since one doesn’t exist.  Instead we are left with the responsibility of deciding for ourselves.  My approach is to take the feed history and calculate the volume of formula milk fed thus:
  1. No of fluid ounces taken on average per feed x 28 equals mls of milk per feed
  2. mls of milk per feed x average daily number of feeds equals daily intake in mls/day
  3. Daily intake divided by weight (Kg) gives feed volume by weight in mls/Kg/day

If I believe that the child has GORD and the feed volume is quite a lot more than 150ml/kg/day then I will recommend a trial period of reducing the daily feed volume to 150ml/kg/day and make sure that no one feed is greater than 30ml/kg.  If they get better, it might be by random fluctuation or it might be my intervention.  Either way the child is better.  If they don’t get and stay better, I move on to the next intervention.

You might notice that I still haven’t given you a number that would qualify as “excessive for the infant's weight.”  Well spotted.  Please let me know if you find one that is evidence based.  In the meantime I will continue to believe that my number is correct.

Edward Snelson
Senior Spitilomancer

Disclaimer: You can't trust my number.  I came up with it by throwing three darts at a dart board.  It was a very good score though.

If you found this helpful you might also like to read:

Why I need GPs to be medical leaders (Easter egg - GORD in babies)

  1. NICE guideline ‘gastro-oesophagealreflux disease (GORD) in children and young people’ (NG1) 

Saturday, 18 July 2015

Do I have to? (measuring oxygen saturation in bronchiolitis)

When something tells you what you already know...

I was recently contacted by a GP who wanted to know which oxygen saturation probes we use for babies in the Emergency Department where I work.  They were being proactive and trying to equip themselves to meet all the recommendations of the NICE Bronchiolitis guidelines.

[It is worth mentioning here that the understanding of the term bronchiolitis varies around the world.  In this context, it refers to a viral lower respiratory tract infection (in a child usually under the age of 12 months old) which has caused inflammation and secretory mucous plugging in the airways.  Typical features are cough, coryza, wheeze and difficulty feeding.  Bronchiolitis does not respond to inhalers or other medication.]

When I read the guideline, I was struck by a couple of things.  The first is the idea that the child with bronchiolitis would have to look seriously unwell to a General Practitioner before they decided to refer.  Now I know that unwell is a subjective term but my experience is that the vast majority of GPs have an excellent antenna for what I would call an unwell child.  If a child with bronchiolitis looks ‘seriously unwell’ and is in a GP surgery they may well need an emergency ambulance.  I think that the wording in the guideline is probably trying to recognise the fact that a child with bronchiolitis is not technically well.  The may not be well but they should look well.  If not, I would refer.

The next thing that struck me was the issue of persistently low oxygen saturations as a decider for a referral.  Measuring O2 saturations in General Practice is going to be a real challenge.  Most GPs will not have access to suitable probes.  Even if available it is often difficult to get a meaningful reading, especially when a child is snotty and angry.

Now don’t get me wrong, O2 saturations are very important in bronchiolitis.  I use them all the time to decide whether the child should have supplemental oxygen.  It seems like a good way to decide that.  As a doctor in a hospital, when I see a child with bronchiolitis I only really have four questions:
  • Does this child have uncomplicated bronchiolitis?
  • Does this child need feeding support?
  • Does this child need supplemental oxygen?
  • Does this child need resuscitation or critical care?

Back to the GP surgery, the real question is, will a baby with bronchiolitis who persistently has O2 saturations of 91% and below have none of the other features that trigger a referral for hospital inpatient assessment?  In all honesty (and as you can imagine, I am pretty keen not to make myself a target here) I think not.  I have no grade A evidence to back this up so instead I have a factual statement and an opinion:

Another question is: what is of most value in a primary care assessment of a baby with bronchiolitis?  Time is limited and best spent on identifying the features that identify the front of the problem not the back.  If respiratory distress, poor feeding and looking unwell are present before sats drop consistently, then ask those questions first.  Also ask whether this is another condition such as a cardiac defect masquerading as bronchiolitis.

