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Paediatric Trauma Anatomy – Easy as AcBC

Authors: Charlotte Davies and Nikki Abela / Codes: PMP4 / Published: 27/11/2017

The alert phone goes: the ambulance team are bringing in a 2 year old girl who has fallen down a flight of stairs. Her GCS is low, her c-spine is immobilized and she’s tachycardic.

You panic: It has been a while since you managed a trauma patient so young.

“Children are not young adults,” echoes in the back of your mind.

“Why not?”, you think.

The answer is all in their anatomy.

This blog runs through some of the anatomical differences in children, and how they affect the injuries they might present with – and what better order to do this in than AcBCDE?

Airway

Children tend to have a larger tongue, smaller jaw and shorter, narrower, funnel-shaped airway with an anterior larynx. This means that the tongue is more likely to block the airway than in adults. Moreover, the occiput is more prominent meaning that “at rest” their neck is flexed and their airway closed. The narrow airway also means that a very slight amount of oedema leads to significant airway compromise and resistance 1mm of oedema can reduce a patients airway by 60% (You all remember Poiseuille’s law no?).

Foreign bodies are more likely to go through the cords and get stuck at the cricoid, whereas in adults, foreign bodies are more likely to get stuck in the cords. Depending on the age of your patient, they may be loosing their primary incisors which may be your foreign body, or they may be loose or missing affecting your airway management further.

The airway is short, and easily blocked – you might need to put a cushion underneath the shoulders to maintain neutral alignment.

Because the airway is short, if you are intubating, a main bronchus intubation is likely so its really important to do your calculations right and watch the black line on the ETT pass through the cords.

C-Spine

Children have very flexible and elastic spinal ligaments, so there is a lot of c-spine movement. Their vertebra are anteriorly wedged with flat facet joints. This combined with their large head, means that children have a relatively high fulcrum, and the spine moves a lot, with lots of forces being applied to C1and 2.
Although abnormalities between C1 and 2 are more likely, pseudosubluxation is also seen here between C2/3 (24% < 8yrs) and C3/4 (14%). It can be difficult to tell the difference between true subluxation and injury, and a pseudosubluxation. Swischuks Line can be useful – this is a line drawn between the posterior arch of C1 and C2. It is a dislocation if line misses the anterior cortex of C2 by > 2 mm. I think Id be speaking to my friendly radiologist about this.

Collars are unlikely to help immobilise the c-spine in children, and their use in children is not routinely taught on APLS who suggest manual inline immobilsation, followed by blocks and tape when necessary.

Due to the increased risks associated with irradiation, particularly to the thyroid gland, and the generally lower risk of significant spinal injury, CT of the cervical spine probably should NOT ROUTINELY be used and there is more covered on this here. Our local MTC guidelines suggest the standard 3 x-rays in children >10, and in <10 year olds, lateral and AP only.

The Royal College of Radiology guidelines also do not suggest the routine use of CT c-spine in the paediatric population, with exceptions:

  • You are doing a CT head and are worried about the C-spine
  • A GCS less than 13 or patient is intubated
  • Focal neurological signs.
  • Definitive diagnosis of cervical spine injury is needed urgently (for example, before surgery).
  • Another body area scanned
  • There is strong clinical suspicion of injury despite normal X-rays.
  • Plain X-rays are technically difficult or inadequate.

The RCR instead suggest early neurosurgical involvement. They also suggest that C1-3 is included on a head CT, as this is a high risk spot for injury. Interpreting images can be difficult – phone a friend!

Breathing

Children have a very soft, pliable chest wall meaning that pulmonary contusions without rib fractures are possible. Because children’s bones are more compliant, forces applied across the chest wall will cause movement and then recoil.

Children also have horizontally aligned ribs and weak intercostal muscles, so rely more on diaphragmatic breathing than adults. A tension pneumothorax is more likely due to their very mobile mediastinum.
Children also inhale a lot of air, especially when screaming. This can cause gastric dilatation, which in turn can cause an ileus.
When interpreting the CXR, if this is normal, the patient is conscious and clinically stable, a CT is unlikely to be indicated in blunt trauma.

