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Three Part Question

In [children needing intubation] are [cuffed endotracheal tubes] associated with [increased incidence of post-extubation stridor/increased risk of airway mucosal injury]?

Clinical Scenario

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.

Search Strategy

Cochrane and PubMed
Cochrane—endotracheal tube.
Pubmed—cuffed endotracheal tube AND children. Limits—RCT, English and child <18 years.

Search 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).

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Khine et al, 1997	Children aged from term newborns to 8 y who required tracheal intubation as a part of anaesthetic care. 251 children with odd medical record numbers were assigned to the cuffed tube group, and 237 children with even numbers were assigned to the uncuffed tube group. Children with a history or physical evidence of intrinsic or extrinsic airway obstruction or severe pulmonary disease or those who required nasotracheal intubation were excluded	RCT (1b)	Incidence of croup (post extubation stridor)	6 (2.4%) patients in the cuffed tube group and 7 (2.9%) patients in the uncuffed tube group had signs or symptoms of croup and 3 patients in each group were treated with racemic epinephrine. None of them required reintubation	Not blinded. Mallinkrodt Io-pro or Sheridan low-pressure cuffed endotracheal tubes were used and duration of intubation was 60 minutes
			Number of intubations required to achieve an appropriately sized tube.	3 (0.01%) patients in the cuffed tube group required a second tube while 54 (22.7%) patients required a second tube in the uncuffed group
			Concentration of nitrous oxide in operating room	Nitrous oxide concentration at 24 inches from patients mouth were greater when uncuffed tracheal tubes were used (p<0.001)
Deakers et al, 1994	A total of 243 patients had 282 intubations in a paediatric intensive care unit setting. Of the 243 patients, 123 (49%) had cuffed endotracheal tubes. Analysis was performed for 188 (77%) of 243 patients. Patients who died, or had a history of upper airway obstruction or surgery to the upper airway were excluded	Prospective Case control study (3b)	Incidence of post-extubation stridor	Incidence of stridor: (a) cuffed endotracheal tube, 15.1%; (b) uncuffed endotracheal tube, 14.7% [RR 1.02, CI (0.5, 2.34)]	Not randomised. Low pressure, high-volume cuffed endotracheal tubes were used
			Frequency of cuffed endotracheal tube use	2 patients from the cuffed endotracheal group and 4 from the uncuffed group required reintubation for post extubation stridor There was no significant difference in rates of stridor when the subgroups under 1 y and aged 1–5 y were compared
			Any increase risk of long-term post extubation complications	33 (17%) of the 188 patients required readmission to the hospital during the next 18 months. None of these had problems with upper airway
			Aerobic capacity	no significant improvement
			muscle endurance	significant improvements in the pool exercise group
			SF -36 physical component	Signficant improvements in vitality in the pool exercise group
Newth et al, 2004	597 children <5 years of age, with 210 having cuffed tubes and 387 having uncuffed tubes were included. Setting was a paediatric intensive care unit	Prospective case control study (3b	Rate of post-extubation stridor	Racemic epinephrine use in children with uncuffed tube: 6.1% in children <1 month old, 6.7% in children 1–2 years of age, and 9.4% in children 2–5 years of age Racemic epinephrine use in children with cuffed tube: 7.4% in children <1 month old; 9.5% in children 1–2 years of age, and 8.8% in children 2–5 years of age	Not randomised

Comment(s)

Traditionally it has been taught that only uncuffed endotracheal tubes (ETT) should be used for children under the age of 8 years (Motoyama, Fisher). Concerns regarding the use of cuffed ETTs originate from studies in adults (Cooper, Donnelly) and animals (Way). 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. Studies (Joshi) have documented a causal relation between the duration of intubation and the occurrence of laryngeal mucosal inflammation for cuffed and uncuffed ETTs. Subsequent studies (Khine, Deakers, Newth) 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 (Khine) reduce the risk of aspiration, and improve end-tidal CO2 monitoring (Fine) 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 (Wiel). 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)

References

1. Khine HH, Corddry DH, Kettrick RG. et al. Comparison of cuffed and uncuffed endotracheal tubes in young children during general anesthesia. Anesthesiology 1997;86:627–31.
2. Deakers TW. Reynolds G, Stretton M. et al. Cuffed endotracheal tubes in pediatric intensive care. J Pediatr 1994;125:57–62.
3. Motoyama EK. Endotracheal intubation. In: Motoyama EK, Davis PJ, eds. Smith's anesthesia for infants and children, 5th edn. St Louis, MO: CV Mosby, 1990:269-75.
4. Fisher DM. Anesthesia equipment for pediatrics. In: Gregory GA, ed. Pediatric anesthesia, 3rd edn. New York: Churchill Livingstone, 1994:197-225.
5. Cooper JD, Grillo HC. Analysis of problems related to cuffs on endotracheal tubes. Chest 1972;62(suppl):21s-27s.
6. Donnely WH. Histopathology of endotracheal intubation. Arch Pathol 1969:511-20.
7. Way WW, Sooy FA. Histological changes produced by endotracheal intubation. Ann Otorhinolaryngol 1965;74:799–812.
8. Joshi VV, Mandavia SG. Stern. et al. Acute lesions induced by endotracheal intubation. Am J Dis Child 1972;124:646–9.
9. Fine GF, Borland LM. The future of the cuffed endotracheal tube. Paediatr Anaesth 2004;14:38–42.
10. Wiel E, Villette B, Darras JA. et al. Laryngotracheal stenosis in children after intubation. Report of five cases. Paediatr Anaesth 1997;7:415–19.
11. Newth CJL, Rachman B, Patel N. et al. The use of cuffed versus uncuffed endotracheal tubes in pediatric intensive care. J Pediatr 2004;144:333–7.