With regards to the second question, I have asked a few people what they do if they can’t get a sats reading and the answer tends to be the same: look at the child.  When it comes to oxygen saturation, even in some quite acute situations it is additional rather than mandatory information.  A blue child is a blue child.  The O2 saturations are a useful number but I am not going to stand there for five minutes trying to get the probe to read properly before I do something about it.

What about the guidelines though?  We all have to follow guideline don’t we?  Of course you do.  If you have measured the sats and they are persistently below 92% in air, you should refer the child.  This assumes that the child did not otherwise need referral  and you still chose to measure sats.  The NICE guideline does not require you to measure saturations in bronchiolitis, it only requires you to act on the number if you have measured it.

Edward Snelson
Member of a society so secret even I can't remember what it is

Disclaimer: My experience is not transferable as I use a medical tricorder to measure oxygen saturations

Saturday, 11 July 2015

Super-size me - Stratified safety netting

“The delivery of good medical care is to do as much nothing as possible” Law 13 of ‘The House of God’ by Samuel Shem (1)

As clinicians involved in the care of children, we have to do everything in our power to reduce unnecessary tests and treatments.  This can be perceived as inaction but those who know better recognise that there are two important interventions that are incorporated into every patient contact – observation and safety netting.  In paediatrics (including in General Practice and in Emergency Medicine) we rely on a watchful waiting approach to most childhood illness.  When that period of observation occurs in the child’s home, safety netting advice is not just an add-on, it is an intervention in its own right.

Why then do we treat is as a one-size-fits-all part of the consultation?  Why don’t we treat it with the importance that it deserves by quantifying it?  I suspect it is because we don’t know how to measure it.  So, to take this concept further we must first understand what makes up safety-netting.

I was first introduced to the concept of safety netting though the writings of Roger Neighbour.(2)  He wrote that safety netting was built around three questions:
  • If I’m right, what do I expect to happen?
  • How will I know if I’m wrong?
  • What would I do then?

I often ask my junior colleagues what they say to parents at the point of discharge and although they may not have heard of this model, they will tend to cover all of these three aspects leading me to the conclusion that to do so is fairly intuitive.  Where it goes wrong is that it often tends to be generic when it should be specific.

Taking the idea that safety netting is an intervention in its own right I would suggest that as well as making sure that the three dimensions are all present, we need to get the scale correct.  Think of it as you would the treatment of an acute asthma attack.  The British Thoracic Society (BTS) sets out definitions for moderate, severe and lifethreatening episodes* and gives clear guidance about the drugs, doses and routes indicated in each scenario.  I believe that we should consciously be doing the same for safety netting ill children.

* Note the comparison to fast food chain sizes – instead of small, medium and large, we have regular, large and super-sized.

I’ll give you an example.  When I see an ill child and discharge them with advice I could stratify my safety-netting as follows:

Level 1 (e.g. child with temperature, coryza and is running around and playing)

"Your child has a viral illness and at the moment they are reasonably well despite this.  Some children do become more unwell during a viral illness but most will be fine if their discomfort is managed with medicines such as paracetamol (acetaminophen) and they are given adequate fluids to drink.  If they seem to be significantly unwell despite this then further advice should be sought at that stage.  Your child certainly has nothing to suggest meningitis or anything similar at the moment but here is a leaflet showing the things that would suggest such an infection.  We like all parents to have one of these for information."

Level 2 (e.g. Child who is alert, had a high temperature earlier but now looks really well)

"Your child has a viral illness and although they have been unwell with it they have responded nicely to fluids and simple medicines.  As a result there is no reason at the moment to suspect any other infection. As long as they continue to do so they could be expected to be as they are for a few more days.  Occasionally a child will go on to get a second infection on top of the viral illness so if your child looks quite unwell despite the medicines, becomes floppy, lethargic or is unable to drink you should make sure that you get your child seen again fairly urgently.  Here is a leaflet…"

Level 3 (e.g. Child who has clear signs of viral upper respiratory tract infection but no red flags symptoms.  Despite this they are at the upper end of how unwell children are with a viral URTI.)