This means we have to carefully evaluate the chest – we might not see evidence of pulmonary contusions, and we must think twice about whether there is a tension pneumothorax.

Due to the risk of vascular injury, CT is indicated as the primary modality in penetrating trauma.

Circulation

With a smaller circulating volume, children obviously have a lot less blood to lose- so seemingly small losses to an adult may mean a big deal to a child. Their stroke volume is pretty fixed and therefore the only way of increasing their cardiac output is to increase their heart rate so pay attention to a tachycardia.

Whats worse than small circulating volumes, is that they are also more likely to loose it from their lower-riding liver and spleen, that is not protected well from their softer, thinner, abdominal wall (less musculature, less fat, more square abdomen).

Its not just their upper abdominal organs which are more exposed, the bladder is also an intra-abdominal organ in young children (and lies at the level of the umbilicus at birth) so is especially vulnerable.

The intestine also, especially the sigmoid and right colon, are not fully attached in the peritoneal cavity in young children and are more likely to be injured with forces of compression or sudden deceleration.

The Holmes prediction rule can help us to know if children need abdominal imaging or not:

This means we have to examine the abdomen carefully for bruising, and remember that the bladder, spleen and liver have minimal protection against trauma. Blunt renal trauma is also more likely as children have less protective perinephric fact, and the kidneys are relatively large compared to the rest of the abdomen. Significant haematuria should be taken seriously and investigated further.

Not only, but once found, an abdominal injury should alert the physician to re-examine the spine. Dont forget that Chance fractures, a.ka. seatbelt fractures, are commonly associated with abdominal injuries. They are flexion-distraction type injuries of the spine, that typically come about from a poorly restrained (seat-belt only) RTC. They involve all three spinal columns and are unstable injuries.

Thankfully, pelvic fractures are rare, but if suspected they are harder to splint – SAM splints are hard to cut to size, prometheus on the other hand are fairly easy.

Disability

Because the head is so much bigger, the chance of injury is increased in the paediatric population.

In younger children, the cranium is softer, with open fontanelles (until 12 – 18 months), so it is possible to get significant injury, with minimal external signs. Because their craniums arent closed, this means there is extra space for haemorrhage to expand into, meaning a significant injury can hide there without causing a decreased GCS or signs of increased ICH. Don’t forget to palpate the fontanelle, look inside and behind the ears (the younger the child, the less there is to go on so make the most of your examination), and observe the child if needed. The NICE guidelines for head injury are commonly used, and are a good guide for imaging. If sending the parents home, do safety-net appropriately if this is late in the day, I do sometimes advise the parents (with little evidence) to rouse the child overnight to make sure they are ok.

Children also have a higher body surface area to mass ratio with thinner skin and less insulation by subcutaneous tissue so might get cold a lot more quickly than adults- cover them up and warm them appropriately.

Exposure

Exposure in children is a lot more important, as many of them are non-verbal. Remember, non-verbal children wont tell you about the pain in their fractured tibia. Even verbal children tend to get easily distracted, and dont notice quite large injuries so exposing them is key to finding more injuries.

Exposure is also key to picking up multiple injuries in cases of non accidental injuries, and therefore a careful A-E assessment must be done. Remember, non-verbal children can’t tell you what’s happened to them, and it’s your responsibility to double check the history you’ve been given.

However, if faced with a paediatric trauma, it’s safe to allow the voice of Ross Fisher‘s excellent talk at RCEM & EUSEM conferences echo in your mind “paediatric trauma is different”, but the primary survey is not terribly different if you are aware of their anatomy. Mentally rehearse your actions, and you will be fine.

Further reading:

PedEmMorsels: Chance fractures

Paediatric Anatomy and Physiology and the Basics of Paediatric Anaesthesia

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4 Comments

  1. kandaratnami5783 says:

    Very useful

  2. Dawar Amin Muhammad Chughtai says:

    It is a brilliant effort by the author.

  3. kumarn5411 says:

    Excellent work

  4. turkih says:

    Good pice of work, well done.

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