Paediatric critical procedures are rare in the emergency department. Data from one Victorian network showed that 83% of emergency physicians had not performed one in a twelve-month period. We also know from audit data that we seem to have a lower first-pass success rate (around 78%) when it comes to paediatric intubation. We can put in a lot of strategies to increase the chance of first-pass success but what happens if you get into a ‘Can’t Intubate, Can’t Oxygenate” (CICO) scenario?
Those of us that look after adults, as well as children, have a standard response to the CICO scenario using an established algorithm whether it is the Vortex approach or the DAS guidelines. They all end up with a puncture of the neck (be it via scalpel or needle). What approach should be undertaken in children?
[Editors note: At this point, it is worth remarking that children are not heterogeneous creatures and your approach to an unimmunized 2-year-old with nasty epiglottitis is very different from the 12-year-old who has tried to inhale a never-ending gobstopper.]
Stefano Sabato and Elliot Long, both from the Royal Children’s Hospital, Melbourne have reviewed the evidence and tried to answer the question in this article:
How common is the scenario?
The true number of CICO scenarios that occur in a paediatric setting is unknown. There were 13 major complications reported in the NAP4 dataset, representing 7% of all reported cases. Only 5 of these required a surgical airway. This is likely to be an under-representation of true events. Regionalisation of paediatric care and lack of resident ENT staff in the UK may have led to intensivists/anaesthetists having little experience in managing sick children.
Some of the potential risks mentioned include:
Failure to use capnography to confirm tube placement
Failure to adequately secure the tube once in place
Management of airway compromise during patient transfer
The incidence of failed intubation (defined as more than three attempts to get the tube through the cords) in healthy kids is around 0.08% rising to 0.24% in infants less than a year old.
Predicting the difficult airway in the child
Anecdotally there has been little emphasis on formal airway assessment in children with the majority of standard tools not validated in the paediatric population. Even when performed in adults an airway assessment might not reduce the risk of the unanticipated difficult airway.
Common sense would suggest that if a child has a history of sleeping issues, perhaps due to adenotonsillar hypertrophy, they may be more likely to obstruct on induction. Looking at the child you might spot drooling or mouth breathing that occurs with enlarged tonsils or upper airway obstruction. Congenital abnormalities or dysmorphic features such as micrognathia in the Cri du Chat sequence or glossomegaly in trisomy 21 can also make intubation a challenge.
Formal airway assessment should include:
Assessment of dentition for loose or protruding teeth
Presence of soft tissues mass in the mouth?
Tempero-mandibular joint (TMJ) mobility
The Mallampati score is impractical in children as they have a tendency not to do what is required, especially when scared and Kopp et al LINK found it to be a poor predictor of glottic view.
Needle versus Knife?
Whilst a formal tracheostomy by a qualified ENT surgeon would be fabulous, most of us don’t have Dr Eric Levi on speed dial. The options seem to be split between the ‘knife‘ (a scalpel-based approach) or the ‘needle‘ (a narrow or wide bore cannula or formal needle cric set).
If you look after adults as well as children you should be familiar with the scalpel-finger-bougie technique so I won’t go into the details. The 4th National Audit Project from the Royal College of Anaesthetists in the UK suggested that a scalpel technique was preferable to the alternatives unless practitioners were more experienced in alternative techniques. Failure to commit to a ‘surgical’ airway in a timely fashion was highlighted as a key issue.
So why can’t we do the same with children?
Sabato and Long remind us that we are dealing with extremely small targets. The neonatal cricothyroid membrane is only about 2.6mm in length and 3.0mm in width. That is smaller than a grain of rice!
Identifying the appropriate anatomy will become easier as we become more proficient with the use of bedside ultrasound to identify landmarks.
The authors of the article recommend a needle-based approach using as shallow an angle of approach as possible (with extension of the neck to expose the cricothyroid membrane) to avoid transfixing the trachea by puncturing the posterior wall. There are a number of commercial kits available but poverty of choice is important. Should a CICO situation arise the last thing you need to be worrying about is which kit to use. A 16g cannula based kit is their recommendation. Children die because of a lack of oxygenation not a lack of an airway. The goal is to provide adequate oxygenation until expert help arrives.
For more on the various devices available then read this excellent article.
So what should we do?
Call for help early and get your friendly ENT surgeon involved. If that is not an option then the authors recommend a needle-based approach for front of neck access. They give examples of the kit used at the Royal Children’s Hospital. You can see the kit here. Being aware of the principles is one thing but like all emergencies, we have to be prepared to perform when the time comes. Mental rehearsal of your preferred technique helps, as does using part-trainers or practice in the animal lab but they do little to help one overcome the fear of performing the procedure. When intubating adults I use a checklist and call out my failed intubation plan, ending with a check of my surgical equipment. I must admit to having been more blasé about doing the same for paediatric intubations. This will no longer be the case.
How should you do it?
The Difficult Airway Society suggest the following approach.
Extend the neck (making the target as big as possible)
Stabilize the larynx with the non-dominant hand
Access the cricothyroid membrane with a dedicated 14/16g cannula
Aim in a caudal direction
Confirm position with aspiration of air into a syringe containing saline
Connect to an oxygen source
– adjustable, pressure limiting device
– 4bar O2 source – matching l/min with age
Slowly increase inflation pressure/flow rate to achieve maximal chest rise
Maintain upper airway patency to aid expiration
DAS recommend following adult guidelines once the child is over the age of 8. Needle cricothyroidotomy is not without risk and though it may be successful on the first go in up to 70% of cases there is a high risk of perforation of the posterior wall of the trachea. Trans-tracheal cannulation is not a failure of the technique if oxygenation is maintained.
Perhaps the easiest way to connect to an oxygen source is to attach a 3mm ETT tube connecter. You then have a universal 22mm connector to attach to your circuit.
How do we train for it?
Cliff Reid has written in the past about using the greatest piece of virtual reality hardware there is – the brain – to prepare for such a rare event. There are part-task trainers for adult practice but I challenge the readers to find one for use in paediatric practice.
The first key step is reducing the risk of it happening in the first place through proper training and preparation. More than two attempts at tracheal intubation are associated with an increased risk of complications and each further attempt incrementally increases the risk. Techniques such as the use of video laryngoscopes and optimum pre-oxygenation and apnoeic oxygenation may modify some of the risks but sometimes there is no accounting for anatomical variation.
Of course, this article could have been called The Needle and the Damage Done after this song, from the amazing Neil Young about a very different type of needle.
With thanks to @NicholasChrimes, @DrEricLevi, @airwaycam, @DitchDoc14, and especially @kovacsgj
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