Top tips for intubating a baby
My own kids terrify me.
But they aren't nearly as terrifying as someone else's child, when they're seriously unwell on a resus bed in front of you at three in the morning and it's your job to get them safely onto a ventilator before the boss shows up or the retrieval team arrive.
Thankfully it's a relatively rare occurrence to find yourself totally on your own when dealing with sick kiddos - even as a consultant - and you'll almost always have senior colleagues, experienced paediatric nurses and a paediatric team to help you.
But you should prepare yourself as if you're doing it all on your lonesome.
That way, when the worst happens, you know you're as prepared as possible to give that child the best chances of a good outcome.
They're not small adults
Just kidding, they totally are.
Okay not really.
Children are like tiny drunk dysmorphic adults with a disproportionately large head-to-lung size ratio and the metabolic rate of a large squirrel, upon whom drugs have never been thoroughly tested because the researchers are also terrified of kids, and for whom apparently 5ml of Calpol and a lolly are the golden bullet for every disease ever.
Oh and their necks are made of playdough.
But hey. What could go wrong?
The first step is preparation
"Give me six hours to chop down a tree and I'll spend the first four sharpening the axe"
Abraham Lincoln
As always in anaesthesia, 90% of the work happens before the procedure, and it's no different when kids are involved. Being well prepared with a host of back up plans and equipment will ensure two things:
- The intubation is as easy as possible
- If it's tricky, you have the best chance of fixing things quickly
So here is our list of top tips for preparing to intubate a child:
Call the boss
The second you get wind of a sick child, your consultant wants to know about it.
And the vast majority of the time, they want to be there too, so get on the phone the minute you have evidence of a child that might require airway intervention.
If you're more experienced, and are comfortable assessing a child first, then go ahead, but if you're fairly new to the game then please rest assured that it is entirely reasonable to say,
"The paediatric team have just told me about a struggling bronchiolitic baby in resus - please can you help me out?"
The answer is usually "Yes, I'm on my way"
Get an app
Nowadays pretty much all of the thinking is done for you.
Just plug the age, sex and weight in, and up comes the recipe for a successful RSI, as well as drug doses for managing the most serious and common emergencies.
I would strongly suggest you learn the relevant calculations as a back up, so you can at least sense-check the volume of rocuronium you're about to inject, just in case you added an extra zero in the throws of your 4am concentration slump.
You also need to know the doses for the exams.
I use paediatric emergencies, PICU tools and the STRS guidelines.
Four tubes
- IV access
- NG tube
- Endotracheal tube
- Suction catheter
In that order.
It is fabulously easy to ventilate a baby's stomach, and fabulously difficult to deal with the ensuing diaphragmatic splinting and respiratory distress.
Insert an NG tube before induction, and ideally have someone actively aspirating it throughout the procedure.
Have an appropriately sized suction catheter ready to go, and avoid suctioning for more than 10 seconds at a time as it will suck out all of your hard-earned preoxygenation.
Positioning
- Raise the bed so the entire baby is at the level of your xiphisternum - this will feel and look ridiculous, until you start laryngoscopy, and realise just how tiny they are
- Place a roll of towel or a blanket under the shoulders
- Have the head in a neutral position
Baby's necks will obstruct both in flexion and extension, so a neutral position is key for adequate ventilation and laryngoscopy.
Their large occiputs mean their shoulders benefit from lifting off the bed.
Communicate
- Everyone needs to know who everyone else is, what they're doing and why
- Appoint a scribe and then say what you're doing at each step
- Ensure everyone in the room knows what is happening and why, and what to do if things start to go wrong
Where are we going next?
- You're going to feel fantastic when you visualise those tiny cords and deftly slide the tube between them
- You're going to feel somewhat less fantastic when you realise you're now stuck with an intubated baby with no plan as to where you're going next or how long you need to stay with the child
Before you intubate, make sure you know who is taking over the care of the child, where they are, when they're going to be here and where the baby is going.