"Your child has a viral illness and although they are unwell with it I am sure that there are no signs of other infections such as pneumonia or meningitis at the moment.  When children are unwell with viral illnesses they are more prone to getting those more serious infections though so if they become any more unwell than they are now they should be reassessed urgently.  If a child has a straightforward viral illness their discomfort will usually respond to medicines such as paracetamol and they will usually drink enough to pass urine regularly.  If your child looks quite unwell despite doing these things, becomes floppy, lethargic or is unable to drink you should make sure that you get your child reassessed urgently.  Here is a leaflet…"

Hopefully, you can imagine all three children in your head.  There is a big element of this that doesn't translate well into written word.  With so much communication being non verbal, a script is only a taste of this concept.  When I give my super-sized safety net advice, I use every non-verbal cue at my disposal to communicate the importance of what I say.  I hope that this approach to safety netting will ensure that the children most at risk of secondary infections have had the level of illness taken into account and thus receive the appropriate level of the intervention.  This might address one of the common pitfalls of safety-netting which is that parents sometimes come away with the impression that the doctor thought that nothing was wrong and so were reluctant to seek further assessment when the situation changed. (3,4)

So, next time you are safety netting a child at the end of an encounter, think of it as an intervention and decide on whether it should be a small, a medium or a large one.

Edward Snelson
Available to crew any good sized Mediterranean yacht

  1. Samuel Shem. The House of God. 1979. ISBN 0-440-13368-8.
  2. Roger Neighbour. The Inner Consultation. 2nd edition 2004 ISBN 10: 1857756797

Saturday, 4 July 2015

More?!? The Salbutamol Paradox

Dosing in children is quite frankly a nightmare.  While formularies such as the BNFc are excellent and easy to follow, there are always pitfalls.  There are maximum doses and there are age related doses, weight related doses and doses that are the same at any age or weight.

Despite all the potential to get it wrong, I am pleased to report that with very few exceptions, the children presenting to the Paediatric Emergency Department where I work are prescribed the correct doses of their medicines.  This is less often the case for inhalers.  It is not uncommon for me to send a 2 year old child home with instructions to continue salbutamol (via a spacer of course) four puffs four hourly and then have another health care professional advise the parent that this is too large a dose.  If the next healthcare professional that they see applies the 'smaller children need smaller doses' principle, the parent may be advised to reduce the amount of bronchodilators to two or even one puff every four hours.

I can see the logic there.  Why would you give more puffs of inhaler to a 2 year old than a 20 year old?  Inhaled bronchodilators are a perfect example of why therapeutics in children is not governed by one or two simple principles.  In the case of treating wheeze in children it is not the size of the child or the age of the age of the child.  Once more we must turn to physics for the answer.

Delivery of the bronchodilator to the airways of the lung works best when you have good inspiration, without turbulence, through open tubes.  In a two year old, you have none of these things.  Crying looks as though it should do the job but studies have shown this to be wrong.  Aerosol deposition during crying is poor.  Even if the child is complying, they are still a victim of physics.  The flow through any tube is inversely proportional to the diameter to the power four.  This means that if the wheeze has halved the diameter of a bronchus, one sixteenth of the air will get through.  If there is turbulence of that air flow then the flow is at least halved again.  So, assuming mucous is rattling around, it doesn't take much bronchospasm to reduce the air getting to your alveoli substantially.  When you are two years old, your trachea is about 6-7mm internal diameter and your bronchi even smaller, so any reduction from bronchospasma and mucous is going to have a huge impact.

Suddenly four puffs doesn’t seem like a lot to give.  I wonder if we studied the salbutamol paradox properly if we would find that there is an argument for age banding salbutamol reliever puffs so that we give even more to the under 5 year olds as a standard reliever dose.

Edward Snelson
Using Real Science to save small lives

Disclaimer:   None of the children in medical research have ever consented to being a point mass in a vacuum. 

The Salbutamol Paradox is based on the ladder paradox, a physics thought experiment that involves getting something that seems too big into what appears to be too small a space.  Just like the ladder paradox, the salbutamol needed for a child's wheeze goes up substantially as the pace of the clinical scenario increases.