Do you anaesthetise this snotty child?
"Hi my name's Will, I'm your anaesthetist today, I've just come to talk through the anaesthetic plan if that's alright. Who's this then?"
'Hello, this is Billy and we're having our tonsils out today aren't we bub.'
Billy sneezes.
"And how long has Billy been sneezing?"
'Ah he's had a rotten cough and a cold for about three days now.'
"Any fevers?"
'Yesterday, but it's settled now. Still has a cough mind you.'
Uh oh.
It's one of the trickier decisions to make as an anaesthetist, do you go ahead with this elective paediatric surgery or reschedule for when they're better?
Hopefully this example is fairly straightforward - Billy's not having his tonsils out today - but what about those kids that are a 'bit' snotty, or those that are always snotty, or those who are catching every virus going because their tonsils are the problem and the only way to make it stop is to take them out and they've already been cancelled five times and please just take the damned tonsils out!?
Not so easy.
If only there were some decision tool to help us...
What's the big deal?
You'll probably know from personal experience that when you have an upper respiratory tract infection, everything becomes vastly more irritating to your throat and lungs, and that's before you add in the stress of surgery and anaesthesia.
If you don't have an upper respiratory tract infection, your risk as a child of having a perioperative respiratory problem sits at around 10 to 15% as a baseline.
If you throw an URTI into the mix, you bump that up to 30%.
What do we mean by 'perioperative respiratory adverse events'?
This is literally any issue that affects the respiratory system between induction of anaesthesia and discharge back to the ward from recovery.
It's a broad term that includes all the terrifying stuff that keeps us up at night:
- Breath holding
- Laryngospasm
- Bronchospasm
- Desaturation
- Severe persistent cough
Why do we worry about them?
Well not only are perioperative respiratory adverse events hardly conducive to a relaxing day at the office, they also contribute to:
- Needing to abandon the case
- Aspiration
- Airway obstruction
- Prolonged oxygen requirement
- Reintubation
- Emergency admission to intensive care
- Longer hospital stay
- Death
So yeah, not to be sniffed at.
What is an URTI?
We know one when we see it, but it's not exactly easy to give an exact definition.
What are the symptoms?
- Sore throat (or scratchy throat)
- Sneezing
- Rhinorrhoea
- Nasal congestion
- Malaise
- Cough
- Fever over 38°C
Two of the above constitutes an URTI.
What are the common causes?
- Rhinoviruses
- Respiratory syncytial virus
- Influenza and parainfluenza
- Adenovirus
- Metapneumovirus
- Coronavirus
RSV is the commonest cause of severe viral illness in children, and we think it is so sensitising to bronchospasm that it can contribute to the development of asthma as well.
The vast majority of the time they get better with ice-cream and television, as the child passes it onto their parent to take to work with them.
This usually isn't a huge deal, unless you've got a child needing an operation and today is the only day you can make it work, and you've driven forty miles to the hospital, and your kid is fasted and very cross.
Given the average three year old has eight URTI's a year, it's hardly surprising that this situation arises fairly frequently.
Symptoms tend to be worst at around day 3 and the overall duration is usually a week to ten days when you're talking about a common viral cold. Of course there's always the risk of superadded bacterial nonsense to consider as well.
How do bacterial complications of URTIs tend to manifest in children?
- Acute otitis media
- Sinusitis
- Pneumonia
Why does it cause a problem with anaesthesia?
Whatever the cause, the effect is that the airways become ultra-sensitive or hyperresponsive due to the acute inflammatory process that the immune system has launched to kill the trigger.
- Increased mucus production
- Vasodilatation and nasal congestion
- Tracheal oedema
- Immune cell infiltration into the mucosa and smooth muscle
All of these make the airway muscles more twitchy, responding to even the slightest irritation with profound bronchospasm or laryngospasm.
If you already have a lung condition such as asthma or cystic fibrosis, or were born prematurely, this compounds the risk of a problems developing even further.
Furthermore, you've relaxed the respiratory and abdominal muscles, and if they've had abdominal surgery they're going to be splinting their abdomen and taking much shallower breaths.
So the child is likely already not going to be breathing as effectively anyway, and that's without a hyperreactive set of lungs to complicate things further.
Imagine trying to breathe through a drinking straw while somebody punches you in the stomach.
What did the APRICOT study show?
This was a large European study that found:
- Children with an URTI in the two weeks before surgery had a relative risk of 2.82 of severe respiratory badness*
*Perioperative bronchospasm, laryngospasm or stridor.
So who's at risk?
As soon as you see the word risk, start thinking in terms of patient factors, anaesthetic factors and surgical factors that contribute to the patient's risk profile.
Patient risk factors
- History of prematurity (especially if bronchopulmonary dysplasia)
- Age <4 (especially <1)
- ASA 3 or worse
- Respiratory comorbidity (asthma, bronchiectasis, cystic fibrosis)
- Neuromuscular comorbidity (cerebral palsy, muscular dystrophy)
- Cardiac comorbidity
- Obesity
- Family history of hay fever or atopy
- Nocturnal cough
- Sleep disordered breathing
- Smoker in the family
Anaesthetic risk factors
- Using an endotracheal tube
- Experience of operator
Er.. that's it really.
Surgical risk factors
- Any airway surgery
Again, pretty much it for now.
Can I use a calculator?
Of course you can, here's the COLDS score, compiled in 2014 and gaining increasing traction as a useful guide as to whether you should be cracking on or sitting tight.
The COLDS Score
There are five domains:
- Current signs and symptoms
- Onset
- Lung disease
- Device (airway)
- Surgery
Each domain wins either 1, 2 or 5 points, giving a total score of 5 to 25.
Current signs and symptoms:
- 1 point for no symptoms
- 2 points for mild rhinorrhoea or sore throat, sneezing or a dry cough
- 5 points for green discharge, wet cough, fever, bad lung sounds or lethargy
Onset:
- 1 point for more than 4 weeks ago
- 2 points for 2-4 weeks ago
- 5 points for within the last two weeks
Lung disease:
- 1 point for no lung disease
- 2 points for mild asthma, snoring or passive smoker
- 5 points for persistent asthma, OSA or pulmonary hypertension
Device:
- 1 point for facemask or other
- 2 points for supraglottic device
- 5 points for tracheal tube
Surgery:
- 1 point for non airway surgery (such as grommets)
- 2 points for minor airway surgery (such as tonsils, dental extractions and flexible bronch)
- 5 points for major airway surgery (such as max fax and rigid bronchoscopy)
If you score 5 in any domain, you need seriously good reason to press on with the operation.
The issue that immediately jumps to mind is by that logic this score implies you should never proceed with a tracheal tube as that immediately scores you five points in a single domain.
Presumably the author of this score is expecting a modicum of common sense peppered with a dash of pragmatism.
Does it work?
Maybe.
It's quite tricky to test as you might imagine, what with the enormous variation in symptoms and severity combined with all the different surgeries, anaesthetic techniques and airway devices in circulation.
It seems to be a fairly sensible extra bit of reassurance to back you up if your gut is telling you it's not safe to put a kid to sleep.