'The consultant - coffee room - 2 minutes - PICU on the second floor'
is a very different prospect to
'The retrieval team - the M25 - maybe an hour - Manchester'
What are the differences between intubating an adult and a child?
This isn't just popular exam fodder for the FRCA Exams, it's actually really important and useful knowledge to use when intubating children.
Children are different to adults both anatomically and in their physiological status, largely as a result of their need not only to maintain homeostasis, but to enable growth.
So, starting as always with :
Airway
Babies have:
- Big heads
- Sticky-out occiputs
- All perched on short floppy neck
This means even the slightest bit of extension or flexion can obstruct the airway. Babies need a neutral head position, which usually means propping the shoulders up with a towel or rolled up inco pad.
Babies also have:
- Flat nasal bridges
- Tiny chins
Because facemask ventilation isn't difficult enough already. Use a correctly sized mask, which will almost certainly feel too small.
Oh and if your fingers so much as touch the baby's neck as you try and hold the shaking mask on their face, their airway will obstruct. Fingers on mandibles only please.
Ready to move on from airway? Good, because we're not.
Next up is:
- Enormous tongue
- Short mandible
- Fragile palate
- Often big adenoids and tonsils
- Elliptical airway (so supraglottic airways don't sit as well)
- Anterior larynx
- Vocal cords angled slightly antero-inferior, making tube insertion harder
- An epiglottis that's so effective at blocking the entrance to the trachea it might as well be called Cerberus
It is long, U shaped and very floppy, so poking around for the hyoepiglottic ligament in the vallecula with a standard laryngoscope blade is likely to do naff-all.
Finally on airway, their larynx is funnel shaped, with the narrowest point at the cricoid, below the glottis (which is the narrowest point in adults). Also the cricoid is at C4 in babies, compared to C6 in adults, and the upper airways are more compliant and can be more easily obstructed or kinked.
This means your tube might fit beautifully between the cords but then get lodged in the cricoid, so don't go too big on tube size.
And all of the above is in a normal child with no congenital facial anatomical anomalies.
Phew. Those paediatric airways sound like a nightmare. At least there aren't any tricksy respiratory differences to worry about.
Oh wait.
Breathing
Baby lungs are rather small lungs.
Small lungs with:
- Underdeveloped alveoli
- Teeny tiny volumes and capacities
- High resistance airways with turbulent flow
- A predisposition to being completely compressed by any pressure in the abdomen
The functional residual capacity is the volume in the thorax when the baby has fully exhaled and the outward pull of the thoracic cage and in the inward pull of the lungs are in equilibrium. This is your reservoir of oxygen that the baby is going to use up while they're not breathing and waiting patiently for you to intubate - and oh wait guess what - it's tiny, so babies desaturate fast.
On top of that there's a little concept called closing capacity
Everyone has a closing capacity, which is the volume in the thorax at which the airways start to collapse and obstruct.
If this volume is smaller than your FRC, then that's fine, because you exhale down to your FRC, and stop there - the volume is greater than the closing capacity - so the airways remain open.
If, however you have a chronic lung disease, are older than 65, or younger than six, then your closing capacity is greater than your functional residual capacity, meaning as you exhale down to that balance point, a proportion of your airways will obstruct, further reducing the useful areas for ventilation.
Because why not?
Next up let's look at the ribcage
Babies have horizontal ribs which mean the thorax can't really expand very far anteriorly, making them highly dependent on diaphragmatic breathing and their work of breathing harder.
This means they can spend as much as 10% of their available oxygen on just breathing, so they fatigue very rapidly.
Oh and by the way, they're obligate nasal breathers as well, so a stuffy nose can stuff up your oxygenation as well.
Finally, you've got the reason you've been asked to intubate in the first place, which is usually something like bronchiolitis, severe asthma or other respiratory or neuromuscular condition that is going to reduce the FRC and safe apnoea time even further.
Oxygen consumption can be up to 6ml/kg/minute, compared to a meagre 3 in adults, and CO2 production is up to double that of an adult as well.
