Using Cuffed or Uncuffed Endotracheal Tubes in Children Raises Questions

NASHVILLE—Are cuffed endotracheal tubes (ETTs) as safe as uncuffed tubes in pediatric patients? At the Society of Critical Care Medicine’s 2009 Critical Care Congress, Vinay M. Nadkarni, MD, was asked to present points supporting the view that cuffed ETTs are at least as safe as uncuffed ETTs. Richard J. Brilli, MD, however, was asked to present counterpoints that cuffed ETTs should not be used or used with caution. They agreed that properly placed and managed, cuffed ETTs are generally as safe as uncuffed ETTs and that individual consideration of the risks and benefits of either apparatus should be based on patients’ anatomy and physiology and the ability of the practice environment to monitor cuff pressures.

DISMANTLING MYTHS ABOUT CUFFED ETTS

Cuffed ETTs are no longer rough or made from rubber—and properly placed, they do not damage the trachea or vocal cords, explained Dr. Nadkarni from the Department of Anesthesia, Critical Care, and Pediatrics at the University of Pennsylvania School of Medicine, Philadelphia.

“Properly placed and managed, cuffed tubes are essential because they can maintain an appropriate or minimal leak, can guarantee tidal volume, and reduce the number of times we have to change tubes—particularly during critical times,” Dr. Nadkarni pointed out. “They can conserve gas and prevent pollution caused by toxic anesthetic gases or nitric oxide.”

With regard to safety, an early study by Joshi et al examined acute lesions induced by endotracheal intubation, all with uncuffed tubes, Dr. Nadkarni noted. In another study, researchers compared the use and outcome of cuffed and uncuffed ETTs in 282 consecutive intubations in the pediatric ICU for seven months. After adjusting for covariates, the study authors observed that cuffed ETTs were not associated with an increased risk of postextubation stridor or significant long-term sequelae.

In a randomized controlled trial, the use of cuffed and uncuffed ETTs was compared in 488 mechanically ventilated children ages 0 to 8 years who required general anesthesia. Cuffed ETTs were found to reduce the need for repeat laryngoscopy, conserved the use of low fresh gas flow, and reduced the concentration of detectable anesthetics in the operating room, compared with uncuffed ETTs.

A 2004 prospective case control trial of 860 critically ill children with long-term intubation showed no significant difference between patients with cuffed or uncuffed ETTs in any age group in the use of racemic epinephrine for postextubation subglottic edema, the rate of successful extubation, or the need for tracheostomy.

“The usual argument is that the smaller internal diameter of a cuffed ETT significantly increases the work of breathing—like breathing through a straw,” Dr. Nadkarni continued. “But it is well known that the subglottic area of an infant is 20 times greater in proportion to body size than that of his or her adult counterpart.”

A TALE OF CAUTION

Using cuffed ETTs may not be necessary, said Dr. Brilli of Nationwide Children’s Hospital in Columbus, Ohio, because uncuffed ETTs seal the cricoid sufficiently in most situations, while cuffed ETTs require an ETT with smaller internal diameter and may increase airway resistance. Furthermore, most children who require mechanical ventilation via ETT do not have severe lung disease and therefore usually do not need an ETT that fully seals the airway leak. An uncuffed ETT is best suited to maintain such a leak with the lowest resistance to airflow delivery, according to Dr. Brilli.

“A leak around an ETT is usually good, though some people might argue against that to avoid aspiration,” he acknowledged. “However, I am not sure that a cuffed ETT or an uncuffed tube fully prevents the risk of aspiration,” Dr. Brilli argued. “But I do know that a tube that is less tight is less likely to cause airway damage.”

The increased risk of airway mucosal injury, potentially causing subglottic stenosis, may be the most cited concern against the use of cuffed ETTs, stated Dr. Brilli. Risk factors associated with subglottic stenosis include prolonged tracheal intubation, large tubes, and gastrointestinal reflux, he explained.

Dr. Brilli also raised the issue of tracheal tube cuff pressure management, citing a 2008 survey conducted in the United Kingdom. Of the 25 pediatric intensivists and 15 anesthesiologists who responded, only 5% and 7%, respectively, indicated that they routinely used cuffed ETTs in children younger than 8. The most common reason for nonuse was minimal benefit gained over using an uncuffed tube and the most common reason for cuffed ETT use was the management of children with reduced lung compliance. Further, 45% of pediatric intensivists and 100% of anesthesiologists reported not routinely monitoring intracuff pressure.

In 2003, investigators assessed the percent of cuffed ETTs that spontaneously deflated over time. They found that 70% of cuffs were adequately inflated after 30 minutes, 50% after an hour, and only 25% after 90 minutes. “I submit to you—if there is a significant degradation in cuff pressure over time, how often should we be checking cuff pressure and is that interval practical? This data would suggest that to maintain adequate cuff pressure to ‘seal the leak’ yet avoid cuff pressures that are too high, one would need to check cuff pressures every 30 to 60 minutes. That is not practical,” Dr. Brilli stated.

Furthermore, research has shown that deflated cuffed tubes have sharp edges that might cause airway mucosa damage and that manufacturing standards are lacking. In a 2004 study of 11 cuffed and four uncuffed ETTs from four different manufacturers, Weiss et al found that pediatric tracheal tubes were poorly designed. “Ideally, cuffed tubes need an anatomically correct depth mark, a short distally-placed cuff, a subglottic cuff-free space, high volume and low pressure, and automatic cuff pressure initiation,” Dr. Brilli suggested. In some situations, if a cuffed ETT was positioned at the mid-trachea point, the proximal end of the cuff was in the glottic opening. There are inconsistencies between manufacturers and even within the same manufacturer about ETT depth markings, such that the ETT could be easily malpositioned if the laryngoscopist was not meticulous in assuring that the tube was properly positioned. Manufacturers should also make cuff and tube size recommendations, he added.

“Cuff-to-cuff, tube-to-tube, they may not be the same—be careful,” he emphasized in his closing statement. “My message is a tale of caution.”

—Frederique H. Theuvenin

Suggested Reading
Deakers TW, Reynolds G, Stretton M, Newth CJ. Cuffed endotracheal tubes in pediatric intensive care. J Pediatr. 1994;125(1):57-62.
Felten ML, Schmautz E, Delaporte-Cerceau S, et al. Endotracheal tube cuff pressure is unpredictable in children. Anesth Analg. 2003;97(6):1612-1616.
Flynn PE, Black AE, Mitchell V. The use of cuffed tracheal tubes for pediatric tracheal intubation, a survey of specialist practice in the United Kingdom. Eur J Anesthesiol. 2008;25(8):685-688.
Newth CJ, Rachman B, Patel N, Hammer J. The use of cuffed versus uncuffed endotracheal tubes in pediatric intensive care. J Pediatr. 2004;144(3):333-337.

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