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You are a paediatric registrar on the children’s intensive care unit. You are about to intubate a 2 year old child with severe meningococcal septicaemia. Your recent experience in ventilating children with this condition is that they often develop acute respiratory distress syndrome, and require high pressures to maintain adequate oxygenation and ventilation. At these high pressures significant leaks occur around the endotracheal tube, impairing effective ventilation, and on occasion it is necessary to change to an endotracheal tube of greater diameter. Re-intubation under such circumstances carries a greater risk of hypoxia because of the inevitable loss of positive airway pressure during the procedure. You think it would be wise to insert a cuffed endotracheal tube, in which the cuff could be inflated if leak becomes a problem. It has been traditionally taught that only uncuffed endotracheal tubes should be used for intubation in children under the age of 8 years to decrease the risk of airway mucosal injury and post-extubation stridor. You wonder if there is any evidence to the above statement.
Structured clinical question
In children needing intubation [patients], are cuffed endotracheal tubes [intervention] associated with increased incidence of post-extubation stridor/increased risk of airway mucosal injury [outcome]?
Search strategy and outcome
Strategy
Cochrane and PubMed.
Cochrane—endotracheal tube.
Pubmed—cuffed endotracheal tube AND children. Limits—RCT, English and child <18 years.
Outcome
Cochrane central register of controlled trials—1.
Pubmed—1 RCT (same study as in Cochrane register). Limits excluding RCT—15 hits, of which 3 were relevant (1 review and 2 case control studies).
See table 4⇓.
Commentary
Traditionally it has been taught that only uncuffed endotracheal tubes (ETT) should be used for children under the age of 8 years.4,5 Concerns regarding the use of cuffed ETTs originate from studies in adults6,7 and animals8 which indicate that cuffed tubes impair tracheal mucosal blood flow and are associated with higher incidence of post-extubation laryngeal oedema and tracheal stenosis. The pathological process of stenosis is thought to begin with tracheal tube pressure on the laryngotracheal mucosa, especially when the tube is too large or when the cuff is too inflated, causing mechanical oedema and ischaemic necrosis, followed by organisation into fibrotic tissue. However these data described the use of high-pressure, low-volume cuffed ETTs. Studies9 have documented a causal relation between the duration of intubation and the occurrence of laryngeal mucosal inflammation for cuffed and uncuffed ETTs. Subsequent studies1–3 using the modern high-volume, low-pressure cuffs have not shown any increase in the incidence of post-extubation stridor. In fact cuffed ETTs have been shown to decrease the number of laryngoscopies,1 reduce the risk of aspiration, and improve end-tidal CO2 monitoring.10 None of the studies were designed to compare incidence of subglottic stenosis between children intubated with cuffed or uncuffed endotracheal tubes. A cases series from France of five children with subglottic stenosis found that only one had immediate post-extubation stridor, with the others developing symptoms of dyspnoea 4–13 days after extubation.11 For this reason, it cannot be assumed that the absence of immediate post-extubation stridor means that subglottic stenosis will not develop. Future studies should be designed with subglottic stenosis as an endpoint before routine use of cuffed endotracheal tubes could be recommended.
CLINICAL BOTTOM LINE
The use of low-pressure, high-volume cuffed endotracheal tubes is not associated with increased incidence of post-extubation stridor in children. (Grade C)
There are no studies which adequately assessed potential long term consequences such as subglottic stenosis. (Grade D)
In selected cases in whom high airway pressures are anticipated during their intensive care stay, cuffed endotracheal tubes can be used to avoid the need for reintubation because of air leak around the ETT. (Grade C)
Footnotes
This case is based on experience from several cases. Details have been altered to ensure patient anonymity
Edited by Bob Phillips