ICU and You · Aphorism Series · Number 38
“They are not little adults — except when they are.”
An aphorism is a compressed argument, not a rule. It earns its shape by leaving things out, which is exactly what makes it memorable and what makes it arguable. Every one in this series is contestable, and chosen because it is.
Each is a mantra, a paradigm, a truism or occasionally a plain myth — something repeated in our units often enough that nobody examines it any more. The piece sets out the case for it, the case against it, and the case for something in between, and then asks which you hold.
There is no right answer waiting at the bottom. The point is to find out what you actually believe and why, because the beliefs that run your practice at three in the morning are mostly ones you have never said out loud.
It is the most repeated sentence in paediatrics, and it has saved a great many children. It is said to every medical student, on every paediatric term, usually while somebody is being stopped from giving an adult dose of something. As a warning about the first years of life it is simply true: a neonate is not a small adult in any useful sense, and a toddler is not either.
Then, somewhere around school age, it quietly stops being the most useful thing to say.
By eight or nine the airway is close to an adult's and the cords rather than the cricoid are the narrowest point. The circulation is no longer substantially rate-dependent. Blood pressure is climbing towards adult numbers, the resistance is rising, and from twelve there is at last agreement on a target. The algorithms become adult ones at puberty. A twelve-year-old having an asthma attack is having an asthma attack, and much of what you know is now transferable.
The mantra does not come with an expiry date, and nobody announces the changeover. So it keeps being recited over a child for whom it is decreasingly true, and the cost of that is not theoretical. It shows up as hesitation — as a phone call made instead of a decision taken, as analgesia withheld because the numbers feel unfamiliar, as a registrar who would have acted in a heartbeat on an adult standing at the end of a bed working out whether paediatric rules apply.
And the changeover is not a birthday. It happens system by system, at different ages, and in a different order in every child. A ten-year-old may have adult respiratory mechanics, adolescent pharmacokinetics, and the emotional resources of someone much younger, all at once. That is the real reason the mantra survives: it is wrong, but it is safe, and nobody has managed a better single sentence.
Which is what this aphorism is for. Not to discard the warning, but to put a hinge in it — to say that the interesting clinical question at this age is no longer how are they different? but in which respects are they still different, and in which are they not?
Where have you seen “they are not little adults” cause a delay rather than prevent an error?
Or the opposite: the case where somebody treated a big ten-year-old as an adult and it went badly. Send it back to me either way, with your Yes, No or Maybe. Themes, and the best of your responses, go into a coming newsletter.
The button opens a reply straight to me. If your device blocks it, write to icuandyou@icloud.com instead.