The debate over uncuffed versus cuffed endotracheal tubes (ETTs) is a long-standing one. In a paper published in Pediatric Anesthesia this week, one paediatric critical care unit has published the results of their experience of introducing cuffed ETTs.
Greaney D, Russell J, Dawkins I, Healy M, A retrospective observational study of acquired subglottic stenosis using low-pressure, high-volume cuffed endotracheal tubes. Pediatric Anesthesia, 2018, DOI: 10.1111/pan.13519
What’s the background?
Many intensive care units use uncuffed ETTs in neonates due to concerns of cuff-related trauma and subglottic stenosis. The estimated incidence of ETT-related subglottic stenosis (SGS) ranges from 0.3-11%.
The benefits of a cuffed tube are thought to be: accurate ETCO2 monitoring, protection from aspiration, fewer tube changes due to air leaks, and continuous lung recruitment.
The concerns about cuffed tubes are that they cause increased trauma and that this trauma can lead to erosion, infection, cricoid perichondritis, and ultimately sub-glottic stenosis.
The author introduced the use of Microcuff ETTs into their unit hypothesizing that it may lead to less ulceration, chondritis, and fibrosis in the subglottic space. Microcuffs are a specific type of ETT (low-pressure, high-volume), but the smallest type is 3.0mm internal diameter which is not recommended for neonates less than 3kg.
Who were the patients?
This was a retrospective analysis of all patients admitted to the Paediatric Critical Care Unit in Australia over a five year period.
Patients were included if they also had a microlaryngobronchoscopy (MLB) procedure.
Patients were excluded if they were >18 years old; had congenital SGS; had previous airway surgery, or had a previous SGS diagnosis.
What were the outcomes?
MLB reports were reviewed to look for findings consistent with clinically significant acquired endotracheal tube-related pathology (within six months of intubation).
Demographics were analyzed including age, sex, prematurity, comorbidities, duration of ventilation, number of intubations, duration of admission.
What did they find?
There were 5309 PCCU admissions over the five year period, and 61% required intubation.
297 patients had an MLB.
23 children (0.68% of all intubations) had a clinically significant ETT-related pathology: 8 had acquiredsub-glottic stenosis; the other 15 had other ETT-related pathology (granulomas, ulcers, or cysts).
5 of the 8 children with sub-glottic stenosis required tracheostomies.
All those who required surgical correction of the SGS were ex-prem neonates who had received invasive ventilation in a NICU with an uncuffed tube prior to admission to PCCU.
What conclusions did they draw?
They demonstrated a low incidence (but high morbidity) of acquired SGS.
There were a few issues around the conclusions drawn:
- The authors state ‘there was no single case of de novo clinically significant acquired SGS with the use of cuffed ETTs‘. I’m not sure that this is a fair conclusion, as there were 8 cases of acquired SGS. Yes, these cases all had an uncuffed tube initially in NICU, but they also had a cuffed tube in PCCU.
- It would be good to be able to compare the rates of SGS before the introduction of Microcuff ETTs with these rates after its introduction – this would help to see whether rates have increased. It would also be helpful to look at the neonatal group in particular as this study reports the overall percentage of SGS in all patients, and then draws conclusions about its safety in neonates.
However, in spite of concerns around the use of cuffed tubes that exist, no study has previously shown that cuffed ETTs lead to a higher incidence of SGS than uncuffed ETTs. This is an interesting paper to open the discussion around the use of cuffed ETTs in neonates.
If you want to learn more about tiny tubes then catch this talk from Shabs Rajapaksa from DFTB18.
Expert Opinion – Eric Levi, Consultant Paediatric Otolaryngologist
I would love to see other data to enhance this paper: comparison with rates of SGS prior to cuffed tubes and comparison of rates of SGS in other patients who did have an uncuffed tube but did not develop SGS. Surely in the 3000 or so intubations, there would have been others who were also tubed with uncuffed tube and yet not develop any tube related pathology.
Although this is not a perfect paper, I do think the authors are onto something, and that they are adding to the body of knowledge suggesting that in their cohort, cuffed tubes are not associated with SGS.