Given the tidal volume is more in keeping with adult values per kg, it becomes clear to see why infants need such high respiratory rates to eliminate enough CO2 for homeostasis.
Fun.
Circulation
Right. Let’s look at the circulation. As you’re probably aware the foetal circulation is structurally very different to that of an adult and undergoes enormous changes at birth.
Neonates have
- Increased heart rate, so relative cardiac output is 40% higher than adults
- Under developed sympathetic system meaning a markedly reduced ability to increase stroke volume, so their cardiac output is rate dependent
- Very small blood volume, with little reserve to compensate for blood loss
- High surface to volume ratio so they lose heat very quickly
- Enormous metabolic rate with predisposition to hypoglycaemia
We won't go into detail about the differences in foetal or congenital syndrome circulations here, these are just the main issues that will affect your anaesthetic and intubation.
Neurological
- Increased MAC requirement
- Under-developed sympathetic nervous system
- Nerves not fully myelinated until 6 months
- Spinal cord terminates at L3 (shouldn't impact your RSI but examinable)
- Immature blood brain barrier
- Muscles tire very quickly
Other bits and bobs
Gastro and Liver
- Immature enzymes with rubbish metabolism
Renal
- Large extracellular fluid component, especially in very premature babies
- High volume of distribution
- Reduced GFR
- High renal vascular resistance
- Reduced renal concentrating ability
Haematology
- Inefficient foetal haemoglobin that won't offload oxygen to the tissues
- 80% Foetal Hb at delivery, 5% at 3 months
- Reduced vitamin K clotting factors
Having said all of this, once you've got your preparation sorted, and senior support available, paediatric intubations can end up being extremely rewarding procedures to do!
High Yield Exam Questions
Why might a paediatric airway be difficult?
- Syndrome
- Pathology
- Physiology
- Neonatal anatomy
- Functional
What are the signs of hypoxia in a child?
- Rapid, labored breathing
- Nasal flaring
- Use of accessory muscles
- Grunting
- Wheezing
- Abnormal breath sounds
- Subcostal recession
- Tracheal tug
- Positioning (tripod)
- Irritability
- Lethargy
- Exhaustion
- Cyanosis
Can you name some congenital syndromes that make airway management more difficult?
- Down syndrome - atlanto-occipital instability, small mouth, big tongue
- Treacher Collins - small mouth, micrognathia, hypoplastic zygoma
- Apert syndrome - stiff neck, big tongue, micrognathia
- Pierre Robin - micrognathia, cleft palate, glossoptosis
- Klippel-Feil - fused cervical vertebrae
- Edwards syndrome - micrognathia
The key formula for paediatric ET tubes
- Uncuffed tube size = (age/4) + 4 (age > 1 years)
- Cuffed tube size = (age/4) + 3
- Depth from lower lip (cm) = age/2 + 12 (oral intubation)
- Depth from nare (cm) = age/2 + 15 (nasal intubation)
Have 0.5mm larger and smaller tubes available.
Uncuffed tubes were traditionally used due to the concern of tracheal stenosis due to pressure from the cuff. More modern tubes have high volume, low pressure cuffs that have much lower risk of traumatising the airway.
We asked ChatGPT to write a poem about the challenges presented to the anaesthetist by a patient with Down sydrome
Anaestheasier ltd.
We also wrote a post on answering CRQs on neonatal resuscitation
Anaestheasier ltd.
Useful Tweets
AiR - Learning from the Airway Registry (September 2021). With a focus on paediatric intubation, soiled airway and some other useful CMAC videos. https://t.co/sH2bLP80xl
— SydneyHEMS (@SydneyHEMS) September 30, 2021
Something that comes up @resuscitology regularly is paediatric airway management, particularly in major trauma - so here's a short thread 🧵 with the way I think about it. This is for you particularly if you *aren’t* a paediatric anaesthetist…!
— Natalie May (@_NMay) December 6, 2022